ASTM D1015-99
(Test Method)Standard Test Method for Freezing Points of High-Purity Hydrocarbons
Standard Test Method for Freezing Points of High-Purity Hydrocarbons
SCOPE
1.1 This test method describes a procedure for the precise measurement of the freezing points of high-purity hydrocarbons.
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 2, 3, and 4. Note 1-For the calculation of the molal purity of essentially pure compounds from measured freezing points and for procedures to be used for the sampling and determination of purity of certain specific compounds, see Test Method D1016.
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An American National Standard
Designation: D 1015 – 99
Standard Test Method for
Freezing Points of High-Purity Hydrocarbons
This standard is issued under the fixed designation D 1015; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Significance and Use
1.1 This test method describes a procedure for the precise 4.1 The freezing point measured by this test method, when
measurement of the freezing points of high-purity hydrocar- used in conjunction with the physical constants for the hydro-
bons. carbons listed in Test Method D 1016, allows the determination
1.2 The values stated in SI units are to be regarded as the of the purity of the material under test. A knowledge of the
standard. The values in parentheses are for information only. purity of these hydrocarbons is often needed to help control
1.3 This standard does not purport to address all of the their manufacture and to determine their suitability for use as
safety concerns, if any, associated with its use. It is the reagent chemicals or for conversion to other chemical inter-
responsibility of the user of this standard to establish appro- mediates or finished products.
priate safety and health practices and determine the applica-
5. Apparatus
bility of regulatory limitations prior to use. For specific hazard
statements, see 5.1, 6.1 and 6.2. 5.1 Freezing-Point Apparatus, as shown in Fig. 1, Fig. 2,
and Fig. 3, comprising a freezing tube, a metal sheath for the
NOTE 1—For the calculation of the molal purity of essentially pure
freezing tube, a Dewar flask for the cooling bath, a Dewar flask
compounds from measured freezing points and for procedures to be used
for the warming bath, a stirring mechanism, suitable clamps
for the sampling and determination of purity of certain specific com-
and holders for the parts, and the absorption tubes. The outer
pounds, see Test Method D 1016.
walls of all Dewar flasks can be covered with adhesive tape to
2. Referenced Documents
minimize danger from glass in case of breakage. (Warning:
2.1 ASTM Standards: When using liquid nitrogen as a refrigerant, provide a means to
D 1016 Test Method for Purity of Hydrocarbons from prevent condensation of oxygen in the space between the
Freezing Points freezing tube and the metal sheath and subsequent sealing of
D 1265 Practice for Sampling Liquefied Petroleum (LP) the space by ice forming on the asbestos collar. Provide the
Gases (Manual Method) metal sheath with suitable openings in the sides and bottom.
D 4057 Practice for Manual Sampling of Petroleum and Failure to do this may result in breakage of the freezing tube
Petroleum Products when the liquefied oxygen evaporates within the sealed space.)
5.2 Resistance Bridge, Mueller type, reading from 0.0001
3. Summary of Test Method
to 50 V, in steps of 0.001 V.
3.1 The precise experimental measurement of the freezing
point is made from interpretation of time-temperature freezing
A suitable apparatus is available from Reliance Glass Works, Inc., Bensenville,
or melting curves.
IL, Cat. No. R6878–100.
Apparatus described in 5.2, 5.3, 5.4 and 5.5 was manufactured by the Leeds and
Northrup Co., Philadelphia, PA, under the following catalog numbers: resistance
This test method is under the jurisdiction of ASTM Committee D-2 on bridge, No. 8069 B; platinum resistance thermometer, No. 8163 B; galvanometer,
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee highest precision, No. 2284 D; galvanometer, routine precision, No. 2430 A; lamp
D02.04.OD on Physical Methods. and scale, No. 2100. The galvanometer, routine precision, No. 2430-A, and the lamp
Current edition approved Nov. 10, 1999. Published December 1999. Originally and scale, No. 2100, are still available from Leeds and Northrup. The platinum
published as D 1015 – 49 T. Last previous edition D 1015 – 94. resistance thermometer, No. 8163-B, is no longer available from Leeds and
Annual Book of ASTM Standards, Vol 05.01. Northrup, but is available with the same part number from Yellows Springs
Annual Book of ASTM Standards, Vol 05.02. Instrument Co., Yellow Springs, OH. The resistance bridge No. 8069-B, and the
For details not given here, see Glasgow, A. R., Jr., Rossini, F. D., and Streiff, galvanometer, highest precision, No. 2284-D, are no longer available; however, they
A. J., “Determination of the Purity of Hydrocarbons by Measurement of Freezing may be obtainable from instrument exchanges or used equipment suppliers. If other
Points,” Journal of Research, JNBAA, National Institute of Standards and Tech- available instrumentation is substituted for the original, the precision statement of
nology, Vol 35, No. 6, 1945, p. 355. Section 13 will not apply.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D1015–99
Legend for Fig. 1 (see following page):
A—Bracket for motor, with rubber pad.
