1、Designation: D1016 05 (Reapproved 2010)Standard Test Method forPurity of Hydrocarbons from Freezing Points1This standard is issued under the fixed designation D1016; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the sampling and determinationof purity of essentially pure compounds for which the freezingpoints
3、for zero impurity and cryoscopic constants are given.2The compounds to which the test method is applicable are:(WarningExtremely flammable liquids and liquefied gases.)n-butane 1,3-butadieneisobutane isoprene(2-methyl-1,3-butadiene)n-pentane benzeneisopentane toluene (methylbenzene)n-hexane ethylben
4、zenen-heptane o-xylene (1,2-dimethylbenzene)n-octane m-xylene (1,3-dimethylbenzene)2,2,4-trimethylpentane p-xylene (1,4-dimethylbenzene)methylcyclohexane styrene (ethenylbenzene)isobutene1.2 The values stated in SI units are to be regarded as thestandard. The values in parentheses are for informatio
5、n only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For spe
6、cific hazardstatements, see Sections 1, 6, 8, and 10-26.NOTE 1This test method covers systems in which the impurities formwith the major component a substantially ideal or sufficiently dilutesolution, and also systems which deviate from the ideal laws, providedthat, in the latter case, the lowering
7、of the freezing point as a function ofthe concentration is known for each most probable impurity in the givensubstance.2. Referenced Documents2.1 ASTM Standards:3D1015 Test Method for Freezing Points of High-PurityHydrocarbons3. Summary of Test Method3.1 After measurement of the freezing point of th
8、e actualsample, purity can be calculated from the value of thedetermined freezing point and the values given for the freezingpoint for zero impurity and for the applicable cryoscopicconstant or constants.43.2 For the equilibrium between an infinitesimal amount ofthe crystalline phase of the major co
9、mponent and a liquid phaseof the major component and one or more other components, thethermodynamic relation between the temperature of equilib-rium and the composition of the liquid phase is expressed bythe equation:521n N1521n 1 2 N2! 5 Atf 02 tf!1 1 Btf 02 tf! 1 . (1)where:N1= mole fraction of th
10、e major component,N2=(1N1) = sum of the mole fractions of all the othercomponents,tf= freezing point, in degrees Celsius, of the givensubstance (in which the mole fraction of the majorcomponent is N1), defined as the temperature atwhich an infinitesimal amount of crystals of themajor component is in
11、 thermodynamic equilibriumwith the liquid phase (see Note 3 of Test MethodD1015),tf0= freezing point for zero impurity, in degrees Celsius,for the major component when pure, that is, whenN1=1orN2=0,A = first or main cryoscopic constant, in mole fractionper degree, andB = secondary cryoscopic constan
12、t, in mole fraction perdegree.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0D on Physical and Chemical Methods.Current edition approved May 1, 2010. Published May 2010. Originallyapproved
13、in 1949. Last previous edition approved in 2005 as D1016 05E2. DOI:10.1520/D1016-05R10.2Numerical constants in this test method were taken from the most recentlypublished data appearing in “Tables of Physical and Thermodynamic Properties ofHydrocarbons and Related Compounds,” or ASTM DS 4A, Physical
14、 Constants ofHydrocarbons C1to C10, or both, prepared by the American Petroleum Institute,Research Project 44.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the st
15、andards Document Summary page onthe ASTM website.4For a more complete discussion of this test method, see Glasgow, A. R., Jr.,Streiff, A. J., and Rossini, F. D., “Determination of the Purity of Hydrocarbons byMeasurement of Freezing Points,” Journal of Research , JRNBA, NationalInstitute of Standard
16、s and Technology, Vol 35, No. 6, 1945, p. 355.5For details, see Taylor, W. J., and Rossini, F. D., “Theoretical Analysis ofTime-Temperature Freezing and Melting Curves as Applied to Hydrocarbons,”Journal of Research, JRNBA, Nat. Bureau Standards, Vol 32, No. 5, 1944, p. 197;also Lewis, G. N., and Ra
17、ndall, M., “Thermodynamics and the Free Energy ofChemical Substances,”1923, pp. 237, 238, McGraw-Hill Book Co., New York, NY.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Neglecting the higher terms not written in the brackets, Eq
18、1can be transformed to the equation:log10P 5 2.00000 2 A / 2.3026!tf 02 tf!1 1 Btf 02 tf!# (2)where:P = purity of the given substance in terms of mole percentof the major component.4. Significance and Use4.1 The experimental procedures and physical constantsprovided by this test method, when used in
