x>EPA
United States
Environmental Protection
Agency
Office of Mobile Source Air Pollution Control
Emission Control Technology Division
2565 Plymouth Road
Ann Arbor, Michigan 48105
EPA 460/3-84-016
November 1984
Air
Survey of Safety Related
Additives for Methanol Fuel
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EPA 460/3-84-016
Survey of Safety Related Additives
for Methanol Fuel
by
E. Robert Fanick
and
Lawrence R. Smith
Southwest Research Institute
6220 Culebra Road
San Antonio, Texas 78284
Contract No. 68-03-3162
Work Assignment 5
EPA Project Officer: Robert J. Garbe
Task Technical Officer: Thomas M. Baines
Prepared for
ENVIRONMENTAL PROTECTION AGENCY
Office of Mobile Source Air Pollution Control
Emission Control Technology Division
2565 Plymouth Road
Ann Arbor, Michigan 48105
November 1984
-------
This report is issued by the Environmental Protection Agency to report
technical data of interest to a limited number of readers. Copies are available
free of charge to Federal employees, current contractors and grantees, and
nonprofit organizations - in limited quantities - from the Library Services
Office, Environmental Protection Agency, 2565 Plymouth Road, Ann Arbor,
Michigan, 48105.
This report was furnished to the Environmental Protection Agency by Southwest
Research Institute, 6220 Culebra Road, San Antonio, Texas, in fulfillment of
Work Assignment 5 of Contract No. 68-03-3162. The contents of this report are
reproduced herein as received from Southwest Research Institute. The
opinions, findings, and conclusions expressed are those of the author and not
necessarily those of the Environmental Protection Agency. Mention of
company or product names is not to be considered as an endorsement by the
Environmental Protection Agency.
Publication No. EPA 460/3-84-016
ii
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FOREWORD
This project Work Assignment was conducted for the U.S. Environmental
Protection Agency, 2565 Plymouth Road, Ann Arbor, Michigan, 48105, by the
Department of Emissions Research of Southwest Research Institute, 6220
Culebra Road, San Antonio, Texas, 78284. This project, authorized by Contract
68-03-3162, Work Assignment 5, was initiated on July 18, 1983 and completed
February 18, 1984. The EPA Project Officer was Mr. Robert 3. Garbe and the
EPA Task Technical Officer was Mr. Thomas M. Baines, both of the Emission
Control Technology Division, Environmental Protection Agency. The SwRI
Project Leader was Dr. Lawrenc~ R. Smith and the principal researcher at SwRI
was Mr. E. Robert Fanick. The SwRI Project Manager was Mr. Charles T. Hare.
This project was identified within Southwest Research Institute as (initially) 05-
7338-005 and (later) 03-7338-005.
ill
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ABSTRACT
This report describes the effort to determine what additives may be
feasible for use with 100% methanol motor vehicle fuel to increase the safety
associated with the use of methanol as a motor vehicle fuel. A survey of the
literature was conducted to determine candidate additives that would 1) ensure
methanol burns with a visible flame, 2) prevent improper use of the fuel as a
degreaser or cleaning agent, 3) give the fuel an unpleasant taste causing
expectoration of any methanol accidentally in one's mouth, and 4) act as an
emetic. Candidate additives were evaluated as to effectiveness, cost, ease of
production, health problems associated with the additive, and estimated effects
on vehicle performance.
iv
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TABLE OF CONTENTS
Page
FOREWORD iii
ABSTRACT iv
LIST OF FIGURES vi
LIST OF TABLES vii
I. SUMMARY 1
II. FLAME LUMINOSITY 3
A. Literature Search 3
B. Evaluation 15
III. TASTE DETERRENTS 18
A. Literature Search 18
B. Evaluation 26
IV. DYES AND COLORANTS 29
A. Literature Search 29
B. Evaluation 33
V. EMETIC 34
A. Literature Search 34
B. Evaluation 34
VI. ODORANTS 37
A. Literature Search 37
B. Evaluation 42
VII. OTHER METHODS TO INCREASE SAFETY 44
REFERENCES 47
APPENDIX
A. BACKGROUND AND HISTORY
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LIST OF FIGURES
Figure Page
1 Experimental Rate of Absorption for Methanol Versus Time 30
2 Warning Sign for Storage Tanks and Containers 45
3 Warning Sign for Areas in Which Methyl Alcohol is Present 45
vi
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LIST OF TABLES
Table Page
1 Potential Flame Luminosity Enhancers 5
2 Relative Radiation Characteristics of a Variety of
Pure Hydrocarbons 4
3 Time Dependent Flame Luminosity with Methanol 7
4 Azeotrope Systems with Methanol 11
5 Effect of Water on Luminosity of Dimethylether-
Primed Methanol 13
6 U.S. Government-Authorized Denaturants for Completely
Denatured Alcohol (C.D.A.) and Specially Denatured
Alcohol (S.D.A.) 19
7 Denaturant Formulas for Ethanol and Other Fuels 20
8 Compounds for Foul Taste 24
9 Current Costs of Several Widely used Taste Deterrents 27
10 Methanol Absorption Rate through the Skin at Different
Exposure Times 31
11 General Automotive Fluid Colors 32
12 Therapeutic Category - Emetic 35
13 Odorant Tests: Odor of Various Odorants Above a Solution
in Methanol 38
14 Odorant Tests: Evaporation of a Solution in Methanol
into a Closed Room 39
15 Malodorous Substances 40
vii
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I. SUMMARY
The objective of this program was to evaluate additives which may be
feasible for use with 100% methanol motor vehicle fuel to increase the safety
associated with the use of the methanol fuel. These additives were evaluated
regarding their ability to 1) ensure that methanol burns with a visible flame, 2)
discourage improper use of the fuel as a degreaser or cleaning agent, 3) give the
fuel an unpleasant taste causing expectoration of any methanol accidentally
taken into the month, and 4) act as an emetic. The effectiveness, cost, ease of
production, health problems associated with use, and estimated effects on
vehicle performance were taken into account when evaluating the additives.
Information for the study was obtained from a survey of the literature and from
contact with numerous individuals having experience related to methanol, fuels
in general, specified types of additives, and health and safety.
The scope of this study did not encompass the question of whether or not
a given methanol fuel safety aspect should be addressed by use of fuel
additives. Rather, the study departed from the position that the methanol fuel
safety aspect should in fact be addressed by additives. Thus, this study was
limited to issues such as additive effectiveness, cost, east of production, etc.
Due to methanol's low odor intensity, harmful levels of methanol vapor
could go undetected. For this reason, the use of odorants as additives to
methanol was also investigated. Additional safety measures, not related to the
use of additives, were suggested in the literature and by several researchers.
These additional measures are discussed briefly in Section VI of the report. A
substantial amount of background information on methanol was also assembled
during the course of the study, and this information has been summarized in an
appendix for use as required.
The observations and conclusions that were reached in this study are
listed below. The conclusions are based on information obtained from the
literature and elsewhere.
1. For flame luminosity enhancement, the most practical and effective
additives appear to be highly complex mixtures of hydrocarbons such
as a reformate fraction distilling in the range of 55 to 220 C (4
volume percent addition) or unleaded gasoline (10 to 15 volume
percent addition). These additives increase the cost of methanol
fuel on the order of 10 to 15 percent, however, a large portion of
this would be offset by the higher energy content of the hydrocarbon
mixtures. These mixtures form a number of azeotropes with
methanol which burn with a visible flame that persists throughout
the duration of combustion of the mixtures fire. The addition of
complex mixtures of hydrocarbons, such as unleaded gasoline, also
aids in other related areas such as reducing the f lammability of the
methanol vapor in a closed system (i.e., fuel tank), increasing the
ability to start an engine at low ambient temperatures, and
increasing the odor and taste intensity of the fuel blend.
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2. For taste deterrence, two additives appear viable. Gasoline (or
other complex mixtures of hydrocarbons) also appears to be a
reasonable additive to methanol as a taste deterrent. Gasoline can
not be removed easily from a mixture with methanol, and
researchers have reported that even a determined consumer would
have difficulty in swallowing such a mixture. Bitrex (a taste
deterrent used in paints, detergents, and other products) is one of
the most bitter substances known to man and would also be a prime
candidate as a taste deterrent for methanol. If used in methanol at
concentrations similar to those used in other applications (2-9 ppm),
Bitrex would be relatively inexpensive (0.5 to 2.1 cents per gallon of
methanol) and effective taste deterrent.
3. Dyes appear to be the best way to discourage the use of methanol as
a degreasing or cleaning agent. A number of dyes in a variety of
colors are soluble in methanol. Commercial methanol products have
typically been blue in color, and a continuation of this practice
would be logical for fuel methanol. A concentration of only 4
milligrams of dye per gallons of methanol (at a cost of 0.02
cents/gallons methanol) has been found to give an easily
recognizable color. A concentration of 400 milligrams per gallon,
however, was needed to stain the skin. This concentration of dye
would cost about 2 cents per gallon of methanol. However the
desirability of the use of such large concentrations of dyes would
have to be investigated, as a methanol fuel containing a sufficient
dye to stain the skin could result in irreversible coloration of
clothing and vehicle components, could cause excess engine wear
due to deposits, and could lead to additional exposures to toxic
cleaning compounds when trying to remove the dye from skin or
clothing.
4. The use of an emetic as an additive for methanol was evaluated to
determine if its use would be practical to induce vomiting if the
methanol fuel was consumed. This appears impractical, however, as
the necessary concentration of an emetic (such as ipecac) in
methanol required to induce vomiting was found to be about eight
volume percent. The cost for such a quantity of ipecac would be
$85/gallon of methanol and its use would drastically reduce the
availability of emetics for established applications. The use of a
large quantity of an emetic in fuel could also cause engine damage
if the selected emetic differs greatly in composition from the fuel.
5. Due to methanol's low odor intensity, added odorants are necessary
to enhance olfactory detection of methanol vapors. Mercaptans
have been shown to be effective odorants for methanol at
concentrations as low as 200 mg per gallon methanol. Mercaptans
are used in natural gas, so their use in methanol could cause some
confusion (i.e., is it a methanol spill or natural gas leak) when their
odor is detected. The more chemically stable organic sulfides,
which have a slightly different but equally intense odor, may be
more desirable.
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. FLAME LUMINOSITY
One of the chemical properties of neat methanol is that pools of liquid
methanol burn with a low luminosity, bluish flame which is essentially invisible
especially in daylight. Methanol flame radiation occurs primarily at infrared
wavelengths that are invisible to the naked eye. The property of low flame
luminosity is not desirable because an invisible fire is difficult to detect and
thus more difficult to extinguish. A visible flame increases the safety factor,
since one could adequately detect any accidental fires and move to safety or
take steps to extinguish the flame.
A. Literature Search
The luminosity of a burning substance is in part related to the formation
of submicroscopic soot particles during the combustion process. These
carbonaceous particles are heated by the flame and subsequently emit "grey-
body" radiation at visible light wavelengths. Methanol is unusual because it
burns with a cooler flame, and its combustion produces no carbonaceous
particles. Since no "grey-body" radiation occurs with methanol, the flame
radiates at infrared wavelengths derived from the heated gaseous combustion
products. Neat methanol has one of the lowest radiation characteristics during
combustion compared to other hydrocarbon materials. The addition of
hydrocarbons is one means of enhancing the luminosity of methanol in a flame
by increasing the tendency to produce "grey-body" radiation.
Methanol has been used in racing fuels for more than 40 years. It is used
as the base fuel and blended with other substances in drag racing applications or
neat in "Indianapolis car" applications. Other racing applications, including
Formula I, CAN-AM, stock, sports and production cars, use a conventional
gasoline fuel with octane boosters. The National Hot Rod Association (NHRA),
the International Hot Rod Association (IHRA) and the American Hot Rod
Association (AHRA) do not have fuel specifications/1) with the exception that
hydrazine and compressed gases (i.e., nitrous oxide) are to be used only in Top
Fuel and AA/Funny Car Classifications/2) In the "alcohol only" racing
classifications, no additives are introduced specifically to increase flame
luminosity or for other safety purposes. A color indicator dye, however, is used
in nitromethane to indicate the presence of hydrazine. The substances that are
added to drag racing fuels are for the purpose of increasing power rather than
flame luminosity. Some of these additives do enhance the flame luminosity,
although many of them could not be used for street vehicle applications. At
least one fuel supplier, Lindele Corp., advertises a methanol fuel, "Racing
Blue," which is said to burn with a red/orange flame for increased flame
luminosity however, the contents of the additive package were not disclosed.
Lindele Corp. company also produces a red-dyed methanol fuel that is designed
for street vehicle use.
The Champion Auto Racing Team (CART) and the United States Auto
Club (USAC), which run the Indianapolis cars, specify neat methanol as the
fuel.O) prior to 1973^ tne fuej suppiiecj to the racers was free, and any blend
could be used. From 1973 until the present, methanol was specified because it
is readily available, uniform in composition, easily identified and controlled,
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and reasonable in cost. CART and USAC have investigated a few additives for
flame luminosity enhancement, but to date no data have been published. Flame
luminosity is not considered a necessarily desirable property for racing
applications. Instead, safety precautions and education are considered more
desirable and effective. Ground wires for the vehicles, dry break systems (a
fuel tank to fuel filler nozzle connection that, upon uncoupling, shuts off the
fuel flow) with gravity fill for fueling, fire proof uniforms, anodized aluminum
tanks, and most important, education of the pit crew and drivers to the dangers
involved with methanol, are all used to reduce the potential hazards of a
methanol fire rather than improving the flame luminosity of the methanol fuel.
These safety measures are used to prevent fires rather than to affect the
results of one. These safety measures will be discussed further in a subsequent
section.
Several researchers have conducted a variety of experiments concerning
the enhancement of the flame luminosity for methanol. Table 1 presents a list
of potential flame luminosity enhancers examined in the studies, as well as
other known luminosity enhancers found in this study.