B—Motor, with reduction gears, to give 120 r/min.
C—Coupling. (See Fig. 3).
D—Wheel. (See Fig. 3).
E—Steel rod. (See Fig. 3).
F—Bearing. (See Fig. 3).
G—Support for bearing. (See Fig. 3).
H—Support for freezing tube.
I—Adjustable clamp holder.
J—Clamp for freezing tube.
K—Stirrer. (See Fig. 3).
L—Thermometer.
M—Tube for inlet of dry air, with 12/5 spherical joint.
M8—12/5 spherical joint connection to rotameter.
N—Cork stopper, with holes as shown, plus a small hole for the “seed” wire.
O—Freezing tube, with silvered jacket. (See Fig. 2.)
P—Stopcock on freezing tube.
P8—Stopcock (high vacuum) to drying tube.
P9—Stopcock (high vacuum) to vacuum line.
Q—Asbestos collar.
1 1
R—Brass cylinder, 317.5 mm (12 ⁄2 in.) in length and 54 mm (2 ⁄8 in.) in inside diameter, with bakelite collar; when liquid nitrogen is used, the metal shield
must be provided with suitable openings in sides and bottom (see 5.1). If liquid air is used, the metal shield should be constructed so as to keep hydrocar-
bon from contact with liquid air (see 6.2).
S—Dewar flask, for cooling or warming bath; approximate inside diameter, 101 mm (4 in.); approximate inside depth, 330 mm (13 in.).
T—Asbestos pad at bottom of cylinder R.
U—Wood block support.
V—Table top.
W—Wall.
X,X8—Spherical joint, 18/7.
Y—Standard metal (copper or brass) to glass taper connections soldered.
Z—Connection to vacuum pump.
a—Anhydrous calcium sulfate, with indicator.
b—Anhydrous magnesium perchlorate, granular.
d—Separating layer of glass wool.
e—Ascarite.
f—Anhydrous calcium sulfate.
g—To air.
h—To source of compressed air.
i—Flow meter, for rates of 10 to 20 mL/min.
5.3 Platinum Resistance Thermometer, precision grade, 6. Materials
with a resistance near 25.5 V at 0°C, calibrated by the National
6.1 Carbon Dioxide Refrigerant—Solid carbon dioxide in a
Institute of Standards and Technology for the range from −190
suitable liquid. ( Warning: Extremely cold (−78.5°C). Liber-
to 500°C.
ates heavy gas which can cause suffocation. Contact with skin
5.4 Null Point Indicator, may be either a galvanometer or a
causes burns or freezing, or both. Vapors can react violently
microvolt ammeter.
with hot magnesium or aluminum alloys.) Acetone is recom-
5.4.1 Galvanometer, having a sensitivity of 0.1 mV/m at 1
mended. (Warning—Extremely flammable. Harmful if in-
m for highest precision or a sensitivity of 0.5 mV/m at1mfor
haled. High concentrations can cause unconsciousness or
routine precision.
death. Contact can cause skin irritation and dermatitis. Use
5.4.2 Microvolt Ammeter.
refrigerant bath only with adequate ventilation.)
5.5 Lamp and Scale, any suitable type.
6.2 Liquid Nitrogen or Liquid Air—(Warning: Extremely
5.6 Stopwatch or Clock, preferably having graduations in
cold. Liberates gas which can cause suffocation. Contact with
minutes and hundredths of minutes.
skin causes burns or freezing, or both. Vapors can react
5.7 High-Vacuum Oil Pump, capable of evacuating the
violently with hot magnesium or aluminum alloys.) For use as
jacket of the freezing tube to a pressure of 0.133 Pa in 10 min
a refrigerant. If obtainable, liquid nitrogen is preferable be-
or less.
cause of its safety.
5.8 Seeding Apparatus, as shown in Fig. 4, for inducing
6.2.1 Use liquid nitrogen refrigerant only with adequate
crystallization.
ventilation. If liquid air is used as a refrigerant, it is imperative
5.9 Silica Gel Funnel, as shown in Fig. 5, for filtering
that any glass vessel containing hydrocarbon or other combus-
compounds through silica gel to remove water. To be used only
tible compound and immersed in liquid air be protected with a
when specified in Test Method D 1016.
suitable metal shield. The mixing of a hydrocarbon or other
combustible compound with liquid air due to the breaking of a
glass container would almost certainly result in a violent
Model No. 155, manufactured by Keithley Instruments, Inc., 28775 Aurora Rd.,
explosion. If liquid nitrogen is used as a refrigerant, no
Cleveland, OH, or equivalent, has been found satisfactory for this purpose.
hydrocarbon sample should ever be permitted to cool below the
A suitable pump is available from Boekel Industries, Inc. Philadelphia, PA, Cat.
