United States       Prevention, Pesticides     EPA712-C-96-034
          Environmental Protection    and Toxic Substances     August 1996
          Agency        (TS-7101)
&EPA   Product Properties
          Test Guidelines
          OPPTS 830.7220
          Boiling Point/Boiling
          Range

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                           INTRODUCTION
     This guideline is one  of a series  of test guidelines  that have been
developed by the Office of Prevention, Pesticides and Toxic Substances,
United States Environmental Protection Agency for use in the testing  of
pesticides and toxic substances, and the  development of test data that must
be submitted to the Agency  for review under Federal regulations.

     The Office of Prevention, Pesticides and Toxic Substances (OPPTS)
has  developed this guideline through  a  process of harmonization that
blended the testing  guidance and requirements that existed in the Office
of Pollution Prevention and Toxics  (OPPT) and appeared in Title 40,
Chapter I,  Subchapter R of the Code of Federal Regulations  (CFR), the
Office of Pesticide Programs (OPP) which appeared in publications of the
National Technical  Information Service (NTIS) and  the guidelines pub-
lished by the Organization  for Economic Cooperation and Development
(OECD).

     The purpose of harmonizing these guidelines into a single set  of
OPPTS  guidelines is to minimize variations among the testing procedures
that must be performed to meet the data  requirements of the U. S. Environ-
mental Protection Agency  under the Toxic  Substances Control Act (15
U.S.C. 2601) and the Federal Insecticide,  Fungicide and Rodenticide Act
(7U.S.C. I36,etseq.).

     Final  Guideline Release: This document is available from the U.S.
Government Printing Office, Washington, DC 20402 on The Federal Bul-
letin  Board.   By  modem  dial   202-512-1387,   telnet   and  ftp:
fedbbs.access.gpo.gov     (IP     162.140.64.19),    internet:     http://
fedbbs.access.gpo.gov, or call 202-512-0132 for disks or paper copies.
This guideline is available in ASCII and PDF (portable document format)
from the EPA Public Access Gopher (gopher.epa.gov) under the heading
"Environmental Test Methods and Guidelines."

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OPPTS 830.7220  Boiling point/boiling range.
     (a) Scope—(1) Applicability. This guideline is intended to meet test-
ing  requirements  of  both  the Federal  Insecticide,  Fungicide,  and
Rodenticide Act (FIFRA) (7 U.S.C. 136, et seq.) and the Toxic Substances
Control Act (TSCA) (15 U.S.C. 2601).

     (2) Background. The source materials used in developing this har-
monized OPPTS test guideline  are the OPPT  guideline under 40 CFR
796.1220 Boiling Point/Boiling Range,  OPP guideline 63-6 Boiling Point
(Pesticide Assessment Guidelines, Subdivision D: Product Chemistry, EPA
Report 540/9-82-018,  October  1982) and  OECD guideline 103 Boiling
Point/Boiling Range.

     (b) Introduction. (1) Five  methods used  to determine the boiling
point are described in this guideline: The ebulliometric  method is  based
on the ASTM D 1120-72; the distillation method is based on the standards
ISO R 918 and the draft ISO DIS 4626, BS  4359/68, BS 4591/71, DIN
53171; the Siwoloboff method is  based on JIS  K 0064-1966; the photocell
detection method is based on the manufacturer's manual under paragraph
(e)(4) of this guideline; the Dynamic  Method was  tested in the OECD
Laboratory Intercomparison Testing Programme, part  I, 1979, for  vapor
pressure determination.

     (2) Qualifying statement. The methods and devices described  in this
test guideline can be applied to liquids, provided that these do not undergo
chemical  reaction  at  temperatures  below  the  boiling  point  (e.g.,
autoxidation,  rearrangement, degradation, etc.).

     (c) Method. (1) Application and limits of test.  The boiling point of
a substance is an environmentally relevant physical chemical property be-
cause it is important for identification purposes and is one factor influenc-
ing the states  in which the substance will exist in the environment.

