EPA 560/2-77-001
INVESTIGATION OF SELECTED
POTENTIAL ENVIRONMENTAL CONTAMINANTS:
BENZOTRIAZOLES
February 1977
FINAL REPORT
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NOTICE
This report has been reviewed by the Office of Toxic Substances, EPA,
and approved for publication. Approval does not signify that the contents
necessarily reflect the views and policies of the Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
ii
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TABLE OF CONTENTS
Executive Summary x
I. Physical and Chemical Data 1
A. Structure and Properties 1
1. Chemical Structure 1
2. Mixtures 5
3. Physical Properties of the Pure Material 5
4. Physical Properties of Commercial Material 17
5. Principal Contaminants of the Commercial Product 21
B. Chemistry 24
1. Reactions Involved in Uses 24
c
a. Anticorrosion 25
b. Photostabilization 31
c. Photographic Antifoggant 33
2. Hydrolysis 36
3. Oxidation 39
4. Photochemistry 40
5. Other Chemistry 46
II. Environmental Exposure Factors 49
A. Production, Consumption 49
1. Quantity Produced 49
2. Producers . 49
3. Production Methods and Processes 52
4. Market Prices 57
5. Market Trends 59
B. Uses 59
1. Major Uses 59
a. Anticorrosion Applications 60
b. Ultraviolet Stabilization Applications 68
c. Photographic Applications 71
iii
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Table of Contents (continued)
2. Minor Uses 77
3. Discontinued Uses 82
4. Projected or Proposed Uses 82
5. Possible Alternatives to Uses 82
C. Environmental Contamination Potential 84
1. General 84
2. From Production 84
3. From Transportation and Storage 85
4. From Use 85
5. From Disposal 87
6. Potential Inadvertent Production of Benzotriazoles in 87
Industrial Processes
7. Potential Inadvertent Production of Benzotriazoles in 88
the Environment
D. Current Handling Practice and Control Technology 88
1. Special Handling in Use 88
2. Methods for Transport and Storage 90
3. Disposal Methods 91
4. Accident Procedures 91
5. Current Controls and Control Technology Under Development 92
E. Monitoring and Analysis 92
1. Analytical Methods 92
2. Current Monitoring .97
III. Health and Environmental Effects 98
A. Environmental Effects 98
1. Persistence and Biodegradability 98
2. Environmental Transport 99
3. Bioaccumulation and Biomagnification 100
B. Biological Effects 101
1. Toxicity and Clinical Studies in Man 103
2. Effects on Non-Human Mammals 104
iv
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Table of Contents (continued)
a. Absorption/Excretion Studies 104
b. Metabolism and Pharmacology 106
c. Acute Toxicity 114
d. Subacute Toxicity 124
e. Sensitization 126
f. Teratogenicity 126
g. Mutagenicity 129
h. Carcinogenicity 132
i. Behavioral Effects 135
j. Possible Synergisms 135
3. Effects on Other Vertebrates 137
a. Toxicity to Fish 137
(i) Benzotriazole 137
(ii) Tolyltriazole 139
b. Toxicity to Amphibians 139
4. Effects on Invertebrates 141
5. Effects on Plants ' 141
6. Effects on Microorganisms 145
a. Effects on Bacteria 145
b. Effects on Viruses 151
c. Effects on Yeast 154
7. In Vitro and Biochemical Studies 154
a. Effects on Isolated Organs 154
b. Effects on Cell Cultures 155
c. Effects on Isolated Organelles 155
d. Effects on Isolated Enzyme Systems 157
IV. Regulations and Standards 159
A. Current Regulation 159
B. Concensus and Similar Standards 159
Technical Summary 161
References 165
Conclusions and Recommendations 181
v
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LIST OF TABLES
Number Page
1 Molecular Structure of Benzotriazoles 6
2 Physical Properties of Benzotriazole Compounds 9
3 Specific Extinction Coefficients of Several 2-(3',5'-alkyl- 18
2'-hydroxyphenyl)-benzotriazoles
4 Solubilities of Benzotriazole Compounds 19
5 Commercial Specifications for Some Benzotriazole Compounds 22
6 Compounds Used in the Study of Cotton and Scholes (1967) 26
7 Effect of Solvents on Copper-Benzotriazole Complex on 29
Copper Sheets
8 Relative Acid Strength of Some Benzotriazole Compounds 38
9 Photolysis Products of 1-Substituted Benzotriazoles at 300 nm 45
in Various Solvents, % Yields
10 Producers and Production Sites of Benzotriazoles 50
11 Imports of Tinuvin Compounds (pounds) 51
12 Prices of Benzotriazole Compounds 58
13 Typical Glycol-Based Antifreeze Anticorrosion Components 61
14 Major Uses of Benzotriazole Compounds 78
15 Minor Uses for Benzotriazole Compounds 82
16 Methods of Analysis for Benzotriazoles 93
17 Survival of Wastewater Microorganisms in Contact with 99
Benzotriazole
18 Physical Properties of Benzotriazole 106
19 Median Paralyzing Doses of Benzotriazole Derivatives on 107
Intravenous Administration to White Mice
20 Effect of Benzotriazole Against Various Experimental Tumors 110
by Repeated Intraperitoneal Injection
vi
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List of Tables (continued)
Number Page
21 Bioassay of Suspensions of the Nelson Mouse Ascites Tumor HI
Treated with Benzotriazole In Vitro
22 Negative Cancer Chemotherapy Results in Mice 113
23 Acute Toxicity of Benzotriazole and Derivatives in Laboratory 116
Rodents
24 Acute Oral Toxicity to Rats of Varying Doses of Benzotriazole 117
or Tolyltriazole
25 Primary Eye Irritation by Benzotriazole and Tolyltriazole 122
26 Mortality Produced in Rats by Three-Hour Exposure to 123
Aerosolized Benzotriazole
27 Arrest of Rana pipiens Embryos Upon Continuous Exposure from 127
Stage 3
28 Arrest of Rana pipiens Embryos Upon Continuous Exposure to 128
Benzotriazole Derivatives
29 Comparison of Survival of Rana pipiens Embryos Exposed at 130
Tailbud Stage 17/18 to 4-Methoxy-6-nitrobenzotriazole
30 The Effects of Substituted Benzotriazoles on the Growth of 131
Escherj;chia, colj Strain W and Two of Its Purine-Dependent
Mutants, Including the Mutagenic Activity at the Guanine-
Dependent and Streptomycin-Sensitive Loci of Wp~
31 The Antimutagenic Effect of 4-OH-6-N02-Benzotriazole on 133
Mutagenesis in Escherichia coli Wp~ Induced by 4-N00-6-OH-
' ———— ^.
Benzimidazole (NHB)
32 The Effect of Benzotriazole and 5-Methylbenzotriazole on 136
the Incidence of Liver Tumors in Male Rats Produced by
Feeding 3'-Methyl-4-dimethylaminoazobenzene
33 Static and Dynamic Exposure of Bluegills and Fathead Minnows 138
to Benzotriazole
vii
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List of Tables (continued)
Number Page
34 Dynamic Exposure of Fingerling Trout to Benzotriazole 139
35 LC Values (ppm) and Their Confidence Limits (at p = .05) in 140
Fathead Minnows
36 Repression of Cucumber Root Elongation. Elongation of Primary 142
Root, 96 Hours at 25PC
37 Physiological Effects on Plants by 5-Chlorobenzo-l,2,3-triazole 145
38 Effect of Alkylbenzotriazoles on the Growth of Oat Coleoptile 146
Segments In Vitro
39 Bioassay of Benzotriazole Using Various Microbiological Systems 150
40 Effect of Benzotriazole on the Growth of Microorganisms from 149
Wastewater
41 Effect of Tolyltriazole on Biochemical Oxygen Demand and 151
Growth of Wastewater Microorganisms
42 Effect of Benzotriazole and Derivatives on the Multiplication 152
of Influenza B Virus in Chorioallantoic Membrane
43 Effect of Benzotriazole and Derivatives on the Multiplication 153
of Poliovirus Type 2 in Monkey Kidney Cells In_ Vitro
44 Effect of Benzotriazole on the Inhibition of Selected 157
Enzymatic Systems In Vitro
45 Food and Drug Administration Status of Ciba-Geigy Stabilizers - 160
July 1973
viii
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LIST OF FIGURES
Number Page
1 UV Absorption Spectra of Benzotriazole, 5-Chloro-lH- 14
benzotriazole, and 5-Methyl-lH-benzotriazole
2 Specific Extinction Coefficient Spectra - Tinuvin 326 15
and Tinuvin P in Chloroform
3 UV Absorption Spectra of Several 2-(3f,5'-Alkyl-22'- 16
hydroxyphenyl)-benzotriazoles
4 Effect of Temperature on the Solubility of IH-Benzotriazole 20
in Water
5 Suggested Structures of Cuprbus-Benzotriazole Complex 32
Polymers
6 Commercial Preparation of Benzotriazole According to the 53
Method of Long
7 Automotive Antifreeze Thermal Stability Test-Depletion of 52
Additive
8 Effect of pH on Percent Inhibition Efficiency for Steel in 64
Simulated Cooling Water
9 Naturally Occurring Chemical Structures Compared to
Benzotriazole
10 Acute Toxicity in Rats Treated Orally with Various Doses of
Benzotriazole or Tolyltriazole
11 (A) Effect of Certain Benzazoles Upon the Elongation of the 143
Primary Root of Cucumber Seedlings (seedlings grown in
presence of the compound at 258C in darkness for 96 hours);
(B) Effect of Certain Benzazoles Upon Dry Weight of Barley
Roots (seedlings grown in aerated deep cultures, 25°C, in
darkness for 6 days)
12 Growth of Escherichia coli 8242 in Response to Addition of 147
PurjLnes to the Culture Medium
13 Effect of Benzotriazole on the Growth of Escherichia coli 143
8242 in Presence of Guanine
14 Compound Induced Damage-Time Curves with Selected 156
Benzotriazole Derivatives in Monkey Kidney Cells
ix
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EXECUTIVE SUMMARY
The current total production of benzotriazoles is estimated to be approxi-
mately 56 million pounds per year in the United States. Benzotriazoles are
used in three main applications: to prevent the corrosion of metals, especially
copper and materials containing copper (such as brass or bronze); to stabilize
plastics and similar materials against the decomposition which would otherwise
take place upon exposure of these materials to sunlight, fluorescent light, or
other sources of ultraviolet radiation; and in photography, mainly as a con-
stituent of films (antifoggant) to improve their photographic characteristics.
The majority of benzotriazoles produced go into anticorrosion applications.
Typical applications include the protection of copper-containing parts (for
which benzotriazole excels) by inclusion of benzotriazoles in automobile
antifreeze solutions, in recirculating water systems such as power plant and
commercial air conditioning cooling systems, and in coatings for the protec-
tion of copper alloys in architectural and decorative applications.
Approximately 20-30% of all benzotriazole production is used for the
stabilization of plastics, paints, clear coatings, fabrics, and certain oil-
based solvents against degradation on exposure to ultraviolet light. A variety
of chemical derivatives (substitute at the 2-position) of benzotriazole are
used in these applications, generally possessing chemical and possibly bio-
logical properties quite different from the parent compound.
The various photographic applications of benzotriazole consume only a
small quantity of the total production (considerably less than one million
pounds per year).
x
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Only limited information is available on the possible release of benzo-
triazoles to the environment or the fate of benzotriazoles in the environment.
Some 2-substituted benzotriazoles have been detected in ppb in river water and
ppm in river sediment several miles downstream from a production plant. On
the basis of their chemical properties, it is likely that the other benzo-
triazoles will be relatively stable and fairly persistent if released to the
environment. Data on monitoring of the other benzotriazoles in the environ-
ment is unavailable.
Some benzotriazoles can inhibit the growth of bacterial cells and also
cause mutations in some types of bacteria. This is significant because
chemicals which are mutagenic frequently are carcinogenic as well. No studies
of the potential carcinogenicity of benzotriazole have been completed yet,
although work in this area is presently being carried out'. It is therefore
not now known what hazard, if any, benzotriazole may present with respect to
the induction of tumors.
Animal studies have shown that benzotriazole dusts, if inhaled, may
damage the lungs and severely interfere with breathing. The dust is also an
explosion hazard. Benzotriazole dusts are not likely to be a hazard'in
current end use applications of these materials; dust hazard is most likely in
places of manufacturing, packaging, and unpackaging of these chemicals.
Current regulations do not set limits for benzotriazole dusts, but do limit
the concentrations for some of the compounds used as ultraviolet light stabil-
izers in certain plastics consumed in food packaging.
xi
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I. Physical and Chemical Data
A. Structure and Properties
1. Chemical Structure
The benzotriazole compounds are derivatives of a five-member
heterocyclic compound containing three nitrogen atoms and a vicinal pair of
carbon atoms. The five-member heterocyclic compound is named lH-l,2,3-triazole:
The 1H refers to the position of the hydrogen atom associated with the nitrogen
atoms; it may be on the //I or #2 nitrogen atom. The 1H and 2.H isomers are
tautomers:
The numbering system of the molecules is indicated above. The numbers 1,2,3
in the nomenclature refer to the positions of the nitrogen atoms and thereby
distinguish between the v (vicinal) triazoles from the s_ (symmetrical) triazoles.
In the latter the nitrogen atoms are separated by a carbon atom between them
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and they are therefore named 1,2,4-triazoles. An ortho condensation of a ben-
zene ring with a v-triazole ring describes the benzotriazole system (Boyer,
1961), the parent compound of which, and the major focus of this work, is the
tautomer IH-benzotriazole:
.N 2
Other names commonly used for this compound are 1,2,3-benzotriazole and benzo-
triazole. Occasionally (especially in the older literature) the compound is
referred to as azimidobenzene, benzene azoimide, or benzisotriazole. The
accepted Chemical Abstracts numbering system for the atoms, as indicated above,
follows from the numbering system for v-triazoles. In this review, the 1H
structure is often referred to as simply benzotriazole.
There exists the possibility of an alternate (tautomeric) structure
for benzotriazole which is named ZH^benzotriazole (also referred to as pseudo-
azimidobenzene or 2,1,3-benzotriazole):
N-H
The 2E tautomeric structure is known mainly through its derivatives, which
are of considerable theoretical interest because their exact structure is
2
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still a subject of controversy. Compounds of the type:
should be colored (but they are not) and exhibit quinoid properties (which they
do not) (Benson and Savell, 1950). An alternative structure for 2H-benzotria-
zol.es,
•N
is an extremely strained arrangement which appears to be unlikely from geometric
considerations alone (Benson and Savell, 1950). It has been suggested that the
structure of 2H-benzotriazoles cannot be completely described exclusively on
the basis of covalent bonds (Boyer, 1961).
Pure 2H-benzotriazole apparently has not been isolated, although numerous
derivatives are stable (see, for example, Benson and Savell, 1950). X-ray
studies have ruled out the possibility of the presence of symmetrical molecules
in crystalline benzotriazole, suggesting the overwhelming predominance of the
1H tautomer in the solid state (Escande et_ al., 1974 a). This experimental
evidence supports the earlier theoretical work of Kamiya (1970) who used the
semiempirical Pariser-Parr-Pople self-consistent-field molecular orbital method
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to show that the ground energy states of the symmetrical 2H-benzotriazole molecule
are higher than those of IH-benzotriazole, implying the greater stability of the
latter compound as compared to the former. Semiempirical complete-neglect-of-
differential-overlap (CNDO) calculations of Escande e£ al. (1974 b) yielded
results comparable to those of Kamiya (1970). When taken with spectral and
dipole moment data (Mauret et al., 1974) , the evidence supports the conclusion
that, both in solution and the solid state, the 1H_ tautomer of benzotriazole
represents the more stable and essentially exclusive molecular structure
(Escande e_t al. , 1974 b).
There are dozens of benzotriazole derivatives mentioned in the
literature. Only three of these have achieved sufficient commercial status^ to
merit mention by chemical name in the following publications:
Directory of Chemical Producers (SRI, 1975)
Synthetic Organic Chemicals 1974 (USITC, 1975)
Chemical Week 1976 Buyers' Guide (McGraw-Hill, 1975)
Chemical Buyers' Directory (Chem. Marketing Reporter, 1975)
These compounds are, in order of their commercial importance: IH-benzotriazole,
methylbenzotriazole (mixtures of 4- and 5-methyl isomers), and 5-chloro-lH-
benzotriazole. In addition, there are at least eight other benzotriazole
derivatives which have some commercial uses. The most important of these are
members of the class 2-(2'-hydroxy-3',5'-alkylphenyl)-benzotriazole which
have the structure:
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The H bonding of the hydroxyl group keeps the molecule planar, thus allowing
better conjugative overlap between the benzene ring and the benzotriazole system.
Intramolecular hydrogen bonding therefore increases the stability of these com-
pounds, which are marketed under the tradename Tinuvin (Ciba-Geigy, undated).
The R groups on Tinuvins are H, CH_-, t_-butyl, and/or _t-pentyl. The complete
structures are shown in Table 1, along with the structures of other coranercially
significant benzotriazoles.
2. Mixtures
The Sherwin-Williams Chemical Company sells mixtures of 4-methyl-
IH-benzotriazole and 5-methyl-lH-benzotriazole under the tradename Cobratec TT-100.
This material, often referred to as "tolyltriazole," contains approximately
equal amounts of the above two isomers, as well as small quantities of the 6-
and 7-methyl isomers (Anon., undated). Cobratec TT-35-I is a 35% solution of
the sodium salts of tolyltriazole mixtures. The methyl isomers in these salts
presumably are in the same proportions to each other as in the solid tolyltria-
zole product.
3. Physical Properties of the Pure Material
Benzotriazole and its derivatives listed in Table 2 are white
to off-white or light yellow crystalline powders with melting points in the
range 100-150°C (high for aromatic compounds of similar molecular weight) and
generally high boiling or decomposition temperatures (ca. 300°C). In addition
to their thermal stability, they are quite stable to electromagnetic radiation
in the ultraviolet range. They dissipate absorbed ultraviolet energy as heat.
The ultraviolet spectra of some of these compounds are shown in Figures 1, 2,
and 3. The spectra are characterized by broad absorbance below 400 nm. The
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Table 1. Molecular Structure of Benzotriazoles
IH-benzotriazole
CH,
4-methyl-lH-benzotriazole
5-methyl-lH-benzotriazole
-N
5-chloro-lH-benzotriazole
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Table 1. Molecular Structure of Benzotriazoles (Cont'd)
Cl
N
1-chlorobenzotriazole
Ag
•N
\
oi;
^
silver benzotriazole
,Na
N
N
CH3
sodium tolyltriazole
HO
W
CH,
2-(2'-hydroxy-5'-me thyIphenyl)-benzo triazole
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Table 1. Molecular Structure of Benzotriazoles (Cont'd)
C(CH0),
2-(3'-t-butyl-2'-hydroxy-5'-methylphenyl)-benzotriazole
CCCHJ,
2-(3',5'-di-t-butyl-2'-hydroxyphenyl)-benzotriazole
HO
2-(3' ,5'-di-_t-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole
CH,
2- (2-hydroxy-3* ,5' -di-Jt-pentylphenyl)-benzotriazole
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Table 2. Physical Properties of Benzotriazole Compounds
benzotriazole
tolyltriazole
Appearance
Odor
Molecular
Weight
Specific
Gravity (25°C)
Flash Point °C
(Tag Closed Cup)
Bulk Density
(lbs,/cu. ft.)
Melting Point, °C
Vapor Pressure,
torr (°C)
Boiling Point,
°C (torr)
Dipole Moment, esu
(dioxane)
i
Heat of Combustion,'
kcal/mole
white powder
sweet
119.12
1.33
> 150*
40, loose
55, packed
98-99
0.04 (20)
350 (760)
4.07 x 10~13
794.97 + 0.21
off-white
granules
133.16
1.16
> 150*
35-50, loose
40-45, packed
0.03 (50)
160 (2)
Sherwin-Williams Company, product data sheets
2
Fairmount Chemical Company, product data sheets
3
Ciba-Geigy Corporation, product data sheets
Benson and Savell (1950)
5Boyer (1961)
6
Parish Chemical Company (1976), personal communication
*
Sherwin-Williams Company, personal communication
9
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Table 2. Physical Properties of Benzotriazole Compounds (Cont'd)
5-chloro-lJH-
benzotriazole
1-chlorobenzotriazole
\
Appearance
Odor
white powder
Molecular
Weight
Specific
Gravity (25°C)
Flash Point °C
(Tag Closed Cup)
Bulk Density
(Ibs./cu. ft.)
Melting Point, C°
Vapor Pressure,
torr (°C)
Boiling Point,
°C (torr)
4
Dipole Moment, esu
(dioxane)
[
Heat of Combustion,"
kcal/mole
153
153
156-160
103
Sherwin-Williams Company, product data sheets
2
Fairmount Chemical Company, product data sheets
3
Ciba-Geigy Corporation, product data sheets
4
Benson and Savell (1950)
5Boyer (1961)
6
Parish Chemical Company (1976), personal communication
10
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Table 2. Physical Properties of Benzotriazole Compounds (Cont'd)
2-(2'-hydroxy-5'-
methylphenyl)benzo-
triazole^
2-(3' ,5'-di-t-butyl-
2'-hydroxypheny1)ben-
zotriazole3
Appearance
Odor
Molecular
Weight
Specific
Gravity (25°C)
Flash Point °C
(Tag Closed Cup)
Bulk Density
(Ibs./cu. ft.)
Melting Point, C°
Vapor Pressure,
torr (°C)
Boiling Point,
°C (torr)
4
Dipole Moment, esu
(dioxane)
i
Heat of Combustion,"
kcal/mole
crystalline powder
none
225
1.51
128-132
8 x 10"5 (60)
225 (10)
light yellow powder
none
301
305-311
Sherwin-Williams Company, product data sheets
2
Fairmount Chemical Company, product data sheets
3
Ciba-Geigy Corporation, product data sheets
'4
Benson and Savell (1950)
5Boyer (1961)
Parish Chemical Company (1976), personal communication
11
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Table 2. Physical Properties of Benzotriazole Compounds (Cont'd)
2-(3',5'-di-£-butyl-
2'-hydroxyphenyl)ben-
zotriazole^
2-(2'-hydroxy-3',5'-
di^t-pentyl)benzo-
triazole^
Appearance
Odor
Molecular
Weight
Specific
Gravity (25°C)
Flash Point °C
(Tag Closed Cup)
Bulk Density
(Ibs./cu. ft.)
Melting Point, Cc
Vapor Pressure,
torr (°C)
Boiling Point,
°C (torr)
Dipole Moment, esu
(dioxane)
i
Heat of Combustion,'
kcal/mole
light yellow powder
none
301
140-141
pale yellow powder
358
1.20
154-158
Sherwin-Williams Company, product data sheets
2
Fairmount Chemical Company, product data sheets
3
Ciba-Geigy Corporation, product data sheets
4
Benson and Savell (1950)
5Boyer (1961)
6
Parish Chemical Company (1976), personal communication
12
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Table 2. Physical Properties of Benzotriazole Compounds (Cont'd)
2-(3',5'-di-t-buty1-2'-hydroxypheny1) •
5-chlorobenzotriazole3
Appearance
Odor
off-white powder
Molecular
Weight
Specific
Gravity (25°C)
Flash Point °C
(Tag Closed Cup)
Bulk Density
(Ibs./cu. ft.)
Melting Point, C'
Vapor-Pressure,
torr (°C)
0.91
81
10~3 (100)
Boiling Point,
°C (torr)
4
Dipole Moment, esu
(dioxane)
i
Heat of Combustion,"
keal/mole
Sherwin-Williams Company, product data sheets
2
Fairmount Chemical Company, product data sheets
3
Ciba-Geigy Corporation, product data sheets
A
Benson and Savell (1950)
5Boyer (1961)
Parish Chemical Company (1976), personal communication
13
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CD:
NH
— cyclohexane
— NaOH N
-- HCI N
4.5
4.0
3.5
at
O
3.0
2.5
350
300 250
X ( m/a )
0.0
ethanol
200
350
300
250
ill, 14.5
4.0
3.5
3.0
2.5
0.0
200
350
300 250
\ ( mji )
- 2.0
200
Figure 1. UV Absorption Spectra of Benzotriazole, 5-Chloro-lH-benzotriazole,
and 5-Methyl-lH-benzotriazole (Dal Monte et al., 1958)
14
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100
TINUVIN 326t
TINUVIN P*
E = Specific Extinction Coefficient
A=Optical Density
C = Concentration, g/l
L=Cell Length, cm
280
290
300
320
330 340 350 360 370
WAVELENGTHS, MILLIMICRONS
380
390
400
410
420
Figure 2. Specific Extinction Coefficient Spectra-- Tinuvin 326* and Tinuvin Pt in Chloroform
(Ciba-Geigy, undated). (Reprinted with permission from the Ciba-Geigy Corp.)
* 2-(3I-_t-butyl-2l-hydroxy-5'-methylphenyl)-benzotriazole
t 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole
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UV Absorber Extinction Curves
100.0
0.1
300
325 350 375
Wavelength (nanometers)
400
a = Extinction Coefficient
c = Cone, in g/liter
b = Path Length = 1 cm
Figure 3.
* 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole
t 2-(3',5'-di-£-butyl-2'-hydroxyphenyl)-benzotriazole
11 2-(3' ,5'-di-_t-pentyl-2'-hydroxyphenyl)-benzotriazole
UV Absorption Spectra of Several 2-(3',5'-Alkyl-2'-hydroxyphenyl)-
benzotriazoles (Ciba-Geigy Corp., undated)
(Reprinted with permission from the Ciba-Geigy Corp.)
16
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specific extinction coefficients at absorption maxima for two of the 2-(2'-
hydroxyphenyl)-benzotriazoles are listed in Table 3. The 2-(2'-hydroxyphenyl)-
benzotriazoles tend to absorb at longer wavelengths than other benzotriazoles,
hence their pale yellow color when pure.
Table 4 lists solubility data for benzotriazole and its deriva-
tives. They range from insoluble to somewhat soluble in water and nonpolar
solvents, to soluble in most organic polar oxygenated solvents. The solubility
of benzotriazole in water varies widely with temperature, as shown in Figure 4;
it can be as high as 20% (w/v), but is less than 2% (w/v) at temperatures below
30°C. The water solubility of benzotriazole is high enough to be a factor in
the transport of this material in the environment. The solubility of the 2-
(.2'-hydroxyphenyl)-benzotriazoles (Tinuvins) in a given solvent depends to a
large extent on the particular alkyl groups on the 3' and 5' positions. The
solubility of Tinuvin 328 (with J^-pentyl phenyl substituents) in esters and
(nonpolar) xylene is two to four times the solubility of Tinuvin P (with a
single methyl substituent on the phenyl) or Tinuvin 326 (with methyl and _t-butyl
substituents). The water solubility of 2-(2'-hydroxyphenyl)-benzotriazoles
is lower than expected for similar molecules which are not capable of internal
hydrogen bonding; Tinuvins are, in fact, insoluble in water. Solubility data
was not available for compounds not listed in the tables.
4. Physical Properties of Commercial Material
Some commercial applications require a highly purified benzo-
triazole product, whereas technical grade material will do for others. Benzo-
triazole and 5-chloro-lH-benzotriazole which are labeled "photo grade" are
examples of high purity material whose physical properties are as described in
17
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Table 3. Specific Extinction Coefficients of Several 2-(3',5'-alkyl-2'-hydroxyphenyl)-benzotriazoles
(Ciba-Geigy Corp., undated)
00
2- (2'-hydroxy-5'-methylphenyl)-
benzotriazole
chloroform
methanol
A
max.
312
350
298
343
Sp. Ext. Coeff.
46
50
47
51
2-(3'-_t-butyl-2t-hydroxy-5f- 2-(3' ,5' -di-t-butyl-21-
methylphenyl)-benzotriazole hydroxyphenyl)-benzotriazole
A Sp. Ext. Coeff. A Sp. Ext. Coeff.
max. max.
298 61 315 42
340 70 352 47
296 65
345 66
-------
Table 4. Solubilities of Benzotriazole Compounds
BT
Water 1.93
Water, 60°C 7.4
Methanol 71.6
l-Methoxy-2-propanol 55.0
Isopropanol 53.9
Ethylene glycol 50.7
Polyethylene glycol 47.7
Methyl ethyl ketone 46.1
Heptanol 34.6
Benzene 1. 3
White mineral oil 0.004
Tetrachloroethylene 0.06
Turbine oil 0.01
Ethanol (abs.) soluble
Ethyl acetate
Methyl methacrylate
Petroleum ether
Styrene
Toluene
Xylene
Mineral spirits
n-Butyl acetate
Cyclohexane
Hexane
Dioctyl phthalate
Acetone
Methyl cellosolve
KEY: BT Benzotriazole
TTZ Tolyltriazole
(Data for the above
TTZ Cl-BT
0.55 slight
1.8 moderate
71.6 soluble
52.3
52.9
45.6
41.1
41.4
35.9
1.3
0.008
0.13
0.014
4
in wt.% @25°C) (Korpics,
Cl-BT 5-Chloro-lH-benzotriazole (Fairmount Chemical
Tin-P 2-(2'-hydroxy-5'-met
ihylphenyl) benzotriazole
Tin-P Tin- 326
0 0
10 gm/100 gm 2.9
0.3
3.5 2.5
5 4.9
1.8
7.2 12.6
6.0
7 gm/100 gm
1.5
4 gm/100 gm
^.5
2.5
1.7
1974 a)
Co., product data sheet)
Tin-327
0
4
0.3
6
14
14
16
15
5
10 gm/100 gm
8
3
3
Tin- 32 8
0
24 gra/100 gm
20 gm/100 gm
44 gm/100 gm
14 gm/100 gm
28 gm/100 gm
Tin-3C6 2-(3'-J>-butyl-2'-hydroxy-5'-methylphenyl)-benzotriazole
Tin-3^7 2-(3',5'-di-£-butyl-2'-hydroxyphenyl)-benzotriazole
(Data for the above in gm/100 ml solvent, except where indicated otherwise)
(Ciba-Geigy Co., undated)
Tin-328 2-(2'-hydroxy-3',5'-di-£-pentylphenyl)-benzotriazole (Ciba-Gelgy Co., undated)
-------
20
16
12
= 10
.0
3
20 40 60 80 100
Temperature of Water °C
Figure 4. Effect of Temperature on the Solubility of IH-Benzotriazole in Water
(Walker, 1970)
Reprinted from Plating with permission from the American Electroplaters
Society, Inc.
20
-------
the previous section. Applications such as corrosion inhibition utilize technical
grade chemicals or mixtures of benzotriazoles. Tolyltriazole, for example, is a
mixture of the 4-, 5-, 6-, and 7-methyl-lH-benzotriazole isomers. In the appli-
cation for which this material is intended, the efficacy of the mixture is the
same as any single pure isomer would be. Certain physical properties, such as
melting point, may vary for the mixture from the pure material and from batch
to batch of the mixture. The manufacturer's specifications are given in Table 5
for benzotriazole commercial chemicals where the specifications supplement or
are different from the data in Table 2.
5. Principal Contaminants of the Commercial Product
It is likely that the most widely used commercial methods for
large scale preparation of benzotriazole are those suggested by Levy (1966)
and Long (1971) (which are adaptable to the preparation of certain derivatives
of benzotriazole as well), in which 1,2-diaminobenzene (o-phenylenediamine) is
diazotjzed with sodium nitrite in the presence of acetic acid (HAc) in an
aqueous medium;
Time, temperature, and pH factors all affect the yield of the reaction. The
benzotriazole forms as an oily liquid which is separated and purified in a
complex series of steps including water washing, water evaporation, distilla-
tion under reduced pressure, condensation, and solidification. Details of the
21
-------
Table 5. Commercial Specifications for Some Benzotriazole Compounds
Assay, %
Melting Point , °C
Ash , % max.
Loss on Drying @70 C,
% max.
CJ~, Br~, 6, I~
N3
N> Solubility in H.O
Benzotriazole ,
photo grade
99.0, min.
96-100
0.01
0.5
to pass ASA test
1% sol. is clear
1 2
Benzotriazole, Benzotriazole,
technical photo grade
95, min. 98, min.
98-99
1 0.5
2% @25°C 1% sol. is clear
2
Benzotriazole ,
technical
98, min.
94-99
0.5
0.5
Tolyltriazole,
technical
99, min.
0.5
0.5
50 ppm max. Cl
Solubility in
Absolute Ethanol
sol. is clear
Solubiltty in 10% NaOH
Free Amine, % max.