There is no accepted standard for a visible flame. Coward and
Woodhead*11) and Anderson and Siegl have determined the luminosity of a
variety of hydrocarbons.^' The results of these studies were normalized by
Anderson and Siegl to isooctane and are presented in Table 2. From the table,
TABLE 2. RELATIVE RADIATION CHARACTERISTICS OF A
VARIETY OF PURE HYDROCARBONS
Normalized Relative Luminosity
Coward & WoodheadUU Anderson &
i-octane 1.0 1.0 (defined)
Heptane 0.71 0.95
i-Pentane « 0.6
Cyclohexane 0.83 0.71
Toluene 0.07a 0.70a
Benzene 0.07a 0.22a
Acetone 0.13 0.25
Methylethy Iketone 0.16 0.18
Ethyl Acetate 0.08 0.04
1-octanol — 0.06
1-butanol 0.21 0.17
2-Methylpropanol 0.34 0.3
2-propanol — 0.19
1-propanol 0.09 0.06
Ethanoi 0.01 0.03
Methanol 0.01 0.0003
aCauses for the variations in the data are not readily apparent
in the references.
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TABLE 1. POTENTIAL FLAME LUMINOSITY ENHANCERS
Compounds References
isopropyl alcohol 4
t-butanol 11
isopentane 5, 11
hexane 11
cyclohexane 12
toluene 6, 7, 8, 11, 12
xylene 11, 12
cat pentane3 11
light cracked naphtha1' 11
hydrof ormatec 11
reformate^ 13
unleaded gasoline 11,13,1^
benzyl alcohol 9
xylenol (isomers) 16
anisoie 16
ethoxybenzene 16
2-phenylethanol 16
o-ethylphenol 16
sodium acetate 12
metal-organic salts 12, I**
organometallic compounds 1^
alkyl borates 10, 1*
aCatalytic cracker fraction distilling in the range of
25-150°C
bCatalytic cracker fraction distilling in the range of
30-160°C
CReformate fraction distilling in the range of 55-220°C
^Aromatic gasoline blending stock
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isooctane (gasoline), ethanol and methanol have a 3000:1000:1 luminosity ratio
while burning (i.e., a flame from burning gasoline is approximately three times
more visible than an ethanol flame and 3000 times more visible than a methanol
flame). Anderson and Nichols'^' adopted the luminosity of burning ethanol as a
reasonable target for a visible flame. Most hydrocarbons function as methanol
flame luminosity enhancers; however, concentrations of greater than 10 volume
percent may be required to produce the desired effect. Anderson and Nichols
indicate that 10 volume percent gasoline in methanol has a flame luminosity
equal to that of pure ethanol.
In addition to enhancing the flame luminosity, a desirable characteristic
of an additive would be the persistence of the visible flame until all of the
liquid was consumed or the fire was extinguished. Any additive that does not
provide a luminous flame for the entire length of the burn introduces the risk
that the observer could be misled into believing that the flame is gone when the
color disappears. Several investigators have examined the time-dependent,
flame luminosity for a number of hydrocarbons mixed with methanol. The data
from several such studies are tabulated in Table 3.
Anderson and Siegl'^' proposed that the time-dependent behavior is
readily understood on the basis of the methanol/additive distillation curves, the
concentration of the additive, and the volatility of the additive. Methanol
forms minimum boiling azeotropes with many of the lower-molecular weight
hydrocarbons. Upon burning a pool of liquid, the additive is selectively distilled
from the liquid phase, which concentrates the methanol. After a sufficient
quantity of the additive has been removed during the burning, the methanol
dominates the liquid and the visible flame disappears. Agitation with a
magnetic stirrer has no noticeable effect on either the total duration of the
flame or the duration of the luminous flame. A comparison of additives with
high and low volatility demonstrates the effect on the flame luminosity. A
highly volatile, low boiling additive, such as isopentane, produces a short-
duration, intensely-luminous flame. Once the isopentane burns away, the
remainder of the flame is indistinguishable from a flame of burning neat
methanol. An additive with a higher boiling point such as o-xylene, which does
not form methanol azeotropes, was shown to have a low luminosity initially and
become more luminous following selective distillation of the methanol from the
liquid phase.
A list of azeotropes formed by methanol is included in Table ^. The only
two compounds that form azeotropes at a methanol concentration of greater
than 75 volume percent are methylal and nitromethane. Methylal does not burn
with a visible flame, and would not itself enhance the flame luminosity of
methanol. Methylal will be discussed further in a subsequent section.
Nitromethane is used to increase power in drag racing applications, but it is not
practical for use in street vehicles.
Keller, Nakaguchi, and Ware(6) indicated that the flame luminosity of
methanol containing less than 5 volume percent light hydrocarbons was
generally poor, while increasing the concentration of light hydrocarbons to 10
volume percent substantially increased the flame luminosity and visibility.
Several methanol/pentane blends were examined for burning characteristics.
The blends contained either 5 or 10 volume percent pentane as well as other
6
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TABLE 3. TIME DEPENDENT FLAME LUMINOSITY WITH METHANOL
Additive
methanol
isopropyl alcohol
t-butanoi
light hydrocarbons
light hydrocarbons
DMEb
isopentane
isopentane +
DME
isopentane +
toluene +
DME
Hexane +
DME
Cyclohexane
toluene
toluene
toluene +
pentane
toluene +
pentane
toluene +
pentane
toluene +
pentane
Volume %
of
Additive
—
6
6
5
10
5
6
2
5
2
2
4.6
2
*
10
2
2
5
2
10
5
5
5
10
% Flame
Luminosity
Time3
0
—
—
0
0
0
43
10
33
0
90
50
70
Comments
Not visible except in dark^)
Light yellow flame barely visible^)
Light yellow flame barely visible^)
Generally poor'6'
Substantially improved^'
(4)
Few flashes of yellow^)
Few flashes^)
(4)
(4)
Flame luminosity decreased until it
resembled burning methanol^'
Few flashes of yellow^)
Strong luminosity^)
Substantially increased flame
luminosity and visibility^)
Substantially increased flame
luminosity and visibility^)
(6)
(6)
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TABLE 3 (Cont'd). TIME DEPENDENT FLAME LUMINOSITY WITH METHANOL
Additive
Volume % % Flame
of Luminosity
Additive Timea
Comments
toluene +
DME
toluene +
DME
toluene +
DME
toluene +
DME
toluene +
DME
toluene +
LCNC
toluene +
DME +
LCN
toluene +
DME +
LCN
toluene +
DME +
LCN
toluene +
DME +
LCN
toluene +
DME +
xylene
toluene +
DME +
xylene
2
3.6
2
5.4
4
3.9
H
5.6
6
6
2
8
2
4.5
2
2
3.8
4
2
4.9
4
2
6
4
1
6
1
2
6
2
57
83
82
90
89
56
73
100
100
100
94
(4)
Non-luminous in mid-period^)
(4)
(4)
(4)
(4)
(4)
(4)
(4)
(4)
(4)
(4)
xylene
Few flashes of yellow^)
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TABLE 3 (Cont'd). TIME DEPENDENT FLAME LUMINOSITY WITH METHANOL
Additive
Volume % % Flame
of Luminosity
Additive Timea
Comments
LCN +
DME
LCN +
DME
LCN +
DME
LCN +
DME +
hydroformated
hydroformate
hydroformate +
DME
hydroformate +
DME
hydroformate +
DME
hydroformate +
DME
cat pentane6 +
DME
cat pentane +
DME
unleaded gasoline
(14.5 RVP)
unleaded gasoline
(14.5 RVP)
gasoline
gasoline
gasoline
2
5
4
4
6
5.7
2
tt
2
b
2
4.9
t
3.8
4
4.9
4
5.7
2
5
4
4
6
10
10
10
15
0
23
43
42
100
0
100
100
100
0
0
50
100
50
100
Few flashes^)
(4)
(4)
(4)
Light yellow f lame^
Few flashes^)
(4)
(4)
(4)
Few flashes^)
Few flashes^)
Light yellow f lame^)
(4)
Equal to burning neat ethanolW
(6)
(6)
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TABLE 3 (Cont'd). TIME DEPENDENT FLAME LUMINOSITY WITH METHANOL
Additive
Volume % % Flame
of Luminosity
Additive Timea
gasoline +
pentane
gasoline +
pentane
reformate* +
pentane
ref ormate +
pentane
5
5
5
10
5
5
5
10
20
30
20
30
Comments
Visible f lame*6)
Visible flame<6)
Visible flame<6)
Visible f lame<6)
aPortion of time that flame was yellow and clearly visible
bDimethyl ether
cLight Cat Naphtha-Catalytic cracker fraction distilling in the range of 30-165°C
dReformate fraction distilling in range of 55-220°C
eCatalytic cracker fraction distilling in the range of 25-150°C
^Aromatic gasoline blending stock
10
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TABLE 4. AZEOTROPE SYSTEMS WITH METHANOLU2)
Compound
Boiling
Point. C
Percent Composition
Acetone
Acetonitrile
Benzene
Chloroform
1,1 ,-dichloroethane
Dimethyl acetal
Dimethyl formal
2,5-dimethyl furan
Ethyl acetate
Ethyl butyl ether
Ethylene dichloride
Ethyl formate
Heptane
lodomethane
Isopropyi acetate
Methyl acetate
Methylal
Methyl acrylate
Nitromethane
Octane
Pentane(13)
Toluene
Trichloroethylene
1,1,2-trichlorotrif luoroethane
Trimethyl borate
Vinyl acetate
1 -methoxy-1,3-butadiene
Vinylbutryl ether
Acetone
Chloroform
Acetone
Cyclohexane
Acetone
Methyl acetate
Carbon disulf ide
Methylal
Cyclohexane
Methyl acetate
Hexane
Methyl acetate
Methyl chloroacetate
Water
Binary Systems
55.7
63.5
58.3
53.5
49.1
57.5
41.8
61.5
62.1
62.6
59.5
51.0
59.1
37.8
64.0
54.0
41.8
62.5
64.5
63.0
31
63.7
60.2
39.9
54.0
58.5
62.0
62.0
Ternary Systems
57.5
51.5
53.7
35.6
50.8
45.0
67.9
11
Methanol
ms
12.0
19.0
39.5
13.0
11.5
24.2
7.9
51.0
48.6
56.0
35.0
16.0
51.5
4.5
70.2
18.7
92.2
54.0
92.0
72.0
7
72.4
36.0
6.0
27.0
36.6
57.5
52.0
ems
23.0
16.0
17.4
7.0
17.8
14.0
81.2
A
88.0
81.0
60.5
87.0
88.5
75.8
92.1
49.0
51.4
44.0
65.0
84.0
48.5
95.5
29.8
81.3
7.8
46.0
8.0
28.0
93
27.6
64.0
94.0
73.0
63.4
42.5
48.0
30.0
43.5
5.8
55.0
33.6
59.0
13.54
B
47.0
40.5
76.8
38.0
48.6
27.0
Specific
Gravity
0.795
0.844
1.342
0.841
0.860
0.841
0.846
0.770
1.045
0.816
0.908
0.813
1.126
1.476
0.892
0.880
0.898
0.73
5.26
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additives for increasing the flame luminosity. The additives included toluene,
gasoline, and reformate (an aromatic gasoline blending stock). Of these three,
toluene was found to be the most effective in increasing flame luminosity. As
little as 2 volume percent toluene substantially increased the persistence of the
flame luminosity and the visibility for both methanol/pentane blends. When 5
volume percent toluene was added to both blends, the flame was visible until
about 50 to 70% of the liquid was consumed. The addition of 5 volume percent
gasoline or reformate was less effective, and the visible flame persisted only
until 20 to 30% of the liquid was consumed. With 10 volume percent gasoline in
neat methanol (without the additional pentane), the visible flame persisted until
about 50% of the liquid was consumed. For the flame to last the entire length
of the burn, 15 volume percent or more gasoline was required.
Panzer,(4) whose effort was mostly concerned with the use of dimethyl
ether (DME) as a primer for good cold starting characteristics and water
contamination tolerance, conducted a variety of experiments on the flame
luminosity of methanol. The luminosity was evaluated by igniting 2 cc of each
blend in a shallow aluminum dish. The dish was located in an unlit hood with a
black background. The flame duration was perceived visually and recorded.
Unleaded gasoline as well as some of its component distillation fractions were
examined. Hydroformate, a reformate fraction distilling in the range of 55-
220°C, produced a luminous flame throughout the entire burn at the lowest
concentration (4 volume percent). A concentration of 10 volume percent
unleaded gasoline was required to give a visible flame for the entire burn.
Individual components, such as isopentane, toluene, xylene, and lower
concentrations of unleaded gasoline, were not as effective in enhancing the
flame luminosity.
Panzer^) conducted a number of luminosity experiments on the effect of
additives for DME/methanoi blends. DME does not burn with a visible flame
nor does it increase the flame luminosity of methanol alone. DME does appear
to be involved with the length of time the flame is enhanced. This fact is
illustrated in Table 3. A blend of 2 volume percent toluene with 8 volume
percent LCN in methanol produced a visible flame during 56% of the burn time.
When DME was present in a concentration of 6 volume percent, a visible flame
was produced for 100% of the burn time with as little as 4 volume percent LCN
and 2 volume percent toluene. Another example involved a blend of 2 volume
percent toluene with DME in methanol. By increasing the DME concentration
from 3.6 volume percent to 5.4 volume percent, the luminosity time increased
from 57% to 83%. In this case, the flame was not visible during the middle of
the burn time. A similar increase was observed for toluene with DME in
methanol. The most effective additives in producing visible flames with the
DME/methanol blends were hydroformate and a combination of toluene and
light cat naphtha (LCN), a catalytic cracker fraction distilling in the range of
30-165°C. These DME/methanol/additive blends produced a visible flame for
the entire burn. For example, a combination of 6 volume percent DME, 2
volume percent toluene, and 2 volume percent xylene gave a luminous flame
for 94% of the burn time.