     (2) The emphasis in this test guideline has been placed on the descrip-
tion of the  method using photocell detection, because this  method allows
the determination of melting as well as boiling  points. Moreover, the  meas-
urements can be performed automatically.

     (3) The dynamic method has the advantage that it can also be applied
for the determination of vapor pressure  and  that  it is  not necessary to cor-
rect the boiling temperature to the normal pressure (101.325 kPa) because
the standard pressure can be adjusted during the measurement. However,
this method is  not at present automated. (For a detailed description, see
OPPTS  830.7950 for the vapor pressure  curve.

     (4) Note:  In the literature,  different boiling points  are sometimes
quoted for the same substance. These differences are  due to such variables
as the dimension of the apparatus (for example, the fit of the thermometer),
the type of the  thermometer, the stem correction, the pressure correction,

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     and the accuracy of the pressure measurement. Therefore, the above-men-
     tioned international and national standardized methods contain precise re-
     quirements for these specified conditions.

         (5)  The influence of impurities on the determination of the boiling
     point depends  greatly upon the kind of impurity. Thus, the effect can be
     considered if a highly volatile solvent is present in the sample. Impurities
     will usually increase/decrease the measured boiling temperature.

         (6)  Definitions and units, (i) The standard boiling point is described
     as the temperature  at which the pressure of the saturated vapor of a liquid
     is the same as the standard pressure.

         (ii)  The measured boiling point is dependent on the atmospheric pres-
     sure. This dependence can be described  quantitatively by the Clausius-
     Clapeyron equation as follows:

         log p = - AHv/2.3 RT

     where p is the  vapor pressure of the substance, AHV is its heat of vaporiza-
     tion, and R is  the  universal molar gas constant, R =  8.31441  J moHK-1
     The temperature T  is expressed in K).

         (iii) The temperature at the boiling  point (boiling temperature) is stat-
     ed  in K, with  regard to the ambient pressure during the measurement. If
     no  pressure is given,  the result refers to  a  standard pressure  of 101.325
     kPa.

         (iv) Conversions:


100 kPa =
133 Pa = 1
Pressure
(units kPa)
1 bar= 0.1 MPa1 	
mm Ha = 1 torr2 	
Temperature
(units K)
t = T- 273. 15
t in °C. and T in K
1   "Bar" units are still permissible but not recommended.
2   The units mm Hg and torr are no longer permissible.

         (A) At small deviations from  the normal pressure  (max. + 5 kPa),
     the boiling point temperatures are normalized to Tn by means of the fol-
     lowing number-value-equation by Sidney-Young:

         Tn=T + fTAp

     where:
     Ap = (101.325 - p) (note sign)

     p = barometer measurement in kPa
     fx = rate of change of boiling point with pressure in K/kPa

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T = measured boiling temperature in K
Tn = boiling temperature corrected to normal pressure in K
     (B) The temperature-correction factors fx and  equations for their ap-
proximation are included in the international and national standards men-
tioned in paragraph (e)(2) of this guideline for many substances. For exam-
ple, the DIN 53171 method mentions the following rough corrections for
solvents included in paints under the following table 1:
                Table 1.—Temperature Correction Factors fT
Temperature
(T,K)
323.15
348.15
373.15
398.15
423.15
448.15
Correction factor
(fT, K/kPa)
0.26
0.28
0.31
0.33
0.35
0.37
Temperature
(T, K)
473.15
498.15
523.15
548.15
573.15
Correction factor
(fT, K/kPa)
0.39
0.41
0.44
0.45
0.47
     (C) A table of temperature-correction factors for organic solvents (see
ISO/DIS 4626 is included in the following table 2:
       Table 2.—Temperature-Correction Factors for Organic Solvents (See ISO/DIS 4626)