1% sol. is clear
0.2
Fairmount Chemical Company, Newark, New Jersey
2
Sherwin-Williams Chemical Company, Cleveland, Ohio
-------
processes are given in Section II-A-3. Most of the product nominally lost in
the purification steps (i.e., dissolved in the wash water) is recovered and
recycled, resulting in a high overall yield of 97%. The product is also high
in purity. Sherwin-Williams Co. (undated), for example, specified 98% minimum
purity for technical grade benzotriazole, and 99% minimum purity for technical
grade tolyltriazole. The typical assays for these products yield a purity
of 99.5%. Moisture and ash account for 0.5-1.0% of the remainder. The tolyl-
triazole product can have up to 0.2% free amine (possibly aniline) and 50 ppm
chloride ion. One important commercial test for the purity of these products
is based on their nearly colorless (white) appearance when pure. The oxida-
tion products of the benzotriazoles are dark in color; hence, the darker the
material (in solution), the more impurities are present. The major impurities
are likely to be oxidation products of the starting material, 1,2-diaminobenzene,
including o-nitroaniline, 1,2-dinitrobenzene, nitrosamine intermediates, and
possibly polyamines. The -extent of the side reactions which produce these
undesired contaminants is controlled by reaction conditions (Long, 1971). These
impurities are most tolerable in benzotriazoles intended for anticorrosion
applications, less so in benzotriazoles intended for use as ultraviolet absorbers
(especially in plastics where color imparted by an additive, even in small
quantities, is usually undesirable), and least tolerable in benzotriazole
intended for photographic applications because the contaminants are usually
photographically active. "Photograde" benzotriazole is the highest purity
commercially available grade, essentially free of colored contaminants.
In summary, benzotriazole commercial chemicals, even the technical
grade, are high purity materials as supplied. The principal contaminants are
23
-------
likely to be moisture, ash, and some oxidation products of the 1,2-diaminoben-
zene starting material, which impart a dark color to benzotriazole and are
measured by standard colorimetric tests.
B. Chemistry
1. Reactions Involved in Uses
The major uses to which benzotriazoles are put, namely as anti-
corrosion agents, plastics stabilizers, and photographic antifoggants, depend
on physical and chemical properties which are a unique combination of chemical
versatility and stability. Stability is a key concept in benzotriazole chemis-
try. Although the molecule will undergo, under the proper conditions, a wide
variety of reactions (including aryl and N-halogenation, nitration, hydroxyla-
tion, acylation, alkylation, oxidation, hydrogenation, condensation, and
arylation, to name a few), the Integrity of the triazole ring is almost never
compromised (Sherwin-Williams Co., undated). Benzotriazole compounds react
readily to form stable metal complexes which are capable of protecting the
metal (particularly copper) from further chemical attack. Although practic-
ally colorless to the human eye, benzotriazole compounds absorb over a broad
range in the ultraviolet region of the electromagnetic spectrum and dissipate
the absorbed energy, usually not by bond breaking and free radical formation,
but by harmless physical vibration and the emission of heat. Benzotriazole
compounds are therefore capable of protecting less stable molecules from
degradation on exposure to ultraviolet radiation. It is, then, the combina-
tion of chemical versatility which allows modifying solubility, absorption
spectra, compatibility with plastics, etc., of benzotriazoles on the one hand,
and the relative physical and chemical stability of the benzotriazoles on the
other, which chiefly characterizes benzotriazole and its derivatives in their
major commercial applications. The chemistry of these applications is considered
in detail below.
24
-------
a. Anticorrosion
Benzotriazole's anticorrosion properties were recognized
long before the mode of protection began to be understood. One of the earliest
efforts to elucidate the mode of protection involved a study of the effect of
benzotriazole on copper electrodeposits (Prail and Shreir, 1961).. It was
recognized that the association of the benzotriazole and copper was not simply
that of a protective physical coating adsorbed on the metal surface, but a
more intimate chemical association described as a "cuprous benzotriazolate"
complex. It was also suggested (erroneously, as it turned out) that in order
for benzotriazole to be effective in protecting copper, it must be "released
from the metal complex during the corrosion process."
On the basis of electrochemical investigations, Dugdale
and Cotton (1963) concluded that prevention of copper corrosion results from
the formation of a copper-benzotriazole complex which acts as a cathodic in-
hibitor for the oxidative reaction, assisted by the physical barrier the
complex presents on the metal surface.
The particular features of the benzotriazole molecule which
make it an excellent anticorrosion agent were reported by Cotton and Scholes
(1967) in a study of copper complexes with the compounds listed in Table 6.
Neither indole nor 1-methylbenzotriazole formed insoluble complexes with
either cupric or cuprous ions. Consequently, physical protection is not
possible with these materials; apparently both the 111 hydrogen atom and at
least two nitrogen atoms are needed in the five-member ring to obtain anti-
corrosion properties. Benzimidazole (a weak base) formed a dark red, insoluble
complex with copper, but failed to protect copper against corrosion, suggesting
25
-------
Table 6. Compounds Used In the Study of Cotton and Scholes (1967)
•N
IH-benzotriazole
indazole
benzimidazole
indole
1-methylbenzotriazole
26
-------
that the two nitrogens in the ring must be adjacent to each other. Both
indazole (a neutral compound) and benzotriazole (a weak acid) formed dark
green, insoluble complexes and both compounds protected copper from tarnish.
However, copper treated with benzotriazole could be washed with chloroform
and still retain its resistance to tarnish, whereas indazole-treated specimens
did not retain their resistance to corrosion after rinsing in chloroform.
Modifications to the benzene ring have little effect on the anticorrosion
properties of benzotriazole. Thus, the following compounds behave similarly
with respect to preventing the corrosion of copper: benzotriazole, 4-, 5-,
6-, or 7-methylbenzotriazole, 4-, 5-, 6-, or 7-chlorobenzotriazole, and nap-
thotriazole. However, the six-member aromatic ring appears essential, because
five-member heterocycles (and their derivatives), such as imidazole, 1,2,4-
triazole, and pyrazole, showed little or no inhibitive properties.
In 1969 Bonora et al. confirmed the presence of a protec-
tive layer on copper sheets treated with benzotriazole and suggested that
oxygen playas a part in the formation of the layer. Moreover, it was shown that
benzotriazole inhibits both anodic and cathodic polarization on copper in
saline solution, whereas another commonly used anticorrosion agent, 2-mercapto-
benzothiazole, inhibits only the cathodic polarization.
Poling (1970) used infrared reflectance measurements to
determine the structure of the copper-benzotriazole complex formed on copper
sheets in neutral solution. This was the first attempt to examine the nature
of the complex in situ as opposed to the complex which precipitates from a
solution of cuprous ions when benzotriazole solution is added. Polymeric
films of copper-benzotriazole complex formed in acidic (pH = 3) aqueous solu-
tions of sodium chloride were found to be from 2300-5000 X thick on the surface
27
-------
of the sheets of copper, in contrast to the monomolecular film (ca. 50 A thick)
reported by Cotton and Scholes (1967). The films were inert to the common organic
solvents listed in Table 7. They were attacked by pyridine, formic acid, and
disodium (ethylenedinitrilo)-tetraacetic acid. Prolonged heating in air at
140°C had little effect on the films. After heating for two hours at 250°C,
however, a film which was 2300 A thick prior to heating evaporated to a thick-
ness of 400 A. No changes were noted in the infrared spectrum of the residual
film. The rate of oxidation of the underlying copper was reduced significantly
by the presence of the films as deduced from relative intensities of Cu_0 spectra.
The mechanism of growth of the polymeric films of Cu(I)-benzotriazole below the
initial layer was attributed to the diffusion of cuprous ions through the sur-
face of the films, which was encouraged by the presence of a corrosive solution
at the surface (and also polarization of the copper samples). In addition, the
films formed a protective barrier which inhibited oxygen transport to the
copper below the surface.
In spite of the new information, the exact nature of the
polymer film was yet to be determined. Angely et al. (1971) took a step in
that direction with the demonstration of a 2:1 ratio between the number of
copper atoms and benzotriazole molecules in the films. Electrochemical tech-
niques led to the quantification of the enthalpy of the reaction between benzo-
triazole and the copper surface, which is 11 kcal/mole. The adsorption energy
was shown to exceed the desorption energy by 9.4 kcal/mole, confirming the
irreversibility of the reaction between copper and benzotriazole.
In 1973 Mansfield and Smith resolved the discrepancy between
the findings of Cotton that the copper-benzotriazole layer is about 40 X thick
(Dugdale and Cotton, 1963; Cotton and Scholes, 1967) and Poling (1970) who found
28
-------
Table 7. Effect of Solvents on Copper-Benzotriazole Complex on Copper Sheets
(Poling, 1970)
Inert To
heptane
benzene (hot or cold)
carbon tetrachloride
chloroform
ethyl ether
acetone
methyl isobutyl ketone
ethyl acetate
acetonitrile
dimethylformamlde
nitromethane
Slowly Dissolved By
pyridine
formic acid
disodium (ethylenedinitrilo)-
tetraacetic acid
29
-------
it to be several thousand angstroms thick. The thickness of the complex layer
was shown to be a function of the pH at which it is formed. At the low pH's
Poling used, a thick porous salt film forms. This thick film does not form at
or near neutral pH's. The salt film can easily be wiped off, but the under-
lying film (60-140 X) cannot.
Benzotriazole generally causes a reduction in the pH of
solutions to which it is added. This effect has been attributed to minimiza-
tion of the cathodic reactions which tends to increase pH (Walker, 1970):
2H+ + 2e
H,
2H 0 + 0 + 4e -»• 40H
At the same time, benzotriazole tends to buffer the solution in the following
manner:
Using X-ray photoelectron spectroscopy, Roberts (1974)
determined that the rate of adsorption of benzotriazole depends not only on pH
but also on the nature of the surface of the copper, a cuprous oxide surface
adsorbing benzotriazole faster than a cupric oxide surface. The Cu -benzo-
triazole complex which forms is at least ^15+7 X thick and gradually
30
-------
+2
oxidizes to Cu -benzotriazole. Several possible structures for the complex
have been suggested and are shown in Figure 5.
Ogle and Poling (1975) confirmed Roberts's findings that
the composition of the protective surface film is primarily Cu -benzotriazole.
In acidic solutions, in which Cu 0 is unstable, the film network consists of
acircular crystals of Cu -benzotriazole several thousand angstroms thick.
Electrochemical polarization curves indicate that protection is afforded mainly
via the physical barrier presented by the film. Excess benzotriazole in the
corrosive environment prolongs the protection due to the possibility of repair
to the physical defects which may develop in the film barrier.
In summary, the evidence indicates that benzotriazole forms
a thin, highly stable, monomolecular polymeric film on copper surfaces con-
sisting mainly of cuprous benzotriazole monomeric units. The film is thermally
and chemically quite stable. At low pH's the film may be overcoated with a
porous metal-benzotriazole salt layer.
b. Photostabilization
The Tinuvin compounds (2-(2'-hydroxyphenyl)-benzotriazoles)
are photochemically stable materials capable of adsorption of electromagnetic
radiation in the ultraviolet range between approximately 300-5,400 nm, and dis-
sipation of the energy as heat. They are therefore useful in preventing the
decomposition of substrates which are otherwise degraded by exposure to ultra-
violet light from the sun and fluorescent lamps. Typical substrates include
polyolefins, clear coatings, and paints. Intramolecular hydrogen bonding in
the Tinuvins is the key to their effectiveness as UV stabilizers. This effective-
ness is diminished significantly if the hydroxyl hydrogen is replaced by an
31
-------
to)
1C)
Figure 5. Suggested Structures for Cuprous-Benzotriazole Complex Polymers
(Roberts, 1974)
Note: Structure (b) is structure (a) with the atoms placed in proportion to
their relative inter-atomic distances. Thus, utruci.urt' (b) dull I'.nlt-n
overlapping of benzene rings.
Reprinted with permission from the American Elsevier Publishing Co., Inc.
32
-------
alkyl or acyl group (Rothstein, 1968). The physical relationship the protect-
ing compound has with the substrate also determines its effectiveness. In
polypropylene, for example, dissolved Tinuvins are accumulated mainly in non-
crystalline regions, which happen to require the most protection against photo-
chemical decomposition (Frank and Lehner, 1970). In addition to the primary
site of accumulation of the UV stabilizer, its relation to the substrate with
respect to migration is an important factor in the length of time protection is
afforded. The concentration of Tinuvins tends to be more stable in polypropy-
lene films than other stabilizers (Vink, 1973). However, the vapor pressure of
most Tinuvins is so high that after eventual diffusion of the molecule to the
surface of the substrate, evaporation takes place almost immediately (Durmis et
al., 1975). The loss of stabilizer is thus a function of its diffusion rate in
the substrate even for those stabilizers with relatively low vapor pressures,
and, of course, increases with increasing temperature. It has been shown that
a linear phenyl substituent reduces the diffusion of the stabilizer more effec-
tively than a branched substituent (Durmis et al., 1975). Application of UV
stabilizing benzotriazoles to specific substrates is discussed in Section II-B-1.
c. Photographic Antifoggant
Photographic emulsions contain silver halide grains which,
upon exposure to light, become semipermanently excited. This excitation or
"memory" manifests itself in their increased electrophilicity, that is, greater
reducibility than unexposed crystals. Hence, in the presence of mild reducing
(developing) agents such as _p_-aminophenol or hydroquinone, colorless silver
halide grains which have been exposed to light are reduced to black grains of
silver metal:
Ag Br~ + e~ -> AgO + Br~
colorless black
33
-------
The remaining silver ions which were unexposed to light and therefore not re-
duced, are removed from the emulsion by complexation with, typically, thiosulfate
ions, which react rapidly with silver ions to form a very stable water soluble
complex; at the same time thiosulfate is relatively unreactive towards the
silver atoms which make up the developed, visible photographic image:
Unfortunately, even if they have not been exposed to light,
all photographic emulsions tend to form metallic silver on treatment with re-
ducing agents. This unexposed but developed image is known as "fog" (John and
Field, 1963). Because it reduces the effective dynamic range of shading (con-
trast) of the film as well as its relative sensitivity to light (speed), fog
is considered undesirable. Fog is analogous to "noise" in electronic parlance
where design parameters are usually optimized to give the highest signal-to-
noise ratio possible. Photographers seek to achieve the highest possible mini-
mum image density-to-fog density ratio.
The causes of fog are complex and varied. They include
manufacturing conditions, storage conditions of the film before and after
exposure, nature of the developing agents, pO of the developer, contamination
of the film by foreign airborne substances, such as H S, the presence of silver
halide solvents in the developer (i.e., thiosulfate or thiocyanate ions), and
exposure of the film to X-rays, gamma rays, or a weak source of light prior to
or during development.
There are two chemical approaches generally taken to mini-
mize fog. One, almost universally practiced, is to add Br~ to the developer
34
-------
(John and Field, 1963). Since Br is formed during development (see equation
above), the Law of Mass Action predicts that excess bromide ion will retard
development. Retarding the formation of the image and fog by the same amount
has the effect of reducing the fog level significantly, much as negative feed-
back loops in electronic amplifiers reduce noise levels while simultaneously
sacrificing some gain in signal level. Bromide ion is therefore more correctly
viewed as a development restrainer than an antifoggant. The second chemical
approach to fog reduction is to employ a substance which reduces fog levels
while having little effect on image density. Such substances are said to
satisfy the following relation (Mees and James, 1971), and benzotriazole is
one of the more commonly employed among them:
K „ a -
AgBr Z
X ' " ™"
KAgZ aBr"
where the K' s are solubility product constants of AgBr and the silver salt of
Z, the antifoggant, and a - and a - are the activities of these ions in the
Br Z
developer solution. Thus, for K _ - 7.7 x 10 (Weast, 1967), K _ = 2.2 x 10
AgBr AgBt
(Havir, 1967) , and assuming the activities = concentrations of Br and benzo-
- -2 - -5
triazole ion for typical formulations in which {Br } = 10 and {Bt } - 10 ,
then the value of the expression above = 4. Benzotriazole is an effective
antifoggant in relatively small concentrations (i.e., ca. 10 M (Battaglia,
1970)) so that its activity as an antifoggant is not entirely attributable
to a decrease in effective (Ag } due to the formation of a relatively insolu-
ble silver benzotriazole compound on the surface of a silver halide crystal
35
-------
(Sahyun, 1970; Mees and James, 1971). Apparently, some type of kinetic process,
such as activation energy, is also a factor (Battaglia, 1970).
Benzotriazole is known to react with free radicals (Broyde,
1970). Although it is not certain that free radicals are present in fog centers,
it has been shown that benzotriazole does react selectively with fog center sites
rather than with the silver halide grain surface in general (Sahyun, 1971).
Consequently, benzotriazole would be expected to supress fog arising from a
free radical source.
On the other hand, it has also been suggested that benzo-
triazole adsorbed on the surface of silver halide grains interferes with desorp-
tion of bromide ion, which is necessary to maintain crystal stoichiometry
during reduction (Sahyun, 1974). This restraining action would reduce both
image and fog density.
In summary, it is clear that the question of the exact
mode of action of this and other similar antifoggants is far from settled.
2. Hydrolysis
Benzotriazole, a weak acid, is somewhat soluble in water (see
Section I-A-3). Many of its derivatives, such as the 2-(2'-hydroxyphenyl)-
benzotriazoles, are not soluble in water to any appreciable extent. Solutions
of benzotriazole in pure water are acidic because of the reaction:
36
-------
The pK for this reaction is 8.2 (Boyer, 1961). Benzotriazole becomes a
Si
stronger acid as chlorine is substituted on the benzene ring (see Table 8).
The insolubility of the 1- and 2-alkyl substituted benzotriazoles is attributable
to the fact that these compounds cannot hydrolyze as does benzotriazole in the
above reaction. The above equation also suggests that benzotriazole will be
less soluble in solutions of pH < 7 (such as rainwater) and more soluble in
solutions of pH > 7 (such as seawater) than in distilled water. Benzotriazole
reacts with solutions of alkali metal hydroxides producing soluble alkali salts:
NaOH +
Treatment of benzotriazole with an aqueous acid followed by
alkali causes hydroxylation (Sherwin-Williams Co., undated):
OH
/
1. H SO,
2. KOH
This reaction is unlikely to take place in the environment.
In the presence of strong acids, benzotriazole behaves as a
Lewis base. Therefore, benzotriazole, 5-chlorobenzotriazole, and 2-methyl-
benzotriazole are soluble in aqua regia, but 4,5,6,7-tetrachlorobenzotriazole,
a much stronger acid than the others, is not soluble (Boyer, 1961).
37
-------
Table 8. Relative Acid Strength of Some Benzotriazole Compounds
LO
00
iJH-Benzotriazole
5-Chloro-lH-benzotriazole
4-Bromo-lH-benzotriazole
5-Nitro-lH-benzotriazole
4,5 ,6,7-Tetrachloro-lH-benzotriazole
2-(2'-Hydroxy-5'-methylphenyl)-benzotriazole
2-(3'-^-Butyl-2'-hydroxyphenyl)-benzotriazole
pKa
9.1
8.2
8.0
7.7
7.9
6.5
5.5
5.2
-1.068
-1.114
Solvent
50% aq.
Water
50% aq.
Water
50% aq.
50% aq.
Water
50% aq.
80% aq.
80% aq.
ethanol
ethanol
ethanol
ethanol
ethanol
dioxane
dioxane
Source
Biichel and Draber
Boyer, 1961
Biichel and Draber
Boyer, 1961
Biichel and Draber
Bvichel and Draber
Boyer, 1961
Buchel and Draber
Ciba-Geigy Corp. ,
Ciba-Geigy Corp. ,
, 1969
, 1969
, 1969
, 1969
, 1969
1972
1972
-------
3. Oxidation
The triazole ring is extremely resistant to oxidation (Sherwin-
Williams Co., undated). The benzene ring is relatively stable, but will undergo
oxidation under strenuous conditions:
HOOC
N
Alkyl substituents, if present, are oxidized in preference to the aromatic ring.
Thus, for tolyltriazole:
COOH
'Benzotriazole will undergo substitution rather than oxidation in the presence
of certain strong oxidizing agents:
N NaOCl
N'
The pure solid 1-chlorobenzotriazole is considered an unstable compound, known
to have burst into flame while being packaged (Hopps, 1971).
39
-------
Because of their resistance to oxidation under environmental
conditions, benzotriazoles placed in the environment, by whatever means, are
likely to persist for long periods of time.
4. Photochemistry
Considering that benzotriazoles generally exhibit broad ultra-
violet absorption (see Section I-A-3), the compounds which are the main concern
of this work are, on the whole, remarkably stable to ultraviolet radiation,
particularly at wavelengths encountered at the surface of the earth (300-400 nm).
Nevertheless, benzotriazole and especially 1- and 2-substituted derivatives have
been shown to rearrange and decompose if irradiated under certain laboratory
conditions. These reactions and a theoretical explanation for the photochemical
stability of the 2-(2'-hydroxyphenyl)-benzotriazoles are discussed below.
Irradiation in methanol at 300 nm transforms benzotriazole and
certain of its 1-substituted derivatives into aniline and aniline derivatives,
due to loss of nitrogen from the triazole ring and reaction with the solvent
(Boyer and Selvarajan, 1969) :
OCR,
CH,
CH,, CH
\/ 3
N NH
N CH.qOH, hv^
-N2
OCH,
(trace)
40
-------
hv
(carbazole)
The low yield o-anisidine product results from using methanol as the solvent.
In benzene, the sole product is phenylaniline; in acetonitrile or cyclohexane,
the sole product is aniline (Tsujimoto et_ al. , 1972):
or
Either an electron delocalized intermediate or a benzoazirine,
N-R
is believed to be the intermediate for these reactions. Similarly, benzotria-
zoles with 1-pyridyl and similar substituents produce mainly carbazole-like
products on irradiation in ethanol with a high pressure mercury arc lamp
(Hubert, 1969):
41
-------
hv
1-(2-pyridyl)-benzotriazole
N
hv
hv
After four hours exposure to a 200 watt high pressure mercury arc lamp surrounded
by a quartz filter (allows passage of 254 nm light), 1-benzylbenzotriazole pro-
duces the following products in solvent-dependent reactions (Tsujimoto et^ ad. , 1972)
42
-------
These products are quite different from the main product of thermal decomposi-
tion of 1-benzylbenzotriazole, which is phenanthridine. Like 1-benzylbenzotria-
zole, 1-benzoylbenzotriazole also gives quite different products under conditions
of thermal and photolytic degradation (Tsujimoto et^ al^. , 1972):
-------
A
A summary of the products formed'during the photolytic decomposition of
1-benzylbenzotriazole at 300 nm in various solvents (Serve" and Rosenberg, 1973)
is listed in Table 9, which also lists the decomposition products of photolysis
of 1-hydroxybenzotriazole and 1-methoxybenzotriazole at 300 nm in various
solvents (Serve', 1974 a, 1974 b).
From the foregoing examples, it can be seen that the photolysis
of 1-substituted benzotriazoles leads to the expulsion of nitrogen. This is
accompanied by the generation of diradicals which are stabilized through intro-
molecular chemical reactions or reaction with the solvent (Servfi and Rosenberg,
1973). In spite of the amount of attention these compounds have received in
photochemical studies, it appears that 1-substltuted benzotriazoles are not
particularly important commercial materials.
44
-------
Table 9. Photolysis Products of 1-Substituted Benzotriazoles at 300 nm in Various Solvents, % Yields
(Serve" and Rosenberg, 1973; Serve, 1974 a, 1974 b)
-p-
Ui
Product
Phenanthridine
Ben zylidineani line
Bibenzyl
Benzot riazole
N-Benzy 1-2-aminophenyl
Ant line
Benzylanillne
b-Anisidine
N - Ben zy laniline
o- Me thoxy-N-benzy laniline
1-Me thy Ibenzot riazole
Aniline
Benzot riazole
Azobenzene
In Benzene
2
1
4
2
80
13
63
In Methanol
1
42
3
3
15
5
13
5
2
9
4
9
61
In Acetonitrile In Cyclohexane In Water In Dioxane
1-Benzy Ibenzot riazole
1
69
10
2
8
2
1-Me th oxyben zo t ri a zo le
6 15
8 4
28
81 11
2-Aminobiphenyl
B Lpheny1
Bicyclohexy1
N-Cyclohexylaniline
Nit rosobenzene
Azobenzene
Diphenylamine
2-Hydroxyazobenzene
Azoxybenzene
1-Hydroxybenzot riazole
67
6
6
45
11
10
13
18
-------
The 2-(2'-hydroxyphenyl)-benzotriazoles, with intramolecular
hydrogen bonds, have low quantum yields in photochemical reactions (Otterstedt,
1973). The hydrogen bond can induce rearrangement of the molecular structure
in the first excited state. The rearrangement, from enol to keto tautomeric
forms, facilitates return to the ground state, thus providing a high degree of
photostability for these compounds. The following equation illustrates the
conversion of light into heat via an enol-keto-enol rearrangement (Tozzi, 1974) :
hv +
H — 0
+ kT
Self-consistent-field linear-combination-of-atomic-orbitals molecular orbital
calculations (Otterstedt, 1973) indicate that the energy difference between
the first excited state and the ground state is smaller in the keto form than
in the enol form. Thus, conversion to the keto form in the first excited
state provides a pathway for rapid nondestructive reversion to the ground
state, and accounts for the photochemical stability of the Tinuvin compounds.
5. Other Chemistry
Some reactions which are of interest because of their potential
environmental and/or toxicological impact include halogenation, nitration, and
hetero-ring cleavage and rearrangement.
46
-------
Both chlorination and bromination of the benzene ring will take
place under the following strongly acidic, high temperature conditions:
Br
Br,,
Br2, HN03
reflux 1/2 hr.
aqua regia
3 hr. reflux
Because of the strenuous conditions required to completely halogenate the
benzene ring, it is not likely these reactions will take place, for example,
in a water processing or purifying plant where benzotriazole is present in
the water either'from external sources or from the use of anticorrosives on
the machinery in the plant. Monohalogenation possibly occurs under somewhat
milder conditions. Halogenation of the benzene ring increases the acidity
of the hydrogen on the //I nitrogen atom (see Table 8).
Nitration is achieved by reacting benzotriazole with nitric acid;
HMO 3,
47
-------
A rare and interesting cleavage and rearrangement of the triazole
ring occurs when benzotriazole is reacted with thionyl chloride. The product is
1-(2-benzothiazolyl)-benzotriazole:
dioxane
-N2
-2C1
N
48
-------
II. Environmental Exposure Factors
A. Production, Consumption
1. Quantity Produced
There are currently only five manufacturers of benzotriazole
compounds in the U.S.A. Three of these produce benzotriazole itself. The
remainder of the benzotriazole product line of each producer is unique. It
would be relatively easy to trace production figures on the latter compounds to
specific companies, were such figures available. Consequently, it is not
surprising that production figures are not to be found in the literature ex-
amined, and the major companies involved are reluctant to discuss them. Never-
theless, based on information supplied in part by manufacturers and in accord-
ance with the applications of these products, broad general statements can be
made about production quantities of these materials. Even if vague, such
statements are useful because they allow a better assessment of the potential
environmental effects of these materials than would be possible without any
figures at all.
The total production of benzotriazoles in this country probably
ranges from about 4-10 million pounds per year, with 5-6 million pounds a most
likely figure. The majority of this production is for the anticorrosion market.
The Tinuvins account for perhaps 20-30% of production. Photographic uses
consume roughly 200,000 pounds per year. 1-Chlorobenzotriazole is manufactured
principally for use as a reagent chemical (it is an oxidizing agent) and is
produced in quantities of about half a dozen pounds annually.
2. Producers
Table 10 lists the producers and production sites of benzotria-
zoles of commercial interest. Table 11 shows import data for Tinuvin compounds
49
-------
Table 10. Producers and Production Sites of Benzotriazoles
Producer
Chemicals
Sherwin-Williams Chemical Company
501 Murray Road
St. Bernard, Ohio A5217
IH-benzotriazole*
monomethylbenzotriazoles (isomeric mixtures)*
sodium tolyItriazole (aqueous solution of methyl benzotriazole isomers)
Fairmount Chemical Company
117 Blanchard Street
Newark, New Jersey 07105
IH-benzotriazole
5-ch lor o-IH-benzotriazole
5-me thy 1-IH-benzotriazole
Ui
O
Eastman Kodak Company
343 State Street
Rochester, New York 146-50
IH-benzotriazole
5-methyl-IH-benzotriazole
silver benzotriazole
Parish Chemical Company
815 West Columbia Lane
Provo, Utah 84601
1-chlorobenzotriazole
Ciba-Geigy Corporation
Polymer Additives Department
Ardsley, New York 10502
2-(2'-hydroxy-5'-methylphenyl)-benzotriazole (Tinuvin P)
2-(3' ,5'-di-_t-butyl-2'-hydroxyphenyl)-benzotriazole (Tinuvin 320)
2- (3' -_t-buty 1-2'-hydroxy-5' -methy Iphenyl)-benzotriazole (Tinuvin 326)
2-(3' ,5'-di-_t-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole (Tinuvin 327)
2-(3' ,5'-di-_t-pentyl-2t-hydroxyphenyl)-benzotriazole (Tinuvin 328)
35-50% isopropanol solutions of these chemicals are also produced.
-------
Table 11. Imports of Tinuvin Compounds (pounds) (U.S. International Trade
Commission)
Tinuvin 1970 1971 1972 1973 1974
320 2,315 2,646 2,204 6,613 22,047
326 9,701 24,476
327 22,046 55,115
327, MB-30, ES 90,058
120 3,306
P 23,777
51
-------
over the last five years for which data is available. The general trend shown
in the table is towards importing increasing amounts of these compounds.
3. Production Methods and Processes
Benzotriazole may be prepared on an industrial scale with yields
up to 95% of theory according to the method of Levy (1966) by dissolving a
quantity of 1,2-diaminobenzene (o-phenylenediamine) in water, acidifying with
acetic acid (HAc), heating to 50-100°C and, while at this temperature, adding a
sodium nitrite solution over a period of 0.5-2.0 hours, then continuing heating
for a further period of time. The salt reacts with the acid to form nitrous
acid which in turn reacts with the 1,2-diaminobenzene to form o-aminophenyl-
diazonium acetate which cyclizes to benzotriazole (see Section I-A-5). All
reagents are added in stoichiometric quantities. The product may be extracted
with a water-insoluble alcohol (butanols, heptanols, hexanols, etc.) and the
extracted product recovered by solvent evaporation under reduced pressure.
The product at this point is of relatively high purity, but may be further
purified, if necessary, by recrystallization from a different solvent, such
as benzene.
The main drawback to the above process is the solvent extraction
step, without which the product is crude and must be cleaned up considerably,
especially for photographic applications. The production of a high purity
product without the need for the solvent extraction step (an expensive and
time-consuming process on the industrial scale) is achieved by the method of
Long (.1971) (see Figure 6) wherein the pH of the reaction mixture is carefully
controlled, initially to between 1.0-5.3 and after completion of the diazoti-
zation to 5.0-6.0. The benzotriazole oil which forms is separated from the
52
-------
NaNO2 MAC
It I
Diazotization
at 50 - 100°C
( adjust pH to 1 - 5.8 with HCI ]
After completion of reaction adjust pH to 5.0 — 6.0
with Na-benzotriazole solution and NaOH.
Hold 30 min. @ 50 - 110° C.
Crude Benzotriazole Oil
Holding Tank
Waste
Water
Water-Wash Column
Water Stripper
Condensed
Water
Continuous Still
Still
Residue
Solidification Belt
Pure Benzotriazole
to Packaging
Periodic
Processing
Extraction With
Water-Insoluble Alcohol
Alcohol
Quantitative Extraction
With 10% NaOH
Steam Distillation
to Remove Alcohol
Sodium
Benzotriazole
Solution
Water
- Layer
Discarded
Vapors
Discarded
Figure 6. Commercial Preparation of Benzotriazole According to the Method of
Long (1971)
53
-------
reaction mixture and placed in a holding tank from which it is pumped through
a column where it is washed with water. (The wash water goes back into the
crude oil holding tank to prevent loss of the benzotriazole dissolved in it.)
The washed oil is then stripped of water at IZS-ISO'C and 80-100 torr. (The
distillate is condensed and also returned to the holding tank to avoid loss of
benzotriazole with the water.) The dry oil is then fed into a continuous still
at 155-175°C and 3-5 torr. (The still residue is returned to the holding tank.)
The distilled benzotriazole is condensed onto a stainless steel belt in a thin
film. The solidified sheet is ground and packaged. Meanwhile, the remaining
material in the holding tank is periodically processed prior to combination
with the next batch of crude benzotriazole oil from the diazotization step.
The processing involves filtering, discarding the solid waste, extraction of
the benzotriazole with 2-ethylhexanol or similar water-insoluble alcohol (the
aqueous layer is discarded), and quantitative extraction of the benzotriazole
from the alcohol into a stoichiometric quantity + 10% of a 10% aqueous NaOH
solution. The sodium salt which forms is soluble in water, but insoluble in
the alcohol. The alcohol is removed by physical separation, then sufficient
steam distillation is used to remove the remaining alcohol. The aqueous sodium
benzotriazole solution is added to the reaction mixture containing crude benzo-
triazole. The overall yield of the process is 97% and the purity, measured
colorimetrically, easily exceeds "photograde" specifications. Figure 6 outlines
the steps of this process, which clearly are adaptable to the economics of a
large scale, continuous, industrial process. It should also be obvious that
the process is adaptable to the manufacture of various derivatives of benzotria-
zole. For example, starting with l,2-diamino-3-methylbenzene instead of 1,2-
diaminobenzene would yield a product mixture of 4- and 7-methylbenzotriazole.
54
-------
The method of Long described above is likely the major industrial
manufacturing method currently in use in the U.S.A. because a patent on it is
held by the major producer of benzotriazoles, Sherwin-Williams Chemical Company.
There are, however, other techniques described in both the patent and chemical
literature for preparing benzotriazoles which may possibly be in use, especially
in smaller scale operations. These, and a scheme for production of Tinuvin-
type benzotriazoles, are discussed below.
