ASTM D1016-05(2010)
(Test Method)Standard Test Method for Purity of Hydrocarbons from Freezing Points
Standard Test Method for Purity of Hydrocarbons from Freezing Points
SIGNIFICANCE AND USE
The experimental procedures and physical constants provided by this test method, when used in conjunction with Test Method D1015, allow the determination of the purity of the material under test. A knowledge of the purity of these hydrocarbons is often needed to help control their manufacture and to determine their suitability for use as reagent chemicals or for conversion to other chemical intermediates or finished products.
SCOPE
1.1 This test method covers the sampling and determination of purity of essentially pure compounds for which the freezing points for zero impurity and cryoscopic constants are given. The compounds to which the test method is applicable are: (WarningExtremely flammable liquids and liquefied gases.) n-butane1,3-butadiene isobutaneisoprene(2-methyl-1,3-butadiene) n-pentanebenzene isopentanetoluene (methylbenzene) n-hexaneethylbenzene n-heptaneo-xylene (1,2-dimethylbenzene) n-octanem-xylene (1,3-dimethylbenzene) 2,2,4-trimethylpentanep-xylene (1,4-dimethylbenzene) methylcyclohexanestyrene (ethenylbenzene) isobutene
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 Sections 1, 6, 8, and 10-26.
Note 1—This test method covers systems in which the impurities form with the major component a substantially ideal or sufficiently dilute solution, and also systems which deviate from the ideal laws, provided that, in the latter case, the lowering of the freezing point as a function of the concentration is known for each most probable impurity in the given substance.
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Designation: D1016 − 05(Reapproved 2010)
Standard Test Method for
Purity of Hydrocarbons from Freezing Points
This standard is issued under the fixed designation D1016; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method covers the sampling and determination 2.1 ASTM Standards:
of purity of essentially pure compounds for which the freezing D1015Test Method for Freezing Points of High-Purity
points for zero impurity and cryoscopic constants are given. Hydrocarbons
The compounds to which the test method is applicable are:
(Warning—Extremelyflammableliquidsandliquefiedgases.) 3. Summary of Test Method
n-butane 1,3-butadiene
3.1 After measurement of the freezing point of the actual
isobutane isoprene(2-methyl-1,3-butadiene)
sample, purity can be calculated from the value of the
n-pentane benzene
isopentane toluene (methylbenzene)
determinedfreezingpointandthevaluesgivenforthefreezing
n-hexane ethylbenzene
point for zero impurity and for the applicable cryoscopic
n-heptane o-xylene (1,2-dimethylbenzene)
constant or constants.
n-octane m-xylene (1,3-dimethylbenzene)
2,2,4-trimethylpentane p-xylene (1,4-dimethylbenzene)
methylcyclohexane styrene (ethenylbenzene) 3.2 For the equilibrium between an infinitesimal amount of
isobutene
thecrystallinephaseofthemajorcomponentandaliquidphase
ofthemajorcomponentandoneormoreothercomponents,the
1.2 The values stated in SI units are to be regarded as the
thermodynamic relation between the temperature of equilib-
standard. The values in parentheses are for information only.
rium and the composition of the liquid phase is expressed by
1.3 This standard does not purport to address all of the 5
the equation:
safety concerns, if any, associated with its use. It is the
21n N 521n 1 2 N 5 A t 2 t 11B t 2 t 1… (1)
~ !
~ !@ ~ ! #
1 2 f 0 f f 0 f
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
where:
bility of regulatory limitations prior to use. For specific hazard
N = mole fraction of the major component,
statements, see Sections 1, 6, 8, and10–26.