Product
Acetone 	
Aceto nit rile
Allyl alcohol
Allyl chloride
n-Amyl acetate 	
n-Amyl alcohol 	
Aromatic solvent naptha 	
Benzene
Isobutyl acetate
n-Butyl acetate
sec-Butyl acetate 	
Isobutyl alcohol 	
n-Butyl alcohol 	
sec-Butyl alcohol
terf-Butyl alcohol
p-terf-Butyl toluene
Cumene 	
Cyclohexane 	
Cyclohexanone 	
Diacetone alcohol
Diisobutyl ketone
Diisobutylene
1,2-Dichloroethane 	
Dichloromethane 	
Diethyleneglycol 	
Diethylene glycol mono-n-butyl
ether
Diethylene glycol monoethyl
ether 	
Diethylene glycol monomethyl
ether 	

Thermometer
°C
39
40
40
38
102
41
42
40
41
41
40
40
40
40
40
104
102
40
102
102
103
40
40
38
106
105
104
104
Boiling
at
101.325
kPa
56.1
81 6
969
45 1
149.5
138.0

80 1
1173
126 1
112.4
107.9
117.7
995
825
1928
152.4
80.7
155.7
1692
1693
101 4
83.5
39.8
245.8
2304
201.9
193.8
Rate of change of boiling p
K'°C/0.1 kPa (°C/mbar)
0.029
0032
0028
0029
0.036
0.031
0.037
0032
0034
0034
0.034
0.027
0.028
0026
0025
0042
0.038
0.033
0.038
0038
0038
0034
0.032
0.028
0.038
0038
0.036
0.035
oint with pressure
K °C/mmHg
0.039
0043
0038
0039
0.048
0.041
0.049
0042
0045
0045
0.045
0.036
0.037
0035
0033
0056
0.051
0.044
0.051
0050
0051
0046
0.043
0.037
0.050
0051
0.048
0.047

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   Table 2.—Temperature-Correction Factors for Organic Solvents (See ISO/DIS 4626)—Continued

Product
Dimethyl formamide
Dipropylene glycol 	
Diisopropyl ether 	
Ethyl acetate 	
Ethyl alcohol 	
Ethyl benzene
Ethylene glycol
Ethylene glycol mono-n-butyl
ether
Ethylene glycol monoethyl ether
Ethylene glycol monoethyl ether
acetate 	
Ethylene glycol monomethyl
ether
Ethylene glycol monoisopropyl
ether
2-Ethyl hexanol 	
Ethyl isoamyl ketone 	
n-Hexyl acetate 	
Hexylene glycol 	
Isophorone
Mesityl oxide
4-Methoxy-4-methyl-2-pentanone
Methanol
Methyl isoamyl acetate 	
Methyl isoamyl ketone 	
Methyl isobutyl carbinol 	
Methyl isobutyl ketone 	
Monoethanol amine
Perchloroethylene
n-Propyl acetate
/so-Propyl acetate
n-Propyl alcohol 	
Isopropyl alcohol 	
Propylene glycol 	
Propylene oxide 	
Pyridine
Toluene 	
Triethylene glycol 	
Triethylene glycol monoethyl
ether
Trichloroethylene 	
Vinyl acetate
White spirit
Xylene (isomer mixture) 	
m-Xylene
o-Xylene
/>Xvlene 	

Thermometer
°C
102
106
39
39
39
41
104
103
102
102
41
102
104
103
103
104
105
41
103
39
102
102
41
41
103
41
40
40
40
40
104
38
41
41
107
106
40
39
103
41
41
41
41
Boiling
nnint °P
at
101.325
kPa
1530
232.8
68.3
77.2
78.3
1362
1976
171 2
135.1
156.3
1245
1428
184.8
158.2
171.6
197.1
2153
1298
160.6
646
146.2
144.9
131.8
116.2
1707
121 2
101 6
885
97.2
82.3
187.6
34.3
1154
110.6
287.6
2554
87.1
727