Prior to the availability of the Long (1971) method for producing
benzotriazoles, various procedures were in use to purify the crude diazotization
product. These may still be used where access to the Sherwin-Williams technology
is not available. One such method employs activated charcoal to remove colored
impurities from the benzotriazole (Miller and Schlaudecker, 1958; Geigy Co. Ltd.,
1965). Prior to charcoal filtration, the crude benzotriazole is dissolved in
ethylene glycol or polyethylene glycol (McTeer and Kelso, 1972).
5-Substituted benzotriazoles can be prepared via diazotization
from starting materials such as:
and reduction of the intermediate with a Raney nickel catalyst (J.R. Geigy A.G.,
1965). A variety of R groups can thus be introduced to the benzotriazole mole-
cular structure at the 5 position. If R is -N0_, it can be reduced in the
presence of a metal hydrogen catalyst to -NH . Acylation of -NH in turn can
yield an amide substituent. An -NH can be replaced with a chlorine atom by
heating in 1:1 HC1 with CuCl (Arient and Dvorak, 1956).
55
-------
Benzotriazoles substituted at the 6 position have been prepared
by the reduction of 1-hydroxybenzotriazoles with PX , where X is a halogen, alkoxy,
or phenoxy group (Randell and Hargreaves, 1970 a, b). 6-Substituted benzotria-
zoles have thereby been prepared where R is methyl, raethoxy, and chloro.
Triazinones have been converted into benzotriazoles in high
yield (Rees and Sale, 1971), but like the 1-hydroxy synthetic route above, this
is not a viable commercial method.
1-Aminoalkyl benzotriazoles have been prepared from benzotriazole
and dialkylaminoalkyl chlorides in basic solution (Sparatore and Pagani, 1962).
These are not of commercial interest, although they are of theoretical importance
because the products are invariably mixtures of 1- and 2-substituted isomers,
and the structure of the latter molecular type is still a matter of some debate
(see Section I-A-1).
A wide variety of benzotriazoles have been prepared by the re-
action of various organic azides with benzyne (Reynolds, 1964). 1-Substituted
benzotriazoles, especially aliphatic substitutions, have recently been of interest
because of their reported anti-inflammatory activity in rats (Kreutzberger and
Van der Goot, 1974). The only 1-substituted benzotriazole that is commercially
significant (in terms of monetary value of product manufactured) is 1-chloro-
benzotriazole. This material is produced by the reaction of benzotriazole and
NaOCl (see Section I-B-5). The reaction is rapid and quantitative; it probably
proceeds by a free radical mechanism (Rees and Storr, 1969).
Compounds of the Tinuvin type [2-(2'-hydroxyphenyl)-benzotriazoles]
may be prepared by coupling, under basic conditions and at room temperature, an
£-nitrobenzenediazonium chloride with an appropriate phenol (Boyle and Milionis,
56
-------
1965). A recent German patent (Herlinger and Kuester, 1975) describes the
preparation of Tinuvin type compounds via the following reaction scheme:
1.Diazotization
».NO 3-Cyclization with Zn-NaOH
2
COOH
1. Conversion to acid chloride
NH
2. Reaction with
N N
OH
C(CH3)3
4. Market Prices
Benzotriazole costs about $2.75/lb. in 100-pound lots of
technical material suitable for anticorrosion purposes. Photograde material
is a good deal more expensive at approximately $6-10/lb. on the same basis.
Photograde derivatives of benzotriazole are priced considerably higher, espe-
cially in small quantities. 1-Chlorobenzotriazole, for example, sells for
$30/100 grams or about $150/lb. (see also Anon., 1975; Anon., 1976).
Prices for Tinuvins are slightly higher than for other benzo-
triazoles made on a large scale, but price comparisons are not particularly
meaningful since Tinuvins and other benzotriazoles are not competitive with
each other.
Complete price listings are given in Table 12.
57
-------
Table 12. Prices of Benzotriazole Compounds
00
Chemical
Benzotriazole (technical) (Cobratec 99)
Benzotriazole (50% in isopropanol) (Cobratec 50-1)
Benzotriazole (technical)
Benzotriazole (practical)
Benzotriazole (photograde)
Benzotriazole (photograde)
Benzotriazole (photograde)
Tolyltriazole (technical) (Cobratec TT-100)
Tolyltriazole (35% in isopropanol) (Cobratec TT-35-I)
Tolyltriazole, sodium salt (50% aq.) (Cobratec TT-50-S)
5-Methylbenzotriazole (photograde)
Silver benzotriazole (photograde)
Tinuvin P '
Tinuvin 3201"
Tinuvin 326f
Tinuvin 327f
Tinuvin 32 8f
Basis
200 Ibs.
400 Ibs.
100 Ibs.
500 gms.
100 Ibs.
100 Ibs.
1 Ib.
200 Ibs.
400 Ibs.
500 Ibs.
1 Ib.
5 gms.
100 Ibs.11
100 Ibs.11
100 -Ibs.11
100 Ibs.11
100 Ibs.11
Price (Ib.)
2.80
1.60
"-3
51.04
5.50
-W
26.00
1.93
.95
.97
55.55
3300.00
6.35
6.35
8.50
6.75
6.95
Effective
Date
2/76
2/76
1/76
1/76
2/76
1/76
1/76
2/76
2/76
2/76
1/76
1/76
8/74
8/74
8/74
8/74
8/74
Manufacturer
Sherwin-Williams
Sherwin-Williams
2
Fairmount
Eastman Kodak
Sherwin-Williams
2
Fairmount
*Eastman Kodak
Sherwin-Williams
Sherwin-Williams
1
Sherwin-Williams
4
Eastman Kodak
Eastman Kodak
Ciba-Geigy
5Ciba-Geigy
Ciba-Geigy
Ciba-Geigy
Ciba-Geigy
*Available in smaller quantities at higher per pound prices - see Anon., 1975.
HFor quantities 25-100 Ibs., prices are about 5% higher; for less than 25 Ibs., about 10% higher.
tSee Table 10 for chemical names of the Tinuvins.
Sources: 1. Sherwin-Williams Co., 1975; Anon., 1976 b
2. Personal Communication
3. Anon., 1976
4. Anon., 1975
5. Ciba-Geigy Corp., 1974
-------
Sherwin-Williams Company announced a 10% price increase effective
February 2, 1976 (Anon., 1976 b), which is reflected in Table 11. Prices for
small quantities from Eastman Kodak have decreased significantly (approximately
halved) over the period 1974-1976 (Anon., 1974; Anon., 1976). The Kodak prod-
ucts, however, represent a very small part of the total benzotriazole market.
5. Market Trends
The trend appears to be towards increased production, especially
in the dominant application, anticorrosion. Sherwin-Williams is doubling its
capacity to produce benzotriazole and tolytriazole over the period 1976-1978
(Anon., 1976 a), which indicates the company's confidence in this market. If
there is growth in the production of plastics which require the use of UV
absorbers (polyolefins, for example), and photographic films, coupled with
continued use of benzotriazoles in these products at present concentrations,
total production of benzotriazoles could grow as high as 15-20 million pounds
per year in the 1980's.
B. Uses
1. Major Uses
The major commercial applications of benzotriazoles are, in
estimated order of quantity used: as an anticorrosion agent (particularly for
copper and copper alloys); as an ultraviolet light stabilizer for plastics
(especially polyolefins); and as an antifoggant in photography. Each of these:
major use categories is considered in turn below. Although photographic
applications may consume a relatively small share of benzotriazoles, they are
grouped with major uses because: 1) they represent a steady, well-established,
and growing market for these chemicals; 2) there is an extensive literature
(both chemical
59
-------
and photographic) on these applications; and 3) the quantity of benzotriazoles
consumed in photography is probably much larger than all of the minor uses in
Table 15 (p. 82) put together.
a. Anticorrosion Applications
The theoretical work of Dugdale and Cotton (1963), Cotton
and Scholes (1967), and others (see Section I-B-1) on the mechanism of corrosion
inhibition of benzotriazoles was preceded by many years of practical experience
with benzotriazoles in anticorrosion applications. By the late 1950's the
principal anticorrosion applications of benzotriazoles had been well-established.
Benzotriazole was included in glycol-based antifreeze formulations in concen-
trations of 0.01-2.0% (Meighen, 1957), used for inhibiting corrosion of water
pipe systems made of iron, copper, or their alloys in concentrations of 0.05%
(Liddell and Birdeye, 1958), and also for inhibiting corrosion in hot water
boilers in concentrations of 0.01-0.20% (Krietsch, 1958). In all of these
applications, benzotriazole is used with other inhibitors. In the last case,
for example, 1-2% triethanolamine phosphate is also present. Combinations of
benzotriazole with nitrites and berates have been recommended (Liddell, 1959).
In such formulations benzotriazole was found to be a more effective inhibitor
than equivalent concentrations of thiocyanate ion or 2-mercaptobenzothiazole
(Kendall et_ al. , 1959) .
Antifreeze applications have been the subject of a number
of patents, a typical example of which is illustrated by the recipe given in
Table 13 for a glycol-based antifreeze which provides good protection for the
metals customarily found in cooling systems, with outstanding protection for
brass (Weichert and Hegemann, 1965).
60
-------
Table 13. Typical Glycol-Based Antifreeze Anticorrosion Components
(Weicher and Hegemann, 1965)
Inhibitor Content, %, based on glycol
Sodium benzoate 1.50 - 3.00
Sodium benzotriazole 1.50-3.00
Borax 0.50 - 1.50
Sodium nitrite 0.50 - 1.50
Sodium carbonate 0.10 - 0.20
Benzotriazole 0.05 - 0.15
Sodium metasilicate 0.02 - 0.10
N-Methylmorpholine 0.01 - 0.10
Benzotriazoles can often replace sodium 2-mercaptobenzo-
thiazole (NaMBT) on a cost-performance basis in glycol-type antifreezes. In
one case 0.05-0.15% by weight benzotriazole was shown to give equivalent
protection to 0.25% NaMBT when all other variables were held constant (Anon.,
undated). Not only does benzotriazole provide similar protection for copper,
brass, bronze, cast iron, and steel components of automobile radiators, but it
also provides superior thermal stability, chemical stability, stability to
ultraviolet radiation, resistance to oxidation, a protective film which in-
creases its protection with time, and lower toxicity than NaMBT (Anon., un-
dated). The following examples illustrate some of these comparisons. In the
presence of antialgal and antislime coolant additives, such as Chloramine-T,
benzotriazole is stable, but NaMBT is destroyed by the released chlorine
(Hatch, 1960; Albright and Wilson, 1961). At an operating temperature of
61
-------
113°C for 1000 hours, the NaMBT content of an antifreeze was reduced by 88.5%,
whereas under the same conditions the benzotriazole concentration was reduced
by only 13.9% (Korpics, 1974 a). This data is shown graphically in Figure 7.
The mechanism by which
I O.IO-i
(D
I 0.09 -
0.08-
.5 0.07-
00
§ 0.06 -
o
.| 0.05 -
•5
< 0.04 -
0.03 -
0.02 -
0.01 -
0.0
2—Mercaptobenzothiazole
o
o
Tolyltriazole
200
400 600
Hours
800
1000
Figure 7. Automotive Antifreeze Thermal Stability Test-Depletion of Additive
(Korpics, 1974 a)
benzotriazole and sodium 2-mercaptobenzothiazole function as anticorrosion
agents is fundamentally different. Benzotriazole forms a polymeric film
(i.e., chemical bonds) on the surface of the metal, one or more layers of
which shield the underlying metal molecules from further chemical attack.
Sodium 2-mercapto-benzothiazole forms insoluble complex salts which coat the
metal surface, protecting it from further oxidation (Santodonato et a_l.,
1976), but which can be removed or disturbed by physical and chemical means
more easily than the polymer coating formed with benzotriazole.
62
-------
The stability of the metal-benzotriazole polymer coating
(particularly when the metal is copper) allows successful treatment for con-
tinuous protection of transient (as opposed to recirculating) water systems,
such as domestic copper water lines. Surfaces to be exposed to water are
degreased, washed with acid, then exposed to an isopropanol or water solution
of benzotriazole or benzotriazole vapors. Copper-containing specimens con-
tacted for two minutes at 60-100°C with 2% aqueous benzotriazole and dried at
60-90°C in the same vapor showed no pitting after three months in water that
caused severe pitting in untreated specimens (Cotton, 1963), in a demonstration
of the continuity of protection provided by benzotriazole.
Besides copper, benzotriazole is effective in protecting
steel and other metals against corrosion in acidic aqueous environments (Sath-
ianandhan ^t aJ., 1970). Derivatives of benzotriazole are effective as well.
For example, 1-hydroxybenzotriazoles have been used to inhibit corrosion in
boilers, coolers, and storage tanks (Tanaka and Tanigawa, 1974). Aluminum and
mild steel, as well as brass and copper, were protected in a closed water
system simulating a cooling tower by benzotriazole and triethanolamine mixtures
(Chemed Corp., 1975).
A combination of molybdates and benzotriazoles has inhibited
corrosion of brass/steel systems more effectively than the single active com-
ponents used alone, and was significantly superior to 2-mercaptobenzothiazole,
especially at higher pH's (see Figure 8) (O'Neal and Borger, 1975). Similar
results are claimed in a study commissioned by the Sherwin-Williams Chemical
Company (Sherwin-Williams, undated a) in which the superiority of benzotriazole
over 2-mercaptobenzothiazole is demonstrated in a nitrite-borax inhibitor system
63
-------
D
to
1
100-1
80-
60-
o
z
uu
o
LLI
Z
o
co 40
I
20-
TT/MoOj
BT/MoO;
MBT/MoO;
i
7
\
8
i
9
PH
MBT/MoO
tolyltriazole + molybdate
1H — benzotriazole + molybdate
2 — mercaptobenzothiazole + molybdate
% Inhibition Efficiency = 100 x ( 1 -
weight loss inhibited sample
weight loss control
Figure 8. Effect of pH on Percent Inhibition Efficiency for Steel in Simulated
Cooling Water (O'Neal and Borger, 1975)
-------
at pH 8.5. At pH 8, benzotriazoles teamed with lhydroxyethylidene-l,l-diphos-
phoric acid (HEDP, marketed by Monsanto Co. under the tradename Bequest) out-
perform triazolemolybdate combinations, especially with respect to the protec-
tion of steel (O'Neal and Borger, 1975).
An example of a specific application of benzotriazole for
inhibition in a water-cooled stator in a power plant has been described by
Wall and Davies (1965). One problem encountered with corrosion in such situa-
tions is that it leads to an increase in conductivity of the water, which in-
creases the risk of energy losses and flashovers (sparks) since the stator and
heat exchanger are approximately 7,000 volts apart in potential. It was con-
cluded that the rate of increase of conductivity of the cooling water was reduced
with the use of benzotriazole, thus increasing usage periods between system
flushing. Also, 20-100 ppm of benzotriazole in the cooling water eliminated
the need for a costly demineralizer system. In another study concerning the
use of benzotriazole in a closed water cooling system, Hoyer et al. (1968)
concluded that benzotriazole reduced corrosion in a high energy particle accel-
erator, the inhibiting effect manifesting itself as an apparent reduction in
the available copper surface area.
Benzotriazole is incorporated into wax and polishing
formulas designed for cleaning and protecting copper and other metals. Con-
centrations of 0.1-10% benzotriazole dissolved in the wax or polish or added
in a solvent proved effective in protecting copper sheets exposed 24 hours to
a 0.25% salt solution mist which badly stained unprotected samples (Cotton,
1964). Typical concentrations of benzotriazole in these formulations are 0.1-1.0%
(Geigy A.G., 1965 a). Chromium plated steel can be protected by the same for-
mulations (Cotton, 1965). It is likely that benzotriazole is in polishes and
cleansers currently marketed for chrome plated automobile parts as well as body
waxes.
65
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Machined and fabricated parts of copper or copper alloys
manufactured for later assembly are effectively protected against staining and
corrosion in storage and transportation by enclosure in tissue paper, kraft
paper, or paperboard containing 2% benzotriazole or tolyltriazole by weight
(Korpics, 1974 b). This "vapor phase" protection is possible because of the
appreciable vapor pressure of these benzotriazoles under ambient conditons.
Tissue paper is impregnated by spraying with a 1% isopropanol solution. Paper-
board is impregnated so that the final concentration is about 0.2 gram benzotria-
zole per square inch. At these concentrations effective protection can be expec-
ted for more than one year in an industrial environment.
The natural color of copper suggests many decorative
architectural uses, particularly outdoors. In such applications the color can
be maintained for at least several years by coating the copper with a trans-
parent lacquer containing benzotriazole corrosion inhibitors. Incralac, a
finish developed by the copper industry, is an example of such a lacquer which
preserves copper and copper alloy architecture both outdoors and in (Anon.,
1969). Incralac contains an acrylic ester resin dissolved in a solvent such
as toluene, benzotriazole, and epoxidized soya bean oil as a leveling agent.
A UV absorber (such as Tinuvin) and an antioxidant are also added to prevent
breakdown of the lacquer under the influence of UV radiation. The final clean-
ing step prior to application of the lacquer consists of wiping the metal sur-
face with a solution containing 40 grams benzotriazole per gallon of water.
The 230,000 square foot geodesic dome copper roof of the Sport Palace in
Mexico City erected for the 1968 Olympics is an example of an outdoor structure
protected by Incralac (Anon., undated). One limitation of Incralac is that
66
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the coating is rather soft. Therefore, for handrails and other items subject
to wear and/or physical abuse, coatings have been developed based on polyure-
thanes containing 1.5% benzotriazoles (Walker, 1970).
There are a number of other film-forming products which
contain 0.05-1.0% benzotriazoles to prevent discoloration. These include bronze-
pigmented paints, inks, and lacquers (Aiken et_ aL. , 1965; Keino and Nakato, 1972).
In addition to protecting newly manufactured articles, benzotriazole is used
to protect restored ancient bronze objects. After cleaning, vacuum impregna-
tion and the use of lacquers are the chief methods of applying the inhibitor
(Madsen, 1971; Marabelli and Guidobaldi, 1972).
Benzotriazoles are added to lubricants, greases, and
dielectric oils to prevent them from attacking metals in contact with them.
For example, organosiloxane greases useful as lubricants, dielectrics, and
sealing compounds are made less corrosive to copper and steel by the addition
of 0.02-0.06% benzotriazole (Midland Silicones Ltd., 1959). Greases thickened
with organophilic bentonite are rust-inhibited by the addition of less than
0.5% by weight benzotriazole (Donaldson et aJL , 1965). Lubricating oils are
protected against oxidation by the addition of benzotriazole (Malec, 1975).
Hydraulic fluid consisting of a mixture of polyglycol ethers and vegetable oils
is effectively prevented from chemical interaction with rubber and metal parts
of hydraulic systems by the addition of ^0.25% benzotriazole (Stein, 1961).
Sulfur containing insulating oils (dielectrics) are inhibited from attacking
copper without influencing the efficiency of the electrical apparatus by the
addition of 1-50 grams of benzotriazole per kiloliter of oil (Fugita, 1974).
A copper sheet dipped into inhibited oil containing 0.22% sulfur reacted with
67
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1.4 yg of sulfur when 30 kilovolts electromotive force was applied, whereas
13.9 yg of sulfur was consumed from uninhibited oil.
t
Finally, benzotriazoles are used in anticorrosion applica-
tions in both aqueous and nonaqueous cleaning systems. Dry cleaning solvents
(such as chlorinated hydrocarbons and petroleum naphthas) and detergents (such
as petroleum sulfonates, alkylamine sulfonates, aryl phosphates, and benzene
sulfonates) cause corrosion of the metals in the cleaning machines, especially
copper, which results in discoloration of the cleaning fluid and the possibility
of staining light colored clothing. Corrosion can be prevented by the initial
addition of 10-250 ppm benzotriazole or alkylbenzotriazole to the solvent-
detergent system. As long as at least 10 ppm benzotriazole are maintained in
the system, corrosion is prevented (Levy et^ al., 1967). Benzotriazole and
alkylbenzotriazoles have also been recommended in the formulation of dishwater
detergents (Ciba-Geigy, 1972 a). Approximately 0.05% benzotriazoles prevents
the corrosion of copper and metal parts of the washing machine, and inhibits
tarnishing of metal pots and silverware by other detergent ingredients.
•
b. Ultraviolet Stabilization Applications
A number of polymers, especially certain polyolefin plastics,
some oils, and various paint pigments which are subject to degradation upon
exposure to ultraviolet light are protected from the consequent undesirable
physical changes which ensue by incorporation of ultraviolet stabilizers, such
as benzotriazoles. Benzotriazole stabilizers absorb incident ultraviolet radia-
tion and dissipate it harmlessly as heat. The discussion below includes specific
examples of the kinds of materials which have been successfully stabilized against
UV degradation by benzotriazoles. It is interesting to note that this applica-
tion is not restricted to 2-(2'-hydroxyphenyl)-benzotriazoles (Tinuvin type).
68
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Although the Tinuvins are better UV absorbers than most other benzotriazole
derivatives, the simpler structures are often quite adequate for some applica-
tions.
One of the most widely used plastics stabilized with benzo-
triazoles is polypropylene. Tinuvin type compounds are usually used, generally
in combination with other UV absorbers (Cantatore and Sordini, 1963; Compostella,
1964) and antioxidants (Balaban, 1964). Other plastics and polymeric materials
which have been protected with benzotriazoles include polyesters (Yamaguchi et al.,
1975), cellulose acetate, nylons, polyvinyl chloride, and polymethyl methacrylate
(Heller et al., 1961). Plastics pigmented with titanium dioxide have improved
ultraviolet stability when a 2-(2'-hydroxyphenyl)-benzotriazole is included in
the formulation (Zannucci et_ a^L. , 1975). Plastics intended to be light-degradable
have been insured stability while still in service by means of a water soluble
coating containing a Tinuvin type compound. Upon discarding the container,
the coating is readily washed away, leaving the plastic subject to rapid degrada-
tion by light (Fischer, 1973). Such an external coating also has the advantage
of avoiding the possibility of migration of the stabilizer into the original
contents of the container. This is very important when such contents are food
products. The Food and Drug Administration has set the maximum concentration
of 2-(2'-hydroxyphenyl)-benzotriazoles at 0.25% in polystyrene and/or rubber
modified polymers intended to contact nonalcoholic food (Anon., 1972).
Degradation of polypropylene is catalyzed by copper. Con-
sequently, copper electrical wires with polypropylene insulation have presented
a special problem, since unprotected wiring exposed to sunlight and copper de-
grades quite rapidly (Hansen et^ al., 1965). Benzotriazoles have been among the
69
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most successful stabilizers in retarding both the interaction of ultraviolet
light with the polypropylene insulation and also the copper wire with the
polypropylene (Hansen, 1968). Benzotriazoles thus used include the parent
compound and the 5-chloro, 5-methyl, 5-nitro, and 5,6-dimethyl derivatives
with and without antioxidants. In an application where copper sheets were
laminated on both sides with polyethylene, the polymer was protected from
catalytic degradation by incorporation of zinc benzotriazole and lead benzo-
triazole salts into the polymer matrix (Kuroha et al., 1975).
Besides clear polymer coatings', some paint and varnish
coloring matter is also stabilized by benzotriazoles. For example, the dis-
coloration of nitrophenol azo dyes in varnishes due to contact with iron in
the presence of small amounts of water is prevented by including 0.005-0.2%
by weight benzotriazole in the formulation (Werner and Langstroth, 1958).
Treating a red pyrazolone pigment with a chlorobenzotriazole (probably 5-
chlorobenzotriazole) stabilizes it when used as a polymer dye (Kriisa, 1970).
Benzotriazole has also been used to stabilize oils used
as solvents for fungicides intended for tropical and semitropical crops, in-
cluding citrus fruit, bananas, cacao, and coffee. Ultraviolet radiation cata-
lyzes the oxidation of the solvent oils, resulting in the formation of acids
and perioxides which are toxic to the plants and cause almost as severe a crop
loss as the fungi the spray is supposed to control. The addition of benzotria-
zole to the oil (antioxidants can be substituted as well) protects the
oil from oxidation and prevents crop losses from that source (Harrison, 1963).
In other biocontrol applications, Tinuvin products have been used to stabilize
an insecticide which inhibits larval development (Letchworth and Pallos, 1972),
70
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for photostabilization of insect moulting hormones (Ferrari et al., 1973) , and
for the protection of silk fibres from photodegradation (Kuwahara ejt al. , 1974).
Tinuvin compounds have also been used in suntan lotions,
ostensibly to reduce the level of ultraviolet light absorbed by the human skin
(Heller et al., 1961).
c. Photographic Applications
Benzotriazoles are well-known antifoggants which are present
in small quantities in the emulsions of many photographic products. They are
effective for the same purpose in photographic developers, although they are
not found in the standard formulas used for general amateur and professional
photofinishing. Benzotriazoles are also used in a variety of other photographic
applications including monobaths, heat sensitive copying, and dye diffusion
processes (as typified by Polaroid Land products). Most of the information
on these various uses is available in the patent literature, and it is there-
fore not possible to be certain that currently marketed processes conform
exactly to these descriptions. However, the examples below were chosen because
they appear to be relevant to presently available products.
The diversity of benzotriazole derivatives useful as anti-
foggants is exemplified by an Ilford Ltd. patent (Brown et al., 1971) which
describes at least two dozen benzotriazoles which are useful as antifoggants
for X-ray film at concentrations of 330 mg/g-mole silver halide in the emulsion.
Image (optical) densities of fog value 0.04 are obtained with 4-nitro-5-methyl-
IH-benzotriazole in the emulsion as compared to 0.35 fog density without the
antifoggant. Also, the contrast range of the emulsion with the antifoggant is
about 20% greater than the contrast range without the antifoggant. A General
Aniline and Film Corp. patent (Popeck and Sottysiak, 1959) describes the use
71
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of 5-nitro-lH-benzotriazole in a paper emulsion. The benzotriazole is incor-
porated into the emulsion (250 mg/100 gm AgNO ) and also into a protective
gelatin overcoating (30 mg/kg gelatin), yielding a fog-free image resistant to
fading or aging. Fuji Photo Film Co. (Ohkubo j2t a±., 1971) reports that 5-bromo
and 5-methylbenzotriazoles in paper emulsions in concentrations of approximately
-5-3 +
10 - 10 mole/mole Ag , produce low fog, high density, high contrast images.
The presence of IH-benzotriazole in paper emulsions tends
to result in a "cold" image tone; the image is often described as "blue-black"
rather than "neutral-black" (John and Field, 1963). Velox and Velox Premier
papers manufactured by Eastman Kodak Company, widely used in large mass pro-
duction commercial photofinishing operations, are examples of well-known blue-
black emulsions which almost certainly contain benzotriazole. Tone differences
between blue-black and neutral-black emulsions processed in the same developer
are subtle; emulsion tone can be widely varied, however, by length of exposure,
chemical composition of the developer, and the use of chemical toning processes.
There is no indication that benzotriazole in developers or toners affects emul-
sion tone. However, when benzotriazole and l-phenyl-5-mercaptotetrazole are
incorporated into a cover layer (but not the emulsion layer), the resulting
paper print image is resistant to changes in image tone produced by high gloss
heating (drying), methods typical of mass photofinishing (Gaffin, 1970).
Antifoggants usually reduce effective film speed by their
restraining action on the developer. However, the effect of benzotriazoles on
film speed seems to be variable. Silver benzotriazole appears to reduce emul-
sion speed (Faerman and Pletnev, 1957), but 1-methylbenzotriazole is said to
increase emulsion speed (Sturm and Kralove, 1961).
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Benzotriazole is occasionally added to standard developer
formulas when films or papers tend to show fog from excessive age, unfavorable
storage conditions, or when long periods of time have elapsed between exposure
and development (Anon., 1973). While this is a commonly cited use in black
and white photography, it probably accounts for an insignificant quantity of
the benzotriazole used in photography. The only regular employment of benzo-
triazole in processing solutions in the available literature is in monobath
formulations such as Speers (1974). A monobath is a solution which develops
and fixes film in one step. The developing agent must be of high activity and
the silver ion solvent of relatively low activity. Although useful in certain
extremely urgent applications or recording instrument data readouts, films
processed in monobaths usually lack characteristics desirable in general photog-
raphy, such as fine grain, high acutance, and good shadow detail.
Although less sensitive to light than silver halides, silver
benzotriazole in combination with silver halides is adaptable to certain photo-
copying techniques. It is used in a heat-developable copy system in which the
light sensitive material is developed, after exposure, by heating for 10 seconds
at 160°C. Once developed, the copies are stable to further exposure to light
e>
(Ohkubo et^ al. , 1972). A similar material containing silver 5-chloro-lK[-benzo-
triazole is light insensitive until heating for 5 seconds at 180°C, then may
be exposed as usual and developed by further heating for 5 seconds at 200°C
to yield a brown positive image (Takekawa et^ al_. , 1973). Benzotriazole
has also been used in a non-silver thermographic duplicating process developed
by Minnesota Mining and Manufacturing Co. (1966), but has not become as popular
as the xerographic (electrostatic) processes of Xerox Corp. or IBM Corp. because
it has not been able to compete in terms of clarity and stability of image, time,
and cost. -,.,
-------
Besides being used for document copying, benzotriazole can
be used in processes for rendering documents and microfilms duplication-proof.
Most microfilm copying systems use photosensitive materials that are mainly
sensitive to light in the blue and ultraviolet range, but practically not at
all to green or red. Therefore, the incorporation of an ultraviolet absorbing
2-(2'-hydroxyphenyl)-benzotriazole compound into the emulsion or base of a
microfilm, for example, makes the film opaque to the light to which the copy
material is most sensitive, making it difficult or impossible to achieve clear
copies. At the same time, the benzotriazole-containing base transmits light
visible to the human eye, and so the treated microfilm is as suitable for view-
ing or projection as untreated microfilm (Buckley and Coffee, 1973).
In an Eastman Kodak patent describing silver halide sensi-
tive copper printing plates, 4-nitro-6-chloro-lH-benzotriazole is included in
the emulsion recipe. The presence of benzotriazole in the developer is said
to improve adhesion of the relief image (Abbott, 1969). The extent of the
use of benzotriazoles in photographic printing plate processes is not known.
A final likely application of benzotriazoles to black and
white photography is in stabilization processing in making prints. Stabiliza-
tion processing employs special photographic paper which has developing agents
incorporated into the emulsion during manufacture. The exposed paper is pro-
cessed by inserting it into a machine. In the machine the emulsion of the paper
is coated with a high pH "activator" solution which causes rapid uniform develop-
ment of the image. The paper is then immersed in a low pH "stabilizer" solution,
is squeegeed, and emerges from the machine practically dry, stable to light, and
ready for immediate use. The whole process takes seconds compared to over an
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hour for processing, washing, and drying a conventional photographic paper.
However, because all of the residual silver halide and processing chemicals
have not been removed from the stabilized print, it eventually deteriorates.
Stabilized prints may be made permanently stable by the usual fixing and wash-
ing procedures any time within several months of development (before fading
and staining commence). Stabilization processing enjoys wide use wherever
speed and convenience are critical such as police work, medicine, journalism,
and professional studio proofing, especially when a permanent print is not
necessary. It may eventually become a very significant factor in the home
darkroom market since small processing machines costing as little as $150 are
available. According to Eastman Kodak Company (Anon., 1973 a), which manufac-
tures professional stabilization processing machines as well as paper and chemi-
cals, stabilization activator solutions probably contain less than 0.01% anti-
foggant, stabilizer solutions between 0.1-1.0% antifoggant. The antifoggants,
which are not specified, may or may not be benzotriazoles. Most stabilization
processing formulas are considered proprietary. However, the use of UV absorbers
in the stabilizer solution (as well as the emulsion and base of the paper) would
seem to be a practical means of protecting a nonpermanent image from actinic
light. If benzotriazoles are in the solutions, this would apparently be the
only type of black and white processing solution which regularly contains them,
aside from monobaths, and it is an area where growth in use is expected.
In color photography benzotriazoles are used both as anti-
foggants and ultraviolet stabilizers. In the antifoggant application benzotria-
zoles are apparently incorporated into color emulsions (Moll e£ al., 1973) (as
in black and white photography) rather than developer solutions. The current
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Eastman Kodak Ektachrome E-4 process for transparencies may employ an anti-
foggant in the prehardener solution (Anon., 1973 a), but E-4 will be replaced
between late 1976 and early 1977 with a new process (E-6) which does not have
a prehardener step (Anon., 1976 e). Processed color images consist of complex
dyes which are subject to degradation upon continuous exposure to light, espe-
cially ultraviolet light. Benzotriazoles may therefore be present in color
dye stabilizer solutions (Anon., 1973 a) (usually the last step in a color
process), although protection is apparently more successful when the UV stabi-
lizer is incorporated into the emulsion layers and support base during manu-
facturing (Crawford and Hartman, 1967).
