ASTM_D_1016_-_05_2015.pdf

Designation:D101605(Reapproved 2015)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 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 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-butane1,3-butadieneisobutaneisoprene(2-methyl-1,3-butadiene)n-pentanebenzeneisopentanetoluene(methylbenzene)n-hexaneethylbenzenen-heptaneo-xylene(1,2-dimethylbenzene)n-octanem-xylene(1,3-dimethylbenzene)2,2,4-trimethylpentanep-xylene(1,4-dimethylbenzene)methylcyclohexanestyrene(ethenylbenzene)isobutene1.2 The values stated in SI units are to be regarded as thestandard.The values in parentheses are for information 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 specific hazardstatements,see Sections 1,6,8,and 10 26.NOTE1This 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 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 the 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 component 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 N15 21n1 2 N2!5 Atf 02 tf!11Btf 02 tf!1#(1)where:N1=mole fraction of the major component,N2=(1 N1)=sum of the mole fractions of all the othercomponents,tf=freezing point,in degrees Celsius,of the given sub-stance(in which the mole fraction of the majorcomponent is N1),defined as the temperature at whichan infinitesimal amount of crystals of the majorcomponent is in thermodynamic equilibrium with theliquid phase(see Note 3 of Test Method D1015),tf0=freezing point for zero impurity,in degrees Celsius,forthe major component when pure,that is,when N1=1or N2=0,1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.04.0D on Physical and Chemical Methods.Current edition approved April 1,2015.Published May 2015.Originallyapproved in 1949.Last previous edition approved in 2010 as D1016 05(2010).DOI:10.1520/D1016-05R15.2Numerical 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 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 standards 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,National Instituteof Standards 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 Randall,M.,“Thermodynamics and the Free Energy ofChemical Substances,”1923,pp.237,238,McGraw-Hill Book Co.,New York,NY.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 A=first or main cryoscopic constant,in mole fraction perdegree,andB=secondary cryoscopic constant,in mole fraction perdegree.Neglecting the higher terms not written in the brackets,Eq 1can be trans