19、 conjunction withTest Method D1015, allow the determination of the purity ofthe material under test. A knowledge of the purity of thesehydrocarbons is often needed to help control their manufactureand to determine their suitability for use as reagent chemicalsor for conversion to other chemical inte
20、rmediates or finishedproducts.5. Apparatus5.1 Sampling Apparatus, as shown in Fig. 1, for withdraw-ing liquefied gases (for example, 1,3-butadiene) from pressurestorage cylinders.5.2 Distilling Apparatus, as shown in Fig. 2, for removingsmall amounts of polymer from low-boiling compounds (forexample
21、, 1,3-butadiene) by simple distillation at atmosphericpressure.AThree-way T stopcock, borosilicate glass (similar to Corning Pyrex No. 7420).BConnection to vacuum for purging and for evacuating system CDEGHI.CCapillary tube for venting, to which drying tube is also connected.DJoint, standard taper,
22、12/30, borosilicate glass.ECondensing tube, borosilicate glass.FDewar flask, 1-qt size, borosilicate glass (similar to American Thermos Bottle Co. No. 8645).GTubing, borosilicate glass, 10 mm in outside diameter, with spherical ground-glass joints, 18/7.HTubing, silicate glass, 10 mm in outside diam
23、eter, with spherical ground-glass joints, 18/7.IMetal connection, brass spherical male joint at one end fitting to connection to needle valve at other end.JNeedle valve, brass.KValve on cylinder containing hydrocarbon material.LStandard cylinder containing hydrocarbon material.MFitting to connect ne
24、edle valve J to valve K on cylinder.FIG. 1 Apparatus for Obtaining SampleD1016 05 (2010)25.3 Distilling Apparatus, as shown in Fig. 3, for removingsmall amounts of polymer from compounds with boiling pointsnear room temperature (for example, isoprene) by distillationat atmospheric pressure.5.4 Vacuu
25、m Distilling Apparatus and Transfer Trap,asshown in Fig. 4, for removing dissolved air and large amountsof polymer from a compound (for example, 1,3-butadiene orstyrene), by repeated freezing and evacuation, followed bydistillation of the compound in vacuum in a closed system.6. Materials6.1 Carbon
26、Dioxide RefrigerantSolid carbon dioxide in asuitable liquid. (WarningExtremely cold (78.5C). Liber-ates heavy gas which can cause suffocation. Contact with skincauses burns or freezing, or both. Vapors can react violentlywith hot magnesium or aluminum alloys.) Acetone isrecommended.(WarningExtremely
27、 flammable. Harmful ifinhaled. High concentrations can cause unconsciousness ordeath. Contact can cause skin irritation and dermatitis. Userefrigerant bath only with adequate ventilation!)6.2 Liquid Nitrogen or Liquid Air(WarningExtremelycold. Liberates gas which can cause suffocation. Contact withs
28、kin causes burns or freezing, or both. Vapors can reactviolently with hot magnesium or aluminum alloys.) For use asa refrigerant. If obtainable, liquid nitrogen is preferable be-cause of its safety.6.2.1 Use liquid nitrogen refrigerant only with adequateventilation. If liquid air is used as a refrig
29、erant, it is imperativethat any glass vessel containing hydrocarbon or other combus-tible compound and immersed in liquid air be protected with asuitable metal shield. The mixing of a hydrocarbon or othercombustible compound with liquid air due to the breaking of aglass container would almost certai
30、nly result in a violentexplosion. If liquid nitrogen is used as a refrigerant, nohydrocarbon sample should ever be permitted to cool below thecondensation temperature of oxygen (183C at atm). Thiswould not be likely to occur in normal operation, but mightoccur if the apparatus were left unattended f
31、or some time.7. Procedure7.1 Measure the freezing point as described in Test MethodD1015, using the modifications and constants given in Sections8-26 of this test method for the specific compounds beingexamined.NOTE 2The estimated uncertainty in the calculated value of the purityCDewar vessel, 1-qt
32、capacity, borosilicate glass.DClamp.EDistilling tube, borosilicate glass, 25 mm in outside diameter.FStandard-taper ground-glass joint, 24/40 borosilicate glass.GTubing, 10 mm in outside diameter, borosilicate glass.H, H8Spherical ground-glass joints, 18/7, borosilicate glass.ITubing, 6 mm in outsid
33、e diameter, borosilicate glass.JReceiver, 35 mm in outside diameter, 150 mm in length, borosilicate glass.FIG. 2 Simple Distilling Apparatus for Normally GaseousSubstancesAStandard-taper, ground-glass joint, 24/40, borosilicate glassBDistilling flask, round bottom, 200-mL capacity, borosilicate glas
34、s.CTubing, 10 mm in outside diameter, borosilicate glass.D, D8Spherical ground-glass joints, 18/7, borosilicate glass.EDewar flask, 1-qt capacity, borosilicate glass.FReceiver, same as J in Fig. 2.FIG. 3 Simple Distilling Apparatus for Normally LiquidSubstancesD1016 05 (2010)3as referred to in Secti