Benzotriazole is used in direct-positive dye diffusion-
transfer cplor processes. In an application suggested by Polaroid Corporation
(Cieciuch and Schlein, 1973), Tinuvin 327 or 328 is placed in the polyester
film support beneath the positive image receiving layer in concentrations of
2
50-75 mg/0.09 m . In an Eastman Kodak patent (Crough and Snyder, 1973), the
negative emulsion contains three parts benzotriazole, presumably as an anti-
foggant. Benzotriazole may also be in the monobath (chemical packet whose
contents coats the negative and receiving layers during processing) of dye
diffusion processes, where its presence is said to have a great effect on the
quality of the color image (Loznevoi et al. , 1975). "Instant" color film,
already a significant factor in the amateur market, is likely to become even
more important since Kodak announced its dye diffusion process (Anon., 1976 c),
Cameras and film will be marketed in the U.S. by the end of June, 1976, and
Kodak is offering other camera manufacturers aid in designing cameras to use
the new Kodak film (.Anon., 1976 d).
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A final application for benzotriazoles in color photography,
and one which may have excellent growth potential, is the use of benzotriazole
compounds in heat-developable color emulsions. Eastman Kodak Company has pro-
duced a color process employing silver benzotriazole, which develops by heat
without any chemical solutions (Anon., 1975 b). Based on what is known of the
use of silver benzotriazole in black and white thermal developing copiers, the
most likely use for such a color process seems to be in a color copying and
duplicating device.
The major uses of benzotriazoles are summarized in Table 14.
2. Minor Uses
Under the category of minor uses are applications of benzotria-
zoles in analytical chemistry, the petroleum industry, biology, and numerous
other areas, examples of which are provided below. Obviously, the division
between major and minor applications is somewhat arbitrary, since it cannot be
done on a quantitative basis with any precision, there being little quantita-
tive information on major uses and none at all on minor ones. One yardstick
for categorizing a use as minor has been the amount of available literature
on that use with the assumption that the most economically significant uses
often get the most attention. Another has been the assessment of industrial
sources on the relative importance of various uses to the total market. An
attempt has been made to include under minor uses those applications which may
not at present be of great economic significance, but may have some potential
environmental impact either now or sometime in the future.
,1-H-Benzotriazole is an important analytical reagent for noble
metal determinations, especially copper and silver. It forms insoluble complexes
77
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Table 14. Major Uses of Benzotriazole Compounds
ANTI-CORROSION - antifreeze compositions
hot water heaters and associated pipes of iron, copper,
and their alloys
electric generator water cooling systems
cleaning pastes and polishes
impregnated protective paper (for packing, wrapping,
and storage)
dry cleaning fluids
dishwasher detergent
metal lacquers
hydraulic and lubrication fluids
electrolytic deposition (improves hardness and brightness)
ULTRAVIOLET STABILIZATION - plastics, especially polyolefins
other polymers, such as nylons and polyesters
clear coatings
paints and pigments
oils
PHOTOGRAPHY - antifoggants
emulsion tint agent
UV absorber/stabilizer
thermographic photocopying processes
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with both these metals, which reactions are easily adapted to quantitative
gravimetric assays (Akiyama and Terano, 1964). Potentiometric determinations
of the following cations with benzotriazole at various pH values have been re-
• i II I i i I j^ i I t i i [ I
ported (Havir, 1967): Ag , Cu , Cu , Hg- , Cd , Ni , Co , Mh , and Zn .
In a typical assay, samples of silver ion (6-40 mg) were determined with a
l i i i
standard deviation of +1.4% in the presence of 50-65 mg of Zn or Mn , which
i i
did not interfere. The amperometric determination of Cu with benzotriazole
l i i i
(Poddar and Ray, 1970) and Ni and Co (Poddar and Ray, 1973) in the presence
of each other and also ions of calcium, magnesium, aluminum, iron, chromium,
and lead, has also been reported. The lack of cross-interferences in these
methods suggests their use in a number of applications, including mining and
effluent analysis.
Other transition metals form stable complexes with benzotriazole.
Palladium (II), for example, reacts readily to form a bis complex (Watanabe et al.,
1972). The reaction is almost quantitative. An interesting aspect of this reac-
tion is the tendency (shared by other metals) to form salts (rather than coordina-
tion complexes) by replacement of the //I proton with a metal cation. This side
reaction can be avoided by either running the reaction in highly acidic aqueous
media (an environment unfavorable to the ionization of benzotriazole) or in an
aprotic solvent, such as xylene (House and Lau, 1974).
Of the few spectrophotometric methods developed for the determina-
tion of halides, sulfate, sulfide, and like anions, one unique approach involves
exchange spectrophotometry with silver benzotriazole, selected because of its
greater solubility in the water/organic solvent medium chosen than silver salts
of the anions to be determined. In effect, free benzotriazole replaces the
anion of interest in the solution. The benzotriazole concentration, which is
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then equivalent to the concentration of the ion of interest, is measured
spectrophotometrically (Kirsten, 1956).
Benzotriazoles have been involved as synthetic intermediates.
A Japanese review (Munekata and Sahakibara, 1973) discusses the use of 1-hydroxy-
benzotriazole in peptide syntheses.
A number of uses for benzotriazoles have been reported in the
petroleum industry. Small quantities of benzotriazole (or other nitrogen-con-
taining heterocycles) raise the research octane number of gasoline when added
to catalytic cracking feedstocks (Viland, 1958). Synthetic lubricating oils
designed especially for gas-turbine engines are less likely to attack silver
or copper-containing metals if 0.05-5.0% by weight benzotriazole, methyl benzo-
triazole, or other nitrogen heterocycles are included in their formulation
(Elliot and Edwards, 1961). A lubricating emulsion useful in glassworking,
and which may be safely disposed of in a conventional sewage system, contains
0.5% by weight benzotriazole (Zuraw, 1970). This biodegradable lubricant is
said to have no adverse effects on an activated sludge sewage system. No data
was given on the fate of the benzotriazole. Because the lubricant formula
indicates 25% by weight natural winter sperm oil, it probably has been reformu-
lated or abandoned on account of the ban on use or importation of whale products
in this country. The patent (U.S. #3,507,792) is held by Sinclair Research,
Incorporated.
An industrial application for benzotriazoles which could poten-
tially consume large amounts of these chemicals has been described by Hirakawa
and Sakai (1973). They suggest that plating steel tire cord with zinc or a
zinc-copper alloy, followed by treatment with a benzotriazole prior to tire
manufacture, results in a superior rubber-to-cord adhesion and reduced cord
80
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corrosion. There is no information in the available literature as to what
extent, if any, benzotriazoles are being used for this purpose.
Biological applications of benzotriazoles have generally involved
their use to synthesize other complex molecules, such as those containing sul-
fonyl (Sasse e^ _al_. , 1961) or sulfenyl (Margot and Gysin, 1959) moities, which
are properly outside the scope of this report. An example of these is 1-tri-
chloromethanesulfenyl-4-nitro-5-chlorobenzotriazole. These compounds have been
recommended for their antifungal activity when applied as dusts or aqueous emul-
sions on plants, wood, textiles, hides, and leather. Benzotriazoles have also
been studied for their antiviral activity (Tamm et^ al., 1961) (see also
Section III-B-5). Carboxamide derivatives of benzotriazoles have been used for
controlling aphids in nasturium in pot experiments performed by Gulf Research
and Development Company (Dahle, 1974).
An important new use for benzotriazoles, still probably best
considered a minor use, is in waste water treatment for the removal of heavy
metals, especially mercury, copper, and cadmium (Okamoto, 1974). In one trial,
3 ppm copper and 1 ppm cadmium were removed from two volumes of waste water at
pH 7.85 by shaking for 0.13 hour with one volume of benzene containing 40 ppm
benzotriazole (Ochiai et al., 1975). The efficiency of removal of the metals
was 100%. On a large scale application, the one remaining problem would be to
remove from the metal-free water any residual benzene.
The minor uses for benzotriazole compounds discussed above are
summarized in Table 15.
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Table 15. Minor Uses for Benzotriazole Compounds
Analytical Chemistry - determination of noble metals
Petroleum Industry - gasoline and oil manufacturing
Biological Applications - antifungal, antiviral agents; pest control
Waste Water Processing - removal of heavy metals
3. Discontinued Uses
Benzotriazole, methylbenzotriazoles, and/or naphthotriazoles
used to be regularly present in laundry detergent formulations. The triazoles
were included because of their corrosion-inhibiting properties in the presence
of phosphate and perborate (Tanner, 1959). With the ban on phosphates in laundry
detergent products sold in this country, and the consequent reformulation of
these products, benzotriazoles were no longer necessary and are not currently
present in these products.
4. Projected or Proposed Uses
There are no proposed uses revealed in the sources examined that
differ substantially from the uses described in the previous sections. While
consumption of benzotriazoles is expected to grow, projected growth is not
attributable at this time to any radically new uses that are presently obvious.
5. Possible Alternatives to Uses
In anticorrosion applications, sodium 2-mercaptobenzothiazole
(NaMBT) is probably the major currently manufactured heterocycle which could
replace benzotriazole in some applications, although it would not be as effec-
tive as benzotriazole at the same concentrations, especially with regard to
the protection of copper and copper alloys. NaMBT costs less than the comparable
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benzotriazole (about 50£ for NaMBT vs. $1 for sodium tolyltriazole, per pound
of 50% aqueous solution) but the benzotriazole is effective in lower concen-
trations. As a matter of fact, it appears that benzotriazole is likely to make
a significant inroad into the large anticorrosion NaMBT market (^6 million pounds
per year), rather than the reverse.
In recirculating systems, inorganic anticorrosion replacements
for benzotriazoles might include chromates or mercury compounds.
In ultraviolet stabilizer applications, the 2-substituted benzo-
triazoles compete with and could be replaced by substituted benzophenones, 2-
(hydroxyphenyl)-triazines, substituted acrylonitriles (Seymour, 1968), and
phenyl salicylate (Rothstein, 1968). Each of these stabilizers would be used at
about the same concentration (^0.25% weight of polymer). Recently a number of
nickel complexes have been employed as ultraviolet stabilizers (Cesare et^ al.,
1971), including complexes containing benzotriazole-derivative ligands (Mathis,
1975). Complexes with the non-benzotriazole ligands do not have a strong ultra-
violet absorption spectrum, but are believed to protect plastics by deactivating
the excited states which are part of the degradation chain (Cesare et al.,
1971). The presence of nickel in these complexes usually imparts a greenish
color to the plastic or fibre substrate. The color is often considered unde-
sirable. Ultraviolet stabilizing agents which act as screens, such as carbon
black and other pigments, could replace benzotriazoles, but their application is
limited to situations in which the color of the pigment is acceptable.
In photographic applications, 6-nitrobenzimidazole nitrate (Kodak
Anti-Fog No. 2) and related imidazoles are often mentioned as antifogging
agents. Kodak Anti-Fog No. 2 is useful against fog caused by aldehydes in pre-
hardeners and developers and also against fog caused by the aeration of devel-
opers, but it is not considered to be photographically interchangeable with
benzotriazole (Anon., 1973).
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C. Environmental Contamination Potential
1. General
Benzotriazoles in contact with air, water, or sunlight are likely
to be quite stable and persistent. Nevertheless, it is difficult to identify
a single source of significant environmental contamination by benzotriazoles.
Even when a source of environmental contamination can be identified, it has
often been of concern because of another contaminant, and the benzotriazole
present is essentially ignored. Thus, when laundry detergents were singled
out as an environmental problem, it was because of their phosphate content;
no one ever mentioned that benzotriazole was simultaneously being dumped into
sewers and lakes. Similarly, the effluent of photofinishers has caused atten-
tion because of chromates, thiosulfates, amines, etc., not because very small
amounts of benzotriazoles may be present in processing solutions. One must
conclude that at least the perceived potential for environmental contamination
via benzotriazoles has been small, and the attention paid to it thus far has
been negligible.
2. From Production
During the manufacturing of benzotriazole according to the
method of Long (1971), the only outputs from the system, aside from the desired
benzotriazole product, are the result of the periodic processing of the con-
tents of the crude benzotriazole oil holding tank (see Figure 6). The solid
waste from this holding tank probably contains polyazo and polyamine products
arising from contamination of the o-phenylenediamine starting material with
met a and p_ara isomers. If incinerated, these solids would likely burn to pro-
duce CO , HO and nitrogen oxides which, presumably, would be discharged into
84
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the atmosphere. If land-filled, the solids may allow movement of small benzo-
triazole residues into ground or river waters. The water layer discarded after
the alcohol extraction probably contains small amounts of the particular water-
insoluble alcohol used (i.e., a butanol or hexanol) as well as traces of the
benzotriazole product. The vapors discarded during the steam distillation con-
tain mainly water and the alcohol. In sum, therefore, in normal operation, this
process is not likely to be a serious source of environmental contamination by
benzotriazole, although more information on disposal of residues is needed. The
contamination potential of processes using charcoal filtration would likely
arise mainly from periodic disposal of the filtering medium.
Production of the Tinuvin compounds has resulted in some 2-
substltuted benzotriazoles being detected in the water effluent (Jungclaus,
1977). The trickling filter treatment used at the plant did not reduce the
benzotriazole concentrations.
3. From Transportation and Storage
The main hazard in transporting and storing benzotriazole solids
is the possibility of a broken container resulting in high concentrations of
dust from the chemicals, especially in an enclosed area. Besides a health
hazard, dust from benzotriazoles, as dust from wheat in a grinding mill, is an
explosion hazard (Dorsett and Nagy, 1968).
4. From Use
In anticorrosion applications, benzotriazoles have little oppor-
tunity to contaminate the environment, except by slow leaching or migration
processes. Benzotriazole used to protect metals in coating and lacquers pro-
bably has a long half life (years) and may enter the environment at an incon-
sequentially slow rate. Certain high wear items, such as brass handrails, can
85
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be a direct source of contact of benzotriazoles with human skin. An even more
direct source of human contact with benzotriazoles would be through the use of
suntan products containing benzotriazoles as ultraviolet light absorbers.
Benzotriazoles used as ultraviolet absorbers in plastics and
fibres can migrate into the environment by movement to the surface of the sub-
strate and evaporation (see Section I-B-1). They can also migrate into the
contents of a container made of protected material. Edible oil stored in poly-
ethylene and polyvinyl chloride bottles at 45°C for 10 days contained from 2-20
ppm of Tinuvin type ultraviolet absorbers which migrated from the protected
plastic (Uhde and Woggon, 1968). Foods containing oils or fats are more likely
to exhibit this kind of contamination than foods free of the fats and oils in
which the benzotrizaoles are soluble.
It is probable that no current photographic process presents any
significant environmental contamination potential of benzotriazoles. The benzo-
triazoles used in emulsion manufacturing may, to some extent, leach into process-
ing solutions, but, as mentioned previously, at concentration levels which are
insignificant, especially compared to the concentration levels of other photo-
chemicals. Of course, the benzotriazole solid powders could present a hazard to
workers in emulsion manufacturing facilities (which same hazard holds for
workers exposed to benzotriazoles in polymer and anticorrosion formulation work
areas), mainly with respect to the formation of dust.
Biological uses involving sprays or dusts applied in open areas
are the one application in which benzotriazoles in use would directly contamin-
ate the environment an'd possibly food sources. Until the status of benzotriazoles
suggested for such uses is clarified with respect to environmental interaction,
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it is probably wise to restrict widespread use of these compounds for this
purpose. Presently, the quantity used for this application appears to be very
small.
5. From Disposal
There is little doubt that the major environmental contamination
route for benzotriazoles is via spent antifreeze solutions which are periodically
poured down drains. Besides this, most benzotriazole compounds used in liquid
anticorrosion applications are probably also discarded in sewers. What fraction
this represents of benzotriazoles used for anticorrosion, or, indeed, for all
applications, is unknown.
The discarding of plastic objects also eventually leads to environ-
mental contamination with UV stabilizers. In the case of biodegradable plastics
with water soluble UV protective coatings, the stabilizers get into the environ-
ment sooner rather than later.
As mentioned above, the disposal of photographic processing
solutions is probably a very minor source of environmental contamination with
benzotriazoles compared to other large volume uses such as anticorrosion.
6. Potential Inadvertent Production of Benzotriazoles in Industrial
Processes
There is a possibility that benzotriazoles are inadvertently
produced during manufacturing operations in the dye industry. The reaction of m
and £-phenylenediamines with nitrous acid to produce azo dyes is a very im-
portant commercial reaction (Thirtle, 1968). The reaction will also produce
some benzotriazole if the phenylenediamine starting material is contaminated
with ^-phenylenediamine. It is conceivable that a variety of benzotriazoles
could be produced during the course of diazotization reactions. However, the
presence of small quantities of practically colorless benzotriazoles in an azo
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dye batch is not likely to be either.a manufacturing or an environmental prob-
lem, and may even be an advantage if it helps to stabilize the dye to ultra-
violet light.
7. Potential Inadvertent Production of Benzotriazoles in the
Environment
a
The chances of benzotriazoles being produced inadvertently in the
environment are virtually nil. The possible precursors of triazoles are reactive
materials which likely have short half lives if, for example, released into the
sea or air. Furthermore, efficient diazotization requires higher temperatures
than are normally encountered in the environment. Benzotriazole precursors are
sufficiently hazardous in their own right that it is expected efforts would be
made to restrict their contact with the environment primarily for that reason,
rather than for fear they might react to produce benzotriazoles.
D. Current Handling Practice and Control Technology
1. Special Handling in Use
No special handling is required in the normal use of solid
benzotriazole, other than ordinary personal hygiene and the usual precautions
when there is a possibility of dust. Benzotriazole is considered to be of very
low toxicity and low health hazard (Eastman Kodak Company, 1972). The same is
true for methylbenzotriazoles (Sherwin-Williams Co., 1975).
*
The isopropanol solutions of benzotriazole and methyl benzotria-
zoles represent a handling problem only insofar as continuous exposure to high
concentrations of the solvent can produce a narcotic effect and cause mild eye,
nose, and throat irritation. Proper ventilation in the work area and/or res-
piratory and eye protection are recommended where heavy dust and/or isopropanol
vapor are present.
One particular handling practice which should probably be avoided
is the distilling of solid benzotriazole under reduced pressure. An unexplained
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serious detonation of benzotriazole in a vacuum distillation apparatus has been
reported (Anon., 1956). The distillation was proceeding normally in a 500
gallon kettle containing 2,000 pounds of benzotriazole at 2 torr and 160°C when
the pressure began to rapidly rise. Although emergency devices turned off the
heat and opened ventings, detonation occurred shortly thereafter at or above
220°C. The unit had run successfully for four months prior to the explosion,
which completely destroyed it and caused $200,000 in property damages. No
evidence of azoides, lead compounds, or other detonators were found, nor had
extensive lab runs under extreme conditions revealed the potential hazard prior
to the accident.
As a group, the Tinuvins are even less toxic than benzotriazole,
with the acute oral LD^ for the Tinuvins exceeding 5000 rag/kg (Ciba-Geigy,
undated) (see Section III-B). Nevertheless, it is recommended that, in accord-
ance with good industrial practice, unnecessary personal contact with these
chemicals be avoided. Grounding, venting, and explosion relief provisions are
suggested in keeping with good engineering practice to avoid the possibility of '
static electricity igniting chemical dust (Ciba-Geigy Corp., 1972). Benzo-
triazole dust is considered a severe explosion hazard (Dorsett and Nagy, 1968),
besides being a health hazard if inhaled (see Section III-B). Aside from the
potential hazards of dust, no special handling of the Tinuvin compounds is
required in use.
Not all benzotriazole compounds are as relatively free of hand-
ling hazards as the usual commercial materials. Aldrich Chemical Co. exper-
ienced a spontaneous combustion of 1-chlorobenzotriazole while it was being
packaged (Hopps, 1971). Their response was to remove it from their product line
and recommend extreme caution in handling the compound. (No similar hazard has
been reported, nor would be expected, for 5-chloro-lH-benzotriazole where the
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chlorine atom is on the benzene ring rather than the triazole ring). Parish
Chemical Company (1976), which currently manufactures 1-chlorobenzotriazole,
stores the material at -20°C and finds it stable under these conditions for at
least a year.
2. Methods for Transport and Storage
Sherwin-Williams Chemical Company supplies solid benzotriazole
and tolyltriazole in fibre drums of 200 pounds net weight. The isopropanol
solutions of these compounds and the aqueous solution of sodium tolyltriazole
are shipped in 50 gallon steel drums net weight of 500 pounds/drum (Anon.,
undated). Similar bulk packaging is probably used by Fairmount Chemical Company
for solid benzotriazole, 5-chloro-lH-benzotriazole, and 5-methyl-lH-benzotriazole.
Eastman Kodak Company supplies photograde benzotriazole and 5—
methyl-lH-benzotriazole to the photographic trade in bottles containing from
several ounces to one pound of material (Anon., 1975). Eastman Organic Chemicals
(Division of Eastman Kodak Company) supplies practical grade benzotriazole in
100 and 500 gram bottles and occasionally also in bulk lots. Silver benzotria-
zole is also available (Anon., 1976).
Ciba-Geigy Corporation supplies the Tinuvin compound in standard
fibre drum containers with a net weight of 110 pounds. Smaller packages (down
to 25 pounds) are available, presumably in bags.
No special storage or transportation methods or precautions are
practiced with respect to the solid compounds, with the exception of 1-chloro-
benzotriazole which should be stored at low temperatures (i.e., -20°C) and kept
away from reducing agents (Parish Chemical Company, 1976). 1-Chlorobenzotria-
zole slowly decomposes at room temperature. Benzotriazole is heat stable at
330°C, tolyltriazole to 300°C (Anon., undated). Transportation techniques and
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precautions for isopropanol solutions of benzotriazole would be the same as for
any shipment of a relatively volatile, potentially flammable solvent. The 50%
aqueous solutions of sodium tolyltriazole are caustic (pH 13.0-13.5). Exposure
to large amounts of such solution can cause serious injury. Hence, it must be
transported and stored with the care and precautions generally afforded alkaline
solutions (Anon., undated).
3. Disposal Methods
Recommended methods for disposal of benzotriazole waste solids
are: dispose with normal plant waste (Ciba-Geigy Corp., 1972); bury in a land-
fill or incinerate (Ciba-Geigy Corp., 1972) [but not in a closed container
(Sherwin-Williams Co., 1975)]; or dissolve in a flammable solvent and spray into
an incinerator with an afterburner and scrubber (Eastman Kodak Co., 1972).
Because the dust is considered an explosion hazard (Sherwin-Williams Co., 1975),
disposal should be handled in a way which does not encourage the production of
dust. Incineration or ordinary combustion of benzotriazole produces carbon
dioxide, nitrogen, and nitrogen oxides. In limited air, combustion products may
include carbon monoxide and possibly hydrogen cyanide (Sherwin-Williams Co.,
1975).
4. Accident Procedures
Spills of the solids should be swept up promptly. The personnel
involved should use approved respirators (Ciba-Geigy Corp., 1972). Local high
concentrations of dust should be dampened with water and the area well-ventila-
ted (Sherwin-Williams Co., 1975 a).
Spills of solutions involve accident procedures based mainly on
the nature of the particular solvent. The benzotriazoles themselves appear to
present no particular hazard in solutions, although aqueous solutions 'of sodium
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tolyltriazole are alkaline and should be treated with the same procedures as the
spill of any other aqueous caustic.
5. Current Controls and Control Technology Under Development
Present information indicates that benzotriazoles have only been
monitored in the effluent of one production plant (Jungclaus, 1977). That plant
used a trickling filter treatment plant which exhibited very poor treatment
efficiency. Many potential sources of environmental contamination by benzo-
triazoles (such as discarded antifreeze solutions, water-based cooling fluids,
the effluent of photofinishers or film manufacturers) possibly contain many
other more serious environmental hazards at far higher concentrations, which
explains in part the lack of interest in developing controls for benzotriazoles.
E. Monitoring and Analysis
1. Analytical Methods
Since the middle 1960's, interest in developing analytical
methods for benzotriazoles has corresponded to increasing use of these chemicals
for anticorrosion purposes. The analytical techniques summarized in Table 16
were devised principally for anticorrosion applications. A limited number of
general assay techniques have been reported for benzotriazole compounds used in
other than anticorrosion applications.
Benzotriazole is used in metal separations as an analytical
reagent. Benzotriazole itself can be determined using the same reactions
(Harrison and Woodroffe, 1965). In the presence of excess Ag , silver benzo-
triazole precipitates, is isolated, and weighed. An accuracy of better than 5%
is reported for this method with samples containing 100 ppm benzotriazole. No
sensitivity data were given, but sufficient sample to contain at least 50 mg
benzotriazole is recommended. With this method Keil (1971) reported a standard
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Table 16. Methods of Analysis for Benzotriazole
Method Sensitivity
Relative
Error
Principal Features/
Applications
Source
Gravimetric
Polarographic
Potentiometric titration
Gas Chromatography.
Spectrophotometric
Volumetric
GC-MS
0.4 ppm
^0.05 ppm
200 ppm
1 ppb
•v.1%
-------
deviation of 1% for samples containing 1-20 mg benzotriazole, and 2-3% for
samples containing 0.2-1 mg benzotriazole. Of the various analytical procedures
in the literature, this gravimetric method requires the least amount of equip-
ment, but it is relatively slow because starting samples and the silverbenzo-
triazole must be dried to constant weight (Anon., 1975 a). The ions of zinc,
lead, copper, cobalt, nickel, and iron do not interfere. The presence of
stannic ion, however, causes high results which can be significantly reduced by
complexing the tin with tartrate. Other typical components of glycol-based
antifreeze solutions (for which this assay was developed) do not interfere, with
the exception of 2-mercaptobenzothiazole (Harrison and Woodroffe, 1965).
Polarographic reduction of benzotriazole in strongly acidic
solutions (0.2 M HC1) gives rise to a well-defined wave with E ,„ = -0.98 volts
vs. SCE (Harrison and Woodroffe, 1965). The observed wave was attributed to a
one electron reduction of protonated benzotriazole:
+ 2H
N
+2e
N + H,
A linear variation in diffusion current with benzotriazole concentration was
observed over a concentration range of approximately 0.05-2 mM. Other common
ingredients in antifreeze solutions did not substantially alter the polaro-
graphic wave, nor did the presence of Cu , Zn , Fe , Ni , Pb , or Sn
interfere. This method is more rapid and more specific than the gravimetric
method described above, if the equipment needed to perform it is available.
However, the polarographic method is not suitable for determining trace amounts
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of benzotriazole in the presence of relatively large concentrations of 2-mer-
captobenzothiazole (ca. 0.1-0.2%) unless the two are first separated on an ion
exchange resin (Woodroffe and Munro, 1970).
Lund and Kwee (1968) extensively studied the polarography of
benzotriazole, its mono and dimethyl derivatives, as well as 1-methyl and 1-
hydroxybenzotriazoles. They suggested a reduction mechanism which is consid-
erably different from that of Harrison and Woodroffe (1965). Lund and Kwee
attribute the reduction of benzotriazole in acidic solution to a four electron
mechanism whose final product is o-aminophenylhydrazine:
H
While the polarographic data in this work was not gathered specifically in order
to develop analytical techniques for the molecules studied, it demonstrates that
polarography is a feasible technique for the benzotriazole derivatives investi-
gated.
Bezuglyi et al. (1971) have shown that polarography is suitable
for analysis of polyester resins for benzotriazole stabilizers of the Tinuvin
family. The stabilizer is extracted for 5-6 hours at room temperature with
dimethylformamide. In a background electrolyte of 4 N alcoholic HC1, an E.. ,_
value of 0.71 volts is claimed, but no reference electrode is given. The
relative error of the determination is reported to be ±1.7%.
Potentiometry and gas chromatography (with flame ionization
detector) have been used by Morita et^ al. (1973) to determine benzotriazole,
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4-methyl and 5-methyl-lH-benzotriazole in antirust paper, antirust fluid, and
antifreeze. The potentiometry involves titration with standardized silver
nitrate. Recovery of 97-104% is claimed for 2-35 rag samples in 1.5% aqueous
solutions of sodium bicarbonate. A variation of this method involves the use of
a background solution buffered with sodium acetate (Anon., 1975 a), which is
virtually identical to ANSI PH 4.204-1972.
The fastest method for assaying the purity of benzotriazole and
methylbenzotriazole compounds as raw materials is the spectrophotometric tech-
nique of the Sherwin-Williams Company (Anon., 1975 a), which depends on the
characteristic ultraviolet absorption of these compounds at 274 and 276 nm,
respectively. This method is not only rapid, it is highly sensitive (MD.05
ppm).
In the absence of instrumentation for the electrometric or
spectroscopic techniques, benzotriazole and methylbenzotriazole compounds can be
determined in a concentration range of 200-2000 ppm by a volumetric method which
is a variation on the Volhard method for chloride (or silver ion) (Anon., 1975
a). The benzotriazole sample reacts with a known volume of standardized silver
nitrate solution and the excess silver ion is titrated with ammonium thiocyanate
to the pale orange end point.
Kites and his coworkers at MIT (Jungclaus, 1977) have used a gas
chromatography-mass spectrometry (GC-MS) technique for detecting the 2-substi-
tuted benzotriazoles in wastewater effluents and in downstream water and sedi-
ments. The method consisted of methylene chloride extraction followed by GC-MS
analysis and was sensitive down to approximately 1 ppb.
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2. Current Monitoring
Two of the Tinuvin compounds, 2-(2'-hydroxy-5'-methylphenyl)-
benzotriazole and 2-(2'-hydroxy-3', 5'-di-_t-amylphenyl)-benzotriazole, have been
detected in the effluents from a specialty chemical plant located on the Paw-
tuxet River in Rhode Island (Jungclaus, 1977). The two compounds where found in
concentrations of 2.9 ± 1.4 and 2.4 ± 0.85 ppm, respectively, in wastewater;
0.053 ± 0.007 and 0.038 ± 0.006 ppm, respectively, in river water; and 76 ± 52
and 15 ± 6 ppm, respectively, in sediment. These compounds were detected in
samples collected from the most distance sampling site (approximately 4 miles).
No other ambient or effluent monitoring studies have detected
benzotriazoles.
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III. Health and Environmental Effects
A. Environmental Effects
1. Persistence and Biodegradability
On the basis of the chemistry of benzotriazoles (see Section I-
B), these compounds are probably persistent in the environment. The fact that
the Tinuvins have been detected four miles downstream from a product plant
confirms that suggestion, at least for the 2-substituted benzotriazoles. Benzo-
triazole does not oxidize or hydrolyze under environmental conditions. Studies
of photolytic reactions of benzotriazoles under environmental conditions are not
available. However, benzotriazole (in a methanol solution) has been irradiated
with 300 nm light and some ring breakage occurs (Boyer and Selvarajan, 1969).
Nevertheless, the mechanism for the use of benzotriazoles as UV stabilizers
(absorb light and release it as heat without photochemical reactions) suggests
that these compounds are probably stable under sunlight irradiation.
The potential of benzotriazole to interfere with the seed activ-
ity in the standard 5-day BOD test has been briefly studied by Quinn (1972). He
determined the total bacterial count in the seeded dilution waters to which
various concentrations of benzotriazoles were added (no other carbon source
added). The presence of benzotriazole was found to cause an increase in the
number of viable microorganisms over those found in the blank control (Table
17). The author concluded that the benzotriazole may be acting as a growth
promoter. A similar enhancement in the cell numbers would, however, be expected
if benzotriazole served as a carbon source for the microorganisms. This might
suggest that benzotriazole is susceptible to attack by sewage microorganisms.
The evidence is, however, fragmentary and further work is needed to ascertain
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the biodegradability of benzotriazole. A similar study on tolyltriazole
(Quinn, 1973) at concentration levels of 0.2 - 20 mg/& concluded that tolyl-
triazole does not show any sizable oxygen demand over that of controls in this
concentration range. As in the previously cited study, the purpose of this
work was to examine the effect of the compound on the natural flora in a
wastewater treatment plant or receiving stream, rather than to specifically
consider the biodegradability of benzotriazoles.
Table 17. Survival of Wastewater Microorganisms in Contact with Benzotriazole
(Quinn, 1972)
Benzotriazole Concn.
in Seeded Dilution
Water (ppm)
Total Colony Count/m&
After 5 Days
Incubation*
0
0.66
3.3
6.6
13.2
151,000
207,000
217,000
183,000
164,000
Initial colony count/mil = 54,570
2. Environmental Transport
Very little experimental data are available concerning environ-
mental transport and intermedia distribution of benzotriazole and its deriva-
tives. The low vapor pressure of these compounds (Table 2) suggests that they
will not enter and distribute in the atmosphere to a significant extent. Also,
their rate of evaporation from water bodies to the atmosphere will be slow, as
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predicted, using the approach developed by MacKay and Leinonen (1975). For
example, the calculated half life for IH-benzotriazole at less than saturation
concentration in a square meter of water would be 438 hours. (For comparison,
benzene's half life is 4.81 hours.) The equation for predicting approximate
rates of evaporative loss of low solubility contaminants in an air-water system
is based on the assumption that the water column undergoes continuous mixing,
that the compound is present in true solution, and not adsorbed, complexed,
etc. Recently, Billing e_t^ a^. (1975) have found a discrepancy between experi-
mentally determined evaporation half lives for certain chlorinated hydrocarbons
and values calculated according to the equation developed by MacKay and co-
workers. In view of this, it is suggested that the calculated value be treated
only as a rough approximation.
In view of the appreciable'water solubility of some benzotria-
zoles (e.g., IH-benzotriazole, tolyltriazole), it may be expected that they
will migrate through soil and eventually make their way to ground water. Other
virtually water insoluble benzotriazole derivatives (e.g., Tin-P, Tin-326, Tin-
327), have been shown to concentrate in river water sediments at concentrations
almost a thousand times the concentration found in river water (Jungclaus,
1977).