Panzer'*/ also examined the effect of water on the luminosity of DME
primed methanol. Table 5 presents a comparison of the luminosity data with
and without water present. The addition of water to the blends containing
12
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luminosity additives with DME as a cosolvent had no effect on the water
tolerance (phase stability); however, the luminosity was found to decrease as
the water concentration was increased. Panzer suggested that the
hydroformate/methanol blend should not contain more than 5 volume percent
water, and that LCN/methanol blends should not contain more than 3 volume
percent water. An increase in the water concentration from 5 to 10 volume
percent with a small increase in the DME concentration (5.0 to 6.3 volume
percent) decreased the percent of luminosity time from 100% to 65%. A
similar effect was observed for DME/toluene/LCN blends.
TABLE 5. EFFECT OF WATER ON LUMINOSITY OF
DIMETHYLETHER-PRIMED METHANOL
Composition, Volume Percent Luminosity
DME Toluene Hydroformatea LCNb Water Time. %c
2 0
3.9 4 82
5.6 4 90
5.6 4 10 62
1 100
3.8 4 100
4.9 4 100
5.7 4 100
5.0 4 5 100
6.0 4 7 85
6.3 4 10 65
28 56
3.8 2 4 100
4.9 2 4 100
6 24 100
4.9 243 100
3.9 245 73
5.5 247 69
6.0 24 10 55
aReformate fraction distilling in the range 55-220 C
^Catalytic cracker fraction distilling in the range 30-165 C
cPortion of time that flame is yellow and clearly visible
In addition to DME as a cosolvent for luminous flame additives, several
authors have suggested that other alcohols could be used as cosolvents with
methanol. Panzer^ examined the flame luminosity of two low molecular
weight alcohols: isopropyl and t-butyl alcohol. Neither of these two neat
alcohols was effective in providing an adequate luminosity at the concentration
selected (6 volume percent). Although simple alcohols do not contribute
significantly to the flame luminosity, these compounds may serve as cosolvents
13
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for other luminous flame additives. Panzer did not pursue the use of alcohols
for cosolvents.
Higher molecular weight alcohols as cosolvents would help to reduce the
sensitivity of methanol/nonpolar hydrocarbon blends to water and increase the
solubility of these hydrocarbons in the methanol. The most effective cosolvent
for methanol/gasoline blends are €3 to Cg aliphatic alcohols. The effectiveness
of cosolvent alcohols increases with chain length to at least Cg, and decreases
with branching. The effectiveness is also greater for primary than for
secondary or tertiary alcohols. Keller, Nakaguchi, and Ware^6) conducted a
number of cosolvent experiments on the effect of water tolerance for 10 volume
percent methanol blended with gasoline. The alcohols included a €3 - C^
alcohol mixture, isobutanol (C^), amyl alcohol (^5), and 2-ethylhexyl alcohol
(Cg). The transition temperature range, the temperature range at which the
initial appearance of turbidity or visible phase separation occurred, was
determined for each alcohol blend with either 0.25 or 0.50 weight percent water
present. Although these experiments were conducted on gasoline rich blends,
one would expect similar results for methanol fuels. No flame luminosity
studies were conducted by Keller, Nakaguchi, and Ware, but azeotrope
formation with alcohols and flame additives could help to enhance the visible
flame characteristics. No experimental investigations have been conducted
about the effect of increased flame luminosity of alcohols, other than
rudimentary studies by Coward and Woodhead'H), Anderson and SiegK5), and
Panzer.^)
Another means of increasing the flame visibility of methanol involved the
addition of organometallic compounds and/or metal organic salts. In a flame,
metal atoms are excited and emit radiation at visible wavelengths. Anderson
and Siegl(^) examined sodium acetate, a metal-organic salt, as a flame
luminosity enhancer for methanol. Sodium acetate is an ingredient in Sterno, a
commercially available methanol fuel for heating. The problem encountered by
Anderson and Siegl with sodium acetate, as an additive to methanol, was the
inverse relation between concentration of the compound in solution (i.e.,
intensity of the visible radiation in the flame) and the volatility of the
compound. As the flame burned, the metal organic salt was concentrated in the
liquid phase by selective distillation of the methanol, and it precipitated out
when the solubility product was exceeded. Other organometallic compounds
such as tetraethyllead have been used in leaded gasolines for a number of years,
but are slowly being phased out. It is unlikely, however, that organometallic
compounds would produce the desired effect at concentrations that would be
reasonable in motor fuel. In addition, many metals are detrimental to the
operation of engines and exhaust systems of modern catalyst-equipped vehicles.
Alkyl borates and boron esters have been proposed as a means of
enhancing the flame luminosity of methanol/1*) Borates burn with a yellowish
green flame when combined with alcohol/* 2) Blends of alkyl borates have also
been suggested as water scavengers in 85% gasoline/15% methanol blends in a
German patent/1 ®' The blends in the patent contained between 0.5 and 1.5
weight percent trialkyl borate compounds. Alkyl borates in this concentration
range are not expected to enhance the visible flame characteristic of methanol.
14
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There are other potential flame enhancers based on some of the same
chemical and physical properties suggested in the literature. These compounds
include benzyl alcohol, anisole, o-ethylphenol, ethoxybenzene, 2-phenylethanol,
and the isomers of xylenol. No specific reference was found for which these
compounds were tested in methanol flames. They would take advantage of high
aromaticity, and yet be miscible with methanol. Additional candidates would
include compounds such as naphthalenes, phenols, and other substituted
aromatics.
B. Evaluation
As indicated in the literature, there are a number of compounds that can
be added to methanol to increase its flame luminosity. Hydrocarbons,
especially those with a high aromatic content, appear to give the best results
when added to methanol. The aromatics form soot particles in flames, which
emit visible "grey-body" radiation. Aliphatic hydrocarbons also produce visible
flames, but their effects on the flame luminosity are not as significant until the
aliphatic hydrocarbon reaches a chain length of six or more carbons.
In addition to producing a highly visible flame, another key consideration
in selecting an additive is the length of time the flame is visible while methanol
is burning. If the luminosity ceases before the source of the fire is determined,
a fire-fighter may be misled into thinking that the flame has been extinguished.
Highly complex mixtures of hydrocarbons appear to be the most likely additives
for enhancing flame luminosity for the duration of a methanol fire. These
mixtures form a number of azeotropes with methanol, which burn with a visible
flame that persists throughout the time of the fire.
Panzer^) found that a reformate fraction distilling in the range of 55-
220°C was the best flame enhancer at the lowest concentrations. As little as *
volume percent hydroformate produced a light-yellow, visible flame for 100
percent of the burn time. Unleaded gasoline at a concentration of 10 volume
percent was also found to produce a visible flame for 100 percent of the burn.
Keller, Nakaguchi, and Warew, however, found that as much as 15 volume
percent of gasoline was required to produce a luminous flame during 100
percent of the burn time. The difference between the findings of these two
researchers may be due to the qualitative definition of a luminous flame.
When considering an additive to enhance flame luminosity, 10 to 15
volume percent of unleaded gasoline appears to be a likely candidate. Large
quantities of unleaded gasoline could be readily made available for mixing with
methanol, and the necessity of building additional facilities to produce a special
methanol additive would be avoided. There would be some increase in the cost
of a methanol fuel with the addition of unleaded gasoline, depending on the
amount of unleaded gasoline added (10 to 15 percent). Using the average 1983
Gulf Coast spot barge price for methanol, H£ per gallon (ranged from 41 to ^7£
per gallon^*)), and an average 1983 Gulf Coast refinery price for unleaded
gasoline, 84£ per gallon (ranged from 72 to 88£ per gallon^16'), the addition of
10 volume percent unleaded gasoline to methanol would increase the bulk rate
cost of the methanol by about 4£ per gallon, or about 9 percent (addition of 15
volume percent unleaded gasoline would increase the cost by 6£ per gallon, or
1* percent). This estimate assumes that the mixing would be carried out using
15
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pipelines, and that the cost of mixing would be small when compared to the cost
of the fuels. The higher energy content of the added gasoline (approximately
113,000 BTU/gal as compared to 56,100 BTU for methanol) would largely offset
the cost increase of adding the gasoline.
If cosolvents are used to increase the water tolerance of the
methanol/unleaded gasoline blend, additional costs would be incurred. Keller,
Nakaguchi, and Ware(6) estimated that a mixture of C2~C^ alcohols produced in
fuel grade methanol (without purification) by using a non-selective catalyst
would cost about 1.62 times as much as methanol or about 72£ per gallon (1978
estimate). Therefore, each 10 percent of cosolvent added would raise the cost
of methanol by about 3<£ per gallon.
The addition of complex mixtures of hydrocarbons, such as unleaded
gasoline, to increase the flame luminosity of methanol also aids in other safety-
related areas. One of these areas is the f lammability of the methanol vapor in
a closed system. Methanol in the vapor state is flammable over a wide range of
temperatures and concentrations. The flammability limit for methanol in air
ranges from about 36 volume percent as an upper limit to about 6 volume
percent as a lower limit. Below the lower flammability limit, the vapor is to
lean to burn; above the upper limit, it is too rich. By comparison, gasoline has
as much narrower flammability range, with an upper limit of 7.6 percent and a
lower limit of 1.4 percent.
Keller, Nakaguchi, and Ware(6) found that when 5 to 10 volume percent of
€5 to €7 hydrocarbons was added to methanol, the resultant vapor exceeded
the upper flammability limit (i.e., became too rich to ignite when the
temperature of the methanol/hydrocarbon mixture was maintained at or above
-20°C). They found that when 20 volume percent gasoline was used as a
blending agent, the vapor concentration exceeded the upper flammability limit
above -10°C; and that with 25 percent gasoline, the vapor concentration
exceeded the upper flammability limit when the fuel mixture was above -30°C.
Other researchers have produced similar results. Thus, the addition of 10
percent or more unleaded gasoline or other hydrocarbon mixtures would reduce
the possibility of an explosion in the vapor space of a closed space such as
vehicle fuel tank.
Another problem associated with methanol fuel that would be aided by the
addition of a complex hydrocarbon mixture is the vehicle cold startability, i.e.,
the ability to start an engine at low ambient temperatures (Keller, Nakaguchi,
and Ware*6) have defined low ambient temperatures as anything below 10 to
16°C). The problem is related to methanol's relatively high latent heat of
vaporization (506 BTU/lb as compared to 150 BTU/lb for gasoline). Keller,
Nakaguchi, and Ware^6' indicated that the addition of 5 volume percent
pentanes or 12 volume percent gasoline to methanol gave adequate vehicle cold
startability at temperatures down to -10°C. For temperatures down to -30°C,
8-10 volume percent pentanes or 25-30 volume percent gasoline was necessary
for adequate vehicle cold startability. A combination of 15 volume percent
gasoline and 4 volume percent pentanes provided adequate cold startability
down to -29°C.
16
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The addition of gasoline or a hydrocarbon mixture to methanol would
result in some change in the exhaust emissions from the engine. Carburetor or
injection system adjustment, along with the use of emission control systems
found on current vehicles, could minimize differences between the regulated
emissions (hydrocarbons, carbon monoxide, and oxides of nitrogen) from
vehicles using pure methanol fuel and those from vehicles fueled with
methanol/hydrocarbon blends. Other exhaust emissions such as those related to
sulfur content (sulfate, sulfur dioxide, etc.) and aromatics (particulates,
benzene, etc.) would increase as a function of their concentrations in the
additive (i.e., hydrocarbon) material. Aldehyde emissions may be reduced by
the addition of hydrocarbon mixtures to methanol, but an effective vehicle
catalytic converter could render these differences negligible. On the negative
side, the addition of hydrocarbon mixtures to methanol fuel would result in an
increase in the evaporative emissions throughout the fuel supply system and
possibly even for refueling emissions.^, 17) Concern over this problem is
increased by the fact that many of these hydrocarbons are known to be more
reactive in photochemical smog formation than neat methanol. A number of
researchers have conducted air-quality modeling calculations and shown that
substitution of methanol fuel for gfasoline in the calculations would lead to a
reduction in the ozone concentration. These researchers conclude that
methanol would have a very beneficial impact on the air quality and deserves
further investigation.^,19»20)
The toxicity of methanol, along with its lack of taste and low odor
intensity are health effects problems that could be associated with the use of
methanol as a motor fuel. In general, the addition of a complex mixture of
hydrocarbons, such as gasoline, is expected to result in an increase in odor and
taste intensity. The addition of gasoline (15 volume percent) to methanol had
been reported to give the mixture a slight but noticeable odor; and when the
methanol/gasoline blend is mixed with water, to give an unattractive milky
mixture with a strong odor of gasoline.^)
17
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TASTE DETERRENTS
Of the three major routes of methanol poisoning (ingestion, inhalation and
subcutaneous absorption), direct ingestion is the quickest. Methanol does not
have a strong or distinctive taste to identify its presence. In fact, it has been
mistaken for ethanol innumerable times, and consumed with sometimes
disastrous consequences. The addition of a bitter or foul tasting substance
would help to deter accidental poisoning and possibly even prevent some
intentional ingestion of methanol fuel.
A. Literature Search
Hagen(21), and Wimer, Russell and Kaplan(22) have stated that the usual
fatal dose by direct ingestion of methanol is between 50 to 100 ml (2-4 oz.),
although 25-50 ml (1-2 oz.) has often been fatal if not treated immediately.
The lowest reported fatal dose was 3 teaspoons (about 15 ml) of 40% methanol
(approximately 6 ml of pure methanol) and the highest dose of a survivor was
one pint (500 ml) of the same material (approximately 200 ml of pure
methanol). Midwest Research Institute has stated that the chance of a 6 ml
dose causing death is exceedingly low/23) The consumption of ethanol prior to
or in conjunction with methanol has been found to decrease the toxic effect.
Ethanol has been shown to compete effectively for the enzyme responsible for
the conversion of methanol to formaldehyde and formic acid. The production of
formaldehyde and formic acid is suspected of being responsible for some of the
toxic effects of methanol.
Although little information exists on the addition of materials to
methanol to make it undrinkable, denaturants have been added to commercial
ethanol to render it unfit for human consumption for over 60 years. A list of
denaturants that have been used in ethanol is presented in Table 6. Although
denaturants are most commonly involved with ethanol, many of these
substances could be used in methanol as a taste deterrent.