No. 91105. condensation temperature of oxygen (−183°C at 1 atm). This
D1015–99
FIG. 1 Assembly of the Freezing-Point Apparatus (See preceding page for legend.) (continued)
would not be likely to occur in normal operation, but might 7.1.1 Cylinder—Refer to Practice D 1265 for instructions
occur if the apparatus were left unattended for some time. on introducing samples into a cylinder from bulk storage.
6.3 Silica Gel, for use in silica gel funnel. If the gel has
7.1.2 Open Containers—Refer to Practice D 4057 for in-
been exposed to the atmosphere because of punctured or
structions on introducing samples into open-type containers
loosely sealed containers, before use, dry the gel in a shallow
from bulk storage.
vessel at 150 to 205°C for 3 h, then transfer while hot to an
air-tight container.
8. Calibration of Thermometric System and Conversion
of Resistance Readings to Temperature
7. Sampling
8.1 Calibration of Resistance Bridge— The Mueller type
7.1 Sampling from Bulk Storage:
resistance bridge should have its calibration checked at appro-
priate intervals by measurement of a suitable external certified
resistance, with intercomparison of the resistances of the
A satisfactory gel of 28 to 200 mesh may be obtained from the Davison
Chemical Co., Baltimore 3, MD. Specify grade 12. bridge.
D1015–99
and the freezing point of the pure material tf , should be on the same
o
temperature scale. The values of tf given in Test Method D 1016 are on
o
the 1968 IPTS. Therefore, values of t determined using thermometers
f
calibrated on the 1948 scale should be converted to their 1968 IPTS
equivalent. This conversion can be made by applying the appropriate
correction from Table 1.
8.3 Checking of the Ice Point—Frequent measurements (at
least once every month) should be made of the resistance of the
given platinum thermometer at the ice point, 0°C, as measured
on the given resistance bridge. This value should differ only
slightly from the certified value of R . If the difference
becomes appreciable (approaching 0.001 V), the calibration of
the bridge should be checked. If the bridge has not changed, the
change has occurred in the thermometer, and a recalibration of
it is recommended.
8.4 Conversion of Resistance Readings to Temperature—
When determinations are made on a number of substances
having freezing points at different temperatures, time will be
saved by making up a table giving values of the resistance, R,
for each unit degree of temperature in the given range. Values
of resistance for unit degrees, for the ranges from −190 to
+50°C and +50 to 290°C, with differences between successive
unit degrees tabulated for linear interpolation (which is per-
missible), may be easily placed on a single 300 by 400-mm (14
by 16-in.) sheet for each range. Calculate values for the
resistance, R, from unit values of temperature, t, by means of
one of the following equations:
For temperatures below 0°C:
–4 –3 2
R 5 R 1 1 Ct 1 1 0.01 d! 2 10 dt 2 10 b t 2 100!t (1)
$ @~ ~ #%
For temperatures above 0° C:
–4
R 5 R 1 1 Ct@~1 1 0.01 d! 2 10 dt# (2)
$ %
where:
A—High-vacuum stopcock, hollow plug, oblique 3 ⁄2-mm bore.
t = given temperature, °C, on the International Tempera-
B—Inside opening of freezing tube, which must have no bulge at this point.
ture Scale (see Note 2),
C—Slanted connection to jacket of freezing tube.
D—Internal walls of jacket of freezing tube, silvered. R = resistance of the thermometer in ohms at the tempera-
E—Spherical joint, 18/7.
ture t,
FIG. 2 Details of the Freezing Tube R = resistance of the thermometer in ohms at 0°C, and
C, d, and b = constants certified for the given platinum
thermometer by the National Institute of Standards and Tech-
8.2 Calibration of Resistance Thermometer—The platinum-
nology.
resistance thermometer is provided with four calibration con-
stants certified by the National Institute of Standards and
9. General Procedure for Determining a Freezing Curve
Technology for use in converting the resistance of the ther-
9.1 Assemble the apparatus, with no refrigerant and no
mometer into temperature according to the International Tem-
sample yet in place, but with a stream of air, freed of carbon
perature Scale, for use in the range from −190 to 500°C,
dioxide and water, flowing at a rate of 10 to 20 mL/min. Fill the
namely, R , C, d, and b. If the thermometer has been properly
jacket of the freezing tube with air freed of carbon dioxide and
constructed and annealed, the certified constants C, d, and b
water.
will not change significantly with time, but the value of R may
9.2 As required, the operator must be prepared to induce
change slightly.
crystallization in the sample as soon as possible after the
NOTE 2—International Practical Temperature Scale—In 1968 a new
temperature has passed below the freezing point of the sample
IPTS was adopted, replacing the previous scale in use since 1948. The
1948 IPTS was based on the boiling point of oxygen, the sulfur point, ice
point, and steam point. The 1968 IPTS is based on the triple point of
water, tin point, zinc point, and boiling point of oxygen. The differences
The ice point may be measured according to the procedure described by J.
in the two temperature scales T –T vary. Above 100°C the differ
...
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