3. Bioaccumulation and Biomagnification
Bioaccumulation and biomagnification potential of benzotriazoles
has not been reported in the literature. Neely et^ al. (1974) have reported a
linear relationship between octanol-water partition coefficients and biocon-
centration of chemicals in trout muscle. Using the equation of the straight
line of best fit, derived by Neely £t £LL. (1974), the bioconcentration factor
100
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of IH-benzotriazole (log octanol-water partition coefficient, 25°C = 1.34) is
calculated to be approximately 7. The log partition coefficient of IH-benzo-
triazole falls outside the range of the data of Neely et_ al. (1974). Conse-
quently, less confidence must be placed on the prediction.
Biomagnification potential, which refers to concentration of a
compound through the consumption of lower organisms by higher food chain organ-
isms with a net increase in tissue concentration, can be predicted for benzo-
triazoles on the basis of their water solubility. Metcalf and Lu (1973) have
found ecological magnification of several chemicals (concentration in organ-
isms/concentration in water) in their model aquatic ecosystem follows a straight
line relationship with water solubility. From this relationship, the ecological
magnification for IH-benzotriazole and tolyltriazole is calculated to be 4,
which suggests that these compounds will not biomagnify to a significant extent
in food chain organisms. Other benzotriazoles, such as Tin-P, Tin-326, Tin-
327, and Tin-328, which are virtually insoluble in water, may, however, be
expected to biomagnify considerably more.
B. Biological Effects
Interest in the biological properties of benzotriazole and its
derivatives has been prompted, in part, by their general structural similari-
ties to naturally occurring and endogenously important substances in mammalian
systems. Experimentally, the benzotriazoles have demonstrated antagonistic
activity toward utilization of the purines, adenine and guanine, and also show
properties similar to indole. These structures are presented in Figure 9.
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(a)
(b)
(c)
(d)
Figure 9. Naturally Occurring Chemical Structures Compared to Benzotriazole
(a) Benzotriazole; (b) Adenine; (c) Guanine; (d) Indole
The actions of benzotriazoles when introduced into biological systems
may lead to interference with endogenous purine utilization and the consequent
inhibition of protein synthesis. It is suggested that certain benzotriazoles
could act to inhibit enzymes involved in the synthesis of nucleic acid (RNA or
DNA) or perhaps may actually be incorporated into the molecule itself, and
thereby cause abnormal function. Studies conducted with another related purine
antagonist, 8-azaguanine, have shown that it can inhibit growth in both normal
and malignant cells (Kidder et^ al.. , 1949; Gellhorn £t al., 1950). This occurs
by incorporation into the nucleic acids (Smith and Matthews, 1957; Mandel,
1957, 1961) and causes inhibition of protein synthesis (Chantrenne and Devreux,
1958, 1960).
Because they have similar properties to indole, the benzotriazoles
have been investigated for pharmacologic activity, particularly with regard to
effects on the central nervous system. It is known that unsubstituted indole
will produce convulsions originating in the spinal cord and subthalamic areas
of the brain, and benzimidazole (3-azaindole) will cause a transient flaccid
paralysis due to interneuronal depression (Adler and Albert, 1963).
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Benzotriazole and its derivatives have not been extensively studied
for biological activity, especially in recent years. For this reason, subse-
quent sections in this report will present the available data on a number of
benzotriazole compounds which do not have significant commercial importance or
environmental contamination potential. In this manner, however, it may be
possible to make cautious extrapolations of data,from related compounds in
order to provide a reasonable indication of biological consequence for similar
substances where specific data are lacking. In addition, a thorough examina-
tion of the properties of a particular chemical and its substituted derivatives
may indicate the potential harm that may result from environmental alterations
of the parent compound.
1. Toxicity and Clinical Studies in Man
A search of the available literature indicates that occupational
and epidemiologic studies have not been conducted for benzotriazole or its
methyl-substituted derivatives, nor have any poisoning incidents been reported.
Eastman Kodak Company (1975) has stated that their experience in the manufacture
of benzotriazole and handling of solutions containing it "has generally been
very good."
Limited toxicity testing in humans has been conducted with two
benzotriazole-derivative ultraviolet stabilizers, Tinuvin-P and Tinuvin-327
(Ciba-Geigy, 1976). Repeated insult patch tests with a 0.5% solution of
Tinuvin-327 were performed on 55 male and female subjects. The treatment
failed to induce either primary skin irritation or allergic sensitization in
all of the subjects.
Tinuvin-P was patch tested in human females as either a 0.1%
solution (50 subjects) or a 0.5% solution (50 subjects) dissolved in dimethyl
103
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phthalate. The experimental protocol consisted of a 24-hour application three
days per week for three weeks (total of ten applications), followed by a two-
week rest period and then a 48-hour challenge application. This treatment did
not cause irritation or sensitization in any of the subjects.
Ciby-Geigy (1976) also patch tested Tinuvin-P in 25 human males
as a 25% formulation in petrolatum. The material was applied to abraded skin
in five 48-hour applications, with one-day intervals between exposures. Fol-
lowing a two-week rest period, a new area of abraded skin was challenged with a
10% formulation of Tinuvin-P in petrolatum for 48 hours. Sensitization was not
induced in any of the subjects by this treatment.
In addition to being tested for skin irritancy and sensitizing
potential, Tinuvin-P was evaluated for phototoxicity in humans (Ciba-Geigy,
1976). The chemical, when applied to the backs of ten male subjects for 24
hours, did not exacerbate the production of erythema resulting from exposure to
ultraviolet light.
Ciba-Geigy (1976) has stated that no cases of occupational
poisoning have occurred among employees engaged in the manufacture of Tinuvin-
327 and products which contain it. Likewise, they have noted that no symptoms
of poisoning in man have been reported following the ingestion of Tinuvin-P.
2. Effects on Non-Human Mammals
a. Absorption/Excretion Studies
There are no reports in the scientific literature directly
concerned with the absorption or elimination of benzotriazole and its deriva-
tives in animal systems. It is possible, however, to draw a limited number of
inferences regarding the likelihood of these compounds being absorbed. It is
well-known that the relationship between toxicity and degree of absorption for
104
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any foreign compound is largely dependent upon its molecular structure, lipid
solubility, degree of ionization, and vapor pressure. Therefore, based on
these parameters, a reasonable prediction of the ease of entry into the circu-
lation for benzotriazole can be constructed.
When exposure to foreign substances occurs by oral inges-
tion, diffusion across the gastric epithelium will be greatest for lipid-
soluble neutral molecules (i.e., compounds having a high lipid/water partition
coefficient and which are mainly undissociated at the pH of the gastric con-
tents). The absorption and rate of passive diffusion for both organic acids
and bases will decrease with increasing ionization of the undissociated moiety.
Consequently, the absorption of most chemicals will be favored by a pH that in-
creases the proportion of the undissociated form. For the most part, this
relationship also holds true for absorption of foreign substances through the
skin, which also acts as a lipoidal membrane and is most readily penetrated by
lipid-soluble neutral molecules (Schanker, 1964).
The degree of ionization of xenobiotics is a function of
both pH conditions and the pKa value for the particular chemical. The pKa
value is an expression of the pH at which 50% of the compound will be in the
dissociated form and 50% in the undissociated form. Schanker (1964) has noted
that gastrointestinal absorption was greatest for acidic compounds having pKa
values greater than 3 and basic compounds with pKa values less than 8.
The pKa and lipid solubility of benzotriazole, a weak acid,
were determined by Albert £t al^. (1948) and Adler and Albert (1963). Table 18
presents the physical properties of 'benzotriazole and indicates that, as a weak
acid, fairly rapid absorption of benzotriazole is likely to occur across the
intestinal epithelium (pH 6.5). Furthermore, at blood pH (7.4) Adler and
105
-------
Albert (1963) predicted a low degree of lonization for benzotriazole (.0002%)
which suggests that it would easily pass into the central nervous tissue. This
prediciton is supported by toxicologic evidence (see Section III-B-2-b) which
confirms its action on the central nervous system.
Table 18. Physical Properties of Benzotriazole (Adler and Albert, 1963)
Lipid/Water* % Ionized
pKat Distribution Ratio at pH 7.4
8.57 3.0 .0002
* Oily phase used was oleyl alcohol.
t Taken from Albert et al. (1948).
Adler and Albert (1963) noted that benzotriazole is much
less lipid-soluble than the related compounds indole or benzimidazole (lipid/
water distribution ratios of 85 and 16.4, respectively). Nevertheless, the
organosolubility of benzotriazole is apparently sufficient to promote rapid
penetration into the brain, as evidenced by its central effects (see Section
III-B-2-b). Supporting experimental data are not available, however, since the
transport and distribution of benzotriazole have not been studied.
b. Metabolism and Pharmacology
The biological activity of any drug or foreign compound in
the mammal will be dependent upon the rate at which the substance is metabol-
ically transformed into water-soluble inactive products. In many instances,
however, enzymatic conversion of a substance in the body produces an active
metabolite which accounts for the observed effects of the chemical. For benzo-
triazole and its derivatives, there have been no studies conducted to determine
their metabolic products or the primary eliminatlve routes in animal systems.
106
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The only indication of metabolic inactivation of the benzotriazoles is by
noting their duration of action when administered to experimental animals at
toxic doses.
Central Nervous System Effects
Evidence that benzotriazole and its derivations produce
selective pharmacologic effects on the central nervous system was provided by
Domino et^ aJ. (1952). Albino mice (18 to 24 grams) were given benzotriazole or
one of its derivatives by intravenous injection and observed for the develop-
ment of paralysis. A median paralyzing dose (PD,.,,), measured as the dose to
produce a loss of the righting reflex in 50% of the experimental animals, was
determined (Table 19).
Table 19. Median Paralyzing Doses of Benzotriazole Derivatives on Intravenous
Administration to White Mice (Domino et al., 1952)
Compound PDsn*
IH-Benzotriazole 55±3
1-Methylbenzotriazole 230
1-Ethylbenzotriazole 50
* All doses are given in mg/kg ± standard error. Values without standard
error are approximate.
Mice treated with benzotriazole immediately displayed an
increase in activity (running and squeaking) and within a few seconds became
ataxic, culminating in loss of the righting reflex. A semi-flaccid paralysis
was seen, which began in the hindlimbs and was reversible within a few minutes,
107
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Respiration in the mice was increased, but lethal doses of benzotriazole de-
creased the amplitude of respiratory movements and caused death by respiratory
arrest. The actions of benzotriazole were qualitatively similar to those pro-
duced by the related compound benzimidazole, which was somewhat less potent.
The 1-methylbenzotriazole derivative was considerably less
potent than the unsubstituted compound and produced respiratory depression,
hyperreflexia, and tremors. Substituting a 1-ethyl group in benzotriazole
produced a compound with the highest potency of the three tested, which caused
respiratory depression in paralyzing doses.
The site of action for the benzotriazole derivatives was
established as being in the central nervous system, rather than peripheral, by
testing the compounds for curare-like effects (Domino et^ al_. , 1952). Benzo-
triazole was administered in a dose of 1 gm/kg into the ventral lymph sac of
frogs. During the benzotriazole-induced paralysis, responses of the gastro-
cnemius muscle were observed to indirect (nerve) and direct (muscle) electrical
stimulation. Whereas curare, a peripheral nervous system poison, would block
electrical stimulation of muscle contraction, a centrally-acting agent would
not. Stimulation of the sciatic nerve in benzotriazole-poisoned frogs resulted
in contraction of the gastrocnemius muscle, even though the animal was in a
state of flaccid paralysis. Therefore, the observed paralysis was of central
origin since benzotriazole treatment did not impair conduction in peripheral
o
nerves (sciatic) or block transmission across the neuromuscular junction.
In later studies conducted by Adler and Albert (1963),
benzotriazole was investigated for pharmacologic action because of its struc-
tural relationship to naturally occurring indole derivatives. Male albino mice
108
-------
(15 to 20 grams) were treated with benzotriazole by intraperitoneal injection
c
in groups of 8 to 10 mice at four or five dose levels. A median effective dose
(ED _) was calculated for the point at which: (1) 50% of the animals lost the
ability to right themselves when placed on their backs, and (2) the onset of
mild clonic-tonic convulsions. For benzotriazole, the ED was calculated at
250 mg/kg body weight.
The toxic effects of benzotriazole in small doses were
manifested by the sudden onset of occasional clonic seizures (about ten per
minute) superimposed on a flaccid paralysis which abolished the righting
reflex. With almost equal frequency, larger doses produced death either by
tetanic tonic convulsions or respiratory failure. These mixed effects demon-
strated that benzotriazole may produce selective central nervous system stim-
ulation, depression, or both at the same time. Other related compounds were
either exclusively stimulatory (indole) or depressant (benzimidazole) in their
actions on mice (Adler and Albert, 1963).
Effects on Experimental Tumors
Screening programs for the detection of compounds with
antitumor effectiveness have been conducted with numerous animal tumor systems,
both in vivo and in vitro. Benzotriazole was tested against several animal
tumors in vivo by the Cancer Chemotherapy National Service Center (CCNSC)
(Anon., 1958). Three experimental tumor systems were employed: (1) Sarcoma
180 (S180) in Swiss albino mice, (2) mammary adenocarcinoma 755 (Ca755) in C57-
DBA hybrid mice, and (3) lymphoid leukemia (L1210) in C57-DBA hybrid mice.
Screening results are presented in Table 20 and demonstrate that benzotriazole
was found to be tumor inhibitory against Ca755.
109
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Table 20. Effect of Benzotriazole Against Various Experimental Tumors by
Repeated Intraperitoneal Injection
CCNSC Screening Results*
*
S180* Ca755 L1210 Other Screening Datat
-(250) +(225) -(250) 0/3
* Symbols: - = no significant tumor inhibition or increase in survival time
(for L1210); + = significant tumor inhibition in at least two trials.
t Literature survey of animal tumor reports other than CCNSC tests. The
numerator indicates the number of "positive" reports. The denominator
indicates the number of reports in the literature survey.
*
* Number in parentheses indicates the highest nontoxic dose treated.
-------
Inhibition of tumor growth by benzotriazole treatment was
also shown in studies conducted by Tarnowski and Bates (1961). Their technique
involved the direct incubation of tumor fragments with benzotriazole solutions
followed by implantation into susceptible hosts to determine viability of the
treated fragments. Nelson mouse ascites tumor cells, carried in Swiss albino
mice, were collected six to seven days after tumor implantation and diluted to
Q
contain 10 cells per ml. The cell suspension was incubated with benzotriazole
at concentrations ranging from 0.1 to 10 mg/ml for a 24-hour period. A portion
of the incubated suspension, containing 1 x 10 cells, was then injected sub-
cutaneously into mice. A record was kept of the number of tumor inocula grow-
ing in each subcutaneous location (tumor takes) after one, two, and three weeks,
Their results, summarized in Table 21, indicated that benzotriazole produced
moderate to marked inhibition of tumor growth at incubation concentrations of
1 and 10 mg/ml.
Table 21. Bioassay of Suspensions of the Nelson Mouse Ascites Tumor Treated
with Benzotriazole In Vitro (Tarnowski and Bates, 1961)
Dose Number of
mg./ml. Exposures
0 2
.1
1
10
First Week
Takes AWC*
10
10
10 +3.6
10
0
10
0
10
Second Week
Takes AWC Ratingt
10
10
10 +2.2 —
10
3 +
10
0 ++
10
* AWC = % average weight change
t Rating: — = inactive (75 - 100% growing tumor inocula); + = moderate inhibition
(25 - 49% growing tumor inocula); ++ = marked inhibition (0 - WL growing tumor inocula)
111
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Negative results on tumor inhibition by benzotriazole and
two of its derivatives were obtained by Gellhorn et_ _al. (.1953). Mice bearing
either mammary adenocarcinoma 755 or Crocker Sarcoma 180 were treated with re-
peated injections of benzotriazole or its 6-chloro- or 6-nitro-derivative. At
the dose levels employed in this study, tumor inhibition was not seen, although
death and decreased body weight gains were noted in certain groups (Table, 22).
Negative results were also qbtained by Stock est_ al. (1960)
when benzotriazole was tested against Sarcoma 180 in Swiss female mice. Tumor
fragments were cut from portions of a donor tumor and implanted subcutaneously
into the axillary region of five mice. Twenty-four hours after implantation,
therapy was initiated with each mouse receiving 13 daily intraperitoneal injec-
tions of benzotriazole at 400 mg/kg body weight. No deaths resulted and tumor
growth was not inhibited by this treatment.
Although the evidence is not clear, it appears that benzo-
triazole may possess a certain degree of tumor inhibitory activity. This activity
may be related to its structural similarity to the purines which results in a
disruption of nucleic acid metabolism in rapidly dividing tumor cells. Inhibi-
tory effects on bacteria (see Section III-B-6) and tissue cultures of normal and
malignant cells (see Section III-B-7) lend support to the theory that benzotriazole
is capable of disrupting fundamental cellular processes. Furthermore, muta-
genic and inhibitory activity by substituted benzotriazoles on bacterial mutants
having different purine requirements (see Section III-B-2-g) suggests that certain
benzotriazole derivatives can affect the utilization of natural purines.
Uncoupling of Oxidative Phosphorylation
Several derivatives of benzotriazole have been found to be
effective uncouplers of oxidative phosphorylation in rat liver mitochondria
(Parker, 1965). This effect is identical to that produced by 2,4-dinitrophenol,
112
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Table 22. Negative Cancer Chemotherapy Results in Mice (Gellhorn et al., 1953)
Age of
Compound Name
Benzotriazole
6-Chlorobenzotriazole
6-Nitrobenzotriazole
Tumor
755
S180
755
S180
755
S180
Tumor
Days
1-2
1
2
1
2
1
Mouse
Strain
C57
Paris
C57
Paris
C57
Paris
No. of
Deaths/
No. of
Test
Animals
1/40
0/20
1/30
0/20
4/30
0/20
Dose
mg/kg/day
50-150
50
50
50
50
50
Av. Wt.
Change :
treated/
controls
-6/+5
0/+4
0/-3
+2/+4
-61-5
+2/+4
No. of
Treatments
11-15
9
11-15
9
11-15
9
Vehicle
H20
H20
NaOH to
pH8
NaOH to
pH8
NaOH to
pH8
NaOH to
pH8
-------
a classic uncoupler. However, the tetrachloro derivative of benzotriazole is
a much more potent uncoupler than 2,4-dinitrophenol (see Section III-B-7-c).
Accompanying the demonstration of in vitro uncoupling in rat liver mitochondria
by 4,5,6,7-tetrachlorobenzotriazole, 5-chloro-4-nitrobenzotriazole, and 5-nitro-
benzotriazole was the observation that these compounds, when given in lethal
doses to rats, produced an early onset of rigor mortis which was complete at
death. This phenomenon is characteristic of the pharmacologic action of other
uncouplers such as 2,4-dinitrophenol.
c. Acute Toxicity
The acute toxicity of a chemical substance refers to the
adverse physiologic effects produced by single dose exposure. Although the
measurement of an LD,.,, (dose required to cause death in 50% of an experimental
population) is a valuable tool in determining the consequences of overexposure
or accidental poisoning, such investigations bear little resemblance to environ-
mental exposure situations. However, the relationship between varying acute
doses and the effects produced in a group of animals can be used to construct
a graphical representation (dose-response curve) which reveals several important
parameters in characterizing a chemical toxicant. Indications of toxic potency,
maximum effect, response threshold, sensitivity, and biological variability can
all be derived from properly designed acute toxicity studies.
It should be kept in mind that a number of factors can
modify the effects of a chemical substance, leading to qualitative and quantita-
tive discrepancies in experimental results. Among the most important modifying
factors ape species, strain, sex, age, route of administration, rate of bio-
transformation, .tolerance, genetic influence, and chemical interactions.
114
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Only a limited number of acute toxicity studies have been
conducted with benzotriazole derivatives in laboratory mammals. These studies
have been restricted to investigations involving either rats, mice, or rabbits.
Acute Oral and Parenteral Toxicity
' A summary of the published data regarding the median lethal
doses (LD ) for various benzotriazole derivatives by oral and parenteral ad-
ministration is presented in Table 23. The data are not entirely consistent,
nor do they indicate a clear difference in species susceptibility between the
rat and mouse. A comparison of LD values for benzotriazole in the mouse by
intravenous (238±16 mg/kg) and intraperitoneal (500-1000 mg/kg) administration
indicates that considerable detoxification may result due to first-pass metabo-
lism in the liver.
It is also apparent that the addition of bulky substituents
to the benzotriazole moiety, as with Tinuvin-P and Tinuvin-327, considerably
decreases acute toxicity. This effect may be due, in part, to gastrointestinal
factors and bacterial action, since it has been shown that intraperitoneal ad-
ministration of Tinuvin-327 markedly enhances toxicity when compared to the
oral route (Table 23).
An indication of dose-response relationships for benzotria-
zole and tolyltriazole (a mixture containing predominantly 4-methyl and 5-methyl-
benzotriazole) can be derived from data supplied by the Sherwin-Williams Company
(1976). The compounds were administered orally to four groups of ,ten rats
(five male and five female) which were observed for 14 days after treatment.
The dose levels and responses are summarized in Table 24.
When the data from Table 24 are portrayed graphically accord-
ing to the method of Litchfield and Wilcoxon (1949), several relationships become
115
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Table 23. Acute Toxicity of Benzotriazole and Derivatives in Laboratory Rodents
Compound
1-H-Benzotriazole
2-(3' ,5'-di-tert-Butyl-
2 ' -hydroxypheny 1) -5-
chlorobenzotriazole
(Tinuvin 327)
2(2'-Hydroxy-5'-iiiethyl-
phen,yl)benzotriazole
(Tinuvin P)
1-Methylbenzotriazole
5-Methyl-lH-benzotriazole
Tolyltriazole (mixture
containing 4-Methyl-
and 5-Methylbenzotria-
zole)
Animal
Rat (20 male and
20 female)
Rat
Rat
Rat
Mouse (Swiss-Webster
males ; 4 or 5
groups of 8-10
mice each)
Mouse
Mouse (Harlan)
Rat (male and
female)
Mouse (male and
female)
Mouse
Mouse (Harlan)
Rat (male and female)
Mouse (male and
female)
Mouse (Harlan)
Rat
Mouse
Rat (20 male and
20 female)
Route of
Adminis tration*
Oral
Oral
Oral (in H20)
I. P. (in organic
solvent)
I. P. (in oil)
I. P.
I.V.
Oral
Oral
I. P.
I.V.
Oral
Oral
I.V.
Oral
Oral
Oral
Dose
(mg/kg)
560
500
>5000
500-900
500
1000
238±16
>5000
>5000
3000
125
>5000
>5000
375
1600
800
675
(535-851)
Response
LD50
Minimum lethal dose
Lethal dose
Lethal dose
LD50
LD50
LD.Q and standard error
^50
LD50
^50
LD50
LD50
LD50
LD50
^50
LD50
LD with 95% confidence limits
Reference
Sherwin-Williams Co., 1976
Christensen and Luginbyhl , 1975
Eastman Kodak, 1976
Eastman Kodak, 1975
Adler and Albert, 1963
Smith ££ al. , 1963
Domino £t al. , 1952
Ciba-Geigy, 1976
Ciba-Geigy, 1976
Ciba-Geigy, 1976
Domino et al. , 1952
Ciba-Geigy, 1976
Ciba-Geigy, 1976
Domino e£ al. , 1952
Eastman Kodak, 1975
Eastman Kodak, 1975
Sherwin-Williams Co. , 1976
*Symbols: I.P. = intraperitoneal; I.V. - intravenous.
-------
Table 24. Acute Oral Toxlcity to Rats of Varying Doses of Benzotriazole or Tolyltriazole
(Sherwin-Williams Co,, 1976}
Benzotriazole
Dose
(mg/kg)
1001
795
632
502
398
Day of Death
0
—
4/10
0/10
0/10
0/10
1
—
6/10
7/10
2/10
0
2
—
0
:o
2/10
0
Total Dead
Total Treated
—
10/10
7/10
4/10
0/10
Tolyltriazole
Day of Death
0
10/10
6/10
1/10
3/10
__
1
0
1/10
2/10
0
__
2
0
0
0
0
—
Total Dead
Total Treated
10/10
7/10
3/10
3/10
_ —
-------
evident (Figure 10). The steep slopes of the dose-response curves for benzotria-
zole and tolyltriazole immediately suggest a sensitive population with minimal
variability. Benzotriazole is obviously slightly more potent than the methylated
derivative. However, for both compounds the margin of safety between non-toxic
and lethal doses is very small. Since the slopes of both dose-response curves
are similar, it can be predicted that the mechanism of toxic action may be the
same for both chemicals.
Acute Dermal Toxicity
Investigations conducted by the Sherwin-Williams Company (1976)
indicated that neither benzotriazole nor tolyltriazole is significantly toxic
to rabbits by dermal exposure. The compounds were each applied to the clipped
skin of five female rabbits and to the clipped and abraded skin of five female
rabbits. The material remained under occlusive bandage for 24 hours, after
which time the skin was washed with water and daily observations made for two
weeks.
At 2000 mg/kg of body weight benzotriazole produced no
deaths from dermal exposure in any of the rabbits. Three of the five rabbits
having abraded skin developed a well-defined but transitory erythema on day
two of the study. Edema was absent in all test animals. Animals, on the
average, continued to gain weight throughout the experimental period
(average F +83%), but the absence of untreated control rabbits prevented a
quantitative comparison of the rates of body weight gain. Histopathologic
examinations were not conducted upon sacrifice of the animals.
Results of treating rabbits by dermal application of
tolyltriazole at 2000 mg/kg of body weight were essentially identical to those
obtained with benzotriazole. Edema was absent in all animals; three of five
118
-------
D
I
10000
9
8
7
6
5
E 1000
a 9
o 8
O 7
6
5
100
A. Tolyltriazole
LD50 and 95% Confidence Limits = 645 ( 564 - 737 )
Slope =1.30
B. Benzotriazole
LD50 and 95 % Confidence Limits = 550 ( 489 - 619 )
Slope = 1.21
i
0.01 0.05 0.1 0.2 0.5 1 2 5 10
20 30 40 50 60 70 80
% Mortality
90 95 98 99 99.8 99.9 99.99
Figure 10. Acute Toxlcity in Rats Treated Orally with Various Doses of Benzotriazole or Tolyltriazole
-------
rabbits with abraded skin displayed very slight erythema which disappeared
after three days. Four of the ten experimental rabbits showed no gain in body
weight over the 14-day test period; one animal suffered a 3% decrease in body
weight. Once again, the absence of untreated control animals prevented quanti-
tative comparisons. Histopathologic analyses of tissues were not conducted.
Eastman Kodak Company (1975) evaluated the toxicity of
5-methyl-lH-benzotriazole in guinea pigs, when applied as a moistened solid to
the skin under occlusive bandage for 24 hours. Slight skin irritation was pro-
duced by the treatment. The dermal LD n for the compound exceeded 1.0 gm/kg
of body weight in the guinea pig.
Primary Skin Irritation
Benzotriazole and tolyltriazole were evaluated for primary
skin irritation in adult female New Zealand albino rabbits (Sherwin-Williams
Company, 1976). One-half gram of chemical was applied to a one-inch square
area of clipped skin on the backs of twelve rabbits for each compound. Six
of the rabbits in each group were exposed to the compound on abraded skin. The
treated area was covered with tape for 24 hours, after which time the tape was
removed and skin reactions evaluated. A second evaluation was made 72 hours
after the initial treatment. In all cases, the rabbits were completely free of
adverse skin reactions (edema or erythema) resulting from the chemical exposure.
Primary Eye Irritation
Experimental evidence has been presented by Sherwin-Williams
Company (1976) which indicated that both benzotriazole and tolyltriazole were
irritating to the eyes of rabbits.
120
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Six female albino New Zealand rabbits were used in evaluating
each chemical. Animals were treated by instilling 100 mg of chemical in one eye
of each rabbit, the other eye serving as a control. Ocular reactions were graded
at 24, 48, and 72 hours and 14 days. At 24 hours, the eyes were also stained
with fluorescein and examined under ultra-violet light to detect corneal damage.
Results obtained with both chemicals are summarized in Table 25. These results
indicate that benzotriazole and tolyltriazole present significant hazards to
the eye.
The primary eye irritation potential of 5-methyl-lH-benzo-
triazole has been evaluated by Eastman Kodak Company (1975). When "several
crystals" were applied to the eyes of a rabbit, moderate irritation, injection
of the iris, and staining of the cornea were noted. If unwashed, the treated
rabbit eye still displayed edema and erythema 48 hours after application. The
washed rabbit eye returned to normal after 24 hours; the unwashed eye recovered
within two weeks. These results are somewhat consistent with those obtained
using tolyltriazole and thereby confirm the eye irritation potential of these
chemicals.
An evaluation of Tinuvin-P for eye irritation revealed that
the compound was "minimally irritant" and produced mild conjunctival reactions
in two of six treated rabbits (Ciba-Geigy Corp., 1976).
Acute Inhalation Toxicity
A report on the inhalation toxicity of benzotriazole to
rats indicated that the substance may present a severe respiratory hazard
(Sherwin-Williams Company, 1976). Fifty male rats, in five groups of ten
animals each, received a single three-hour exposure to a benzotriazole aerosol
at one of five different concentrations. Exposure levels and mortality data
are presented in Table 26. Data were not supplied on the parameters of aerosol
particle size or relative humidity.
121
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Table 25. Primary Eye Irritation by Benzotriazole and Tolyltriazole (Sherwin-Williams Co. , 1976)
TEST No. Observed/
No. Exposed
Cornea 1/6
1/6
4/6
6/6
NO
K> Iris 5/6
Conjunctival Redness 4/6
2/6
Chemosis 2/6
4/6
BENZOTRIAZOLE*
Reaction
Translucent areas of opacity
No details of iris visible
Complete corneal opacity
Fluorescein examination positive
Moderate circumcorneal injection
Diffuse crimson red
Diffuse beefy red
Swelling with lids about half-closed
Swelling with lids half-closed or greater
No. Observed/
No. Exposed
2/6
3/6
1/6
6/6
4/6
4/6
2/6
1/6
2/6
3/6
TOLYLTRIAZOLE *
Reaction
A diffuse area of corneal opacity
Discernible translucent areas of opacity
No details of iris visible
Fluorescein examination positive
Moderate circumcorneal injection
Diffuse crimson red
Diffuse beefy red
Swelling with partial eversion of lids
Swelling with lids about half-closed
Swelling with lids half-closed or greater
*Dose = 100 mg instilled in one eye.
-------
Table 26. Mortality Produced in Rats by Three-Hour Exposure to Aerosolized
Benzotriazole (Sherwin-Williams Company, 1976)
Exposure Concentration Percent
mg/1 Mortality
0.78 0
1.46 10
2.03 ' 20
2.23 50
2.71 100
AH deaths, except one, occurred during the exposure period;
usually during the final half hour. Those animals which survived the treatment
appeared normal within two or three days. The only sign of intoxication noted
was deep abdominal breathing and open mouth gasping in the rats exposed to the
two highest concentrations. Weight gain was not adversely affected in surviving
animals throughout the 14-day observation period.
Rats which died from exposure to the benzotriazole aerosol
revealed two consistent gross pathological changes upon autopsy. First, the
trachea contained a severe accumulation of white frothy fluid; and second, the
lungs revealed a moderate to severe incidence of dark red hemorrhagic areas in
all lobes. Pulmonary edema was absent.
When the data contained in Table 26 were analyzed by the
method of Litchfield and Wilcoxon (.1949) , the three-hour LC „ was found to be
1.91 mg/1 with 95% confidence limits of 1.59 to 2.29 mg/1. According to the
standards of the Federal Hazardous Substances Act (Federal Register, August 12,
1961), a substance producing an LC of 2.0 mg/1 during an exposure of one hour
or less would be considered highly toxic. In this case, however, the exposure
123
-------
period was three hours and it appeared that death may have been due to local
respiratory damage rather than absorption and systemic poisoning. Nevertheless,
the margin of safety between a no-effect dose and the LC is quite small for
benzotriazole and indicates that exposure to the chemical in air may be extremely
hazardous. In situations outside the workroom environment, it is unlikely that
such exposures to benzotriazole dust would occur.
The inhalation toxicity of Tinuvin-P was evaluated in
studies reported by Ciba-Geigy Corp. C1976). Male and female rats (five of
each sex) were exposed to Tinuvin-P dust at 163 mg/1 in air for 1.2 hours.
No deaths occurred from this treatment, and autopsies performed after 14 days
revealed no specific response to the exposure.
d. Subacute Toxicity
The importance of subacute and chronic toxicity studies in
defining the deleterious effects of a chemical substance is exemplified by the
fact that many humans are exposed to low levels of environmental contaminants
throughout their lifetimes. Furthermore, it has become apparent that single-
dose (acute) exposure to a chemical often does not affect the same target organs
as those following repeated exposures. The additional factors of cumulative
effects on metabolic function and other physiological variables, including
growth, nutrition, reproduction, and tumor formation, make long-term studies
essential in discovering all adverse host-chemical interactions.