The two categories of denaturing formulas for ethanol are (1) completely
denatured alcohol (C.D.A.), and (2) specially denatured alcohol (S.D.A.).
Completely denatured alcohol is ethanol which has denaturants added to render
it entirely unfit for human consumption. This type of denatured alcohol may be
handled for legitimate purposes without filing a bond, obtaining a permit or
paying a tax. Specially denatured alcohol has been denatured so that it can be
used for a special purpose and may be received and blended at bonded facilities
that are subject to rigorous inventory control and government supervision. Two
C.D.A. and three S.D.A. formulas have been authorized by the Federal
government for ethanol use as a fuel. These are listed in Table 7. The
Southwest Alabama Farmer's Cooperative Association also evaluated a
denatured ethanol formula for use in farm equipment.^25) in addition, several
foreign patents exist for denaturing fuel and ethanol. Methanol is included as a
denaturant for ethanol in several of these formulas. Ethanol, on the other hand,
cannot be used as a denaturant for methanol. Ethanol has, however, been used
in the treatment of methanol poisoning victims, and has been reported to help
reduce the effects of methanol poisoning. Only one of the formulas in Table 7
contains substances other than gasoline and/or methanol. Many other S.D.A.
18
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TABLE 6. OS. GOVERNMENT-AUTHORIZED DENATURANTS FOR
COMPLETELY DENATURED ALCOHOL (C.D.A.) AND
SPECIALLY DENATURED ALCOHOL (SJXAjfet)
DINATUMANT
U8IO IN
OINATUMANT
USED IN
Aj-artnnsi N C
Almond oil, bittar N. F
Ammonia solution, strong
Bay oil (myrcia oil) N. F
Camphor LI. S. 9
Caustic soda. "T''"
* a 40
*t n 9^A» 9^-H
e- « t*
f B- *a.«
U. S. P S. D. 36
e n. M.H
,„. ^, « •»-«
* 0. 2S.F,
38-8; 39-0
...... .HU,*. B- *^B
__S. 0. 2-8; 2-Ct 12-A
S. 0. S3-»i ?•-*
« B 1'
i B 4fl
«. B. M,
39WM 394( 40; 4OA
. S. 0. 27; 27-A; 38-8
« a. «
s.n. *i
S. D. 3B-8t 38-F
Cinnamon oil (caaaia oil) U. S. P S. 0. 38-B
MtMMii. «;i, M«U«I „ « n. 9a.a
anehonidlna sulfata N. F.
M V IV
Ctow oil U S P
(*A*I *** II « B
OWry' f*»**«i«««
r^hyi tfHAr l..._11__^ _.,„.
Eucfttyptut oil N. F,
*»•*"•" u $, B ,,_.,_.,,_,..
Formaioanyaa solution U.
iMflna LJ S P
1 aiMnrlAr nil 11 ^ P
Uanthnl, U. 5. 9
Mareurie iodida, rad N. F_
Matnyiana blua N. F
AJAtfty/ .iMMufJ ,_,_. m
Mttfyl 'tooutyl Httona__
'X,-,.,...- ,S. B- f-A
5 1 38-8
s n 97-Ai ia.a
e n «•.•
_^_S. 0 39-8; 39-C
_S. 0 13-A; 19; 32
.,, 5 n •?*-*
5, r> •>•.«
S. P S. 0. 22;
S B. M.A
5 D 17'
38-Bi 38-C 38-0; 38-F
...^^_., s, n ^7
M. n n 4
en 1A*>
19; S. 0. 23-H
Matnyl violat (mathylrosanilina
Mattiyl violat (mathylrosanilina
« a •«
Mustard oil, voiatll* (aityl isothioeya-
n»«), U. S. P, XII,, . — ,.,, c n **-*
NiCOtlna SO*11*'^!!
PaiiiiiaMiiiiiil nil i* « P
Pnanol U. S. °
Phtnyl fwreuric frtnzoata____
Pnanyl mareurie eniorida N. F. C
Pnanyl salieylata (saioi) N. F___
DHnaf Ail, M f
Pftna* tar N P
Potassium iodida. U. S. P S.
PvriritM hMA«
"yf^"**" — ' ^—^^
Quassia, fluid attract of, N. F. vi
OuiniM M«iM*ta M t «
Quinina hydroehiorida u. S. P
Qtlinfn* ful^te y. S, B,.
Rasonln, U B •
Ronmary of, M *
Rubftar hydrocarbon soivantM^^
•^tau
Sodium talicylata, U. S. • — —
Soap hand N F
Soap madictnal soft U S. P
Thimaraul, M. F
Thy™,., M P , S. 0.
Tolu Balsam US"
5 n j
« n •yi.n
.3. 0. 38*8; 46
f- B- *3
( S. 0. 42
S. 0.38.8
a n 1it.B
0. 2S« 2S.A; 42
i* n !•
i « B. 39
>.0. 39^M3»-O
$.0. 39-A
. ,1. I?. W-O
S. D, **-F
A. 0. 27; 38>B
_S. 0. 2-8; 2-C
S. 0.38.8
_3. 0. 23-Ft 39
« B. aa.ji
, S «- ^
_S. 0. M; 25-A
„. ,..,$, n, ^-^
_S. 0. 39; 39-0
_..,,$. 0, 11-A
..S. D. 37-B
..S, 0. 18-fl
_._.s. o, •«-«
37; 38-8; 38-F
-------
TABLE 7. DENATURANT FORMULAS FOR ETHANOL AND OTHER FUELS
1. C.D.A. Formula No. 18: to every 100 gallons of ethyl alcohol of not less
than 160 proof, add:
- 2.50 gallons of methyl isobutyl ketone;
- 0.125 gallon of pyronate or a compound similar thereto;
- 0.50 gallon of acetaldol (b-hydroxybutyraldehyde); and
- 1.00 gallon of either kerosene, deodorized kerosene, or gasoline.
2. C.D.A. Formula No. 19: to every 100 gallons of ethyl alcohol of not less
than 160 proof, add:
- 4.0 gallons of methyl isobutyl ketone; and
- 1.0 gallon of either kerosene, deodorized kerosene, or gasoline.
3. S.D.A. Formula No. 1: to every 100 gallons of ethyl alcohol of not less
than 185 proof, add:
- 5.0 gallons wood alcohol.
4. S.D.A. Formula No. 3-A: to every 100 gallons of ethyl alcohol of not less
than 185 proof, add:
- 5.0 gallons methyl alcohol.
5. S.D.A. Formula No. 28-A: to every 100 gallons of ethyl alcohol of not less
than 185 proof, add:
- 1.0 gallon of gasoline.
6. Southwest Alabama Farmers' Cooperative Association^25^ Formula is 10
gallons of denaturant blended with 90 gallons of gasoline.
- 89.5 gallons of S.D.A. Formula No. 28-A,
- 5.0 gallons gasoline,
- 0.5 gallon methyl isobutyl ketone or tertiary butyl alcohol,
- 5.0 gallons methyl alcohol,
- a dye to color the solution.
20
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TABLE 7 (Confd). DENATURANT FORMULAS FOR ETHANOL AND OTHER FUELS
7. French patent for denaturing fuel (26)
- 100 wt. parts dye (l-(2'-methyl-l'-phenyl-*-azophenylazo)-
2-naphthalenol or l,*-bis(butylamino)anthraquinone)
- 500 wt. parts diphenylamine
- 5-30 wt. parts 3-(oleylamino) propyl amine dioleate
- dilute to 1 g dye/hectoliter of fuel
- sometimes add 0.5-1 g furfural/hectoliter fuel
8. Polish patent(27)
The following by-products of the chemical industry are used as
denaturants. The denaturant is a mixture of two or more components:
- aromatic fraction obtained by separation of gasoline and pyrolysis
products
- ketone oil isolated from wood tar containing alcohols, aldehydes
and ketones
- cumene fraction obtained by alkylation of CgHg
- fraction of higher aliphatic alcohols from oxo synthesis
- gasoline fraction with boiling point between 90-150 C containing 70%
paraffins and 20% naphthenes
One part denaturant added to 99 parts ethanol colored with 18 mg/1 of
crystal violet.
21
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formulas have been authorized by the Federal government, but they have
specific uses ranging from the production of adhesives and binders to the
production of vitamins.
In the 1920's, two ethanol base fuels were produced. One, called Alcogas,
was manufactured by the U.S. Industrial Alcohol Company of New York and
Baltimore. Alcogas contained 33% 180-190 proof ethanol, 35% gasoline, 25%
benzene, and 7% ether. The other fuel, natalite, was made from molasses at
Natal, South Africa. It consisted of 54-60% 190 proof ethanol, 45.8-39% ether.
0.15-1% pyridine, ammonia or trimethylamine, and 0.5% arsenious acid.'25)
During the 1930's, ethanol was denatured in England by adding a small
percentage of pyridine and wood naphtha.^28) However, this formula was not
released from the surveillance of the Excise authorities until at least 25%
hydrocarbons (benzene or gasoline) was mixed with the ethanol.
Mueller Associates, Inc/25) listed several important technical factors
involved in choosing a suitable denaturant for alcohol fuels. The alcohol fuel:
1. Should closely match the thermal and physical properties of the
alcohol to ensure compatibility with the combustion characteristics.
2. Should add to the energy content; preferably in an amount greater
than that required to produce the substance.
3. Should impart a taste or smell sufficiently disagreeable to
discourage human consumption even if diluted, sweetened or
flavored.
4. Should not be capable of being eliminated easily by filtration,
distillation or any other process.
5. Should be capable of being easily and reliably detected.
6. Should not appreciably add to the emission levels from the products
of combustion.
7. Should not leave any objectionable residue to clog or corrode fuel
systems.
8. Should be readily available.
9. Should not add appreciably to the cost.
10. Should not complicate the regulatory compliance.
The Mueller Associates, Inc. paper was primarily concerned with ethanol;
however, the technical factors should also be applicable to methanol.
Nakaguchi, Keller and Wiseman'29) conducted recovery experiments on
various denatured ethanol blends (C.D.A. 19-A, S.D.A. 28-A, and the Southwest
Alabama Farmer's Cooperative Association formula with the t-butyl alcohol
option). The blends were washed with water to remove the gasoline and
22
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extracted with a volatile stove and lantern fuel. The extracted alcohol was air
blown until no hydrocarbon odor was detected. The results showed that the
ethanol recovered from the blends might be deemed sufficiently palatable to
drink by a determined consumer even though small amounts of noxious
compounds remained. Similar experiments were conducted with six additional
compounds as denaturants. These compounds were dimethylformamide (DMF),
isopropyl alcohol, n-butyl alcohol, iso-amyl alcohol, t-butyl mercaptan, and an
odorant (Sindar deodorant oil GD-64262). Of these six compounds ,the most
effective denaturant was found to be DMF. It imparted a highly objectionable
and bitter taste to the extracted alcohol. Although these tests were conducted
with ethanol, similar results may be expected with methanol.
Keller, Nakaguchi, and Ware(*>) have stated that the toxicity of a blend of
gasoline and methanol is only slightly more of a hazard than ordinary gasoline.
This is due to the prominent gasoline odor in the blend and the difficulty in
separating methanol from the blend by "casual" means to be pure enough to be
consumable. The addition of water to a gasoline (5 or more volume percent)
and methanol blend was found to produce an unattractive milky mixture. Lower
concentrations of gasoline were found to be not as objectionable, although the
gasoline odor was still noticeable.
Methylal, which has been added to fuel methanol to increase the engine
cold starting properties, is another additive which could be considered as a
taste deterrent. In April, 1983, the New Gasoline Corp. of Arlington,
Massachusetts was preparing to market the fuel Hydrolene, which contains up
to 10% dimethoxymethane (methylal) blended with methanol/30' Celanese and
Bank of America have also expressed interest in producing blends of methylal
and methanol.'31' Although no claims were made by any of these companies
about the effect on the taste of methylal/methanol blends, methylal should act
as a deterrent to the ingestion of methanol because of its pungent taste and
chloroform-like odor.
A number of other compounds have been proposed and used as additives to
produce a foul- or bitter-tasting product. Several of these compounds are listed
in Table 8, along with their bitterness thresholds (if available), which are
indications of the minimum concentration required to produce a bitter taste.
Proctor and Gamble uses the additive Bitrex (denatonium benzoate) in a number
of its detergent and household cleaning products to prevent unintentional
ingestion/33/ Bitrex has been found to be 20 times as bitter as strychnine/3*)
and is considered the most bitter substance known to man/32) In one study, the
addition of 0.0011*% Bitrex was found to significantly reduce the amount of
liquid dishwashing detergent consumed by 18- to *7-month-old children/3*)
Bitrex is used as a taste deterrent in a number of other applications, including
paints/36*37*38) herbicides/39), insecticides/*0) nailbiting and thumbsucking
deterrent drugs/*1) rubbing alcohol/3*) vegetable oils/*0' and ethanol used for
alcoholic toilet preparations and related articles/*3*****5) The use of Bitrex is
effective in concentrations of 2 to 3 mg/liter and is desirable due to the
minimal residue left after evaporation.