N =(1−N )=sum of the mole fractions of all the other
2 1
components,
NOTE 1—This test method covers systems in which the impurities form
t = freezing point, in degrees Celsius, of the given sub-
f
with the major component a substantially ideal or sufficiently dilute
stance (in which the mole fraction of the major
solution, and also systems which deviate from the ideal laws, provided
component is N ), defined as the temperature at which
that, in the latter case, the lowering of the freezing point as a function of 1
the concentration is known for each most probable impurity in the given an infinitesimal amount of crystals of the major
substance.
component is in thermodynamic equilibrium with the
liquid phase (see Note 3 of Test Method D1015),
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
This test method is under the jurisdiction of ASTM Committee D02 on Standards volume information, refer to the standard’s Document Summary page on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of the ASTM website.
Subcommittee D02.04.0D on Physical and Chemical Methods. For a more complete discussion of this test method, see Glasgow, A. R., Jr.,
Current edition approved May 1, 2010. Published May 2010. Originally Streiff, A. J., and Rossini, F. D., “Determination of the Purity of Hydrocarbons by
E2
approved in 1949. Last previous edition approved in 2005 as D1016– 05 . DOI: Measurement of Freezing Points,” Journal of Research , JRNBA, National Institute
10.1520/D1016-05R10. of Standards and Technology, Vol 35, No. 6, 1945, p. 355.
2 5
Numerical constants in this test method were taken from the most recently For details, see Taylor, W. J., and Rossini, F. D., “Theoretical Analysis of
published data appearing in “Tables of Physical and Thermodynamic Properties of Time-Temperature Freezing and Melting Curves as Applied to Hydrocarbons,”
Hydrocarbons and Related Compounds,” or ASTM DS 4A, Physical Constants of Journal of Research, JRNBA, Nat. Bureau Standards, Vol 32, No. 5, 1944, p. 197;
Hydrocarbons C to C , or both, prepared by the American Petroleum Institute, also Lewis, G. N., and Randall, M., “Thermodynamics and the Free Energy of
1 10
Research Project 44. ChemicalSubstances,”1923,pp.237,238,McGraw-HillBookCo.,NewYork,NY.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1016 − 05(Reapproved 2010)
t = freezingpointforzeroimpurity,indegreesCelsius,for
f0
the major component when pure, that is, when N =1
or N =0,
D1016 − 05 (2010)
6.2.1 Use liquid nitrogen refrigerant only with adequate
A = first or main cryoscopic constant, in mole fraction per
ventilation. If liquid air is used as a refrigerant, it is imperative
degree, and
that any glass vessel containing hydrocarbon or other combus-
B = secondary cryoscopic constant, in mole fraction per
tible compound and immersed in liquid air be protected with a
degree.
suitable metal shield. The mixing of a hydrocarbon or other
Neglectingthehighertermsnotwritteninthebrackets,Eq1
combustible compound with liquid air due to the breaking of a
can be transformed to the equation:
glass container would almost certainly result in a violent
log P 5 2.00000 2 A/2.3026 t 2 t 11B t 2 t (2)
~ !
~ !@ ~ !#
10 f 0 f f 0 f
explosion. If liquid nitrogen is used as a refrigerant, no
hydrocarbonsampleshouldeverbepermittedtocoolbelowthe
where:
condensation temperature of oxygen (−183°C at atm). This
P = purityofthegivensubstanceintermsofmolepercentof
would not be likely to occur in normal operation, but might
the major component.
occur if the apparatus were left unattended for some time.
4. Significance and Use
7. Procedure
4.1 The experimental procedures and physical constants
7.1 Measure the freezing point as described in Test Method
provided by this test method, when used in conjunction with
D1015,usingthemodificationsandconstantsgiveninSections
Test Method D1015, allow the determination of the purity of
8–26 of this test method for the specific compounds being
the material under test. A knowledge of the purity of these
examined.
hydrocarbonsisoftenneededtohelpcontroltheirmanufacture
and to determine their suitability for use as reagent chemicals
NOTE2—Theestimateduncertaintyinthecalculatedvalueofthepurity
as referred to in Sections8–26 is not equivalent to the precision defined
or for conversion to other chemical intermediates or finished
in RR:D02-1007.
products.