Only very limited subacute toxicity data are available
concerning the benzotriazole derivatives. These studies were conducted with
Tinuvin-P and Tinuvin-327. Ciba-Geigy Corp. (1976) reported that two groups
of fl;ve male and five female rats were treated by stomach tube with either
1250 mg/kg or 2500 mg/kg of Tinuvin-P suspended in gum arabic. The compound
124
-------
was administered six days each week for a total of four weeks. No deaths resulted
from the treatment, and no pathological changes were noted upon autopsy. The
same protocol was followed with Tinuvin-327 and produced the same results as for
Tinuvin-P.
In addition to the oral toxicity studies, Tinuvin-327 was
tested for subacute dermal toxicity (Ciba-Geigy Corp., 1976). Five male and
five female rats received 0.4 cc of a 5% suspension of the chemical in gum
arabic applied to the shaved skin of the back. Treatment was made six days
per week for four weeks. At the end of the study, no deaths had been produced
and no local irritation or systemic toxicity was observed.
Tinuvin-P was evaluated for subacute dermal toxicity in
both rats and mice (Ciba-Geigy Corp., 1976). The material was applied to the
shaved backs of five males and five females of each species for five consecutive
days. The compound was applied as a 5% suspension in gum arabic at a dose of
0.1 cc per day for mice and 0.4 cc per day for rats. After eight days of
observation, no deaths or other signs of toxicity were observed in any of the
treated animals.
Two studies have been conducted in which Tinuvin-P was
incorporated into the diet of dogs and rats (Ciba-Geigy Corp., 1976). Forty
young male and female rats were exposed to the compound at levels of 0, 0.2,
1.0, and 5.0% in the diet for 14 weeks. The so-called "no-effect" level of
treatment was found to be the 0.2% dose, and suggests that Tinuvin-P may pro-
duce severe chronic effects.
When tested in three groups of eight beagle dogs at dietary
levels of 1,000, 2,000, and 10,000 ppm for 90 days, Tinuvin-P caused no mortality.
125
-------
However, liver weights were elevated in all treatment groups, and two animals
in the 10,000 ppm group displayed toxic symptoms. These results are consistent
with those obtained from the subacute treatment of rats and indicate that long-
term exposure to Tinuvin-P may cause metabolic alterations of organ function,
particularly in the liver.
e. Sensitization
The ability of the benzotriazole derivatives to produce
contact sensitization of the skin or other delayed hypersensitivity reactions
is apparently very slight. Eastman Kodak Company (1975) has reported that .
5-methyl-lH-benzotriazole failed to sensitize any of five guinea pigs. When
benzotriazole was tested in guinea pigs, a definite sensitization reaction
was not produced.
Studies in humans (see Section III-B-1) have indicated that
neither Tinuvin-P nor Tinuvin-327 caused contact skin sensitization by repeated
patch testing (Ciba-Geigy Corp., 1976).
f. Teratogenicity
The structural relationship of benzotriazole derivatives
to the naturally occurring purines, adenine and guanine, has prompted investi-
gations to determine their ability to produce biochemical interference in cellu-
lar processes. It has been suggested that disruption of nucleic acid metabolism
by the benzotriazole derivatives may ultimately inhibit cell division and growth.
Early studies by Liedke and coworkers (1954) demonstrated
that several substituted benzotriazoles could severely inhibit the development
of frog embryos. Developing eggs of the frog Rana pipiens were selected for
testing at various stages of development: two-cell (stage 3), blastula (stage 8),
126
-------
gastrula (stage 11), and neurula (stage 14). The results of exposing embryos
at developmental stage 3 to several benzotriazole derivatives are presented
/
in Table 27. It is apparent from the data presented that derivative 1 produced
an almost immediate arrest of growth whereas compounds 2 and 3 did not arrest
development until the blastula stage was reached. The authors suggested that
compounds which inhibit growth at early stages of development (stage 3) may
interfere with enzyme systems involved in cell division. Arrest at later
stages (gastrula and neurula) would indicate interference with the process of
differentiation.
Table 27. Arrest of Rana piplens Embryos Upon Continuous Exposure from Stage 3
(Liedke et al., 1954)
Number
1
2
3
Compound
5-Nitro-benzotriazole
4-Methoxy-6-nitrobenzotriazole
4-Hydroxy-6-nitrobenzotriazole
Cone.
mg/100 ml
20
20
20
Arrested
Stage
3-4
7-8
7-8
Continuous exposures to other benzotriazole derivatives
commencing at various stages of differentiation were also evaluated for their
effect on embryo development. The results, summarized in Table 28, indicate
that compounds 2 and 3, which were not inhibitory at the two-cell stage, in-
hibited the neurula very strongly. Compound 2 prevented neurulation in con-
centrations as low as 1.0 mg/100 ml. At concentrations of 0.5 mg/100 ml neuru-
lation was arrested in 50% of the embryos treated at stage 8. Embryos which
127
-------
were not arrested at neurulation progressed only to the tailbud stage (stage 18),
whereupon edematous blisters developed followed by the onset of cytolysis as
manifested by the loss of yolk and cell granules.
Table 28. Arrest of Rana pipiens Embryos Upon Continuous Exposure to Benzotriazole
Derivatives (Liedke et al., 1954)
Number
1
2
3
Compound
5-Nitro-benzotriazole
5-Nitro-7-methoxybenzotriazole
5-Nitro-7-methoxybenzotrlazole
5-Nitro-7-methoxybenzotriazole
5-Nitro-7-hydroxybenzotriazole
5-Nitro-7-hydroxybenzotriazole
5-Nitro-7-hydroxybenzotriazole
5-Nitro-7-hydroxybenzotriazole
Cone.
mg/100 ml
20
20, 10, 5
2.5, 1
0.5
20
10
5
2.5
Exposure Commencing at Stage
3
3-4
7-8
10-11
—
7-8
10-12
11-12
~
8
8
10-11
12-14
14, 18
10-11
12
12-14
14-19
11
11
12-13
12-15
—
12
13-14
12-15
"
14
14-15
14
14-15
--
14
—
18-19
— - .
All of the compounds caused severe arrests in the gastrula and yolk-plug stages
(stages 11-12) which caused the ectoderm of the blastocoel roof to become in-
dented or bulged, and later collapsed and wrinkled. These substances also pro-
duced swollen arrested neurula stages and cytolysis starting at the anterior
neural folds.
A subsequent study was undertaken by Liedke and coworkers
(1955) in which Rana pj.plens embryos were treated in the tailbud stage with
4~methoxy-6-nitrobenzotriazole (MNB). Their results indicated that suscepti-
bility to MNB exposure increased with the age of the embryo. When embryos
128
-------
were exposed at stage 8 (blastula), development was slowed but not arrested.
Embryos at the tailbud stage, however, were immediately arrested and remained
in the same state even after removal from MNB exposure. Table 29 presents the
survival rates of tailbud embryos exposed to various concentrations of MNB.
Treatment with MNB produced severe morphologic and histologic effects on the
developing embryos. These included destruction of the circulatory system, stunt-
ing of growth and differentiation, and abnormal development of the heart, eye,
and other structures. The authors suggested a mechanism of toxic action that
would be consistent with an interference of embryonic differentiation rather
than with cell division in general. At the biochemical level, it was postulated
that MNB might interfere with nucleic acid and protein synthesis by virtue of
its structural relationship to the natural purines. Experimental evidence is
not available, however, to support this theory.
g. Mutagenicity
A number of investigators have demonstrated that certain
purine antagonists are mutagenic in bacterial systems. Evidence is available
which indicates that several benzotriazole derivatives not only exert profound
effects on bacterial growth (see Section III-B-6), but are also mutagenic to
certain bacterial strains. These effects appear to be the result of inter-
ference in nucleic acid synthesis.
In an early study conducted by Greer (1958), several benzo-
triazole derivatives were evaluated for mutagenicity using a purine-dependent
mutant strain of Escherichia colj designated Wp . Table 30 summarizes the
effects of substituted benzotriazoles on the growth of £_._ coli strain W and
its two purine-dependent mutants, and the mutagenic effect of these compounds
129
-------
Table 29. Comparison of Survival of Rana pipiens Embryos Exposed at Tailbud Stage 17/18 to 4-Methoxy-6-
nitrobenzotriazole (Liedke et al. ,
Compound
4-Methoxy-6-nitrobenzotriazole
Cone.
mg/ml
0.1
0.1
0.05
0.05
0.025
0.025
0.01
1955)
Hours
Exposed
10-14
20
18-20
24
20-44
72
96
% Survival When Controls Were at Stage:
18
100
100
100
100
100
100
100
19 20 21
100 100 100
o1
94 94 91
30 0
100 100 100
100 83 83
100 100 90
22 23 24 25
100 97 91 58
77 77 77 73
100 100 100 100
35 0
75 40 0
Single embryos kept in individual dishes sometimes showed 30-50% survival in spite of extreme developmental
arrest.
-------
Table 30. The Effects of Substituted Benzotriazoles on the Growth of Escherichia coll Strain W
and Two of Its Purine-Dependent Mutants, Including the Mutagenic Activity at the
Guanine-Dependent and Streptomycin-Sensitive Loci of Wp- (Greer, 1958)
OH
Effect on Survival and Mutation of Mutant Wp"
Benzotriazoles
Substitution
4
oiT
OCH3
in Position
6
NH
NH,
NO^
Escherichia coli Strain W,
Mutant Wp- and Mutant Hah~*
Concentration of Compound
200 pg/ml
& Concentration
Degree of Inhibitiont (yg/ml)
+ + + + 200
%
Inhibition
of Visible
Colony
Formation
99-9
Mean Factor of Increase Over
Spontaneous Mutant-Frequency
Purine"
to
Purine+
7
Streptomycin
to
Strep tomycinr
18
200
60
*Wp- : requiring guanine, adenine , hypoxanthine, xanthine, or 4-amino, 5-imidazolecarboxamide;
Wah~: requiring adenine or hypoxanthine.
t — no inhibition; + + +, time to reach stationary phase = >2 x control; + + + +, time to reach stationary
phase = >2.5 x control.
-------
at the guanine-dependent and streptomycin-sensitive loci of mutant Wp~. The
growth of E^_ coli in these determinations was limited to one-half maximal by
adding guanine, adenine, or glucose as the limiting growth factor for strains
Wp~, Wah~, and wild-type W, respectively. Mutagenesis was produced by two of
the benzotriazole derivatives which were also shown to be strong growth inhibi-
tors.
Although 4-hydroxy-6-nitrobenzotriazole was a strong growth
inhibitor of E. coli strains, it did not produce spontaneous mutations. It was
subsequently found, however, that the compound significantly depressed induced
mutagenesis by 4-nitro-6-hydroxybenzimidazole (Table 31). This effect was not
thought to result by growth inhibition alone, but rather may have resulted
from replacement of 4-nitro-6-hydroxybenzimidazole by 4-hydroxy-6-nitrobenzo-
triazole within the cell.
Mutagenicity data are particularly important, not only for
the assessment of potential genetic harm, but also in predicting carcinogenicity.
It is widely recognized that carcinogenic chemicals are almost always potential
mutagens as well (Miller and Miller, 1975). The International Agency for
Research on Cancer now includes mutagenicity data in its monographs on the
evaluation of carcinogenic risk of chemicals to man (Loprieno, 1975). However,
since the demonstration of mutagenicity does not establish carcinogenicity,
the data presented above must be regarded as suggestive of the" need for further
research in higher organisms. Also, the more commercially important benzo-
triazoles should be tested first in mutagenicity screening systems.
h. Carcinogenicity
There is no direct evidence yet available to indicate
whether benzotriazole or its derivatives may present a carcinogenic threat to
132
-------
Table 31. The Antimutagenic Effect of 4-OH-6-NO_-Benzotriazole on Mutagenesis in Escherichia coli
Wp- Induced by 4-N02-6-OH-Benzimidazole (NHB) (Greer, 1958)
M
OJ
U>
Marker
Purine
p~ to p+
Streptomycin
Ss to 5^
Time of Plating
Zero
After intermediate cultivation
Zero
After intermediate cultivation
Spont .
m.f.t
(a)
9.3
13
0.25
1.0
None
196 yM
(35 ug/ml)
NHB
induced
m.f.t
(b)
953
4190
137
205
4-OH-6NO -Benzotriazole*. 695 pM
Mean factor
of
increase
(b/a)
103
320
550
205
NHB
m.f.t
25
7.0
0.25
4.0
196 pM
NHB
m.f.t
(d)
173
975
14.8
32.4
Mean factor
of
decrease
(b/d)
5.5
4.3
9.2
6.3
*Antagonist was added to growing bacteria in liquid cultures 3 hours before addition of NHB.
tm. f. = mean mutant frequency x 10-vbacterium.
-------
man. It may only be suggested that because of its potential effects on nucleic
acid metabolism and its actions on the growth of bacterial (see Section III-B-6)
and animal cells (see Section III-B-7) benzotriazole can be suspect as a tumori-
genic agent.
In a report abstracted from the Russian literature
(Vasil'eva, 1970) it was disclosed that benzotriazole was probably not carcino-
genic for rats, but might induce leukemia in hybrid mice. Benzotriazole was
administered orally once weekly for 46 weeks at 100 rag/kg body weight to a
group of 315 male and female (C57 x CBA) Fl mice (weight 18 to 20 grams). The
same dosage schedule was used to treat 272 male and female Wistar and non-
inbred rats by subcutaneous injection. Rats received total doses of 900-1000 mg
while mice received a total of 92 mg.
Three rats developed tumors: one pulmonary fibroma, one
mammary adenoma, and one mesenteric polymorphocellular sarcoma. In addition,
benzotriazole induced an adipose dystrophy of the liver with necrotic foci.
In mice, the results were difficult to interpret due to
the high (55.9%) incidence of tumors in untreated controls (8.5% had malignant
tumors and 3.4% had leukemia). Among the benzotriazole-treated mice, the
incidence of leukemia was 13.7%, which was significantly higher than controls.
However, mice treated by injection with the drug vehicle alone also developed
leukemia in 11.1% of the group. Therefore, the observed incidence of leukemia
in the benzotriazole-treated mice may have been due, at least in part, to the
effect of the chemical solvent.
Extensive carcinogenesis testing with benzotriazole is
presently in progress at the National Cancer Institute (Weisburger, 1976).
134
-------
This work is scheduled to be completed by October, 1976, and should clarify the
observations as reported in the above study.
±. Behavioral Effects
No attempts have been made to determine whether exposure
to the benzotriazole derivatives can alter patterns of behavior. It might be
predicted, however, that, because of its demonstrated effects on central ner-
vous system function, benzotriazole compounds may induce centrally-mediated
behavioral changes. On the other hand, the high dosage level which would
probably be required to act upon the brain essentially precludes the possi-
bility of such an event occurring at predicted environmental levels.
j. Possible Synergisms
The environmental exposure to chemical contaminants rarely
occurs as a contact with a single pure substance. Nevertheless, it is generally
very difficult to obtain data concerning the synergistic toxicity of chemicals
either in the workplace or in the environment.
A single report has been encountered which presented the
effects of feeding benzotriazole or 5-methylbenzotriazole on the incidence of
liver tumors in rats produced by 3'-methyl-4-dimethylaminoazobenzene (Clayton
and Abbott, 1958). The benzotriazoles were added to the diet at a 0.5% level
and fed for eight weeks along with the carcinogen at a level of 0.064%. The
results, as summarized in Table 32, demonstrate that neither of the benzotria-
zoles significantly affected tumor incidence when compared to positive controls.
• ° >
Furthermore, the chronic feeding of the two benzotriazole compounds did not
produce any mortality among treated animals.
135
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Table 32. The Effect of Benzotriazole and 5-Methylbenzotriazole on the Incidence of Liver Tumors in
Male Rats Produced by Feeding 3'-Methyl-4-dimethylaminoazobenzene (Clayton and Abbott, 1958)
3'-Me-DAB*
(weeks fed)
1-8
1-8
1-8
Basal
(weeks fed)
9-16
9-16
9-16
o Other
Compound
None
Benzotriazole
5-Methylbenzotriazole
Additions
Amount Weeks Fed
0.5% 1-8
0.5% 1-8
Survivalt
(16 weeks)
14/15
15/15
15/15
Tumors§
(percent)
86
73
80
*3'-Me-DAB = 3'-methyl-4-dimethylaininoazobenzene.
tSurvival = number at conclusion of experiment over number at start.
§Percent of survivors that had liver tumors.
-------
3. Effects on Other Vertebrates
a. Toxicity to Fish
(i) Benzotriazole
The effects of benzotriazole on several species of
fingerling fish were determined in studies conducted by the Sherwin-Williams
Company (1975). Trout, bluegills, and fathead minnows were treated in static
and dynamic test systems with mortality measurements being made after 48 and
96 hours of continuous exposure. Trout were tested under dynamic conditions
only.
Table 33 presents the survival at various concentra-
tions for bluegills and minnows under static and dynamic conditions. The median
tolerance limit (TL ) values (concentration required to produce death in 50%
m
of the test animals) were found to be 27.5 ppm after 48 hours and 25 ppm after
96 hours in the static system. Under dynamic conditions, the TL values were
30.2 ppm after 48 hours and 28 ppm after 96 hours. The results indicated
that no significant differences in toxicity could be attributed to static
versus dynamic exposure. However, in both systems mortality was higher after
96 hours than after 48 hours. These findings would suggest a possible cumula-
tive toxic effect in fish.
The results of treating fingerling trout with benzo-
triazole under dynamic test conditions are presented in Table 34. The calcu-
lated TL values were 15 and 12 ppm at 48 and 96 hours, respectively. These
m
data indicate that trout are about twice as sensitive to benzotriazole as
bluegills and fathead minnows. Furthermore, it can be seen from the table
that mortality among trout was considerably higher after 96 hours than after
48 hours, and again suggests a possible cumulative toxic effect.
137
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Table 33. Static and Dynamic Exposure of Bluegills and Fathead Minnows to Benzotriazole
(Sherwin-Williams Co., 1975)
Co
oo
Concentration
(ppm) No. Fish
22 15
24 15
26 15
28 15
30
32
34
Control 15
STATIC
% Mortality
48 hour 96 hour No. Fish
00
13.3 46.7
26.7 60.0 15
60.0 86.7 15
15
15
15
00 15
DYNAMIC
% Mortality
48 hour 96 hour
—
—
20
32
41
52
63
0
—
—
35
50
.9 66.
.3 80
.0 95.
0
1
2
-------
Table 34. Dynamic Exposure of Fingerling Trout to Benzotriazole (Sherwin-
Williams Company, 1975)
% Mortality
Concentration
(ppm)
10
12
14
16
Control
No. Fish
30
30
30
30
30
48 hour
3.3
25.0
41.6
55.0
0
96 hour
3.3
30.0
90.0
100.0
0
(ii) Tolyltriazole
The acute toxicity of tolyltriazole to the fathead
minnow has been determined using a static test system (Sherwin-Williams Company,
1975). The protocol employed in the test was that issued by the Pesticides
Regulation Division of the Environmental Protection Agency (January 20, 1971).
For the sake of comparison, the acute toxicity of 74% p, p'DDT was evaluated
under the same conditions as for tolyltriazole. Following a preliminary
screening study, 20 fish were treated at each of four tolyltriazole concentra-
tions: 35.50 ppm, 28.20 ppm, 22.40 ppm, and 17.80 ppm. The resulting LC
(lethal concentration) values, as calculated by the method of Litchfield and
Wilcoxon (1949), are presented in Table 35. It is apparent that tolyltriazole
has a similar toxic potency to benzotriazole, and also may produce cumulative
toxic effects. Clearly, however, p, p'DDT is far more toxic to the fathead
minnow than is either of the benzotriazoles tested.
b. Toxicity to Amphibians
Several benzotriazole derivatives having close structural
similarity to naturally occurring purines were shown to inhibit the development
139
-------
Table 35. LC Values (ppm) and Their Confidence Limits (at p = .05) in Fathead Minnows
(Sherwin-Williams Co., 1975)
74% p, p'DDT
LC1
Lower Limit
Upper Limit
LC50
Lower Limit
Upper Limit
LC99
Lower Limit
Upper Limit
Slope
24 hour
0.0460
0.0438
0.0480
0.1180
0.1124
0.1239
0.3010
0.2867
0.3161
1.49
48 hour
0.0485
0.0462
0.0509
0.1010
0.0962
0.1061
0.2110
0.2010
0.2216
1.37
96 hour
0.0360
0.0343
0.0378
0.0945
0.0900
0.0992
0.2980
0.2838
0.3129
1.51
24 hour
23.00
19.16
27.60
36.90
30.75
44.28
68.50
57.08
82.20
1.14
Tolyltriazole
48 hour
14.00
13.33
14.70
29.80
28.38
31.29
62.50
59.52
65.63
1.38
96 hour
14.20
13.52
14.91
25.50
24.29
26.78
46.00
43.81
48.30
1.28
-------
of the Rana piplens frog embryo (Liedke et_ al., 1954, 1955). These studies
are discussed in Section lII-B-2-f of this report.
4. Effects on Invertebrates
A search of the published literature has not revealed any reports
'concerned with the effects on invertebrates of benzotriazole and its derivatives.
5. Effects on Plants
Several reports have indicated that benzotriazole can produce
distinct morphological changes in a variety of plants. In an early study by
Davis (1954) benzotriazole was shown to cause profound changes in the tomato
plant. These changes were characterized by a breaking of apical dominance,
reduced number of leaflets per leaf, elimination of leaf serrations, cupping
of the leaflets, and elongated petioles which were unable to support the weight
of their own leaves. These formative effects were produced only by exposure
of the tomato plant roots to benzotriazole; application to the foliage in con-
centrations as high as 1000 pppm had no effect. When 50 ml of a 50 ppm benzo-
triazole solution was applied daily for ten days to the sand surrounding tomato
plant roots, formative effects were noted within two to three weeks following
the final application.
Davis (1954) suggested that benzotriazole may be a competitive
antagonist of the important biological molecules, indole, and the purine bases.
However, the effects of benzotriazole could not be reversed by daily applications
of 50 ml of either 0.5 to 50 ppm of indoleacetic acid or 250 ppm adenine sulfate.
The formative effect of benzotriazole on tomato plants could be duplicated by
benzothiazole but not by indole, benzimidazole, benzoxazole, benzothiophene,
benzothiadiazole, thiophene, pyrolle, thiazole, imidazole, or 1,2,4-triazole.
141
-------
The action of benzotriazole on several plant species was later
investigated by Klingensmith (1961). The procedures employed were: (1) root
growth tests in cucumber and barley seedlings, (2) gross morphological studies
i£ tomato, bean, coleus, soybean, and wheat, and (3) tissue culture studies
using tobacc* stem tejflXasST^
Benzotriazole and 5-chlorobenzotriazole were evaluated for
repression of root elongation in cucumber seedlings. A substituted purine,
6-imethylmercaptopurine, was also included for comparison purposes. The con-
centration of each compound required* to produce 50% repression of root elonga-
tion is presented in Table 36.
Table 36. Repression^o^Cucum^^TwIHEiongation. Elongation of Primary
Root, 96 Hours at 25°C (Klingensmith, 1961)
Concentration Causing
Compound 50% Repression
_3
Benzotriazole 1 x 10 M
-4
5-Chlorobenzotriazole 1 x 10 M
-4
6-Methylmercaptopurine 3.5 x 10 M
Comparisons were also made of the effects of benzotriazole,
»
benzothiazole, and benzimidazole on the growth of barley roots and cucumber
.roots. The action of these compounds was measured as the effect upon the
conversion of endosperm to dry matter in barley roots (Figure 11) and the
repression of cucumber primary root elongation (Figure 11). Although these
142
-------
:oo
O
GC
1- 80
2
O
O
S5 60
z,
o
o
z
o
_1
LJ
40
(A)
'oil)
MO'5 5«IO-5 I.IO-4 SxlO'4 IxlO'3 5.IO"3 MO'2
MOLAR CONCENTRATION
100
o
EC
I-
z
o
o
X
o
UJ
5
(2)
5,10-5 I.IO'
Figure 11. (A) Effect of Certain Benzazoles Upon the Elongation of the Primary
Root of Cucumber Seedlings (seedlings grown in presence of the
compound at 25°C in darkness for 96 hours); (B) Effect of Certain
Benzazoles Upon Dry Weight of Barley Roots (seedlings grown in
aerated deep cultures, 25°C, in darkness for 6 days)
(Klingensmith, 1961) (1) Benzimidazole, (2) Benzothiazole,
(3) Benzotriazole
Reprinted from American Journal of Botany, 48, 40-5, with permission from
the Botanical Society of America, Inc.
143
-------
compounds were considered to be functional analogs of the purines, the addition
of adenine did not reverse the inhibitory effect of the three chemicals on
cucumber root elongation. In fact, when combined with benzotriazole, adenine
markedly enhanced the inhibition of root growth.
When applied to the soil of existing bushbean plants, benzo-
-2 -2
triazole produced death at 5 x 10 M, and at 1 x 10 M there was nearly
complete inhibition of internodal elongation with simultaneous thickening of
the stem (Klingensmith, 1961). Axillary bud activity was stimulated by the
_2
treatment, however. Similarly, treatment of tomato plants at 5 x 10 M
_2
caused early death, whereas 1 x 10 M concentrations caused persistent mor-
phological changes the same as those previously described by Davis (1954).
_2
When applied at a concentration of 1 x 10 M to the roots of barley, oats,
and wheat, benzotriazole increased the production of tillers and shoots. This
effect was suggested as being due to repression of internodal elongation. At
_2
1 x 10 M, benzotriazole produced a distinct cupping of the leaves in coleus
plants. The cupping of all new leaves persisted for 14 weeks after the appli-
cation of benzotriazole to the root medium.
, Because benzotriazole caused a suppression of apical dominance
in the plants described above, Klingensmith (1961) suggested that the effect
may be correlated with auxin transport in the tissue. When examined in tissue
culture with tobacco stem segments, however, benzotriazole did not inhibit
the polar transport of auxin. Therefore, the suppression of apical dominance
by benzotriazole could not be explained. Furthermore, in light of unsuccessful
attempts to reverse root elongation inhibition by the addition of adenine, it
appears that benzotriazole did not act as a functional purine antimetabolite
in these experiments.
144
-------
The benzotriazole derivative 5-chlorobenzo-l,2,3-triazole was
tested by Schweizer and Rogers (1964) in several plant systems. They found
that the chemical inhibited wheat root elongation and growth of carrot explants,
produced chlorosis (decreased chlorophyll content), and depressed catalase
activity. These results are summarized in Table 37.
Table 37. Physiological Effects on Plants by 5-Chlorobenzo-l,2,3-triazole*
(Shweizer and Rogers, 1964)
Compound
5-Chlorobenzo- 1,2,3- triazole
Carrot
Explant
Growth
(10~3 M)
0.0
Wheat
Root
Elongation
(2.5 x 10~4M)
41.7
Chlorophyll in
Corn (10~3 M)
WF9X
M14 38-11
90 88
Spinach
Catalase
Activity
(10~3 M)
90
*Data are expressed as percent of controls.
Several alkylbenzotriazoles were studied by Picci and Sparatore
(1968) for their effects on the elongation of sections of oat coleoptiles
in vitro. They found that at low concentrations the compounds, including
unsubstituted benzotriazole, were stimulatory to growth, while at higher
_3
concentrations (10 M) almost all were growth inhibitors (Table 38).
6. Effects on Microorganisms
a. Effects on Bacteria
Benzotriazole and many of its derivatives exert profound
effects on the growth and survival of numerous types of bacteria. These effects
145
-------
Table 38. Effect of Alkylbenzotriazoles on the Growth of Oat Coleoptile Segments In Vitro*
(Picci and Sparatore, 1968)
Molar Concentration
Substance
Benzotriazole (1H Jj£ 2H)
1-Methylbenzotriazole
1-Ethylbenzotriazole
1-Propylbenzotriazole
1-Butylbenzotriazole
2-Methylbenzotriazole
2-Ethylbenzotriazole
2-Propylbenzotriazole
2-Butylbenzotriazole
io-3
-25
-25
10
-45
-80
-5
-60
-55
-15
10-*
40
35
20
-20
-35
20
0
-40
35
io-5
50
75
40
5
0
55
40
15
75
io-6
90
115
75
60
15
65
60
40
85
io-7
135
150
50
50
-20
60
55
30
65
*Data expressed as percent increase or decrease over controls.
-------
seem, for the most part, to be related to the ability of benzotriazole deriva-
tives to act as purine antagonists and thereby disrupt vital metabolic processes.
The ability of benzotriazole to act as a potential antipurine
on a purine-requiring strain of E. coli was investigated by Collier and Huskinson
^ ---• r '
(1957). A strain of E. coli had been developed for these studies which required
the presence of adenine, guanine, hypoxanthine, or xanthine for satisfactory
growth. This strain was used as a means of detecting antipurine activity by
chemicals which inhibited the growth of the bacteria in the presence of added
purines. The purine requirement for growth in the E. coli strain is illustrated
in Figure 12.
so-,
45-
4-0-
o 3-5H
<.
UJ
cc
3-0-
i«H
30-
1-5-
1-0-
T6 T9 0-2 0-5 0-8 II 1-4 17 2-0 2-3 2-6 2-9 32 35 38 4-1
LOG. CONCENTRATION PURINE IN pg./ml.
Figure 12. Growth of Escherichia coli 8242 in Response to Addition of Purines
to the Culture Medium (Collier and Huskinson, 1957)
• •: hypoxanthine; 0 0: adenine; X X: guanine
A A: xanthine
Reprinted with permission from the Ciba Foundation.
147
-------
The addition of benzotriazole to culture media containing
serially increasing concentrations of guanine shifted the growth curve as
pictured in Figure 13. While low concentrations of benzotriazole stimulated
bacterial growth, higher concentrations were inhibitory. Since stimulation
was absent from the lower part of the curve, it was suggested that benzotria-
zole cannot replace purjines for E. coli. In actively dividing cells, however,
it appeared possible that benzotriazole might be more efficiently utilized
than purines to form some essential metabolic product. Benzotriazole was not
able to support growth of the purine-requiring E. coli strain in the absence
of adenine or guanine.
6.0-1
5.0-
o>
c
1 4.0-
oc
£
_o
'£ 3.0-
a
2.0-
1.0-
62.5'jug./ml.
Benzotriazole
No Inhibitor
125Mg./ml.
Benzotriazole
Benzotriazole
Figure 13.
i I I I I I I "
0-2 0-50-8 1-1 1-41-7 2-02-3
Log. Concentration Guanine in /ug./ml.
Effect of Benzotriazole on the Growth of Escherichia coli 8242 in
Presence of Guanine (Collier and Huskinson, 1957)
148
-------
The authors also found that the addition of 250 yg/ml phenol
to the test medium doubled growth in the presence of 200 pg/ml guanine. When
benzotriazole was added to this system, growth inhibition was evident at all
benzotriazole concentrations, as manifested by a horizontal shift of the log
purine-growth curve. It was noted that a vertical depression of the growth
curve, as in Figure 13, characterizes inhibition which is non-competitive,
whereas a horizontal shift is typical of competition resulting in an increased
requirement for purine.
As part of a screening program for potential anticancer
agents, benzotriazole was evaluated for its effect on the growth of several
bacterial systems (Foley ejt^ ._al_. , 1958). These results are presented in
Table 39.
Somewhat different results were obtained by the Sherwin-
Williams Company (1976) when they studied the effects of low-level benzotria-
zole exposure on wastewater microorganisms. These investigators incubated a
seed (5 ml per liter of dilution water) prepared from the supernatant of
settled domestic sewage in a waterbath at 20°C for five days with varying
concentrations of benzotriazole. The resultant effects on bacterial growth,
as outlined in Table 40, seem to indicate that benzotriazole may act as a
growth promoter at the concentrations tested.
Table 40. Effect of Benzotriazole on the Growth of Microorganisms from Wastewater
(Sherwin-Williams Company, 1976)
Benzotriazole Added Total Colony Count
(mg/L dilution water) (per ml)
0 initial 54,570
0 5 day 151,000
0.66 5 day 207,000
3.3 5 day 217,000
6.6 5 day 183,000
13.2 5 day 164,000
149
-------
Table 39. Bioassay of Benzotriazole Using Various Microbiological Systems (Foley et al. , 1958)
Ui
o
Incubation
Bioassay Microorganism
Streptococcus fecali
Lactobacillus casei
Escherischia coli
Lactobacillus arabinosus
Lactobacillus arabinosus
Leuconostoc citrovorum
Lactobacillus fermenti
Candida albicans
Saccharomyces
carlsbergensis
Streptococcus fecalis
Lactobacillus casei
Escherichia coli
Tetrahymena pyriformis
Glaucoma scintillans
Colpidium campy lum
Neurospora crassa
Hour
24
48
48
48
48
48
48
48
22
14
22
17
96
96
96
48
°C
37
37
37
37
37
37
37
37
30
37
37
37
25
25
25
32
Test
Vol. (ml)
10
10
10
10
10
10
10
10
6
6
6
6
4
4
4
20
Assay Medium
Folic acid
Rib o flavin
Inorganic salts , glucose
Nicotinic acid
Pantothenic acid
Citrovorum factor
Thiamine
Inorganic salts, glucose
Pantothenic acid plus pantothenate
Hydrolyzed casein, glucose, salts,
vitamins
Hydrolyzed casein, glucose, salts,
vitamins
Inorganic salts, glucose
Amino acids, glucose, salts , vitamins
Casein, amino acids, vitamins, salts
Casein, amino acids, vitamins, salts
Salts, sucrose, biotin
ID50*
(gm/ml)
>io-3
-3
io-3-
>io-3
>io-3
"lo-3 -
io"3 -
io-3-
10- 3
>io-3
io-3-
io-3-
io-3-
io-3-
io-4
io-4
io-4
io-4
io-4
io-4
io-4
io-4
ID,.- = Concentration causing 50% growth inhibition.
