ASTM_D_2191_-_06_2012.pdf

Designation:D219106(Reapproved 2012)Standard Test Method forAcetaldehyde Content of Vinyl Acetate1This standard is issued under the fixed designation D2191;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 tracequantities of acetaldehyde,in the range from 0.00 to 0.05%,contained in 99%grade vinyl acetate.1.2 For purposes of determining conformance of an ob-served or a calculated value using this test method to relevantspecifications,test result(s)shall be rounded off“to the nearestunit”in the last right-hand digit used in expressing thespecification limit,in accordance with the rounding-off methodof Practice E29.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 For hazard information and guidance,see the suppliersMaterial Safety Data Sheet.1.5 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 Section 8.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications3.Summary of Test Method3.1 The acetaldehyde present in the specimen is reactedwith a measured excess of sodium bisulfite.The amount ofsodium bisulfite consumed,determined by titrating the excesswith a standard iodine solution,is a measure of the acetalde-hyde present in the vinyl acetate.4.Significance and Use4.1 This test method provides a measurement of acetalde-hyde content in vinyl acetate.The results of these measure-ments can be used for specification acceptance.5.Interference5.1 Ketones and other aldehydes,if present,cause a positiveinterference.6.Apparatus6.1 Buret,50-mL capacity,graduated in 0.1-mL subdivi-sions,with a funnel or flared top and a ground-glass stopcock.6.2 Erlenmeyer Flask,500-mL capacity,glass-stoppered.6.3 Pipet,50-mL capacity.6.4 Pipet,100-mL capacity.7.Reagents7.1 Purity of ReagentsUnless otherwise indicated,it isintended that all reagents shall conform to the specifications ofthe Committee onAnalytical Reagents of theAmerican Chemi-cal Society,where such specifications are available.3Othergrades may be used provided that it is first ascertained that thereagent is of sufficiently high purity to permit its use withoutlessening the accuracy of the determination.7.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water as definedby Type IV of Specification D1193.7.3 Iodine,Standard Solution(0.1 N)Dissolve 35.0 g ofpotassium iodide(KI)and 13.0 g of resublimed iodine in water,and dilute to 1 L with water.Store this solution in a dark bottleand standardize each day,as required,against a standard 0.1 Nsodium thiosulfate(Na2S2O3)solution.(See standardizationprocedure,9.3 and 9.4.)1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.35 on Solvents,Plasticizers,and Chemical Intermediates.Current edition approved June 1,2012.Published July 2012.Originally approvedin 1963.Last previous edition approved in 2006 as D2191 06.DOI:10.1520/D2191-06R12.2For 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.3Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,see Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.*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 Potassium Iodate(KIO3),primary standard.7.5 Sodium Bisulfite Solution(0.44%)Dissolve 4.4 g ofsodium metabisulfite(Na2S2O5)in 1 L of water.This solutionshould be prepared fresh daily or just before using.7.6 Sodium Thiosulfate,Standard Solution(0.1 N)Weighto 0.1 g 24.8 g of sodium thiosulfate(Na2S2O35H2O)crystalsand dissolve in 500 mL of water.Dilute this solution to 1 Lwith water.Add 0.5 mL of chloroform per litre of solution asa preservative,and store in a clean dark bottle.This solutionshould be standardized weekly,as