ASTM_D_4864_-_14.pdf

Designation:D486414Standard Test Method forDetermination of Traces of Methanol in PropyleneConcentrates by Gas Chromatography1This standard is issued under the fixed designation D4864;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.Scope*1.1 This test method covers the determination of methanolin propylene concentrates in the range of approximately4 mg kg to 40 mg/kg(parts-per-million by mass).1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are for informationonly.NOTE1There is no direct acceptable SI equivalent for screw threads.1.3This 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.Specific warningstatements are given in 11.1.1,11.2.1,and 12.11.2.Referenced Documents2.1 ASTM Standards:2D4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsE260 Practice for Packed Column Gas Chromatography3.Terminology3.1 Definitions:3.1.1 propylene concentrateconcentrate containing morethan 90%propylene.3.2 Definitions of Terms Specific to This Standard:3.2.1 outage tubea length of tubing,usually metal,at-tached to the inside of a valve on a high pressure samplingcylinder such that a fixed percentage of liquid may be expelledfrom the cylinder to create a specified ullage or vapor space forsafety in storage,handling,and transportation.3.2.1.1 DiscussionTypically the outage tube is designed toallow a ullage or vapor space of 15%to 20%of the volumeof the sample cylinder.4.Summary of Test Method4.1 A known mass of water is pressured into a samplecylinder containing a known amount of liquified propyleneconcentrate.The contents in the cylinder are shaken and thewater/methanol phase is withdrawn.A reproducible volume ofthe extract is then injected into the analytical column of a gaschromatograph(GC)equipped with either a thermal conduc-tivity or a flame ionization detector.The methanol concentra-tion is calculated from the area of the methanol peak usingcalibration and extraction factors obtained from syntheticblends of known methanol content.5.Significance and Use5.1 Methanol is a common impurity in propylene concen-trate.It can have a deleterious effect on various processes thatuse propylene concentrate as a feedstock.6.Interferences6.1 There are no known interferences using the GC columnsreferenced in this test method.However,any water-solublecomponent that co-elutes with methanol on any other GCcolumn used would interfere.7.Apparatus7.1 Gas ChromatographAny GC equipped with eitherflame ionization or thermal conductivity detectors with anoverall sensitivity sufficient to detect at least 4 mg/kg ofmethanol.7.2 ColumnAny GC column that separates methanol fromwater,other alcohols,and any co-extracted hydrocarbons.NOTE2See Table 1 for a suitable list of columns and Fig.1 and Fig.2 for examples of chromatograms.Also,refer to Practice E260 for typicalinstructions in preparing such columns.Alternatively,columns can bepurchased from commercial sources.7.3 Data Handling SystemAny commercially availableGC integrator or GC computer system capable of accuratelyintegrating the area of the methanol peak is satisfactory.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricantsand is the direct responsibility ofSubcommittee D02.D0.03 on Propylene.Current edition approved July 15,2014.Published August 2014.Originallyapproved in 1988.Last previous edition approved in 2013 as D4864 90(2013).DOI:10.1520/D4864-14.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.4 RecorderA strip-chart recorder with a full scale re-sponse of 2 s or less and a maximum noise rate of 60.3%fullscale.7.5 Sample Cylinders,300 mLcapacity,stainless steel,TypeDOT 3E(12409 kPa(1800 psig)working pressure).7.6 BalancesAny types capable of weighing a 300 mLsample cylinder and contents accurately to 0.1 g and a 25 mLvolumetric flask and contents accurately to 0.0001 g.7.7 Plug Valve,14in.male NPT or optionally,14in.maleNPT to 6.35 mm outside diameter(14in.)tubing.(See 10.2.1.)7.8 Shut-off Valves,14in.male NPT to 6.35 mm outsidediameter(14in.)tubing.7.9 Regulating Valves,14in.male NPT and14in.male NPTto14in.female NPT.7.10 Hex Nipple