-------
These results should be compared with those obtained by
Foley et_ ail. (1958; Table 39) with regard to the fact that benzotriazole levels
were much lower in this study, and that the wastewater sample contained an
undefined mixture of microorganisms.
Tolyltriazole was incubated with wastewater microorganisms
under similar BOD test conditions as for benzotriazole (Sherwin-Williams Co.,
1976). The results, presented in Table 41, indicate that slight reduction in
colony populations occurred with tolyltriazole treatment.
Table 41. Effect of Tolyltriazole on Biochemical Oxygen Demand and Growth
of Wastewater Microorganisms (Sherwin-Williams Co., 1976)
Sample Concentration
(mg/L)
Dilution Water (control)
Seeded Dilution Water (control)
Tolyltriazole 0.2
Tolyltriazole 2.0
Tolyltriazole 20.0
BOD
(mg/L)
0.67
0.73
0.39
0.45
1.12
Surviving Colonies
per ml BOD Test Solution
601,000
318,000
234,000
441,000
125,000
It was concluded that, at the concentrations tested,
tolyltriazole was not significantly toxic to the wastewater bacteria. However,
it appears that at levels in excess of 20 mg/L tolyltriazole may significantly
increase toxicity and demand for oxygen.
b. Effects on Viruses
Several derivatives of benzotriazole have been shown to
possess very high virus inhibitory activity. Testing was conducted by Tamm
and coworkers (1961) using both influenza B virus in the chorioallantoic mem-
brane in vitro and poliovirus type 2 in monkey kidney cell cultures. These
results are presented in Tables 42 and 43.
151
-------
The data in Table 42 show that benzotriazole was only
one-half as active as benziraidazole. However, increasing chloro substitution
in the benzene-ring portion of the molecule caused considerably enhanced ac-
tivity. The substitution of fluorine for chlorine in the structure was not
as effective in inhibiting viral multiplication.
Table 42. Effect of Benzotriazole and Derivatives on the Multiplication of
Influenza B Virus in Chorioallantoic Membrane* (Tamm et al., 1961)
75% Virus Inhibitory
Benzotriazole Concentration (VIC)a Relative Inhibitory
Derivative (yM) Activity (RIA)b
Benzotriazole
5-Chloro
5, 6- Di chloro
4,5,6-Trichloro
4,5,6,7-Tetrachloro
5-Fluoro
5-Trif luoromethyl
5, 6- Dimethyl
7,500
610
54
12
3
2,600
180
>5,300
0.47
5.7
65
290
1,200
1.3
19
<0.66
*Infected chorioallantoic membrane cultures were incubated at 35°C for
41 hours and influenza virus was measured in the supernatant by the
hemagglutination technique.
o
Concentration (yM) required to cause 75% reduction in yield of influenza
virus.
Relative to benzimidazole.
152
-------
When tested against poliovirus type 2 in monkey kidney
cell cultures, benzotriazole was equal in activity to benzimidazole (Table 43).
Benzotriazole was significantly more effective against poliovirus than influ-
enza, whereas the reverse was true for the tri- and tetrachloro derivatives.
Similar to the previous observation with influenza virus, benzotriazole deriva-
tives became progressively more active as chlorine substitution in the benzene
ring increased.
Table 43. Effect of Benzotriazole and Derivatives on the Multiplication of
Poliovirus Type 2 in Monkey Kidney Cells In Vitro* (Tamm e_t al. , 1961)
Compound
Benzimidazole
Derivative
Benzimidazole
Benzotriazole
5-Chloro
5,6-Dichloro
4,5,6-Trichloro
4,5,6, 7-Tetrachloro
5-Trifluoromethyl
75% Virus Inhibitory
Concentration (VIC)
CyM)
2,800
2,800
500
73
23
8.1
240
Relative Inhibitory
Activity (RIA)b
1
1
5.6
38
120
350
12
*Infected monkey kidney cell cultures were incubated at 36°C for 48 hours and
poliovirus was measured in the supernatant by infectivity titrations.
o
Concentration (yM) required to cause 75% reduction in yield of poliovirus.
Relative to benzimidazole.
During the entire course of their investigations, Tamm
and coworkers (1961) evaluated a total of 65 benzimidazole and benzotriazole
153
-------
derivatives against influenza virus and 25 derivatives against poliovirus.
In both test systems, tetrachlorobenzotriazole was the most potent antiviral
compound tested. However, the mechanism of action for this antiviral effect
was not established.
c. Effects on Yeast
In experiments conducted by Loveless e_t al. (1954) it was
established that benzotriazole was inhibitory to the growth of yeast
(Saccharomyces cerevisiae) at 1 gram/ml but did not affect cell division. In
subsequent studies with the yeast Candida albleans (Bianchi, 1961) , it was
shown that benzotriazole and chlorobenzotriazole at molar concentrations of
-2 -4
10 to 10 increased the growth rate and phenotype of small-type colony
variants. This alteration in growth was temporary only, and colonies reverted
to the small-type when transferred to plates of complete media. These obser-
vations suggested an effect on a metabolic process such as nucleic acid metabo-
lism, which occurred only in the continued presence of the chemical.
7* In Vitro and Biochemical Studies
Several studies have been conducted with benzotriazole and its
derivatives to determine their effects on cultured cells, isolated mitochondria,
and certain isolated enzymes. These investigations have confirmed the sus-
ceptibility of certain cells and metabolic processes to disruption by the
benzotriazoles.
a. Effects on Isolated Organs
A search of the published literature has not identified
any reports on the effect of benzotriazole or its derivatives on isolated or
prefused organs.
154
-------
b. Effects on Cell Cultures
The use of cytotoxicity testing in cell cultures"has been
used as a primary screen for the detection of potential antitumor agents.
Benzotriazole has been tested in tissue culture systems as part of a screening
program. Smith et^ ai. (1959) reported the cytotoxicity of benzotriazole to
cultured KB cells, derived from a human nasopharyngeal epidermoid carcinoma.
They found the ID,.- (concentration that caused 50% inhibition of growth) to
be 150 yg/ml (range = 120 to 190 yg/ml). Eagle and Foley (1958) found the
ID for benzotriazole when incubated with cells isolated from normal adult
human liver to be in the area of 100 yg/ml. It should be noted that traditional
purine analogs (e.g., 8-azaguanine, 6-mercaptopurine) were far more toxic to
cells in culture than was benzotriazole. However, Smith et^ aL^. (1963) demon-
strated that toxicity in whole animals could not be closely predicted from
cytotoxicity data using KB cells.
A number of benzotriazole derivatives were evaluated for
cytotoxicity in a tissue culture system employing monkey kidney cells (Tamm et al.,
1961). The investigators determined the molar concentrations of each compound
required to cause microscopic cell damage. Compound-induced cell injury was
ranked on a scale of 1+ (slight) to 4+ (severe). Figure 14 compares the con-
centration-time dependency of damage produced by various benzotriazoles with
monkey kidney cells in vitro. It is readily apparent from the individual
damage-time curves that increasing chloro substitution of the benzotriazole
molecule markedly enhanced its toxic potency on a molar basis.
c. Effects on Isolated Organelles
In studies employing isolated rat-liver mitochondria, it
was determined that 4,5,6,7-tetrachlorobenzotriazole was a potent uncoupler of
155
-------
Ui
Benzotriazole
• 13,300 pM
O 8,840
A 5,890
A 3,930
» 2.620
5.6 — Dichlorobenzotriazole
. 343 fiM
O 229
A 153
A 102
T 68.0
V 45.3
4,5,6,7 - Tetrachlorobenzotriazole £
. 20.3 jjM
O 13.5
A 9.00
A 6.00
T 4.00
V 2.67
5 — Chlorobenzotriazole
O 1160
A 773
A 515
T 343
4,5,6 — Trichlorobenzotriazole
. 44.5/jM
O 29.7
A 19.8
A 13.2
T 8.80
V 5.87
5 — Trif luoromethylbenzotriazole
. 445 MM
O 297
A 198
A 132
T 88.0
Figure 14. Compound Induced Damage-Time Curves with Selected Benzotriazole Derivatives in Monkey
Kidney Cells (Tamm et al., 1961)
-------
oxidative phosphorylation (Parker, 1965; Jones and Watson, 1967). In producing
this effect, tetrachlorobenzotriazole had more than eight times the potency
of 2,4-dinitrophenol, a classical uncoupling chemical (Jones and Watson, 1967).
Other benzotriazole derivatives which were found to uncouple oxidative phos-
phorylation, but were less active than the tetrachloro derivative, are 5-chloro-
4-nitrobenzotriazole and 5-nitrobenzotriazole (Parker, 1965). Data on the
activity of unsubstituted benzotriazole as an uncoupler were not available.
d. Effects on Isolated Enzyme Systems
Several in vitro enzymatic systems have been employed
for the detection of potential anticancer agents. These assays are designed
to identify compounds which might selectively inhibit a system and result in
more harm to malignant than normal cells. Benzotriazole was evaluated by
Ciaccio ^t. _al • (1967) for the inhibition of several enzyme systems. These
studies are summarized in Table 44.
Table 44. Effect of Benzotriazole on the Inhibition of Selected Enzymatic
Systems In Vitro (Ciaccio et^ al. , 1967)
•
Enzyme System
Dehydrogenase
Glycolysis
Nucleic Acid Enzyme
Test (Substrate)
Lactate Dehydrogenase
Glycerophosphate
Glucose
Deoxyribose Aldolase
Deoxyribose Aldolase
Thymidine Phosphorylase
Neg. Log
Molarity
2.0
2.0
3.0
3.0
3.0
3.0
Percent
Inhibition
0
0
0
59
48
0
157
-------
As indicated in Table 44, benzotriazole was an effective
inhibitor of deoxyribose aldolase. This enzyme was suggested as being part
of one pathway for the biosynthesis of the deoxyribose portion of DNA. A com-
mon purine analog, 8-azaxanthine, was also shown in the same test system to
be an inhibitor of deoxyribose aldolase activity (Ciaccio et al., 1967). How-
ever, it has not been established whether this enzyme inhibitory effect is
correlated with any structural similarities to the naturally occurring purines.
158
-------
IV. Regulations and Standards
A. Current Regulation
A search of the Food Drug Cosmetic Law Reporter (Commerce Clearing
House, Inc., Chicago, Illinois) reveals that no regulations currently exist
for pesticidal, drug, or food applications of benzotriazole.
Several restrictions have been placed on the use of the benzotria-
zole-derivative UV-light stabilizers. These limitations are summarized in
Table 45.
The transportation of hazardous materials by rail and highway is
regulated by the Hazardous Materials Regulation Board of the Department of
Transportation. In January, 1974, the Department of Transportation proposed
extensive changes in the rules governing the transport of hazardous chemicals,
especially by air. These changes, published in the Federal Register (January 24,
1974) listed a large number of chemical substances. However, neither benzo-
triazole nor its derivatives are included on this list or are classified as
being hazardous.
B. Concensus and Similar Standards
Limits have been established for maximum permissible exposure to
hazardous chemicals by several agencies. Threshold limit values (TLV's) for
chemicals in the workroom environment have been established by the American
Conference of Governmental Industrial Hygienists. These TLV's, which are
revised and updated each year, do not, however, include benzotriazole or any
of its derivatives.
Exposure limits for hazardous substances have also been set by the
Occupational Safety and Health Administration and the National Institute for
Occupational Safety and Health. Their list of standards which has been pub-
lished in the Federal Register (October 19, 1972) does not include any deriva-
tives of benzotriazole.
159
-------
Table 45. Food and Drug Administration Status of Ciba-Geigy Stabilizers -
July 1973 (Ciba-Geigy, 1976)
I. Existing Approvals
1. TINUVIN P
A. Acrylics, rigid, semirigid and modified (121.2566/121.2591)
max. cone. - no restrictions
max. thickness - no restrictions
food limitations - no restrictions
B. Rigid vinyl and vinyl chloride copolymers (121.2566/121.2521)
max. cone. - 0.25%
max. thickness - no restrictions
food limitations - no restrictions
C. Polystyrene (121.2566/2510)
max. cone. - no restrictions
max. thickness - no restrictions
food limitations - dry foods with the surface having no
free fat or oil and
Polystyrene and modified polystyrene containing less than
10% rubber (121.2566/2510)
max. cone. - 0.25%
max. thickness - no restrictions
food limitations - nonalcoholic food only
2, TINUVIN 326
Olefin polymers, including EPDM (121.2566/2501)
max. cone. - 0.5%
max. thickness - no restrictions
food limitations - non-fatty foods, food with less than
8% alcohol
3. TINUVIN 328
Adhesives (121.2520)
max. cone. - no restrictions
max. thickness - no restrictions
food limitations - no restrictions
II. FDA Opinions in Effect
TINUVIN 327 may be used at levels up to 0.5% in polypropylene slit film
and related materials in applications involving contact with dry foods
containing no free fat or oil.
160
-------
TECHNICAL SUMMARY
Benzotriazole and its commercially significant derivatives are light colored
powders, relatively insoluble in water, and chemically stable under normal con-
ditions of storage and use. They are characterized by generally broad absorption
in the 300-400 nm region of the UV spectrum (Dal Monte £t jLL., 1958; Ciba-Geigy
Corp., undated).
Commercial production of benzotriazole is via diazotization of £-phenylene-
diamine with nitrous acid (Levy, 1966; Long, 1971). The total production of ben-
zotriazoles is estimated to be approximately 5-6 million pounds per year in the
United States. The majority of this output is used in anticorrosion applications,
especially in the protection of copper and copper alloys. Benzotriazole forms a
thin, highly stable, transparent monomolecular polymeric film on copper surfaces,
consisting mainly of cuprous benzotriazole units (Roberts, 1974; Ogle and Poling,
1975). The film is thermodynamically and chemically quite stable and offers ex-
cellent protection from chemical attack under the usual corrosion inducing con-
ditions. One of the major uses of benzotriazole as an anticorrosion agent is in
glycol-based antifreezes for automotive applications. It is used also in recir-
culating water systems such as power plant cooling units, and for the protection
of copper alloys in architectural and decorative applications.
Approximately 20-30% of benzotriazoles produced are derivatives which are
incorporated into various substrates susceptible to degradation on exposure to
light in the 300-400 nm range. These benzotriazole derivatives (various
2-(2'-hydroxyphenyl)-benzotriazoles) are capable of absorbing light and dissipa-
ting the energy as heat and molecular vibrations, thereby protecting the substrate
161
-------
(Ciba-Geigy, undated). Other than under special conditions of intense radiation
at short wavelengths in the laboratory, benzptriazole compounds are photochemi-
cally stable. Polypropylene is the chief resin that is protected by benzotriazole
stabilizers. Other UV protective applications include paint formulations,
clear coatings, and oils used as solvents and dispersants for insecticides. In
the latter application, the benzotriazole derivative is placed directly into
the environment during use.
There are a number of photographic applications for benzotriazole, all of
which apparently use very small quantities of the material and are unlikely to
result in significant environmental contamination with benzotriazoles.
The photochemical stability of benzotriazoles at wavelengths encountered
at the surface of the earth, coupled with the chemical stability of the benzene
ring and especially the triazole ring, suggest that benzotriazoles in contact
with air, water, or sunlight are likely to be quite stable and persistent. And,
in fact, the 2-substituted benzotriazoles have been detected at ppb in river
water and ppm in river sediment downstream from a production plant (Jungclaus,
1977). While the biodegradability of benzotriazoles has not been studied
specifically, there is some evidence that the flora of wastewater treatment
plants will tolerate these compounds in industrial wastewater effluent in
concentrations on the order of magnitude of 10 mg/ml (Quinn, 1972, 1973).
Also, they will pass through a trickling filter treatment plant (Jungclaus,
1977).
Benzotriazole and its derivatives have not been extensively studied for
biological activity, especially in recent years. They are generally considered
to be relatively hazard-free materials (Eastman Kodak, 1975). Toxicity testing
in humans has been limited mainly to patch tests for allergic sensitization
162
-------
(Ciba-Geigy, 1976) to 2-(2'-hydroxyphenyl)-benzotriazoles, with negative re-
sults. Manufacturers have indicated no experiences with occupational poisoning.
There are no accounts in the literature concerned with absorption or
elimination of benzotriazoles in animal systems, nor have the metabolic pro-
ducts or primary eliminative routes in animal systems been examined. However,
studies on mice at toxic dose levels provide evidence that benzotriazoles at
sufficiently high doses severely affect the central nervous system.
Benzotriazole has been screened for tumor activity and has been found to
be inhibiting against a strain of mammary adenocarcinoma and other tumors
(Anon., 1958; Tarnowski and Bates, 1961). Negative results on inhibition of
the same type of tumor have also been reported (Gellhorn et^ al., 1953). Any
tumor inhibitory activity which benzotriazole may possess is probably related
to its ability to disrupt purine metabolism, which results in impeding nucleic
acid synthesis in tumor cells. Benzotriazoles have been shown to possess
purine antagonist properties in bacterial studies (Greer, 1958).
Benzotriazoles may present a severe respiratory hazard if inhaled (Sherwin-
Williams Co., 1976). Studies of rats indicate that severe local respiratory
damage, rather than absorption and systemic poisoning, is responsible for the
high toxicity of benzotriazole dusts. The dust is also a severe explosion
hazard (Dorsett and Nagy, 1968). In situations outside the manufacturing or
direct usage environments, it is not likely that exposure to benzotriazole -
dusts would occur.
Several benzotriazole derivatives not only exert profound inhibitory
effects on bacterial growth, but are also mutagenic to certain bacterial species
(Greer, 1958). The particular derivatives studied are not among the currently
163
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important commercial benzotriazoles. Although mutagenic chemicals are frequent-
ly carcinogenic (Miller and Miller, 1975), there is no direct evidence yet
available to indicate whether benzotriazole or its derivatives may present a
carcinogenic threat to man. Because of its potential effect on nucleic acid
synthesis and metabolism, and its actions on the growth of bacterial and cancer
cells, benzotriazole may be implicated as a tumorigen. Carcinogenesis testing
of benzotriazole is presently under way at the National Cancer Institute
(Weisburger, 1976), with results expected to be available in late 1976.
Benzotriazole has a cumulative toxic effect on certain tested young fresh
water fish at concentration levels on the order of 12-25 ppm (Sherwin-Williams
Co., 1975). It has been shown to inhibit embryo development in Rana pipiens
(Liedke et^ at!L. , 1954, 1955). Benzotriazole also inhibits plant growth (Davis,
1954), bacterial growth (Foley, 1958), fungal growth (Loveless et^ a^., 1954),
and viral growth (Tamm et al., 1961). These growth inhibiting phenomena are
generally attributed to the tested compound's purine antagonist properties.
Levels of tolyltriazole, for example, above 20 ppm in wastewater would probably
significantly increase the toxicity of the medium to lower vertebrate and in-
vertebrate species, as well as increase oxygen demand (Sherwin-Williams Co.,
1975).
No regulations currently exist for pesticide, food, or drug applications
of benzotriazole. Several restrictions have been placed on the use of 2-(2'-
hydroxyphenyl)-benzotriazoles as UV stabilizers for plastic food containers.
The concentration of the stabilizer is limited to 0.25-0.50% (depending on the
olefin or polystyrene substrate), and the foodstuff must be nonalcoholic and
fat-free.
164
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REFERENCES
Abbott, T.I. (1969), "Silver Halide-Sensitized Copper Printing Plates," French
Demande Patent No. 2,003,606, 10 pp.
Adler, T.K. and Albert, A. (1963), "The Biological and Physical Properties of
the Azaindoles," J. Med. Chem., 6/5), 480-3.
Aiken, J.K., Howard, D.K. and Popplewell, A.F. (1965), "Inhibiting Copper
Corrosion," British Patent No. 994,409, 2 pp.
Akiyama, T. and Terano, Y. (1964), "Determination of Silver and Copper by
1,2,3-Benzotriazole," Kyoto Yakka Daigaku Gakuho, 12, 53-5.
Albert, A., Goldacre, R. and Phillipi, J. (1948), "The Strength of
Heterocyclic Basic," J. Chem. Soc., 1948, 2240-2249.
Albright & Wilson (Mfg.) Ltd. (1961), "Benzotriazole as a Corrosion Inhibitor
for Copper," British Patent No. 865,192.
Angely, L., Bonnemay, M., Bronoel, G. and Peslerbe, G. (1971), "Adsorption of
Benzotriazole on Copper," Metaux, 46/555), 409-13.
Anon, (undated), "Cobratec," Sherwin-Williams Chemical Co., Technical Bulletin
#531.
Anon. (1956), "Benzotriazole Explodes," Chem. Eng. News, 34, 2450.
Anon. (1958), "Summary of Results of Antitumor Tests on 200 Selected Compounds,"
Ann. N.Y. Acad. Sci., 7*, 965-970.
Anon. (1969), "Application Data Sheet," Copper Development Assoc., New York City
Anon. (1972), "Food Additives. Antioxidants and (or) Stabilizers for Polymers,"
Fed. Regist., 37/44), 4711-12, March 4, 1972.
Anon. (1973 a), "Chemical Composition of Photographic Processing Solutions,"
Publication J-47, Eastman Kodak Company, Rochester, New York.
Anon. (1973 b), "Processing Chemicals and Formulas for B & W Photography,"
Publication J-l, Eastman Kodak Company, Rochester, New York, p. 32.
Anon. (1974), Eastman Organic Chemicals Catalog No. 47, Eastman Kodak Co.,
Rochester, New York, pp. 34, 192.
Anon. (1975), "Kodak Photographic Products for the Professional - 1975-76,"
Publication #P2-1, Eastman Kodak Co., Rochester, New York, pp. 92-3.
Anon. (1975 a), "Cobratec Analytical Procedures," Technical Bulletin #550,
Sherwin-Williams Chemical Co.
165
-------
Anon. (1975 b), "Products and Processes," American Metal Marketing, June 20,
p. 26.
Anon. (1976), Eastman Organic Chemicals Catalog No. 48, Eastman Kodak Company,
Rochester, New York, pp. 27, 185.
Anon. (1976 a), "Triazole," Chem. & Eng. News, March 8, p. 10.
Anon. (1976 b), Chemical Marketing Reporter, Feb. 9, 1976, p. 25 from Chem.
Industry Notes, .5(13), 9.
Anon. (1976 c), Eastman Kodak Company 1975 Annual Report, pp. 26-9.
Anon. (1976 d), "Kodak'Finally Unveils Instant Color Camera," Chem. & Eng.
News, _54(18), 4.
Anon. (1976 e), "Third Progress Report on Process E-6," Eastman Kodak Company,
Publication No. Z-203.
Arient, J. and Dvorak, J. (1956), "Chlorobenzotriazoles," Chem. Listy, 50,
1856-8.
Balaban, L. (1964), "Stabilization of Polypropylene Against Ultraviolet
Radiation," Chem. Prumysl, 3.4_(7), 366-9.
Battaglia, C.J. (1970), "The Antifoggant Action of Substituted Benzotraizoles
Using Electrochemical Techniques and Silver-Silver Bromide Electrodes,"
Photogr. Sci. Eng., 1.4(4), 275-82.
Benson, F.R. and Savell, W.L. (1950), "The Chemistry of the Vicinal Triazoles,"
Chem. Revs., 46, 1.
Bergmann, F., Ungar-Waron, H. and Kwietny-Govrin, H. (1964), "Action of 8-
Azaguanine and 8-Azaxanthine on Pseudomonas aeruginosa, " Biochem. J.,
21(2), 270.-6.
Bezuglyi, V.D., Alekseeva, T.A., Borovskaya, N.V., Vekhova, O.A., Novikova, T.S.
and Zaslavskii, N.N. (1971), "Polarographic Determination of Tinuvin P
in Glass-Fiber Reinforced Plastics," Zavod. Lab., _37/10), 1184-5.
Bianchi, D.E. (1961), "Small Colony Variant in Candida albicans," J. Bacteriol.,
82_, 101-5.
Bonora, P.L., Giordano, and Zucchi, F. (1969), "Action of Some Corrosion
Inhibitors in Neutral Solution," Ric. Sci., 39_(2), 145-51.
Boyer, J.H. (1961), "Monocyclic Triazoles & Benzotriazoles," in Heterocyclic
Compounds, Vol. 7, Roht. C. Elderfield, Ed., J. Wiley & Sons, Inc., New York.
Boyer, J.H. and Selvarajan, R. (1969), "Photo-Elimination of Nitrogen From
Fused-Ring Triazoles," J. Heterocycl. Chem., 6/4), 503-6.
166
-------
Boyle, R.J. and Milionis, J.P. (1965), "Benzotriazole Ultraviolet Absorbers,"
U.S. Patent No. 3,213,058, 5 pp.
Brown, J.C., Cheer, R.A. and Keogh, P.J. (1971), "Benzotrlazoles and -diazoles
as Antifoggants in Photographic Silver Halide Emulsions," German Offen.
Patent No. 2,031,254, 16 pp.
Broyde, B. (1970), "Electron-Sensitive Materials," Bell Syst. Tech. J., 49_(9),
2095-104.
Biichel, K.H. and Draber, W. (1969), "Structure-Activity Relationships of
Photosynthesis-Inhibition by NH-Acidic ir-Excessive Heteroaromatica,"
Progress in Photosynthesis Research, Vol. 3, 1777-1788.
Buckley, D.A. and Coffee, W.L. (1973), "Duplication-Proof Documents," German
Offen. Patent No. 2,228,749, 23 pp.
Q
Cantatore, G. and Bordini, F. (1963), "Heat-, Aging-, and Light-Resistant
Polyolefin Compositions," Belgium Patent No. 628,131, 10 pp.
Cesare, F.C., Farber, M. and Cuthbertson, G.R. (1971), "Polypropylene Fiber,"
Kirk-Othmer Encycl. of Chem. Technol., Supplemental Volume, 808-36.
Chantrenne, H. and Devreux, S. (1958), "Effects of 8-Azaguanine on the Synthesis
of Protein and Nucleic Acids in Bacillus cereus," C. R. Soc. Biol., Paris,
152, 1202.
Chantrenne, H. and Devreux, S. (1960), "Effect of 8-Azaguanine on the Synthesis
of Proteins and Nucleic Acids in Bacillus cereus," Biochem» Biophys. Acta.,
.39, 486-499.
Chemed Corp. (1975), "Corrosion Inhibition," British Patent No. 1,290,843,
6 pp.
Christensen, H.E. and Luginbyhl, T.T. (1975), Registry of Toxic Effects of
Chemical Substances, 1975 Edition, U.S. Dept. of Health, Education and
Welfare, Public Health Service, Center for Disease Control, National
Institute for Occupational Safety and Health, Rockville, Maryland.
Ciaccio, E.I., Boxer, G.E., Devlin, T.M. and Ford, R.T. (1967), "Screening
Data From Selected In Vitro Enzymatic Systems. I. Standard Test Compounds
From the Cancer Chemotherapy National Service Center," Cancer Res., 2_7_
(Part 2), 1033.
Ciba-Geigy Corp. (undated), Product Bulletins for the following products:
Tinuvin P, Tinuvin 320 (preliminary), Tinuvin 326, Tinuvin 327, Tinuvin 328.
Ciba-Geigy Corp. (1972), Safety Data Sheets for the following products:
Tinuvin P, Tinuvin 320, Tinuvin 326, Tinuvin 327, Tinuvin '328.
167
-------
Ciba-Geigy Corp. (1972 a), "Corrosion Inhibitors Containing Benzotriazole
Derivatives," French Patent No. 2,114,478, 20 pp.
Ciba-Geigy Corp. (1974), "Tinuvin Price Schedule," Ardsley, New York, August 31.
Ciba-Geigy Corp. (1976), Personal communication.
Cieciuch, R.F. and Schlein, H.N. (1972), "Stabilization of Def-Diffusion Process
Color Pictures, "Ger. Offen. 2,300,173,32 pp.
Clayton, C.C. and Abbott, L.D. (1958), "Inhibitory Effects of Certain Benzi-
midazole Derivatives on the Production of Azo Dye Liver Tumors," Cancer
Res., 1.8, 94-97.
Collier, H.O.J. and Huskinson, P.L. (1957), "The Effects of Potential Anti-
purines on a Purine-Requiring Strain of Escherichia coli," Ciba Foundation
Symposium, Chem. and Biol. Purines, (1957), 146-56.
Compostella, M. (1964), "Stabilization of Polypropylene Against Heat, Light,
and Aging," Belgium Patent No. 635,079, 12 pp.
Cotton, J.B. (1963), "Preventing Corrosion Pits in Copper Domestic Water Systems,"
British Patent No. 933,979, 2 pp.
Cotton, J.B. (1964), "Corrosion Inhibitors for Copper and Its Alloys," British
Patent No. 957,115, 2 pp.
Cotton, J.B. (1965), "Rust Inhibitors for Steel," British Patent No. 1,006,825,
2 PP.
Cotton, J.B. and Scholes, I.R. (1967), "Benzotriazole and Related Compounds
as Corrosion Inhibitors for Copper," Brit. Corros. J., _2_(1), 1-5.
Crawford, I.H. and Hartman, F.M. (1967), "Color Photographic Images Stable to
Ultraviolet Radiation," French Patent No. 1,475,329, 9 pp.
Crough, P.E. and Snyder, H.J. (1973), "Photographic Composition of Sodium and
Potassium Ions for Treating Direct-Positive Emulsions," U.S. Patent
No. 3,733,199, 5 pp.
Dahle, N.A. (1974), "Combating Aphids With Benzotriazolecarboxamides," U.S.
Patent No. 3,808,334, 3 pp.
DalMonte, D., Mangini, A., Passerini, R. and Zavli, C. (1958), "Ricerche
Suglieterociclici - Nota VI. Spetlri di Assorbimento Nel Vicino U.V.
di Triazoli, Benzo-triazolie Fenil-benzotriazoli," Gazz. Chim. Ital.,
88.» 977.
Davis, D. (1954), "Benzotriazole, a Plant Growth Regulator," Science, 120,
989.
168
-------
Dilling, W.L., Tefertiller, N.B. and Kallos, G.J. (1975), "Evaporation Rates
and Reactivities of Methylene Chloride, Chloroform, 1,1,1-Trichlo-
ethane, Trichloroethylene, Tetrachloroethylene, and Other Chlorinated
Compounds in Dilute Aqueous Solutions," Environ. Sci. Technol., £(9),
833-838.
Domino, E.F., Unna, K.R. and Kerwin, J. (1952), "Pharmacological Properties of
Benzazoles I. Relationship Between Structure and Paralyzing Action,"
J. Pharmacol. Exptl. Therap., 102, 486.
Donaldson, E., Fowler, B.T. and Tims, J.M. (1965), "Lubricating Greases,"
British Patent No. 984,488, 3 pp.
Dorsett, H.G., Jr. and Nagy, J. (1968), "Dust Explosibility of Chemicals, Drugs,
Dyes, and Pesticides," U.S. Bur. Mines, Rep. Invest., No. 7132, 23 pp.
Dugdale, I. and Cotton, J.B. (1963), "An Electrochemical Investigation on the
Prevention of Staining of Copper by Benzotriazole," Corrosion Sci., _3_(2),
69-74.
Durmis, J., Karvas, M., Caucik, P. and Holcik, J. (1975), "Loss of Light
Stabilizers from Polypropylene," Eur. Polym. J., 11(3), 219-22.
Eagle, H. and Foley, G.E. (1958), "Susceptibility of Cultured Human Cells to
Antitumor Agents," Ann. N.Y. Acad. Sci., 7<6, 534-541.
Eastman Kodak Co. (1972), "Benzotriazole (Practical)", Material Safety Data
Sheet #902759.
Eastman Kodak Co. (1975, 1976), Personal communication, Rochester, N.Y.
Elliott, J.S. and Edwards, E.D. (1961), "Synthetic Lubricating Oils, Especially
for Gas-Turbine Engines," U.S. Patent No. 2,971,912.
Epstein, S.S., Saporoschetz, I.E., Small, M., Park, W. and Mantel, N. (1965),
"A Simple Bioassay for Antioxidants Based on Protection of Tetrahymena
pyriformis from the Photodynamic Toxicity of Benzo(a)pyrene," Nature
(London), 208. 655-658.
Escande, A., Galigne, J.L. and Lapasset, J. (1974 a), "Crystal and Molecular
Structure of Benzotriazole," Acta Crystallogr., Sect. B., _30(Part 6),
1490-5.
Escande, A., Lapasset, J., Raure, R., Vincent, E.J. and Elguero, J. (1974 b),
"Molecular Structure and Fundamental Properties of the Benzazoles Indazole,
Benzimidazole, and Benzotriazole," Tetrahedron, _30_(16), 2903-9.