Brucine, quassine, and sucrose octaacetate are other commonly used taste
deterrents which have been used in some or all of the following products: hair
and scalp preparations, lotions and creams for the head, face and body,
23
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TABLE 8. COMPOUNDS FOR FOUL TASTE(32)
Compound
Absinthin
Aldehol
Benzyl alcohol
Benzyl benzoate
Benzthiazide
Bitrex
Bitterness Threshold
1:70,000
Comments
Brucine
Capsalcin
Collinsonia extract
Columbin
Condurangin
Dimethylformamide
Ethyl citrate
Furf uryl alcohol
Humulon
1:1,000,000
1:220,000
1:100,000
1:60,000
1:20,000
very bitter; chief bitter
principle of wormwood
disagreeable odor; for de-
naturing alcohol (ethanol)
sharp burning taste; faint
aromatic odor
sharp burning taste; pleasant
aromatic odor
bitter taste
most bitter substance known to
man. Added to toxic substances
as a deterrent to accidental
injestion
very bitter taste; very
poisonous; used in denaturing
alcohols and oils
burning taste
peculiar odor; bitter,
astringent taste
major bitter principle from
the root of Jatrorrhiza palmata
Miers; very bitter
bitter principle from
Condurango bark; astringent,
aromatic bitter
universal organic solvent;
faint amine odor
bitter oily liquid
bitter taste; faint burning
odor; poisonous
bitter taste especially in
alcoholic solutions
24
-------
TABLE S (Cont'd). COMPOUNDS FOR FOUL TASTE
Compound
Isovaleric acid
Lupulon
Marrubiin
o-(p-methoxybenzonyl)
Methylal
Methylarbutin
Methylbenzethonium
chloride
Oleoresin of aspidium
Pyrazole
Pyridazine
Pyridine
Quassin
Quinidine sulfate
Quinine
Strychnine
Bitterness Threshold
Comments
1:60,000
1:30,000 (quinine
hydrochloride)
1:130,000
acid taste; disagreeable
rancid-cheese odor
bitter taste especially in
alcoholic solutions
diterpen lactone principle
isolated from white horehound
bitter taste if used in con-
centrations exceeding 0.2 g/1
pungent taste; chloroform odor;
volatile flammable liquid
bitter
bitter taste
bitter, unpleasant taste
bitter taste; pyridine-like
odor
sharp taste; characteristic
disagreeable odor; flammable,
colorless liquid
one of the bitter constituents
of the wood of Quassia amara L;
very bitter
very bitter
most important alkaloid of
cinchona bark; salts also bitter
very bitter; extremely poisonous
Surcrose octaacetate
Vaccinum
intensely bitter; hygroscopic;
denaturant for alcohol (ethanol)
bitter taste
25
-------
deodorants for the body, perfumes, shampoos, soap and bath preparations,
external Pharmaceuticals, disinfectants, insecticides, fungicides and other
biocides, and cleaning solutions including household detergents.
B. Evaluation
The practice of adding taste deterrents to products for use by the general
public has been used by manufacturing companies for a number of years to
increase the safety of their product. Taste deterrents have been added to
everything from laundry detergents to perfumes, to prevent unintentional
ingestion. Denaturants (which include taste deterrents) have been used
routinely to prevent the consumption of ethanol. In addition to imparting a foul
or bitter taste, an additive for methanol in a motor fuel application must be
compatible with the engine and fuel system components, difficult to separate
from the methanol, and economical in cost.
The addition of gasoline to methanol as a taste deterrent has been
suggested by a number of researchers, and it meets a number of the criteria
established for additives to fuel alcohols. Gasoline has also been used as a
denaturant for ethanol in a number of applications. The addition of gasoline (15
volume percent) to methanol has been reported to give the mixture a slight but
noticeable odor; and when the methanol/gasoline blend is mixed with water, to
give an unattractive mixture with a strong odor of gasoline/6' The use of
gasoline as an odorant for methanol will be discussed in more detail in a
subsequent section. Keller, Nakaguchi, and Warew indicated that
gasoline/methanol blends are only slightly more toxic than gasoline alone, and
the methanol is difficult to separate from the gasoline in a potable form. They
also stated that one would have to be "determined" to drink methanol with even
as little as 1 to 2 percent gasoline added as a denaturant. The impact of
gasoline as an additive on the cost of methanol, on the vehicle exhaust
emissions, and on other safety-related areas has been discussed in detail in a
previous section.
There are a number of compounds that can be added to give methanol a
highly bitter and foul taste. The cost for several of these additives are listed in
Table 9. While these compounds are very effective in imparting a bitter taste
to methanol, they may need to be used in conjunction with other additives
because they may be selectively removed from methanol by distillation. Bitrex
is the most economical of the additives listed in Table 9, due to its relatively
low bitterness threshold and corresponding low cost in use. Bitrex is currently
used in paints, detergents and many other household materials, and is expected
to be available in sufficient quantities to be used in a fuel application. Several
of the other taste deterrents (sucrose octaacetate, brucine, quassin, and
quinine) do not appear to be as practical or economical as Bitrex. The
production of brucine, quassin, and quinine is dependent on environmental
factors (the uncertainty of the raw material yield at harvest), and current
supplies often do not meet the demand. Aa additional demand as a fuel additive
could produce a severe shortage for other areas of use. Some of the taste
deterrent additives are highly toxic (e.g. brucine and strychnine), and their use
is not recommended for this reason. One pound of sucrose octaacetate
(homologous to sugar) is required to denature 100 gallons of ethanol in
toiletries, shampoos, etc. If an equivalent amount is required to denature fuel
26
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methanol, use of the resulting mix could cause excessive engine wear and
carbon deposit buildup in the same way that other sugar compounds do.
TABLE 9. CURRENT COSTS OF SEVERAL WIDELY USED
TASTE DETERRENTS
_ Compound _ Bulk Price Cost Increase/Gallon of Methanol
Bitrex $14 - 17/oz. 2£
Sucrose octaacetate $0.38/oz. 6£
Brucine $3-5/oz. 6£
Quinine hydrochloride $2-3/oz. $1.50
DMF $3.85/gallon
Methylal $2.60/gallon
The cost of Bitrex is expected to have only a small effect on the cost of
methanol fuel produced in bulk quantities. Bitrex is effective as a partial
denaturant in ethanol toilet preparations and vegetable oils at concentrations
not less than 2 ppm.ft2»Wtf At the current market price for Bitrex,
$14/oz,<*6) the cost of adding this concentration of Bitrex to methanol fuel
would be on the order of 0.4C/gallon. A denaturing formula authorized for fuel
ethanol requires the use of 1/8 oz of Bitrex for every 100 gallons of ethanol ( 9
ppm)/*7) If a similar formula is appropriate for use with methanol fuel, the
cost of adding Bitrex would be on the order of 2£ per gallon. This
approximately five-fold increase in the concentration of Bitrex over the
minimum recommended concentration (2 ppm) would help to deter the dilution
of fuel methanol with water or other beverages to make the mixture more
palatable. The costs associated with blending Bitrex and methanol are
estimated to be on the order of 0.1£ per gallon.™ The impact of Bitrex on
exhaust emissions is unknown, but due to the low concentrations of Bitrex
necessary to provide a bitter taste in methanol (2-9 ppm), the exhaust emissions
would not be expected to differ significantly from those of pure methanol.
Other compounds that have been suggested as possible taste deterrents
for methanol include dimethylformamide (DMF) and methylal. DMF was
examined by Nakaguchi, Keller, and Wiseman(29) for denaturing ethanol, and
methylal has been proposed as a cold-starting additive for fuel methanol. Both
compounds are foul-tasting, and would deter the consumption of methanol. The
New Gasoline Corporation of Arlington, Massachusetts has estimated that a
10% methylal/90% methanol fuel could be produced for 45C/gaJlon based on a
Gulf coast spot-barge price of 43£/gallon for methanol.^O) This estimate is
based on a bulk methylal price of 60 to 65£ per gallon. However, the current
price of methylai, $2.60 per gallon, would increase the cost of methanol by 21£
per gallon (48 percent increase). The addition of 5 volume percent of DMF at
27
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$3.85/gallon to methanol would result in an increase of 17£ per gallon based on
current DMF costs.
Both DMF and methylal are low molecular weight compounds, and are not
expected to give regulated exhaust emissions that differ greatly from methanol.
DMF does contain a substantial amount of nitrogen, and its use could result in
an increase in the number and/or concentration of several currently unregulated
pollutants.
28
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IV. DYES AND COLORANTS
Dermal contact with methanol has been shown to be one of the routes in
methanol poisoning. The addition of a dye would help to deter the improper use
of methanol as a degreaser or cleaning agent, during which skin contact and
subsequent absorption could result. If a dye temporarily colored the skin, one
would probably not use the treated methanol as a cleaning solvent. In addition,
an intense or repulsive color would tend to deter the ingestion of methanol.
The color should appear unpalatable even when diluted.
A. Literature Search
The cutaneous exposure of human subjects to methanol has been examined
by a number of investigators. Dutkiewicz, Konczalik, and Karwacki^9'
determined a mean value for the absorption rate of methanol through the skin
of 0.192 mg/cm2/min. Using this value, the researchers calculated the
absorption from immersing the whole hand ( 440 cm2 surface area) in methanol
for twenty minutes. This immersion would result in the absorption of 1.7 mg ( 2
ml) of methanol. The absorption of 2 ml of methanol is approximately 5
percent of the usual fatal dose, and 33 percent of the smallest reported fatal
dose (6 ml) by ingestion. Although it is unlikely that one would immerse a hand
in methanol for twenty minutes without some discomfort, case studies have
shown that industrial workers (painters, varnishers, hatters, etc.) have
experienced blindness or even death from cutaneous exposure to methanol.
Case histories of cutaneous methanol poisoning include a painter who went blind
after spilling methanol on his clothes and shoes, and infants who died from a
methanol soaked compress being applied to their chest or under their rubber
pants.
Dutkiewicz and coworkers also determined that the rate of methanol
absorption was time-dependent.^9^ Table 10 illustrates the absorption rate of
methanol. The absorption rate was found to consist of two phases (Figure 1). In
the first phase, the absorption rate increases with longer exposure times until
about 30 minutes have elapsed. The increase in absorption rate for the first
phase is approximately 0.0053 mg/cm2/min2. The second phase shows a slight
decrease in absorption rate for the remainder of the exposure time (no data
available for exposures longer than 60 minutes). The overall absorption rate of
methanol is considered comparable to those of benzene, xylene, and carbon
disulfide.
Tada, et al,(5°) conducted absorption experiments on male subjects using
methanol, 10 volume percent toluene with methanol, and 50 volume percent
methylchloroform with methanol. The blood methanol content was monitored
during the course of the experiments at regular intervals. The work
demonstrated that methanol could be rapidly absorbed through the skin, and
that cutaneous absorption is a major route for methanol intake.
29
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0.30
0.25
0.20
0
o
pi
o
0.15
(0
0.10
Maximum
y Intercept (~0.065)
0.05
Phase II
(slope —0.0014)
Phase I
(slope ^,-0.0053)
Ol
0
10
20
I
30 40
Time, rain
50
60
70
Figure 1. Experimental rate of absorption for methanol versus time^ "'
-------
TABLE 10. METHANOL ABSORPTION RATE THROUGH THE SKIN
AT DIFFERENT EXPOSURE TIMES(*9)
Absorption Rate Through
Exposure Time Number of Range of absorbed the skin (mg/cm2/mln)
(min) Experiments doses, mg Average Range
15 3 22-27 0.146 0.131-0.161
20 3 38-40.8 0.175 0.169-0.182
30 6 65-81 0.225 0.193-0.241
35 3 81-92 0.220 0.206-0.234
45 3 92-108 0.198 0.182-0.214
60 4 119-130 0.187 0.176-0.193
Mean Value: 0.192
Ferry, Temple and McQueen^51*52) investigated the influence of
combinations of methanol and petrol (gasoline) on dermal absorption. Blends of
85%, 50%, and 15% gasoline with methanol were examined. The effectiveness
of barrier creams for preventing methanol absorption was also studied. After
exposure, the change in skin appearance was noted for each test subject.
Methanol alone caused the least dermal change, while the methanol/petrol
blends caused the skin appearance to be very white and dry. It took several
hours for the skin to return to its normal appearance. The methanol/gasoline
blends were described by the subject as irritating and the most discomfort was
caused by the 50% petrol mixture. The gasoline mixtures modified the
absorption process and allowed greater amounts of methanol to be absorbed.
The use of barrier creams failed to protect the skin from methanol penetration,
and appeared to reduce the capacity of normal skin to resist the absorption of
methanol. In another experiment, 15% methanol in gasoline was applied to a 75
cm2 area of the forearm on two human subjects. After one minute, an increase
in the sensation of heat occurred, and the experiment had to be terminated
after five minutes. The skin remained inflamed for three days but did not
blister. In each of these experiments, it was suggested that the absorption of
methanol from a mixture with gasoline was more likely to be irritating because
of the de-fatting effect caused by the petroleum distillate.
The addition of dyes has historically been used to identify a variety of
fluids used in automotive applications. Table 11 presents a general list of
. fluids and the colors used for identification. This list includes the actual dyes
used if available. A variety of alcohol-soluble dyes are commercially available
in a rainbow of colors. The only colorants previously used in denaturing ethanol
are methyl violet (S.D.A. 33) and iodine. Both of the colorants produce a deep
blue to violet color. Commercial methanol products have typically been blue in
color.(55)
31
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TABLE 11. GENERAL AUTOMOTIVE FLUID
Fluid
Antifreeze
Automobile transmission
Aviation gasoline^*"
Grade 80
Grade 100
Grade 100LL
Brake
DOT 3 and 4
DOT 5
Gasoline
Color
Hydraulic
Window washer solvent
yellow-green
blue
red
red-max. 0.5 mg/gal blue* +
max. 8.65 mg/gal red'3
green-max. 4.7 mg/gal bluea +
max. 5.9 mg/gal yellowc
blue-max. 5.7 mg/gal bluea
colorless to amber
blue
orange-red
green
blue
clear
bronze
green
light blue
al ,4-dialkylamino-anthraquinone
^methyl derivatives of azobenzene-4-azo-2-naphthol
(methyl derivatives of Color Index No. 26105)
cp-diethylaminoazobenzene (Color Index No. 11020)
32
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B. Evaluation
The addition of a dye or colorant to identify and to deter the improper use
of fluid is a common practice. The addition of a dye to temporarily stain the
skin, however, is not a common practice. A methanol fuel containing a dye to
stain the skin could result in irreversible coloration of clothing and vehicle
components, cause excess engine wear due to deposits (although this has not
been thoroughly investigated), and lead to additional exposures when trying to
remove the dye from skin or clothing.