139 1
1444
138.3
Rate of change of boiling p
K'°C/0.1 kPa (°C/mbar)
0033
0.038
0.031
0.031
0.025
0037
0032
0035
0.033
0.035
0031
0033
0.034
0.037
0.038
0.034
0043
0035
0.037
0025
0.036
0.036
0.031
0.035
0030
0036
0032
0031
0.026
0.025
0.032
0.027
0035
0.035
0.038
0038
0.032
0030
0041
0.037
0037
0037
0.037
oint with pressure
K °C/mmHg
0044
0.051
0.041
0.041
0.033
0049
0043
0047
0.044
0.046
0041
0044
0.046
0.049
0.050
0.045
0057
0047
0.049
0033
0.048
0.048
0.041
0.046
0040
0048
0042
0041
0.034
0.033
0.043
0.036
0046
0.046
0.050
0051
0.043
0040
0055
0.049
0049
0050
0.049
     (7) Reference substances. The standard methods listed include speci-
fications for calibration and evaluation substances. These compounds need
not be employed  in all  cases when investigating a new substance.  They
should primarily serve to calibrate the method from time to time and to
offer the chance to compare  the results when  another method is applied.

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     (8) Principle of the test methods. All methods for the determination
of the  boiling point (boiling range)  are based on the measurement of the
boiling temperature.

     (i) Determination by use of the ebulliometer. See paragraphs  (e)(l)
and  (e)(4)  of this guideline. Ebulliometers were originally developed for
the determination of molecular weight by boiling point elevation, but they
are also suited for exact boiling  point measurements. A very simple appa-
ratus is described in ASTM D 1120-72. The liquid is heated in this appara-
tus under equilibrium conditions at atmospheric pressure until it boils. The
determined temperature of  the  liquid,  corrected to standard pressure, is
the boiling point.

     (ii) Dynamic method.  See paragraph (e)(2) of this  guideline.  This
method measures the  vapor recondensation temperature  by means  of a
thermocouple in the reflux  while boiling. The pressure can be varied in
this method.

     (iii) Distillation method for boiling point (and boiling range).  This
method involves distillation of the liquid and measurement of the  vapor
recondensation temperature  and determination of the amount of distillate.

     (iv) Method according to  Siwoloboff.  See  paragraph (e)(2) of this
guideline. A sample is heated in a  sample tube which is immersed in a
heat-bath liquid. A  fused capillary, containing an air bubble in the  lower
part, is dipped in the sample tube. The temperature at which a regular
string  of bubbles escapes from  the capillary or the temperature at which
the string  of bubbles stops and the fluid suddenly starts rising  in the cap-
illary (Siwoloboff under paragraph (e)(2) of this  guideline) is determined.

     (v) Photocell detection. See paragraph (e)(3) of this guideline. Using
the principle according to Siwoloboff. Measurements  are automatic, the
rising bubbles being detected photo-electrically.

     (9) Quality criteria. The different methods  for the determination of
the boiling point (boiling range)  are  compared  with regard to their use
and precision and possibility to standardize/automate in the following table
3:
                      Table  3.—Comparison of the Methods
Method of measurement
Ebulliometer 	
Dynamic method 	
Distillation process (boiling
range).
According to Siwoloboff 	
Photocell detection 	
Differential scanning
calorimetry.
Approximate accuracy
+1.4 K(up to 373 K)1 	
±2.5 K (above 373 K) 1
+0.5 K 	
+0.5 K 	
+1Kto +2K 	
+0.3 K (at 373 K) 	
+0 5 K (up to 600 K)

Ability to standardize
Existing standard ASTM D
1 1 20-72 1.
Possible 	
Existing standards, e.g., ISO/
R 918, DIN 53171, BS
4591/17.
Possible 	
Possible 	
Existing standard

Automation
Difficult as yet
Difficult
Difficult as yet
Automatic method exists (see
photocell detection)
Measurement process works
automatically
Automatic method


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                         Table 3.—Comparison of the Methods—Continued
Method of measurement
Differential thermal analysis

Approximate accuracy
±2.0 K(upto 1273K)
+0 5 K (up to 600 K)
±2.0 K(upto 1273K)
Ability to standardize
ASTM E537-76
Existing standard
ASTM E537-76
Automation
exists
Automatic method
exists
 1 This accuracy is only valid for pure substances and for the simple device as, for example, described in ASTM D 1120-72; it
can be improved with more sophisticated ebulliometer devices.