Faerman, G.P. and Pletnev, A.P. (1957), "Speeds of Reduction of Silver Bromide
and Silver Salts of Photographic Stabilizers," Uspekhi Nauch. Fot.,
Akad. Nauk S.S.S.R. Otdel. Khim. Nauk, 5, 114-26.
169
-------
Ferrari, G., Canonica, L. and Danielli, B. (1973), "Photostabilization of
Insect-Molting Hormones," German Offen. Patent No. 2,247,507, 14 pp.
Fischer, E. (1973), "Light-Degradable Plastics," German Offen. Patent No.
2,201,890, 10 pp.
Foley, G.E., McCarthy, R.E., Binns, V.M., Snell, E.E., Guirard, B.M., Kidder,
G.W., Dewey, V.C. and Thayer, P.S. (1958), "A Comparative Study of the
Use of Microorganisms in the Screening of Potential Antitumor Agents,"
Ann. N.Y. Acad. Sci., 76^ 413-438.
Frank, H.P. and Lehner, H. (1970), "Distribution of Ultraviolet Stabilizers
in Crystalline Polypropylene," J. Polym. Sci., Part C, No. 31, 193-203.
Fujita, S. (1974), "Copper Corrosion-Inhibiting Insulating Oil," Japanese
Patent No. 74,114,100.
Gaffin, C.H. (1970), "Photographic Compositions for Producing High Gloss
Prints," German Offen. Patent No. 1,942,884, 20 pp.
Gale, E.F. and Folks, J.P. (1957), "Assimilation of Amino Acids by Bacteria.
XXIV. Inhibitors of Incorporation of Glycine in Disrupted Staphylococcal
Cells," Biochem. J. , £7_, 507-17.
Geigy Co. Ltd. (1965), "Purification of Benzotriazole," Netherlands Patent
No. 6,408,573, 4 pp.
Geigy, A.-G. (1965 a), "Non-Oxidizing, Tarnish-Preventing Metal Cleaning
Pastes," Belgium Patent No. 656,693, 8 pp.
Geigy, A.-G. (1965 b), "Preparation of 5-Substituted Benzotriazoles,"
Netherlands Patent No. 6,414,144, 19 pp.
Gellhorn, A., Engleman, M., Shapiro, D., Graff, S. and Gillespie, H.B. (1950),
"The Effect of 5-Amino-7-Hydroxy-v-Triazolo(d)Pyrimidine (Guanzolo) on
a Variety of Neoplasms in Experimental Animals," Cancer Res., 10, 170.
Gellhorn, A., Kells, A. and Hirschberg, E. (1953), "Tests of Compounds Against
Various Experimental Tumors," Cancer Res. (Suppl. 1), 40a-44.
Gortner, W.A. and Leeper, R.W. (1969), "Relation of Chemical Structure to
Plant Growth-Regulator Activity in the Pineapple Plant. V. Postharvest
Delay of Senescence of Pineapple Fruit," Bot. Gaz., 130(2), 87-97.
Gillespie, H.B., Engleman, M. and Graff, S. (1954), "Benzimidazoles and Benzo-
triazoles as Growth Antagonists," J. Amer. Chem. Soc., 76, 3531-3533.
Greer, S.B. (1958), "Growth Inhibitors and Their Antagonists as Mutagens and
Antimutagens in Escherichia coli," J. Gen. Microbiol., 18, 543-64.
170
-------
Hansen, R.H. (1968), "Benzotriazoles and Its Derivatives and Related Compounds
as Inhibitors for Oxidation of Polypropylene Electrical Insulation in
the Presence of Copper," U.S. Patent No. 3,367,907, 3 pp.
Hansen, R.H., De Benedictis, T. and Martin, W.M. (1965), "Stabilization of
Polypropylene," Polymer Eng. Sci., 5/4), 223-6.
Harrison, R.D. (1963), "Nonphytotoxic Spray Oil," U.S. Patent No. 3,098,000,
3 pp.
Harrison, S. and Woodroffe, G.L. (1965), "The Determination of Benzotriazole
in Inhibited Glycol Products," Analyst, 90/1066), 44-9.
Hatch, G.B. (1960), "Corrosion Inhibitors for Copper and Cuprous Alloys in
Contact with Water," U.S. Patent No. 2,941,953.
Havir, J. (1967), "Potentiometric Determination of Silver with 1,2,3-Benzo-
triazole," Collection Czech. Chem. Commun., 32.U)» 130-40.
Heinemann, B. and Howard, A.J. (1964), "Induction of Lambda-Bacteriophage in
Escherichia coli as a Screening Test for Potential Antitumor Agents,"
Appl. Microbiol., .12(3), 234-239.
Heller, H., Keller, E., Gysling, H. and Mindermann, F. (1961), "Benzotriazoles
as Ultraviolet Light Absorbers," U.S. Patent No. 3,004,896, 6 pp.
Herlinger, H. and Kuester, B. (1975), "2-Phenylbenzotriazoles," German Offen.
Patent No. 2,413,005, 19 pp.
Hirakawa, H. and Sakai, T. (1973), "Preventing the Deterioration of Adhesion
Between Steel and Rubber," German Offen. Patent No. 2,227,013, 15 pp.
Hopps, H.B. (1971), "Spontaneous Combustion of 1-Chlorobenzotriazole," Chem.
Eng. News, 49_(30), 3 pp.
House, J.E., Jr. and Lau, P-S. (1974), "Complexes of Benzotriazole, Benzoxazole,
and Benzothiazole with Palladium(II)," J. Inorg. Nucl. Chem., 36.(!)» 223-4.
Hoyer, F., Bourges, M. and Deltenre, R. (1968), "Radiolytic Corrosion and Related
Problems in the Cooling Water Circuits of High-Energy Particle Accelerators,"
Eur. Organ. Nucl. Res., CERN, 68-2. 16 pp.
Hubert, A.J. (1969), "Photochemistry of Benzotriazoles,'7 J. Chem. Soc. C, (10),
1334-6.
Jones, O.T.G. and Watson, W.A. (1967), "Properties of Substituted 2-(Trifluoro-
methyl)benzimidazoles as Uncouplers of Oxidative Phosphorylation," Biochem.
J., 102, 564-73.
171
-------
John, D.H.O. and Field, G.T.J. (1963), Photographic Chemistry, Rheinhold
Publishing Co., New York, pp. 24, 80-83.
Jungclaus, G.A. (1977), "Organic Compounds in the Wastewaters and Receiving
Waters of a Small Chemical Manufacturing Plant," Toxic Chemicals in
the Environment; Their Analysis and Assessment MIT, Cambridge, Feb. 15.
Kamiya, M. (1970), "ir-Electronic Structures of Five-Membered Heterocycles
Containing Two or Three Heteroatoms and Their Benzo-Derivatives," Bull.
Chem. Soc. Jap., 43_(11), 3344-53.
Keil, R. (1971), "Gravimetric Determination of Small Amounts of 1,2,3-Benzo-
triazole," Fresenius' Z. Anal. Chem., 257(5), 349-50.
Keino, G. and Nakato, K. (1972), "Hue Stabilizing of Vinyl Chloride Resins
Against Heat," Japanese Patent No. 72 41,735, 4 pp.
Kendall, J.D., Fry, D.J. and Lea, B.A. (1959), "Ethylene Glycol Antifreeze
Solutions," British Patent No. 811,675.
Kidder, G.W., Dewey, V.C., Parks, R.E. and Woodside, G.L. (1949), "Purine
Metabolism in Tetrahymenes and Its Relation to Mice," Science, 109, 511.
Kirsten, W.J. (1956), "Exchange Spectrophotometry. I.", Mlkrochim. Acta,
(1956), 1617-20.
Klingensmith, M.J. (1961), "Effect of Certain Benzazole Compounds on Plant
Growth and Development," Am. J. Botany, ^8_, 40-5.
Korpics, C.J. (1974 a), "Aromatic Triazoles Inhibit Corrosion of Copper and
Copper Alloys," Materials Performance, 13_(2), 36.
Korpics, C.J. (1974 b), "Aromatic Triazoles as Corrosion Inhibitors of Copper
and Copper Alloys," Anti-Corros. Methods Mater., ^1_(3), 11-13.
Krietsch, E. (1958), "Inhibitor for Hot-Water Corrosion in Boilers," German
Patent No. 1,111,900.
Kreutzberger, A. and Dietz, E. (1970), "Synthesis and Antiinf lammatory Action
of 1-Aroyl- and 1-Acylbenzotriazoles," Tetrahedron Lett., (17), 1457-8.
Kreutzberger, A., Van der Goot, H. (1974), "Synthesis and Antiinflammatory
Activity of Aliphatically Substituted Benzotriazoles," Arch. Pharm.
307_(11), 824-8.
Kriisa, A. (1970), "Stabilization of Pigments Used in Dyeing Polymers Against
the Action of Light," German Offen. Patent No. 2,013,648, 6 pp.
Kuroha, T. , Shibuya, S. and Sato, T. (1975), "Anticorrosive Thermoplastic
Compositions," Japanese Patent No. 75 58,147, 3 pp.
172
-------
Kuwahara, A., Watanabe, T. and Machida, Y. (1974), "Photochemical Destruction
of Silk Fibers. V. Adaptation of a U.V. Absorbent of the Benzotriazole
Group to Prevent Yellowing and Destruction of Silk," Nippon Sanshigaku
Zasshi, 43_(6), 445-50.
Letchworth, P.E. and Pallos, P.M. (1972), "Stabilized Insecticidally Active
Compounds," S. African Patent No. 71 05,370, 12 pp.
Levy, J. (1966), "1,2,3-Benzotriazole," U.S. Patent No. 3,227,726, 3 pp.
Levy, S.G., Baker, D.A. and Monroe, R.F. (1967), "Noncorrosive Dry-Cleaning
Compositions," U.S. Patent No. 3,337,471, 2 pp.
Liddell, R.W. and Birdeye, G. (1958), "Inhibiting the Corrosion of Pipe Systems
Made of Iron and Copper, or Their Alloys," German Patent No. 1,046,438.
Liddell, R.W. (1959), "Benzotriazole-Containing Corrosion Inhibitors for Ferrous
Metals," U.S. Patent No. 2,877,188.
Liedke, K.B., Engelman, M. and Graff, S. (1954), "The Selective Response of
Amphibian Embryos to Benzimidazole and Benzotriazole Derivatives," J.
Exp. Zool., 127. 201-217.
Liedke, K.B., Engelman, M. and Graff, S. (1955), "Inhibitors of Amphibian
Development," Anat. Rec., 123, 359-376.
Litchfield, J.T. and Wilcoxon, T. (1949), "A Simplified Method of Evaluating
Dose-Effect Experiments," J. Pharmacol. Exptl. Therap., 96, 99-113.
Long, J.W., III. (1971), "Benzotriazole Production," U.S. Patent No. 3,564,001,
5 pp.
Loprieno, N. (1975), International Agency for Research on Cancer (IARC) Mono-
graphs on the Evaluation of Carcinogenic Risk of Chemicals to Man:
"Relevance of Data on Mutagenicity," Mutation Res., 31, 201.
Loveless, L.E., Spoerl, E. and Weisman, T.H. (1954), "A Survey of Effects of
Chemicals on Division and Growth of Yeast and Escherichia coli," J.
Bact., 68, 637-644.
Loznevoi, G.I., Kosobokova, N.L. and Faerman, G.P. (1975), "Dyeing of Positive
Photographic Images Obtained by the Diffusion Transfer Method," Zh.
Nauchn. Prikl. Fotogr. Kinematogr., .2(3(1), 25-30.
Lund, H. and Kwee, S. (1968), "Electroorganic Preparations. XXV. Polarography
and Reduction of Benzotriazole and Related Compounds," Acta Chem. Scand.,
, 2879-89.
Mackay, D. and Leinonen, P.J. (1975), "Rate of Evaporation of Low-Solubility
Contaminants from Water Bodies to Atmosphere," Environ. Sci. Technol. ,
1(3), 1178-1180.
173
-------
Madsen, H.B. (1971), "Further Remarks on the Use of Benzotriazole for Stabiliz-
ing Bronze Objects," Studies in Conservation, 16, 120-122.
Malec, R.E. (1975), "Lubricating Oil Compositions Containing Trialkyl-substituted
Phenols and Benzotriazole," U.S. Patent No. 3,900,410, 3 pp.
Mandel, G. (1957), "Incorporation of 8-Azaguamine and Growth Inhibition in
Bacillus cereus," J. Biol. Chem., 225, 137.
Mandel, G. (1961), "Further Studies on the Modifications of Nucleic Acid
Synthesis of Bacillus cereus by 8-Azaguamine," J. Pharmacol., 133, 141.
Mansfeld, F. and Smith, T. (1973), "Benzotriazole as Corrosion Inhibitor for
Copper. II. Acid Sodium Chloride Solutions," Corrosion (Houston), 29(3),
105-7.
Marabelli, M. and Guidobaldi, F. (1972), "Efficiency of Some Protective Agents
and Corrosion Inhibitor in Preserving Deteriorated Bronzes," Quad. Ric.
Sci., No. 81, 95-105.
Margot, A. and Gysin, H. (1957), "Benzotriazole Derivatives," U.S. Patent
No. 2,806,035.
Mathis, R.D. (1975), "Nickel Complex-Hydroxybenzotriazole Stabilizer System for
Polyolefins," U.S. Patent No. 3,912,686, 4 pp.
Mauret, P., Fayet, J.P., Fabre, M., Elguero, J. and DeMendoza, J. (1974),
"Study of the Tautomerism of Benzotriazole from Dipole Moment Measure-
ments," J. Chem. Phys. Physicochim. Biol., 7.1(2), 115-16.
McTeer, L.W. and Kelso, R.G. (1972), "Benzotriazoles," U.S. Patent No.
3,639,431, 4 pp.
Mees, C.E.K. and James, T.H. (1971), The Theory of the Photographic Process,
3rd Edition, The Macmillan Co., New York, pp. 344-346.
Meighen, A.D. (1957), "Antifreeze Compositions," U.S. Patent No. 2,803,603.
Metcalf, R.L. and Lu, P-Y. (1973), "Environmental Distribution and Metabolic
Fate of Key Industrial Pollutants and Pesticides in a Model Ecosystem,"
U1LU-WRC-0069, U.S. Nat. Tech. Inform. Serv., PB 225-479.
Midland Silicones Ltd. (1959), "Organosiloxane Greases," British Patent No.
809,731.
Miller, J.A. and Miller, E.G. (1975), "Metabolic Activation and Reactivity
of Chemical Carcinogens," Mutation Res., 33, 25-26.
Moll, F., Morcher, B., Reckziegel, E., and Saleck, W. (1973), "Silver Halide
Emulsions for the Production of Reversal Color Photographic Images,"
U.S. Patent No. 3,779,764.
174
-------
Montgomery, J.A. and Hewson, K. (1965), "Synthesis of Potential Anticancer
Agents.-XXXIV. Flurobenzimidazoles and Fluorobenzotriazoles," J. Med.
Chem., .8(6), 737-740.
Morita, Y., Komatsu, S., Kogure, Y. and Nomura, A. (1973), "Analysis of
Organic Nitrogen Compounds. XV. Simple and Rapid Method for Determination
of Benzotriazole and Methylbenzotriazoles by Potentiometry and Gas
Chromatography," Bunseki Kagaku, ^2_(8), 1036-41.
Miller, E.B. and Schaudecker, G.F. (1958), "Benzotriazoles," U.S. Patent
No. 2,861,078.
Minnesota Mining and Manufacturing Co. (1966), "Thermographic Duplicating
Processes," British Patent No. 1,047,512.
Munekata, E. and Sakakibara, S. (1973), "Application of 1-Hydroxybenzotriazole
to Peptide Syntheses," Yuki Gosei Kagaku Kyokai Shi, 3^(10), 853-8.
Neely, W.B., Branson, D.R. and Blau, G.E. (1974), "Partition Coefficient to
Measure Bioconcentration Potential of Organic Chemicals in Fish,"
Environ. Sci. Technol., JJ(13), 1113-5
Ochiai, M. , Sakurai, H., Sugawa, T. and Furuya, N. (1975), "Removal of Metals
from Waste Water," Japanese Patent No. 75 19,260, 5 pp.
Oddy, W.A. (1974), "Toxicity of Benzotriazole," Stud. Conserv., 19_(3), 188-9.
Ogle, I.C.G. and Poling, G.W. (1975), '-'Corrosion Inhibition of Copper with
Benzotriazole," Can. Metall. Q., ^4(1), 37-46.
Ohkubo, K., Noguchi, J. and Ohmura, K. (1971), "Photographic Silver Halide
Emulsions," German Offen. Patent No. 2,041,019, 15 pp.
Ohkubo, K., Noguchi, J. and Masuda, T. (1972), "Heat-Developable Light-
Sensitive Elements for Making Prints," U.S. Patent No. 3,635,719.
Okamoto, T. (1974), "Removal of Heavy Metals in Waste Water," Japanese Patent
No. 74 81,202, 4 pp.
O'Neal, C. and Borger, R.N. (1975), "Corrosion Inhibiting Synergism by
Triazoles in Aqueous Multimetal Systems," Symposium on Oilfied Chemistry,
Soc. of Petroleum Engineers of AIME, Paper //SPE 5310, Jan. 16-17.
Orth, R.E., Bennett, J.W., Ma, 0. and Young, L. (1968), "Centrally Acting
Isoteric Mannich Bases," J. Pharm. Sci., 5£(10), 1814-17.
Otterstedt, J.E.A. (1973), "Photostability and Molecular Structure," J.
Chem. Phys., _58_(12), 5716-25.
Parker, V.H. (1965), "Uncouplers of Rat-Liver Mitochondrial Oxidative
Phosphorylation," Biochem. J., 97, 658-661.
175
-------
Parish Chemical Co. (1976), Personal communication.
Picci, V. (1966), "Effect of Benzotriazole and of Two Benzotriazolylacetic
Acids on Plant Growth," Farmaco (Pavia), Ed. Sci. , 2^(2), 172-7.
Picci, V. and Sparatore, F. (1968), "Effect of Benzotriazolylalkanoic Acids
and Alkylbenzotriazoles on Plant Growth," Farmaco, Ed. Sci., 23/2), 131-9.
Poddar, S.N. and Ray, K. (1970), "Amperometric Estimation of Copper with
1,2,3-Benzotriazole," Indian J. Appl. Chem., 33(3), 183-8.
Poddar, S.N. and Ray, K. (1973), "Amperometric Estimation of Nickel and
Cobalt with 1,2,3-Benzotriazole," J. Indian Chem. Soc., 513(6), 391-3.
Poling, G.W. (1970), "Reflection Infrared Studies of Films Formed by Benzo-
triazole on Copper," Corros. Sci., 1.0(5), 359-70.
Popeck, S.P. and Sottysiak, J.R. (1959), "Antifogging Agents for Light-Sensitive
Paper Emulsions," U.S. Patent No. 2,915,395.
Prail, J.K. and Shreir, L.L. (1961), "Effect of Codeposited Material on the
Corrision Behavior of Electrodeposits," Corrosion Sci., ±, 181-2.
Preziosi, P., Manca, P. and Paglietti, G. (1965), "Choleretic Activity of
Benzotriazolyl Alkanoic Acids," Ed. Sci., 20/4), 238-47.
Quinn, H. (1972), "Survival Studies of Wastewater Microorganisms in Contact
with Benzotriazole," Agatha Corp. (Private communications to Sherwin
Williams Co.).
Quinn, H. (1973), "Survival of Wastewater Microorganisms in Contact with
Tolyltriazole," Agatha Corp. (Private communications to Sherwin
Williams Co.).
Randell, D.R. and Hargreaves, J.R. (1970 a), "Benzotriazoles from N-Hydroxy-
benzotriazoles," German Offen. Patent No. 2,003,828, 9 pp.
Randell, D.R. and Hargreaves, J.R. (1970 b), "Benzotriazoles from 1-Hydroxy-
benzotriazoles," German Offen. Patent No. 2,003,860.
Rees, C.W. and Sale, A.A. (1971), "New Synthesis of 1,2,3-Triazoles," J.
Chem. Soc. D (1971)(11). 532.
Rees, C.W. and Storr, R.C. (1969), "1-Chlorobenzotriazole: A New Oxidant,"
J. Chem. Soc. C (1969)(11). 1474-7.
Reynolds, G.A. (1964), "Reaction of Organic Azides with Benzyne," J. Org.
Chem., 2^(12), 3733-4.
Roberts, R.F. (1974), "X-ray Photoelectron Spectroscopic Characterization of
Copper Oxide Surfaces Treated with Benzotriazole," J. Elec. Spec, and
Rel. Phen., 4., 273.
176
-------
Rothstein, E.G. (1968), "Clear Coatings," Paint Varn. Prod., _58_(2), 39-43.
Sahyun, M. (1970), "Effect of Benzotriazole on Color Development Kinetics,"
Photogr. Sci. Eng., 14_(3), 192-6.
Sahyun, M.R.V. (1971), "Interaction of Benzotriazole with Development and
Fog Centers," Photogr. Sci. Eng., 15(1), 48-53.
Sahyun, M.R.V. (1974), "Mechanisms of Development Restraint. Chemistry of
6-Nitrobenzimidazole and Benzotriazole," Photogr. Sci. Eng., 18(4),
383-7.
Santodonato, J., Davis, L.N., Howard, P.H. and Saxena, J. (1976), "Investigation
of Selected Potential Environmental Contaminants: Mercaptobenzothiazoles,"
U.S. Environmental Protection Agency, Washington, D.C., EPA-560/2-76-006.
Sasse, K., Wegler, R. and Grewe, F. (1961), "Benzotriazoles and Fungicidal
Compositions Therefrom," British Patent No. 885,843, 5 pp.
Sathianandham, B., Balakrishnan, K. and Subramanyan, N. (1970), "Triazoles as
Inhibitors of Corrosion of Mild Steel in Acids," Brit. Corros. J., _5_(6),
270-3.
Schanker, L.S. (1964), "Physiological Transport of Drugs," Adv. Drug Research,
1, 71-106.
Schweizer, E.E. and Rogers, B.J. (1964), "Structural Requirements of Amitrole
for Physiological Activity," Weed Science, 12, 7-10.
Servg, M.P. and Rosenberg, H.M. (1973), "Photolysis of l-Benzyl-l,2,3-benzo-
triazole," J. Heterocycl. Chem., ^0(2), 245-7.
Serve, M.P. (1974 a), "Photolysis of l-Hydroxy-l,2,3-benzotriazole," J.
Heterocycl. Chem., 11(2), 245-6.
Serve, M.P. (1974 b), "Photolysis of l-Methoxy-l,2,3-benzotriazole," J.
Org. Chem., .39(25), 3788-9.
Seymour, R.B. (1968), "Plastics Technology," Kirk-Othmer Encycl. Chem. Technol.,
2nd Ed., 15, 790-811.
Sherwin-Williams Co. (undated), "Benzotriazole and MET in Closed Recirculating
Water Systems," Technical Bulletin #530, Cleveland, Ohio.
Sherwin-Williams Co. (1976), Personal communication, Toledo, Ohio.
Sherwin-Williams Co. (1975), "Price List - June 1, 1975," Cleveland, Ohio.
Sherwin-Williams Co. (1975 a), "Material Safety Data Sheets - IH-Benzotriazole,
Tolyltriazole".
Sherwin-Williams Co. (undated), "Benzotriazole - Tolyltriazole," Technical
Bulletin #143.
177
-------
Smith, C.G., Lummis, W.L. and Grady, J.E. (1959), "An Improved Tissue Culture
Assay. II. Cytotoxicity Studies with Antibiotics, Chemicals, and Solvents,"
Cancer Res., 19_, 847-852.
Smith, C.G., Grady, J.E. and Northam, J.I. (1963), "Relationship Between
Cytotoxicity and Whole Animal Toxicity," Cancer Chemotherapy, 30, 9-12.
Smith, J.D. and Matthews, R.E.F. (1957), "The Metabolism of 8-Azapurines,"
Biochem. J. , 66_, 323.
Sparatore, F. and Pagani, F. (1962), "Benzotriazole. Synthesis of Some New
Derivatives," Farmaco (Pavia), Ed. Sci., 17, 414-29.
Speers, D.E. (1974), "High-Contrast, High-Capacity Monobath Processing Method
and Composition for Monochrome Film," U.S. Patent No. 3,857,710, 4 pp.
Stein, W. (1961), "Hydraulic Fluid," British Patent No. 867,181.
Stock, C.C., Clarke, D.A., Philips, F.S. and Barclay, R.K. (1960), "Sarcoma
180 Screening Data," Cancer Res., 20/3) Part 2, 1.
Stockdale, M. and Selwyn, M.J. (1971), "Influence of Ring Substituents on the
Action of Phenols on Some Dehydrogenases, Phosphokinases and the Soluble
ATPase from Mitochondria," Eur. J. Biochem., 21(3), 416-23.
Strutz, I., Herbig, H., Poppe, K. and Zinner, H. (1956), "Fungistatic Action
of Benzazoles," Naturwissenschaften, 43, 281.
Sturm, J. and Kralove, H. (1961), "Supersensitization of Photographic Silver
Halide Emulsions," Czechoslovakian Patent No. 98,762.
Takekawa, Y. , Higuchi, T. and Matsui, T. (1973), "Photothermographic Copying
Paper Containing Organic Silver Salts and Halogen Compounds," Japanese
Patent No. 73 89,720, 5 pp.
Tamm, I. (1961), Bablanian, R., Names, M.M., Shunk, C.H., Robinson, F.M., and
Folkers, K.A. "Relation Between Structure of Benzimidazole Derivatives
and Selective Virus Inhibitory Activity; Inhibition of Polio-Virus
Multiplication and Cytopathic Effects by 2-(a-Hydroxybenzyl)benzimidazole
and Its SChloro Derivative," J. Exptl. Med., 113, 625-55.
Tanaka, T. and Tanigawa, K. (1974), "Corrosion Inhibitors for Iron and Steel,"
Japanese Patent No. 74 83,639, 2 pp.
Tanner, E. (1959), "Detergents," German Patent No. 1,059,601.
Tarnowski, G.S. and Bates, L.A. (1961), "Bioassay of Suspensions of the Nelson
Mouse Ascites Tumor Treated With Chemicals In Vitro," Cancer Res., 21(8),
Part 2, 377.
178
-------
Thirtle, J.R. (1968), "Phenylenediamines and Toluenediamines," Kirk-Othmer
Encycl. Chem. Technol., 2nd Ed., 13, 216-24.
Tozzi, A. (1974), "Light Stabilizers for Polyolefins," Polym. Age, .5(10), 272-4.
Tsujimoto, K., Ohashi, M. and Yonezawa, T. (1972), "Photochemical Decomposition
of Benzotriazoles," Bull. Chem. Soc. Jap., 45/2), 515-19.
Uhde, W.J. and Woggon, H. (1968), "Testing of Plastic Commodities. Determination
of the Tendency of Certain Hydroxyphenylbenzotriazoles (Ultraviolet
Absorbers) to Migrate Into Edible Oil," Nahrung, 12/8), 825-34.
U.S. International Trade Commission (1970-1974), Imports of Benzenoid Chemicals
and Products, Washington, D.C.
Vasil'eva, N.N. (1970), "Comparative Evaluation of the Toxic and Possible
Carcinogenic Action of Benzotriazole and Phenidone," Gig. Tr. Prof.
Zabol., 14_(3), 55-6.
Viland, C.K. (1958), "Catalytic Cracking of Hydrocarbon Oils," U.S. Patent
No. 2,844,520.
Vink, P. (1973), "Changes in Concentration of Some Stabilizers During the
Photooxidation of Polypropylene Films," J. Polym. Sci. Polym. Symp.,
No. 40, 169-73.
Walker, R. (1970), "Effect of Benzotriazole on the Stress in Copper Electro-
deposits," Plating, 57/6), 610-14.
Wall, K.H. and Davies, I. (1965), "Corrosion Control in a Water-Cooled Stator,"
J. Appl. Chem., .15(8), 389-92.
Watanabe, Y., Mitsudo, T., Tanaka, M., Yamamoto, K. and Takegami, Y. (1972),
"1,2,3-Benzotriazole Complexes of Palladium(II)," Bull. Chem. Soc. Jap.,
45_(3), 925-6.
Weast, R.C. (1967), Handbook of Chemistry and Physics, 48th Ed., Chemical
Rubber Publishing Co.
Weichert, K. and Hegemann, H. (1965), "Ethylene Glycol-Base Antifreeze for
Cooling Systems of Internal Combustion Engines," German Patent No.
1,201,121, 2 pp.
Weisburger, E.K. (1976), Personal communication, National Cancer Institute,
Bethesda, Maryland.
Werner, R.E. and Langstroth, T.A. (1958), "Stabilized Varnishes Containing Azo
Dyes," U.S. Patent No. 2,838,412.
Woodroffe, G.L. and Munro, J.D. (1970), "Determination of Sodium Mercaptobenzo-
thiazole and Benzotriazole in Inhibited Glycol Products," Analyst (London),
95/1127), 153-7.
179
-------
Yamaguchi, R., Takada, M., Kudo, K. and Echigo, Y. (1975), "Fireproofed
Polyester Fibers," Japanese Patent No. 75 89,631, 8 pp.
Zannucci, J.S. and Lappin, G.R. (1975), "Titanium Dioxide Pigmented Polymer
Compositions with Improved Visible and Ultraviolet Light Stability,"
U.S. Patent No. 3,900,442, 5 pp.
Zuraw, C.L. (1970), "Biodegradable Lubricating Emulsions," U.S. Patent No.
3,507,792, 4 pp.
180
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CONCLUSIONS AND RECOMMENDATIONS
On the whole, it appears from the available evidence that benzotriazoles
of current commercial significance present no particularly serious health or
environmental hazards at present use levels and applications. However, this
conclusion must be tempered with the understanding that a great deal is as yet
unknown about the subacute effects of benzotriazoles in plant and animal systems,
and especially in man. Market studies indicate the production of benzotriazoles
is increasing and may be more than doubled by the end of this decade. Signifi-
cantly increased usage of benzotriazoles could affect their status as environ-
mental hazards, especially to aquatic life, for which benzotriazoles may be
more of a hazard than for man. Currently, benzotriazoles enter the environment
mainly via discarded antifreeze and discarded plastic products which have been
UV-stabilized with benzotriazoles. A significant increase in certain other
uses (for example as UV stabilizers in oil-based insecticides) could result
in additional environmental loading.
Animal tests have shown that benzotriazole dust is a respiratory hazard.
It is also an explosion hazard. In spite of this, no standards have been set
for benzotriazoles for threshold or exposure limit values in (at least) the
workroom environment by any of the agencies or groups responsible for such
standards. Standards are also lacking for those few uses which place benzo-
triazoles directly into the environment. Of course, the setting of such stan-
dards would depend heavily on the status of benzotriazole and its derivatives
as serious poisons or tumorigens, the possibility of which is indicated by
their apparent ability to disrupt nucleic acid synthesis or endogenous purine
utilization. Carcinogenicity testing of benzotriazoles is currently underway.
181
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These studies are well warranted and their results ought to have a major
impact on the regulatory standards for benzotriazoles which should be forth-
coming thereafter.
In summary, industrial experience with benzotriazoles has been good.
Nevertheless, the environmental.consequences of current use patterns cannot
presently be evaluated due to the lack of sufficient monitoring data. Since
these compounds are likely to be persistent if placed in the environment,
selective effluent and ambient monitoring of benzotriazoles would be desirable,
along with the simultaneous development of information on the chemical and
biological interaction of benzotriazoles with living systems.
182
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TECHNICAL REPORT DATA
, (Please read Instructions on tlic reverse before completing/
1. REPORT NO. 2.
EPA 560/2-77-001
4. TITLE AND SUBTITLE
Investigation of Selected Potential Environment*
Contaminants: Benzotriazoles
7.AUTHOR1S)
Leslie N. Davis, Joseph Santodonato,
Philip H. Howard, Jitendra Saxena
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Center for Chemical Hazard Assessment
Syracuse Research Corporation
Merrill Lane
Syracuse, NY 13210
12.
15.
It).
17.
it.
IS.
EPA
SPONSORING AGENCY NAME AND ADDRESS
Office of Toxic Substances
U.S. Environmental Protection Agency
Washington, D.C. 20460
SUPPLEMENTARY NOTES
3. RECIPIENT'S ACCESSION-NO.
5. REPORT DATE
ll
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO
TR 76-585
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
EPA 68-01-3416
13. TYPE OF REPORT AND PERIOD COVERED
Final Technical Report
14. SPONSORING AGENCY CODE
ABSTRACT
Benzotriazoles are produced in approximately 5-6 million pounds per year in
the United States. The majority are used in anticorrosion applications. Approxi-
mately 20-30% are used as UV stabilizers, many of which are 2-substituted benzo-
triazoles. Small amounts are used for photographic applications. Information
on production, use, transport and handling, environmental fate, and toxicity are
reviewed.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS b.lDENTIFI
Benzotriazoles
Tinuvins
Anticorrosion agents
UV stabilizers
DIW^VWEaWlable to the public ".SECUR,
through the National Technical Informa-
tion Service, Springfield, VA 22151 20 SECURI
Form 2220-1 (9-73)
EOS/OPEN ENDED TERMS c. COSATI Field/Croup
TY CLASS (Thin Report) 21. NO. OF PACifcS
191
TY CLASS (Thispage) 22. PRICE
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