8. n-Butane (Warning—Extremely flammable liquefied
5. Apparatus
gas under pressure. Vapor reduces oxygen available for
5.1 Sampling Apparatus, as shown in Fig. 1, for withdraw-
breathing.)
ing liquefied gases (for example, 1,3-butadiene) from pressure
8.1 Determine the freezing point from freezing curves, with
storage cylinders.
thecagestirrer,withacoolingbathofliquidnitrogen(orliquid
5.2 Distilling Apparatus, as shown in Fig. 2, for removing
air), with a cooling rate of 0.3 to 0.8°C/min for the liquid near
small amounts of polymer from low-boiling compounds (for
the freezing point, and with crystallization induced immedi-
example, 1,3-butadiene) by simple distillation at atmospheric
ately below the freezing point by means of a cold rod.
pressure.
8.2 The method of obtaining the samples shall be as
5.3 Distilling Apparatus, as shown in Fig. 3, for removing
follows: Assemble the apparatus for obtaining the sample as
smallamountsofpolymerfromcompoundswithboilingpoints
shown in Fig. 1, but with no lubricant on the ground-glass
near room temperature (for example, isoprene) by distillation
joints and with the valve at the bottom of the cylinder, so that
at atmospheric pressure.
sampling is from the liquid phase. Attach to C an absorption
5.4 Vacuum Distilling Apparatus and Transfer Trap, as
tube containing anhydrous calcium sulfate or other suitable
shown in Fig. 4, for removing dissolved air and large amounts
desiccant (except magnesium perchlorate) so that water is not
of polymer from a compound (for example, 1,3-butadiene or
introduced into the system (Note 3). Fill the flask F with the
styrene), by repeated freezing and evacuation, followed by
carbon dioxide refrigerant to within about 51 mm (2 in.) of the
distillation of the compound in vacuum in a closed system.
top. After about 20 or 30 min, when the system will have
cooled sufficiently, remove the absorption tube and begin the
6. Materials
collection of liquid n-butane by opening the valve K and
6.1 Carbon Dioxide Refrigerant—Solid carbon dioxide in a
adjusting the needle valve J so that the sample is collected at
suitable liquid. (Warning—Extremely cold (−78.5°C). Liber-
a rate of 1 to 2 mL (liquid)/min in the condensing tube E.
ates heavy gas which can cause suffocation. Contact with skin
NOTE3—However,ifsomewaterdoescondensewiththehydrocarbon,
causes burns or freezing, or both. Vapors can react violently
the freezing point will not be affected significantly because of the
with hot magnesium or aluminum alloys.) Acetone is
extremely low solubility of water in the hydrocarbon at the freezing point
recommended.(Warning—Extremely flammable. Harmful if
of the latter.
inhaled. High concentrations can cause unconsciousness or
8.3 Assemble the freezing point apparatus. Place the cool-
death. Contact can cause skin irritation and dermatitis. Use
ing bath in position around the freezing tube (O in Fig. 1 of
refrigerant bath only with adequate ventilation!)
Test Method D1015), letting the temperature as read on the
6.2 Liquid Nitrogen or Liquid Air—(Warning—Extremely
platinum thermometer reach about −80°C when all the sample
cold. Liberates gas which can cause suffocation. Contact with
has been collected.
skin causes burns or freezing, or both. Vapors can react
violently with hot magnesium or aluminum alloys.) For use as
For further details, see Glasgow ,A. R., Jr., et al. “Determination of Purity by
a refrigerant. If obtainable, liquid nitrogen is preferable be-
Measurement of Freezing Points of Compounds Involved in the Production of
cause of its safety. Synthetic Rubber,” Analytical Chemistry, ANCHA, Vol 20, 1948, p. 410.
D1016 − 05 (2010)
A—Three-way T stopcock, borosilicate glass (similar to Corning Pyrex No. 7420).
B—Connection to vacuum for purging and for evacuating system CDEGHI.
C—Capillary tube for venting, to which drying tube is also connected.
D—Joint, standard taper, 12/30, borosilicate glass.
E—Condensing tube, borosilicate glass.