           (10) Description of the test procedures. The procedures of several  of
      the test  methods  have been established by various international and na-
      tional standards mentioned above. Reference is made here to those  stand-
      ards which prescribe  details of preparations, test conditions,  and conduct
      of the test.

           (i) Ebulliometer. See ASTM D  1120-72, Standard Test Method for
      Boiling Point of Engine Antifreezes, and reference under paragraph (e)(4)
      of this guideline.

           (ii)  Dynamic method.  See  OPPTS  830.7950  for Vapour  Pressure
      Curve, Principle  of the test methods. The boiling  temperature observed
      with an applied pressure of 101.325 kPa is recorded.

           (iii) Distillation process (boiling range). See ISO/R 918, Test Method
      for Distillation (Distillation Yield and Distillation Range); ISO 4626/1980,
      Volatile  Organic  Liquids—Determination of Boiling  Range  of Organic
      Solvents Used as  Raw Materials; BS 4349/68, Method for Determination
      of Distillation of  Petroleum Products; BS 4591/71, Method for the Deter-
      mination of Distillation Characteristics;  DIN 53171,  Losungsmittel fur
      Anstrichstoffe,  Bestimmung des  Siedeverlaufes;  DIN  51751,  Priifung
      flussiger Mineralkohlenwasserstoffe—Bestimmung des Siedeverlaufes.

           (iv) Method  according to Siwoloboff. (A) The sample  is heated  in
      a  melting  point apparatus in a sample  tube, with a diameter  of approxi-
      mately 5 mm in the following figure 1:

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   FIGURE i—APPARATUS FOR THE DETERMINATION OF MELTING AND
 BOILING POINT (JISK 0064-1966), WITH SPECIFICATIONS IN MILLIMETERS
                 A: MEASURING TUBE
                 B: CORK STOPPER
                 C: VENT
                 D: THERMOMETER
                 E: AUXILIARY THERMOMETER
                 F: BATH LIQUID
                 G: SAMPLE TUBE; MAX. 5mm OUTER DIAMETER;
                   CAPILLARY TUBE, APPROX. 1 mm INNER
                   DIAMETER, AND APPROX. 0.2mm TO
                   0.3mm WALL-THICKNESS
                 H: SIDE TUBE
     (B) A capillary tube (boiling capillary) fused about 1 cm above the
lower end is placed in the sample tube. The level to which the test sub-
stance  is filled is such that the  fused section of the capillary is below
the surface of the liquid. The sample tube containing the boiling capillary

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is fastened either to the thermometer with a rubber-band or is fixed with
a support from the side under the following figure 2:

          FIGURE 2—PRINCIPLE ACCORDING TO SIWOLOBOFF
                                8

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     (C)  The bath liquid is chosen according to boiling temperature. At
temperatures of up to 573 K sulfuric acid or silicon oil  can be used; if
sulfuric acid is used, this liquid must be handled with extreme care. Liquid
paraffin may only be used up to 473 K. The  heating of the bath liquid
should be adjusted to a temperature rise of 3  K/min at first.  The bath
liquid must  be  stirred. At  about 10  K below the  expected boiling point,
the heating  is reduced so  that the rate  of temperature rise is  less than
1 K/min. When the boiling temperature  is approached, bubbles begin to
emerge from the boiling capillary.

     (D)  The boiling point is reached when the  string of bubbles  stops
and fluid suddenly starts rising in the capillary. The corresponding ther-
mometer reading is the boiling temperature of the substance.

     (E) In the modified principle, under the following figure 3, the boiling
point is determined in the melting point capillary which is stretched to
a fine point about 2 cm in length  (A) and a small amount of the sample
is  aspirated. The open end of the  fine capillary is closed by melting, so
that a small air bubble is located at  the end.  When heated in the melting
point apparatus (B), the air bubble  expands. The boiling point corresponds
to  the  temperature  at which  the substance plug reaches the level of the
surface of the bath liquid (C).