The concentration of dye in methanol needed to stain the skin is also
considerably higher than the concentration of dye needed to give a distinctive
color to methanol. Five methanol-soluble dyes were obtained from Pylam
Products Company, Inc. for evaluation. These dyes included Pylam Bright Red,
Pylam Blue, Pylam Orange, Pylam Lemon Yellow and Rhodamine B (rose color
at high dilution). All five dyes gave discernable colors at a concentration of 4
mg per gallon methanol, however, only the colors for the Pylam Blue and
Rhodamine B remained intense. Concentrations on the order of 400 mg of dye
per gallon were needed to cause staining of the skin, but only the Pylam Blue
caused a significant discoloration. For comparison, the dyes used in gasoline
are present at concentrations up to 10 mg per gallon.
One company, the Lindele Corporation in Orange, California, produces
two methanol fuels containing dyes. One is for a racing application (Racing
Blue) and the other for street vehicles (Red fuel). Both contain proprietary
additive packages, however, the dyes used in these fuels are present as a
method of leak detection rather than as a stain for the skin.
A number of alcohol soluble dyes are available on the market in a rainbow
of colors. While a variety of dye colors could be used for various applications,
the use of a blue dye as a colorant would conform to the coloration used in
commercial products containing methanol. The blue dyes also give a more
intense color than other dyes at equivalent concentrations (i.e., the Pylam
dyes).
If the average price for 100 pound quantities of the Pylam dyes,
$19/pound (1981 price list), is used to calculate the cost impact of adding dyes
to methanol, then a 4 mg/gallon dye concentration would only increase the cost
of methanol 0.02£ per gallon. This 4 mg/gallon concentration of the Pylam dyes
is the amount needed to give methanol a distinctive color. If the 400 mg/gallon
concentration is used for skin coloration, a 2£ per gallon increase in the cost of
methanol is calculated. The blending costs in either case would be on the order
of 0.1£/gallon if the costs for blending with methanol are comparable to those
for gasoline.
The use of dyes in methanol would probably have little or no impact on
the exhaust emissions, if the dyes were used at concentrations equal to or lower
than those currently used in gasoline (up to 40 mg per gallon). The impact on
the exhaust emissions from higher dye concentrations would depend on the
chemical makeup of the dye. Dyes containing metals such as manganese
(permanganate) or halogens (chlorine, bromine, iodine) should be avoided
because they may damage the emission control devices and may result in
exhaust emissions that could represent human health hazards.
33
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V. EMETIC
The use of emetics as additives to methanol is another means of reducing
the severity of poisoning due to its ingestion. An emetic is an agent or
substance that induces vomiting, which allows the victim from an accidental or
intentional ingestion of a hazardous substance to eliminate it before the body
has time to absorb the poison. Posnen5^) was one of the first researchers to
suggest the use of an emetic as an additive to methanol. Another related group
of compounds, "antialcoholics," is also a possible means of deterring the
consumption of methanol.
A. Literature Search
The usefulness of emetics generally occurs after a poison has been
ingested, rather than acting as a deterrent. The addition of an emetic
substance should be in high enough concentration to induce vomiting even if
diluted, should be reliable, and should act in a very short period of time to
minimize the absorption by the body. Common practices to induce vomiting
include the administration of 10 g of table salt in 200 ml of warm water (2
teaspoons in a glass of warm water'57)), the administration of 2 teaspoons of
sodium bicarbonate (baking soda) in a glass of water,^2) or the administration
of 30 ml (1 oz.) of syrup of ipecac to the victim.(5S)
Ipecac, the emetic generally recognized by the medical profession, is
obtained from the dried rhizome and root of a plant that grows in Tentral and
South America. It consists of a variety of alkaloids which include emetine,
cephaeline, emetamine, ipecacuanhic acid, psychotrine and methyl psychotrine.
Ipecac is available in two forms: pure extract, and tincture. Emetine is one of
the principal alkaloids of Ipecac, and it is used in Great Britain as an emetic^50'
and in third world countries as an antiamebic. A list of possible emetics which
would be added to methanol is included in Table 12. It should be noted that
many of the substances are derived from plant tissues.
Compounds in another group (antialcoholics) are administered to
individuals before injection of ethanol, and are used to treat chronic alcoholics
as a means of reducing their dependency on ethanol. After the administration
of antialcoholics such as disulfiram (tetramethylthiuram disulfide) or citrated
calcium cyanamide, a patient experiences a number of physical responses,
including vomiting, when ethanol is ingested. Disulfiram is also used in the
rubber industry as an accelerator and vulcanizer, as a seed disinfectant, and as
a fungicide. Since antialcoholics must be administered before the consumption
of an alcohol, their use is impractical as an emetic additive to methanol.
B. Evaluation
Based on the large quantity of an emetic which would need to be added to
methanol to produce the desired effect and the corresponding cost associated
with this amount of emetic, the use of an emetic in methanol motor fuel would
probably not be practical. About 2 ml of pure ipecac extract or about 30 ml of
the syrup of ipecac (ethanol base) are required to induce vomiting/55) A dose
of 25 ml of methanol has been reported as fatal in some cases if not treated
immediately; therefore, 2 ml of ipecac extract would be required for each 25
34
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TABLE 12. THERAPEUTIC CATEGORY - EMETIC<32)
Compound
Apocodeine
Apomorphine
Bay berry bark
Gephaeline
Citrated calcium cyanamide
Disulfiram
Dodine
Emetine
Eupatorin
Ipecac
Nabam
Oil of Chamomile
German
Roman
Sea onion
Stillingia
Source or Comments
codeine
morphine
dried root bark of Myrica
cerifera L, Myricaceae
alkaloid of ipecac
antialcoholic
alcohol deterrent
agricultural fungicide
Alkaloid of ipecac
root of Unagaga ipecacuanda or
Uragoga acuminata
in presence of alcohol can cause
violent vomiting
aromatic bitter
volatile oil from flowers of
Matricaria chamomilla L
volatile oil from flowers of
Anthemis nobilis L
fleshy inner bulb scales of the
white variety of Urginea marithima
root of Stillingia sylvatica L
35
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mi of methanol fuel (8 percent). With the current cost of ipecac at $120/lb,(59)
the cost impact of a methanol/ipecac fuel would be on the order of $8*/gallon,
a prohibitive figure. The individual alkaloid emetics that make up ipecac are
even higher in cost. Emetine hydrochloride, for example, a derivative of
emetine, fluctuates in price due to availability from $2200 to $2700 per pound.
The use of the relatively inexpensive materials such as table salt or
sodium bicarbonate as emetics in methanol would also require excessive
amounts of the additives (one half pound per gallon of methanol). These
materials are only slightly soluble in alcohols and their effectiveness as emetics
in alcohols is unknown. Table salt and sodium bicarbonate are not considered
viable additives.
The effect of an emetic such as ipecac on the exhaust emissions from a
vehicle operating on a methanol blend is unknown. Large quantities of the high
molecular weight emetic would, however, likely be detrimental to the operation
of spark ignited engines and possibly even to spark-assisted diesel methanol
engines.
36
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VI. ODORANTS
Another major route of methanol poisoning is inhalation. Methanol does
not have a strong or distinctive odor to identify its presence, and when pure,
has such a low odor intensity that one could be exposed to hazardous levels
without realizing it. The addition of odorants would help identify the presence
of methanol, and serve as a warning of possible hazardous conditions. A
suitable odorant would need to coevaporate with methanol and be detectable at
a much lower concentration than methanol vapor alone.
A. Literature Search
The Occupational Safety and Health Administration (OSHA) has set a
workplace ceiling level standard of 150 ppm (200 mg/m3) for methanol in air.
Other standards for methanol exposure include the American Conference of
Governmental Industrial Hygienists (ACGIH) and OSHA threshold limit value
(TLV) of 200 ppm (260 mg/m3), ACGIH short term exposure limit of 245 ppm
(310 mg/m3), and the American National Standard Institute (ANSI) ceiling
concentration of 600 ppm (760 me/m3) and eight hour, time weighted
concentration of 220 ppm (260 mg/m3). The IDLH (Immediately Dangerous to
Life or Health) value for methanol is set at 25,000 ppm, and the lower
explosive limit is approximately 67,000 ppm. The values for the odor threshold
have been reported to range from 100 to 2000 ppm.(23> Varying levels of
impurities in methanol may account for this discrepancy; since compounds of
low odor are greatly influenced by the presence of odorous impurities. If the
odor threshold was at the upper end of the range, then one might not be able to
detect levels where physiological effects could result.
Keller, Nakaguchi and Ware^6) screened eight substances for their effect
on the odor threshold of methanol. These substances were screened initially by
preparing solutions with methanol in open volumetric flasks (Table 13). The
more promising of these substances in terms of cost effectiveness and odor
threshold were tested further in a closed room. A measured quantity of each
solution was allowed to evaporate in the room to give a 480 ppm (610 mg/m3)
concentration of methanol. The odor in the room was then evaluated by two or
more individuals. The results of this second experiment are presented in Table
14. The odor threshold for reagent grade methanol used in this study was
approximately 400 ppm (505 mg/rrP).
The most effective odorants tested in the study were determined to be n-
butyl mercaptan and ethyl acrylate. Gasoline, giving an "old paint" odor to the
blend, was not considered as effective as the others. At very low concentration
levels, the odor of ethyl acrylate was described as pleasant, while at higher
concentrations, the odor was found to be extremely irritating. The two
mercaptans screened in the study produced very distinctive odors even at very
low concentrations, however, n-butyl mercaptan was considered more
unpleasant than t-butyl mercaptan. One disadvantage of using mercaptans as
methanol additives is possible confusion with a natural gas leak. Natural gas
also contains mercaptans as odorants. A number of other malodorous
substances which could be used as odorants in methanol are listed in Table 15.
37
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TABLE 13. ODOR ANT TESTS: ODOR OF VARIOUS ODOR ANTS ABOVE A
SOLUTION IN METHANOL
(In An Open Volumetric Flask)
Compound
Toluene
"Xylenes"
Gasoline
(estimated mol. wt. 100)
Ethyl acrylate
Acrolein
Crotonaldehyde
Molarity in
Methanol
1.0
0.1
0.01
1.0
0.1
0.7a
o!o7
1.0 x 10-3
l.Ox 10-*
1.0 x 10'5
1.0 x 10-6
0.01
0.01
Odor
very strong
slight
not detectable
strong
slight
strong
slight
very slight
strong and irritating
strong
slight and not irritating
slight and not irritating
slight
slight
n-butyl mercaptan
t-butyl mercaptan
a!0 vol % or 9 wt % gasoline
b2 vol % or 1.8 wt % gasoline
5.1 x 10-*
strong and very unpleasant
strong and unpleasant
38
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TABLE 1*. ODORANT TESTS: EVAPORATION OF A SOLUTION IN
METHANOL INTO A CLOSED ROOM*
Odorant
Gasoline
Ethyl acrylate
t-butyl mercaptan
n-butyl mercaptan
Methanol only
Concentration
in Methanol
Molarity
1.2C
1.0 x 10-4
5.1 x 10-4
1.7 x 10-4
5.1 x lO'5
5.4 x 10-4
1.8 x 10-4
5.4 x 10~5
Approximate
Concentration
of Odorant in
Air, ppm by Vol
6
18
0.002
0.01
0.003
0.001
0.01
0.004
0.001
330e
Observations
no noticeable odor
odor "like old paint,"
"sweet", not very
alarming^
odor very noticeable,
distinctive, rather
sweet, "like plastic"
odor strong, unpleasant,
"like natural gas"
odor fairly strong,
unpleasant, "like natural
gas"
odor noticeable,
unpleasant
odor very strong, very
unpleasant
odor very strong,
unpleasant
odor noticeable, more
unpleasant than
t-butyl mercaptan
odor noticeable, rather
sweet but irritating
to nose and throat
Sufficient to give 480 ppm (vol) methanol in the air
b5 wt % gasoline
C15 wt % gasoline
^The odor was not recognizable as that of gasoline to anyone.
eMethanol did not completely evaporate.
39
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TABLE 15. MALODOROUS SUBSTANCES
Compound
Aldehol
Acrolein
Bis(methylthio)methane
Trans-2-butene-1 -thiol
n-butyl mercaptan
sec-butyl mercaptan
t-butyl mercaptan
Crotonaldehyde
Dimercaprol
Ethyl acrylate
Ethyl mercaptan
Ethyl sulfide
Gasoline
Isoamyl mercaptan
Isoamyl sulfide
Isobutyl mercaptan
Isobutyl sulfide
Methyl acrylate
3-methylbutanoic acid
3-methyl-l -butanethiol
2-methyl-2-burtene
Methyl-l-(trans-2-
buteryDdisulfide
Odor
disagreeable odor
pungent odor
odorous principle of white
truffle
scent of skunk
heavy skunk odor
heavy skunk odor
heavy skunk odor
vapor extremely irritating
pungent offensive odor of
mercaptans
acrid, pentrating odor
penetrating leek-like odor
etheral odor
characteristic odor
repulsive odor
heavy skunk odor
acid odor
disagreeable, rancid-cheese
odor
scent of skunk
disagreeable odor
scent of skunk
Source
9
6
9
60
6
9,61
6,61
6
9
6
9
61
6,61
9
9
6
9,61
9
9
60
9
60
4Q
-------
TABLE 15 (Cont.d). MALODOROUS SUBSTANCES
Compound
Methyl mercaptan
M ethyl sulfide
2-naphthyl mercaptan
1-octanol
2-octanol
1-pentanethiol
1,3 propanedithiol
Pyrazine
Pyrazole
2-pyrazoline
Pyridine
Pynolidine
3-pynoline
Thiophene
Toluene
Xylenes
Odor
odor of rotten cabbage
disagreeable odor
disagreeable odor
penetrating, aromatic odor
aromatic, yet somewhat
unpleasant odor
penetrating, unpleasant odor
disagreeable odor
strong pyridine-like odor
pyridine-like odor
faint amine odor
characteristic disagreeable
odor
unpleasant ammonia-like odor
unpleasant ammonia-like odor
slight aromatic odor
resembling that of benzene
benzene-like odor
Source
9
9,61
9
9
9
9
9
9
9
9
9
9
9
17
6
6
41
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B. Evaluation
Methanol's low odor intensity allows unsafe concentrations of methanol
vapor to go undetected. An additive with a high odor intensity that would
coevaporate with methanol should be used to indicate the presence of methanol.