35、ons 8-26 is not equivalent to the precision defined inRR:D02-1007.8. n-Butane6(WarningExtremely flammable liquefiedgas under pressure. Vapor reduces oxygen available forbreathing.)8.1 Determine the freezing point from freezing curves, withthe cage stirrer, with a cooling bath of liquid nitrogen (or
36、liquidair), with a cooling rate of 0.3 to 0.8C/min for the liquid nearthe freezing point, and with crystallization induced immedi-ately below the freezing point by means of a cold rod.8.2 The method of obtaining the samples shall be asfollows: Assemble the apparatus for obtaining the sample asshown
37、in Fig. 1, but with no lubricant on the ground-glassjoints and with the valve at the bottom of the cylinder, so thatsampling is from the liquid phase. Attach to C an absorptiontube containing anhydrous calcium sulfate or other suitabledesiccant (except magnesium perchlorate) so that water is notintr
38、oduced into the system (Note 3). Fill the flask F with thecarbon dioxide refrigerant to within about 51 mm (2 in.) of thetop. After about 20 or 30 min, when the system will havecooled sufficiently, remove the absorption tube and begin thecollection of liquid n-butane by opening the valve K andadjust
39、ing the needle valve J so that the sample is collected ata rate of 1 to 2 mL (liquid)/min in the condensing tube E.NOTE 3However, if some water does condense with the hydrocarbon,the freezing point will not be affected significantly because of theextremely low solubility of water in the hydrocarbon
40、at the freezing pointof the latter.8.3 Assemble the freezing point apparatus. Place the cool-ing bath in position around the freezing tube (O in Fig. 1 ofTest Method D1015), letting the temperature as read on theplatinum thermometer reach about 80C when all the samplehas been collected.8.4 When 50 m
41、L of liquid (temperature about 80C) hasbeen collected in the condensing tube, close the valve K (Fig.1) and allow the liquid which has collected at I to warm andtransfer to the condensing tube (Note 4). Replace the attachingtubes G and D on the condensing tube by caps. The liquidsample is now ready
42、for introduction into the freezing tube (Oin Fig. 1 of Test Method D1015).NOTE 4In case the original sample contained water, there will remainat I some water that may be discarded after the hydrocarbon portion hasbeen collected as outlined above.8.5 When the temperature of the platinum thermometer i
43、snear 80C, remove the condensing tube (E in Fig. 1) from theDewar flask. Wrap a cloth around the upper portion of thecondensing tube (for ease of handling and for preventing the6For further details, see Glasgow, A. R., Jr., et al. “Determination of Purity byMeasurement of Freezing Points of Compound
44、s Involved in the Production ofSynthetic Rubber,” Analytical Chemistry, ANCHA, Vol 20, 1948, p. 410.A, A8Standard-taper ground-glass joints, 14/35 borosilicate glass. G and G8Ceramic (or glass) fiber pad.BTubing, 27 mm in outside diameter, borosilicate glass. H, H8,H9Stopcock, ground for high vacuum
45、, borosilicate glass.C, C8Clamp. ISpherical ground-glass joint, 18/7, borosilicate glass.D Brass cylinder, 273 mm (1034 in.) in length, 28.6 mm (118 in.) in inside JCondensing tube, used as trap (see E in Fig. 1).diameter; for precautions in use of liquid nitrogen and liquid air, see R in KConnectio
46、n to vacuum system.legend to Fig. 1 of Test Method D1015 and Notes 2 and 3 of Test Method L, L8Stopcock, ground for high vacuum, borosilicate glass.D1015. MStandard-taper ground-glass joint, 24/40 borosilicate glass.D8 Brass cylinder, 254 mm (10 in.) in length, 47.6 mm (178 in.) in inside diameter,
47、NReceiver withdrawal, 36 mm in outside diameter, borosilicate glass.(see D above). ODewar flask, 0.0005-m3(1-pt) capacity, borosilicate glass.EOriginal sample. PConnection to vacuum.E8Distilled sample. QFunnel with extension, 4 mm in inside diameter, borosilicate glass.F, F8Dewar flask, 0.0009-m3(1-
48、qt) capacity, borosilicate glass. RConnection to drying tube, borosilicate glass.FIG. 4 Apparatus for Simple Vacuum DistillationD1016 05 (2010)4refrigerating liquid from contaminating the sample on pour-ing), and after removing the caps on the condensing tube, raisethe stopper holding the platinum t
49、hermometer, and pour thesample through the tapered male outlet of the condensing tubeinto the freezing tube (O in Fig. 1 of Test Method D1015).Quickly replace the stopper holding the platinum thermometer,and start the stirrer, with dry air flowing into the upper portionof the freezing tube through M (Fig. 1 of Test Method D1015).8.6 Because the material is normally gaseous at roomtemperature, care should be taken in disposing of the samplesafely.8.7 For n-butane, the freezing point for zero impurity