                    FIGURE 3—MODIFIED PRINCIPLE
                                        (C)

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     (v) Photocell detection. (A) The sample is heated in a capillary tube
inside a heated metal block. A  light beam is directed via suitable holes
in the block through the substance onto a precisely calibrated photocell.
During the increase of the sample  temperature, single air bubbles emerge
from the boiling  capillary. When the boiling temperature  is reached,  the
amount of bubbles increases  immensely.

     (B) This causes a change in the intensity of light, which is  recorded
by a photocell and gives a stop  signal to the digital indicator reading  out
the temperature of a platinum resistance thermometer, located in the block.

     (C) This method is especially  useful because it allows determinations
below room temperature as low as 253.15 K (-20 °C) without any changes
in the apparatus.  The instrument merely has to be  placed  in a cold room
or cooling  bath.  The exact  execution of the boiling point determination
can be obtained from the instrument manual.

     (vi)  Differential scanning  calorimetry.  See ASTM  E 537-76 and
OECD 103. Samples of the test substance  and a  reference material  are
subjected to the same controlled temperature program. The difference in
energy input necessary to maintain identical temperatures in the substance
and the reference material is recorded. When the sample undergoes a tran-
sition involving a change in enthalpy (endothermic on boiling), that change
is indicated by a departure  from the base line  of the heat flow record.

     (vii) Differential thermal analysis. See ASTM E 537-76 and  OECD
103. The difference in temperature between the substance and a reference
material, which are both subjected to the same controlled temperature pro-
gram, are  recorded. When the sample undergoes a transition involving a
change in enthalpy (endothermic in the  case  of boiling), that change is
indicated by a departure from the base line of the temperature record.

     (11) General remarks, (i) The  results obtained  for mixtures or impure
samples are to  be interpreted with care.  With an impure  sample,  for in-
stance, the emergence  of a  low  boiling component will be registered as
the boiling point. Repeated  determinations with the same  impure sample
can  change the composition from  measurement to measurement,  due to
the volatilization of low boiling components:  continously increasing values
are obtained in these circumstances.

     (ii) Liquids with a tendency to  superheat can  yield incorrect results.
The  values obtained are usually too high. This happens more frequently
at higher temperatures. Distillation  methods or the dynamic vapor pressure
method are more suitable for these types of compound.

     (d) Data and reporting—(1)  Treatment of results,  (i) The boiling
point to be determined should be  a  mean of at least two measurements,
which are  in the range of approximate accuracy indicated in table 2 under

                                 10

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paragraph (c)(9) of this guideline. If determinations are not reproducible,
other methods should be considered (see General remarks, above).

     (ii) The  measured boiling points and their  mean should be stated in
K, and the pressure(s) at which the measurement(s) was (were) made
should be recorded in kPa. Where a test substance boils over a temperature
range,  this range should  be provided. The measured values should also
be corrected  to standard  pressure.  Estimates of accuracy should be pro-
vided for all results.

     (iii) The method used should  be indicated, including  any  deviations
from procedures described in this test guideline.

     (2) [Reserved]

     (e) Literature references. The following references should be con-
sulted for additional background material on this  test guideline.

     (1) Kienitz, H. Methoden der Organischen Chemie ed.  Houben-Weyl,
Vol.  2, (Georg Thieme Verlag, Stuttgart,  1953, pp. 815-821.

     (2)  Test  Guideline  104  for  Vapour  Pressure   Curve,  A  80/5
Umweltbundesamt, Berlin (1980).

     (3) Siwoloboff, A. Berichte-Deutsche Chemische Gesellschaft 19: 795
(1886).

     (4) Manual of Apparatus FP  5+FP 51,  FP 52 and FP 53, Mettler
Instrumente AG, CH-8606 Greifensee-Ziirich, Switzerland.

     (5) European Pharmacopoeia,  1:75 (1974).

     (6) Organization for  Economic Cooperation and Development, Guide-
lines for The Testing of Chemicals,  OECD  103,  Boiling Point/Boiling
Range, OECD, Paris, France.

     (7) ASTM Standard  Method E 537-76, Standard Method for Assess-
ing the thermal stability of Chemicals by Methods of Differential Thermal
Analysis (ASTM Annual Index, latest edition).
                                 11

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