1、Designation:D208608(Reapproved 2012)Standard Test Method forAcidity in Vinyl Acetate and Acetaldehyde1This standard is issued under the fixed designation D2086;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision
2、.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 totalacidity as acetic acid in refined vinyl acetate and acetaldehyde.1.2 The values state
3、d in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 For purposes of determining conformance of an ob-served value or a calculated value using this test method torelevant specifications,test result(s)shall be rounded off“tothe nearest unit”in the
4、 last right-hand digit used in expressingthe specification limit,in accordance with the rounding-offmethod of Practice E29.1.4 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 wit
5、h 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 R
6、eagent WaterE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE200 Practice for Preparation,Standardization,and Storageof Standard and Reagent Solutions for Chemical Analysis3.Summary of Test Method3.1 The specimen is mixed with either an equal volume
7、ofchilled water or an equal volume of ethyl alcohol and titratedat reduced temperature with aqueous sodium hydroxide solu-tion to a phenolphthalein end point.4.Significance and Use4.1 This test method provides a measurement of total acidityin vinyl acetate and acetaldehyde.The results of these mea-s
8、urements can be used for specification acceptance.5.Interferences5.1 Any material or contaminant that will react with NaOHunder the test conditions will affect the results.5.2 Vinyl acetate will decompose on storage,typically byway of hydrolysis,to form acetic acid.5.3 Acetaldehyde will react with o
9、xygen,either dissolved orin a storage container,to form acetic acid.5.4 Various acids or other acidic materials may be present.Common practice,including the method used here,calculatesthese as acetic acid.The actual weight percent of acidicmaterials may be different.6.Apparatus6.1 Buret,10-mL,gradua
10、ted in 0.05-mL subdivisions.6.2 Erlenmeyer Flask,250-mL capacity.6.3 Graduated Cylinder,50 or 100-mL capacity.6.4 Cold Bath,maintained at 0C or below.7.Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall con
11、form to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the
12、 determination.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 Nov.1,2012.Published November 2
13、012.Originallyapproved in 1962.Last previous edition approved in 2008 as D2086 08.DOI:10.1520/D2086-08R12.2For 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 D
14、ocument 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
15、 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 7.2 Purity of Wate
16、rUnless otherwise indicated,referencesto water shall be understood to mean reagent water as definedby Type IV or higher purity of Specification D1193.7.3 Ethyl Alcohol(Ethanol),95 volume%,minimum.NOTE1Denatured ethyl alcohol conforming to Formula No.3Aof theU.S.Bureau of Alcohol,Tobacco and Firearms is suitable for use as asolvent.7.4 Phenolphthalein Indicator Solution(10 g/L)Dissolve1 g of phenolphthalein in 100 mL of methanol,ethanol,orisopropanol.7.5 Sodium Hydroxide,Standard Solution(0.05 N)
