ASTM_D_2193_-_06_2012.pdf

Designation:D219306(Reapproved 2012)Standard Test Method forHydroquinone in Vinyl Acetate1This standard is issued under the fixed designation D2193;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 hydroqui-none in the range from 1 to 20 ppm in refined,commerciallyavailable,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 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 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.1.5 For hazard information and guidance,see the suppliersMaterial Safety Data Sheet.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 vinyl acetate is evaporated at room temperature in astream of inert gas or clean air to minimize the loss ofhydroquinone by evaporation.The hydroquinone is dissolvedin water and titrated with dilute standardized ceric acid sulfateusing diphenylamine as indicator.4.Significance and Use4.1 This test method provides a measurement of inhibitorlevel in vinyl acetate.The results of these measurements can beused for specification acceptance.5.Apparatus5.1 Buret,25-mL,graduated in 0.1-mL subdivisions.5.2 Beakers,50 and 600-mL capacity.5.3 Volumetric Flask,1000-mL capacity.5.4 Erlenmeyer Flasks,100 and 250-mL capacity.5.5 Nitrogen Cylinder,or source of clean air.5.6 Pipets,10 and 50-mL capacity.6.Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform 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 determination.6.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water conformingto Type IV of Specification D1193.6.3 Ceric Acid Sulfate,Standard Solution(0.002 N)Dissolve 1.096 g of ceric ammonium nitrate(NH4)2-Ce(NO3)6)in 28.0 mL of concentrated sulfuric acid(H2SO4,spgr 1.84)contained in a 50-mL beaker.Slowly pour the cericsolution,while stirring,into 200 mL of water contained in a600-mL beaker.When solution is complete,transfer thismixture to a 1000-mL volumetric flask and dilute to the markwith water.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 D2193 06.DOI:10.1520/D2193-06R12.2For 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 6.4 Diphenylamine Indicator SolutionDissolve 0.1 g ofdiphenylamine in 100 mL of H2SO4(sp gr 1.84)and store thissolution in a brown glass bottle.6.5 Hydroquinone StandardDissolve 200.0 mg of hydro-quinone,weighed to the nearest 0.1 mg,in water and dilute to1000.0 mL in a volumetric flask.This solution is unstable andshould be discarded after 1 week of normal use.7.Standardization7.1 Pipet 10-mL portions of the hydroquinone standard(see6.5)into each of two 100-mL Erlenmeyer flasks.Add 3 dropsof diphenylamine indicator solution to each flask.Using a25