F—Dewar flask, 1-qt size, borosilicate glass (similar to American Thermos Bottle Co. No. 8645).
G—Tubing, borosilicate glass, 10 mm in outside diameter, with spherical ground-glass joints, 18/7.
H—Tubing, silicate glass, 10 mm in outside diameter, with spherical ground-glass joints, 18/7.
I—Metal connection, brass spherical male joint at one end fitting to connection to needle valve at other end.
J—Needle valve, brass.
K—Valve on cylinder containing hydrocarbon material.
L—Standard cylinder containing hydrocarbon material.
M—Fitting to connect needle valve J to valve K on cylinder.
FIG. 1 Apparatus for Obtaining Sample
8.4 When 50 mL of liquid (temperature about −80°C) has 8.5 When the temperature of the platinum thermometer is
been collected in the condensing tube, close the valve K (Fig. near−80°C,removethecondensingtube(EinFig.1)fromthe
1) and allow the liquid which has collected at I to warm and Dewar flask. Wrap a cloth around the upper portion of the
transfer to the condensing tube (Note 4). Replace the attaching condensing tube (for ease of handling and for preventing the
tubes G and D on the condensing tube by caps. The liquid
refrigerating liquid from contaminating the sample on
sample is now ready for introduction into the freezing tube (O pouring), and after removing the caps on the condensing tube,
in Fig. 1 of Test Method D1015).
raise the stopper holding the platinum thermometer, and pour
the sample through the tapered male outlet of the condensing
NOTE 4—In case the original sample contained water, there will remain
tubeintothefreezingtube(OinFig.1ofTestMethodD1015).
at I some water that may be discarded after the hydrocarbon portion has
been collected as outlined above. Quicklyreplacethestopperholdingtheplatinumthermometer,
D1016 − 05 (2010)
C—Dewar vessel, 1-qt capacity, borosilicate glass.
D—Clamp.
E—Distilling tube, borosilicate glass, 25 mm in outside diameter.
A—Standard-taper, ground-glass joint, 24/40, borosilicate glass
F—Standard-taper ground-glass joint, 24/40 borosilicate glass.
B—Distilling flask, round bottom, 200-mL capacity, borosilicate glass.
G—Tubing, 10 mm in outside diameter, borosilicate glass.
C—Tubing, 10 mm in outside diameter, borosilicate glass.
H, H'—Spherical ground-glass joints, 18/7, borosilicate glass.
D, D'—Spherical ground-glass joints, 18/7, borosilicate glass.
I—Tubing, 6 mm in outside diameter, borosilicate glass.
E—Dewar flask, 1-qt capacity, borosilicate glass.
J—Receiver, 35 mm in outside diameter, 150 mm in length, borosilicate glass.
F—Receiver, same as J in Fig. 2.
FIG. 2 Simple Distilling Apparatus for Normally Gaseous Sub-
FIG. 3 Simple Distilling Apparatus for Normally Liquid Sub-
stances
stances
and start the stirrer, with dry air flowing into the upper portion
of the freezing tube through M (Fig. 1 ofTest Method D1015).
9. Isobutane (Warning—Extremely flammable gas under
8.6 Because the material is normally gaseous at room
pressure. Vapor reduces oxygen available for breathing.)
temperature, care should be taken in disposing of the sample
safely.
9.1 Determine the freezing point from freezing curves with
thecagestirrer,withacoolingbathofliquidnitrogen(orliquid
8.7 For n-butane, the freezing point for zero impurity, in air
at 1 atm, is as follows: air), with a cooling rate of 0.3 to 0.8°C/min for the liquid near
the freezing point, and with crystallization induced immedi-
t 52138.36260.025°C (3)
f 0
ately below the freezing point by means of a cold rod.
and the cryoscopic constants are:
9.2 Obtain the samples as follows: Assemble the apparatus
A 5 0.03085molefraction/°C and (4)
for obtaining the sample as shown in Fig. 1, but with no
lubricant on the ground-gla
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