The use of an additive to impart an odor to methanol parallels the role of
mercaptans in providing an odor to otherwise odorless natural gas.
Keller, Nakaguchi, and Ware(6) investigated a number of odorous additives
for methanol. Four additives (gasoline, ethyl acrylate, n-butyl mercaptan and
t-butyl mercaptan) were evaluated extensively. As mentioned previously in this
report, a 15 volume percent addition of gasoline was found to produce an "old
paint" odor when coevaporated with methanol. While extremely irritating at
high concentrations, the odor of ethyl acrylate in methanol was determined as
pleasant at very very low concentrations. The two mercaptans produced very
distinctive odors even at low concentrations, with the n-butyl mercaptan being
considered the more unpleasant of the two.
While the mercaptans were found to be effective odorants in Keller's
work, their odor could produce confusion about the source since mercaptans are
also added to natural gas. Mercaptans are also feared to be susceptible to
oxidation while standing in methanol fuel for long periods of time. This
oxidation process would convert the mercaptans to sulfur oxides, which have a
much lower odor intensity. Organic sulfides (i.e., methyl sulfide, ethyl sulfide)
have an odor slightly different from, but equivalent in intensity to, that of the
mercaptans. They are also more resistant to oxidation, and would be viable
alternates for odorous additives to methanol. Vehicles using methanol fuel with
mercaptans or organic sulfides as odorant additives would produce exhaust
emissions containing sulfur dioxide and sulfate. These exhaust emissions would
be nonexistent when using pure methanol, however the levels of sulfur dioxide
and sulfate emissions would be on the order of one-tenth those from the sulfur
in conventional gasoline.
The use of mercaptans or organic sulfides at the levels necessary to
produce a strong and unpleasant odor in methanol should not provide any
problems with vehicle operation or with the health of people using the fuel
blend. The use of ethyl acryiate as an odorant may not be as practical as the
sulfur-containing odorants, since ethyl acrylate levels that were high enough to
be detected were also irritating. This irritation of the eyes and mucous
membranes could be a problem in itself. The use of unleaded gasoline as an
additive was discussed in detail in Section II of this report. Bulk costs for
mercaptans and organic sulfide odorants are similar, and range from $1.04 to
$1.08 per pound.f61? The cost of the mercaptans or sulfides necessary to give a
gallon of methanol a strong and unpleasant odor is approximately 0.05£ (cost of
0.2 grams).
In addition to identifying the presence of methanol vapor, the use of
odorants would also act as deterrents for the ingestion and for the dermal
contact of methanol fuel. Prior to 1880, the only commercially available
source of methanol was in the form of wood alcohol, which had a vile taste and
disgusting odor. For this reason, methanol was rarely ingested or used in
contact with the skin. After an inexpensive method of deodorizing wood
42
-------
alcohol was introduced, methanol became a substitute for ethanol and as many
as one thousand uses of poisoning were attributed to methanol between 1988
and 1913.(22) An odorant added to methanol fuel should discourage the
ingestion or dermal contact of methanol fuel as did the unpleasant odor of wood
alcohol.
43
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YD. OTHER METHODS TO INCREASE SAFETY
In addition to chemical means for improving the safety of methanol,
several additional methods have been proposed. They include fuel labeling,
antisiphoning methods, sealed fuel handling systems and methanol education.
These additional measures would help to increase the safety associated with the
use of methanol as a motor fuel.
In 1976, the National Institute for Occupational Safety and Health
(NIOSH) recommended standard labeling of methanol containers and areas
where methanol was present.(62) The language of the warning signs is
presented in Figures 2 and 3. Methanol is regulated by the Federal Hazardous
Substances Act and must be labeled with "Danger," "Poison," "Cannot be made
nonpoisonous," and the skull and crossbones symbol. The statement of hazard
must include the language "Vapor Harmful." Wood and Buller(63) suggested
labeling with "not to be taken internally" in 190&. Hagen^D, and Anderson and
Nichols^8', and Wimer, Russell and Kaplan^8' have suggested similar language
including the avoidance of such terms as "wood alcohol" or "methyl alcohol,"
since the lay person identifies the term alcohol with ethanol and deduces that it
is drinkable. All references to "alcohol" should be avoided in the distribution
and discussion of methanol. A term such as "fuel methanol" would be
preferable.
Posner(-51) has suggested the use of antisiphoning devices or techniques to
remove the possibility of oral or dermal contact with fuel methanol. Very few
individuals die or suffer residual effects from the ingestion of gasoline.
However, the aspiration of gasoline into the lungs can cause pneumonia and
sometimes even death. The ingestion or aspiration of methanol into the body is
more harmful than the ingestion or aspiration of gasoline since small quantities
of methanol can cause temporary or permanent blindness, and large quantities
can cause death. The ingestion of methanol may also trigger abuse due to its
inebriating quality. Hagenfcl) suggests that strict measures must be taken to
prevent oral consumption, and oral fuel siphoning should be strictly avoided.
Posner(51) has also suggested the use of sealed handling systems and
redesigned fuel delivery systems. A closed system would help to eliminate
dermal contact and exposure to methanol vapors. The racing organizations
(CART and USAC) have been using a closed fueling system, called a "dry break"
system, for many years on their racing vehicles. The system is composed of
self-closing, spring-loaded valves which do not allow the fuel to flow until the
union has been completed. This system, in conjunction with ground wires and
fire proof clothing, helps to reduce exposure to methanol and the possibility of
fire-related accidents.
Education of the general public to the dangers related to methanol would
also be of great importance. Although this is probably the least cost effective
method of safety enhancement, the frequency of serious accidental ingestion or
exposure should be appreciably reduced. The NIOSH report^62' concludes that
the safe handling of methanol depends to a great extent upon the effectiveness
of employee education, intelligent supervision, and the use of safe equipment.
Training programs for new and experienced employees should be conducted
44
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METHYL ALCOHOL
(METHANOL)
WARNING FLAMMABLE
CAN BE FATAL OR CAUSE BLINDNESS IF SWALLOWED
Keep away from heat, sparks, and open flame.
No smoking permitted.
Do not take internally.
Keep container closed.
Avoid prolonged or repeated breathing of vapor
or contact with skin.
Avoid contact with eyes.
Use with adequate ventilation.
First Aid; In case of eye or skin contact, flush thoroughly with copious
amounts of water. In case of accidental swallowing, call a
physician and induce vomiting if the patient is conscious.
Change clothing if contaminated.
In case of:
Fire; Use water, spray, "alcohol" type foam, dry chemical,
or carbon dioxide extinguishers.
Spill; Flush area with water spray.
Figure 2 . Warning sign for storage tanks and containers
(62)
METHYL ALCOHOL
(METHANOL)
WARNING FLAMMABLE
HARMFUL IF INHALED
CAN BE FATAL OR CAUSE BLINDNESS IF SWALLOWED
IRRITATING TO SKIN OR EYES
No smoking permitted.
Provide adequate ventilation.
Figure 3 . Warning sign for areas in which methyl alcohol is present^2)
45
-------
periodically. There have been documented cases in which methanol has been
used in an infant's formula (mistaken for water), applied to the skin with
methanol-soaked compresses on the chest or under babies' rubber pants, spilled
on clothing of workers, and abused in every form from antifreeze to solvents to
alcohol fuel (Sterno). Although education is not the complete answer, it would
help to reduce many of the accidental hazards involved with methanol.
46
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REFERENCES
1. Private conversations, Bruce Mabrito (SwRI), David McGee (IHRA), Vance
Brady (AHRA), October 1983.
2. National Hot Rod Association, "1980 Drag Rules Drag Racing's Official
Competition Guidelines," 1979.
3. Private conversations, Kirk Russell (CART) and Ray McMahan (USAC),
September 1983.
4. Panzer, 3., "Characteristics of Primed Methanol Fuels for Passenger
Cars," Society of Automotive Engineers, SAE 831687, 1983.
5. Anderson, J.E., and Siegl, W.O., "Use of Co-Fuels to Increase the
Luminosity of Methanol Pool Fires: Some Preliminary Findings,"
Symposium on Chemistry of Oxygenates in Fuels, Div. of Petroluem
Chemistry, American Chemical Society, Kansas City, September 1982.
6. Keller, J.L., Nakaguchi, G.M., and Ware, J.C., "Methanol Fuel
Modification for Highway Vehicle Use," U.S. Department of Energy,
Washington, D.C., HCP/W3683-18, July 1978.
7. Private communications, Dave NaegeJi nad Ed Dimitroff (SwRI),
September 1983.
8. Anderson 3.E., and Nichols, R.J., "Fuel Methanol Additives: Issues and
Concerns, Energy Technology X "A Decade of Progress," Proceedings of
the Tenth Energy Technology Conference, Dr. Richard F. Hill ed.,
Washington, D.C., 3une 1983.
9. Author
10. German Patent, Pat. No. 3,039,225, 1982.
11. Coward, H.F., and Woodhead, D.W., Third International Symposium on
Combustion, Combustion Institute, Pittsburgh, PA 1949.
12. Weast, R.C., ed., Handbook of Chemistry and Physics, The Chemical
Rubber Co., Cleveland OH, 1973.
13. Gordon, A.J., and Ford, R.A., The Chemist's Companion A Handbook of
Practical Data, Techniques, and References. John Wiley and Sons, Inc.,
New York, 1972.
14. Private communication, Dr. Henry Hamil, (SwRI), September 19&3.
15. Alcohol Week, January 19 through December 14, 1983.
16. The Oil Daily, January 3 through December 30, 1983.
47
-------
REFERENCES (Cont'd)
17. Keller, J.L., "Alcohols as Motor Fuel?" Hydrocarbon Processing, May
1979.
18. Whitten, G.Z. and Hogo, H., "Impact of Methanol on Smog: A Preliminary
Estimate," Prepared for ARCO Petroleum Products Co., Publication No.
830W, February, 1983.
19. O'Toole, R., et al. "California Methanol Assessment Volume II: Technical
Report," prepared for Electric Power Research Institute and Energy
Resources Conservation and Development Commission, State of
California, GPL Publication 83-18 (Vol. II), March 1983.
20. Whitten, G.Z. and Pullman 3.B., "Methanol Fuel Substitution Can Reduce
Urban Ozone Pollution," Sixth International Symposium on Alcohol Fuels
Technology, Volume II, Ottawa, Canada, May 1984.
21. Hagen, D.L., "Methanol as a Fuel: A Review with Bibliography," Society
of Automotive Engineers, SAE 770792, 1977.
22. Wimer, W.W., Russell, J.A., and Kaplan, H.L., Alcohols Toxicology, Noyes
Data Corp., Park Ridge, N.J., 1983.
23. Midwest Research Institute, "Methanol Health Effects." Environmental
Protection Agency, PB 82-160797, 1981.
21. U.S. Industrial Chemical Co., Ethyl Alcohol. New York, NY. 1960.
25. Mueller Associates, Inc., "Denaturants for Ethanol/Gasoline Blends," U.S.
Department of Energy, Washington, D.C., HCP/M2098-01, UC-98, 1978.
26. French Patent, Pat. No. 2,396,069, 1979.
27. Polish Patent, Pat. No. 66,638, 1973.
28. Ogston, A.R., "Alcohol Motor Fuels," Journal of the Institution of
Petroleum Technologists, Vol. 23, 1937.
29. Nakaguchi, G.M., Keller, 3.L., and Wiseman, E.L., "Ethanol Fuel
Modification for Highway Vehicle Use," U.S. Department of Energy,
Washington, D.C., ALO-3683-T1, July 1979.
30. "Dimethoxymethane About to Enter Methanol Fuel Market, Says
Company," Alcohol Week, April 18, 1983.
31. "Celanese, B of A Testing Methylal as Neat Methanol Additive," Alcohol
Week, June 13, 1983.
32. Windholz, M. ed. Merck Index an Encyclopedia of Chemicals and Drugs,
9th Ed., Merck and Co., Inc., Rahway, N3, 1976.
48
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REFERENCES (Cont'd)
33. Private communication, Dr. BUI Watson, (UTHSC), September 1983,
34. Watson, R.C., "Alcohol: Denatured and Illegal Varieties," Alcohol Health
and Research, Experimental Issue, 1975.
35. "Denatonium Benzoate as a Deterrent for Ingestion of Liquid Household
Cleaning Products by Children," Research Disclosures, Vol. 216, 1982.
36. U.S. Patent, Pat. No. 4,005,038, 1977.
37. U.S. Patent, Pat. No. 3,935,137, 1976.
38. U.S. Patent, Pat. No. 4,064,316, 1977.
39. European Patent, Pat. No. 12,525, 1980.
40. "Bendicarb/Bitter Substance," Research Disclosures, Vol. 211, 1981.
41. "Nailbiting and Thumbsucking Deterrent Drug Projects for Over-the
Counter Human Use; Establishment of a Monograph," Federal Register,
October 17, 1980.
42. Damon, C.E., and Pettitt, B.C., 3r., "High-Performance Liquid
Chromatographic Determination of Denatonium Benzoate in Rapeseed
Oil," Journal of Chromatograph, Volume 195, 1980.
43. Sugden, K., Mayne, T.G., and Loscombe, C.R., "Determination of
Denaturants in Alcoholic Toilet Preparations," Analyst, Vol. 103, June
1978.
44. Glover, M.3., and Blake, AJ., "Separation and Thin-layer
Chromatographic Determination of Denatonium Benzoate and Other
Quaternary Ammonium Denaturants in Spirituous Preparations," Analyst,
Vol. 97, November 1972.
45. Alsmeyer, E.G., and 3ungst, R.W., "Identifying Alcohols by Their
Denaturants," Soap Cosmetics Chemical Specialties, March 1972.
46. Private communication, Ralph Fried (Robeco Chemicals, Inc.), February
1984.
47. Federal Register. Volume 45, No. 121, Friday, 3une 20, 1980, Rules and
Regulations.
48. Private communication, Mr. Perlick (Howell Hydrocarbons), February
1984.
-------
REFERENCES (Cont'd)
49. Dutkiewicz, B., Konczalik, 3., and Karawacki, W., "Skin Absorption and
Per Os Administration of Methanol in Men," Int. Arch., Occup., Environ.,
Health, 47, 1980.
50. Tada, O., Nakaaki, K., Fukabori, S., and Yonemoto, 3., "An Experimental
Study on the Cutaneous Absorption of Ethanol in Man," 3. Science of
Labour, Volume 51, No. 3, 1975.
51. Ferry, D.C., Temple, W.A., nad McQueen, E.G., "The Percutaneous
Absorption of Methanol After Dermal Expsoure to Mixtures of Methanol
and Petrol," Proceedings Fifth International Alcohol Fuel Technology
Symposium, Volume 3, Aukland, New Zealand, May 1982.
52. Ferry, D.C., Temple, W.A., and McQueen, E.G., "Toxicity of
Methanol/Petro Mixtures," Proceedings of the Third International
Symposium on Alcohol Fuel, Volume 3, Asilomar, California, May 1979.
53. Private communication, David Brian Holland, October 1983.
54. ASTM
55. Private communication, Dr. Bill Watson (UTHSC), November 1983.
56. Posner, H.S., "Biohazards of Methanol in Proposed New Uses," 3ournal of
Toxicology and Environmental Health, Volume 1, 1975.
57. Steere, N.A., ed., Handbook of Laboratory Safety. Second Edition, The
Chemical Rubber Co., Cleveland, Ohio, 1971.
58. Private communication, Dr. Bill Hall (SwRI), September 1983.
59. Private communication, Mr. Curran (Chart Corp.), February 1874.
60. Research Reporter, Chemistry, July - August 1975.
61. Private communication , Mr. Leuck and Mr. Ralph Williams (Phillips
Chemical Co.), February 1984.
62. "Criteria for a Recommended Standard...Occupational Exposure to Methyl
Alcohol," National Institute of Occupational Safety and Health, U.S.
Department of Health, Education and Welfare, NIOSH 76-148, March
1976.
63. Wood, C.A., and Buller, F., "Poisoning by Wood Alcohol: Cases of Death
and Blindness from Columbian Spirits and Other Methylated
Preparations," 3ournal of the American Medical Association, Volume 43,
1904.
50
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APPENDIX A
-------
BACKGROUND AND HISTORY
Methanol is the simplest of alcohols. Synonyms include methyl alcohol,
wood alcohol, wood spirit, carbinol, methylated spirit, Columbia spirit, colonial
spirit, odiophorous spirit, pyroxylic spirit, methylol, monohydroxymethane, and
methyl hydroxide. Methanol is a flammable, toxic liquid which burns with a
non-luminous, bluish flame. It has a slight "alcohol" odor when pure, but the
crude material may have a repulsive, pungent odor. It is miscible with water,
ethanol, ether, benzene, ketones and most other organic solvents; is usually a
better solvent than ethanol; and forms azeotropes with a number of compounds.
Methanol is used as an industrial solvent, an ingredient in antifreeze, a
denaturant for ethanol, a fuel for picnic stoves and soldering torches, an
extractant for animal and vegetable oils, a softening agent for pyroxylin
plastics and many other applications. The chemical and physical properties of
methanol are listed in Table A-l.
Methanol can be produced from raw material sources that can be burned
to produce CO and \\2 (synthesis gases). The sources of methanol include non-
renewable ones such as coal, natural gas, petroleum, and oil shale as well as
renewable sources such as municipal trash, agricultural and animal wastes, and
wood and wood waste. The destructive distillation of wood as a method of
production for methanol has completely disappeared in the United States,
although some methanol is made commercially as a by-product in the
production of charcoal. The conversion of natural gas to methanol is currently
the major source. Gasification of coal and the pyrolysis of waste have become
much more popular, however. Recently, work has begun by a group of
microbiologists in England to grow bacteria capable of converting methane to
methanol.(l)
The original production of alcohols is lost in antiquity. Evidence of
fermentation has been found depicted on Mesopotamian pottery dated circa
4200 B.C. A wooden model of an Egyptian brewery dated circa 2000 B.C. has
also been found. In 1661, Boyle discovered a volatile compound in products from
the dry distillation of hardwood which he named "odiophorus spirit." This crude
form of methanol was later referred to as wood alcohol. Methanol was
confused with the fermentation product, ethanol, for over a century and
until its chemical structure was determined by Dumas and Peligot in 1831
In about 1830, alcohol became a popular fuel for lighting, replacing the
malodorous fish and whale oil. By the middle of the nineteenth century,
methanol was widely used in France as a heating, lighting, and cooking fuel. By
the 1880's, kerosene had replaced methanol as a lighting fuel because of its
more luminous flamed
The use of alcohol (ethanol) as a fuel for internal combustion engines was
first attempted in Germany at the turn of the century. Alcohol was found to be
impractical as a fuel for engines of that era since most of them were single-
cylinder and had a low-compression ratio (3 or k to 1). Mixing of alcohol and
gasoline was not considered because the commercially produced alcohol of that
A~2
-------
TABLE A-l. PROPERTIES OF METHANOL^)
Property
Value
Formula
Molecular Weight
Carbon to Hydrogen Weight Ratio
Carbon, % by Weight
Hydrogen, % by Weight
Oxygen, % by Weight
Autoignition temperature, °C
Boiling Point at 760 mm HG, °C
Critical Pressure, Atmospheres
Critical Temperature, °C
Dielectric Constant at 20°C
Dielectric Constant at 25°C
Dipole Moment at 25°C Debye Units
Electrical Conductivity, at 25°C
ohm-l/cm
Flammability Limits, in air, Vol. %
Lower Limit (at 25°C)
Upper Limit (at 60°C)
Flashpoint (ASTM Tag Open Cup), °C
Freezing Point, °C
Heat of Combustion, gross, of liquid
at 25°C cal/mole
Heat of Combustion of liquid at 20°C
kcai/moke
Heat of Vaporization at bp
-------
TABLE A-l (Cont'd). PROPERTIES OF METHANOL<1,2)
Property
Value
Heat of Formation at 25°C, cai/mole
of liquid
of vapor
Heat of Fusion at -97.8°C cal/g
Ignition Temp, in Air (atm, Pressure),°C
Ignition Temp, (apparent), in Air, <>C
Melting Point, oc
Refractive Index, n 20/D
Specific Conductivity at 25°C
Specific Gravity at 20/4°C
Specific Heat, Liquid, cal/g
0-3°C
5-10°C
15-20°C
25-30°C
35-40°C
Surface Tensions, dynes/cm
at 15°C
at 20°C
at 30°C
Vapor Density (air = 1)
Vapor Pressure, mm Hg
at 10°C
at 20°C
at 30°C
at 40°C
at 50°C
at 60°C
at 64.5°C
Viscosity, cP
at 15°C
at 2QOQ
at 25°C
at 30°C
57,036
^8,100
22.0
385
470.0
-97.8
1.3286
1.5 x 10-9 mhos/cm
0.7915
0.565-0.575
0.579-0.587
0.594-0.600
0.605-0.609
0.613-0.616
22.99
22.55
21.69
1.11
29
52
96
159
258
410
630
760
0.6405
0.5945
0.5525
0.5124
A-4
-------
time period had a water content of not less than 5 to 6%, rendering it
immisable with gasoline/*)
With the advent of World War I, interest in alcohol as a fuel was revived
in Germany, which faced serious petroleum shortages. Alcohol mixed with
benzene and available gasoline was used as fuel for German airplanes,
Zeppelins, and ground transportation, as well as to manufacture explosives and
other war materials. In Sweden, the only fuel available was a mixture of
alcohol, benzene, acetone, and turpentine. After World War I, legislation was
enacted by Austria, Brazil, Czechoslovakia, France, Germany, Hungary, Italy,
Yugoslavia, Latvia, Poland, Spain, and Sweden to enforce the use of ethanol as
a motor fuel. Even in the United States, which had a surplus production of
petroleum relative to domestic requirements, the farming community pushed
for legislation (the 1906 Industrial Denatured Alcohol Act) to enforce the use of
ethanol/gasoline mixtures aided by tax exemptions. In the United Kingdom and
Australia, ethanol fuels were marketed without Government compulsion/*)
Just before and during the second world war, petroleum was again in short
supply. A relatively small number of vehicles were operated on the fumes from
burning wood. These fumes contained carbon moxoxide, methane, and hydrogen
as well as some methanol. About 9000 passenger buses, trucks, pleasure cars,
and even two taxi cabs used wood as a fuel source. The majority of the wood
burning vehicles were operated in France (4500), Germany (2200), and Italy
(2200). Wood filling stations began to dot the countryside in these countries, and
wood was sold in bundles of 30 to 60 pounds/5'
Following World War II, a promotional effort was undertaken to use
water-alcohol injection in spark-ignited automobile and truck engines. Since
that time, methanoi has been used in all types of engines ranging from aircraft
engines to racing vehicles. More recently, interest in methanol as a fuel
resulted from the possible reduction of exhaust emissions, independence from
foreign oil supplies, and utilization of domestic surpluses of biomass.w
The toxicity of methanol in an industrial environment was first noted by
MacFarlanv) in 1855, among cabinet workers, metal workers, and hatters who
used wood naphtha and methylated spirits. Prior to 1880, the only commercial
source of methanol was from the destructive distillation of wood and poisioning
from methanol was virtually unknown. Wood alcohol, the product from the
destructive distillation of wood, had a vile taste and disgusting odor and was
rarely ingested. In the 1890's, a relatively inexpensive method of deodorizing
wood alcohol was introduced. The resulting products were packaged under
various names such as Columbia Spirits, Purified Wood Alcohol, and Colonial
Spirits and were advertized as a substitute for ethanol. Uses included the
manufacture of varnishes, liniments, tinctures, hair dyes, fuels for lamps and
stoves, toilet articles, perfumes, alcoholic extracts, cheap whisky and patent
medicines. Not until 1923, when a group of dock workers in Germany were
poisoned by ingestion, did the public finally realized that methanol really was a
poison. During World War II, it was estimated that about six percent of the
nonfatal cases of blindness to servicemen were caused by methanol/2^
Even today methanol poisoning is not uncommon. Methanol is purchased
in many forms and used as a substitute for ethanol in order to enhance the
A-5
-------
intoxicating effects. Methanol has also been mistaken for water in infants
formula and for ethanol or rubbing alcohol in chest compresses. A number of
infants have died from prolonged skin contact to methanol applied under rubber
pants. These cases and many others reflect the ignorance of the public to the
toxic effects of methanol.
A-6
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APPENDIX REFERENCES
1. Baratz, B., Ouellette, R., Parks, W., and Stopes, B., "Survey of Alcohol
Fuel Technology, Volume I," National Science Foundation, Washington,
D.C., NSF-C925, PB-256 007, November 1975.
2. Wimer, W.W., Russell, J.A., and Kaplan, H.L., Alcohols Toxicology, Noyes
Data Corp., Park Ridge, N.3., 1983.
3. Reed, T.B., and Lerner, R.M., "Methanol: A Versatile Fuel For Immediate
Use," Science, Volume 182, No. 4119, December 1973.
*. Ogston, A.R., "Alcohol Motor Fuels," Journal of the Institution of
Petroleum Technologists, Volume 23, 1937.
5. Egloff, G., "Motor Fuel Economy of Europe," Industrial and Engineering
Chemistry, Volume 30, No. 10, October 1938.
6. Hagen, D.L., "Methanol as a Fuel: A Review with Bibliography," Society
of Automotive Engineers, SAE 770792, 1977.
7. MacFarlan, J.F., "On Methylated Spirits, and Some of its Preparations,"
Pharm. 3. Trans., 1855.
A-7
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TECHNICAL REPORT DATA
ff lease read Instructions on the reverse before completing}
"EPA "460/3-84-016
4.
7.
9.
TITLE AND SUBTITLE
SURVEY OF SAFETY RELATED ADDITIVES
FOR METHANOL FUEL
AUTHOR(S)
E. Robert Fanick
Lawrence R. Smith
PERFORMING ORG -VNIZATION NAME AND ADDRESS
Southwest Research Institute
Department of Emissions Research
6220 Culebra Road
San Antonio, Texas 78284
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Protection Agency
2565 Plymouth Road
Ann Arbor, Michigan 48105
3. RECIPIENT'S ACCESSION-NO.
5. REPORT DATE
November 1984
6. PERFORMING ORGANIZATION
8. PERFORMING ORGANIZATION
CODE
REPORT NO.
1O. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-03-3162
13. TYPE OF REPORT AND PERIOD COVERED
Final Report (7/18/83-2/18/84)
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
This report describes the effort to determine what additives may be feasible for
use with 100% methanol motor vehicle fuel to increase the safety associated with
the use of methanol as a motor vehicle fuel. A survey of the literature was
conducted to determine candidate additives that would 1) ensure methanol burns
with a visible flame, 2) prevent improper use of the fuel as a degreaser or
cleaning agent, 3) give the fuel an unpleasant taste causing expectoration of any
methanol accidentally in one's mouth, and 4) act as an emetic. Candidate additives
were evaluated as to effectiveness, cost, ease of production, health problems
associated with the additive, and estimated effects on vehicle performance.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
Methanol Fuel
Alternate Fuels
Fuel Additives
Fuel Safety
Release Unlimited
b. IDENTIFIERS/OPEN ENDED TERMS
Safety Related Fuel
Additives
Methanol Fuel Safety
19. SECURITY CLASS (This Report)
Unclassified
20. SECURITY CLASS (This page)
Unclassified
. COSATI Field/Group
21. NO. OF PAGES
64
22. PRICE
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