1、lDesignation:D2120-87AMERICANSOCIETYFORTESTINGANDMATERIALS1916RaceSt.,Philadelphia,Pa.19103ReprintedfromtheAnnualBookofASTMStandards,CopyrightASTMIfnotlistedInthecurrantcombinedIndex,willappearInthenextedition.StandardTestMethodforInhibitor,p-tert-Butylcatechol,inStyrene Monomer1This standardisissue
2、d under the fIxed designation D 2120;the number immediatelyfollowingthedesignation indicates the yearoforiginal adoption or,inthecaseofrevision,the year ofleSt revision.A numberinparentheses indicates the year oflast reapproval.Asuperscript epsilon(.)indicatesaneditorial change since the last revisi
3、onorreapproval1.Scope.1.1This test method covers the measurementoftheamountofresidual p-tert-butylcatechol in styrene monomerin the range from 0 to100ppm.Any other compoundknown to produce color when contacted with aqueoussodium hydroxide solutionwillinterfere,but may be com-pensatedforby including
4、it in the preparationofthestandard solutions,ifits identity and concentration in thesample are known.NOTEI-Thistestmethoddoesnotnecessarilymeasuretheamountofp-tert-butylcatecholoriginallyaddedtostyrene.Itisknownthattheoriginalamountgraduallydiminishesonstorage.1.2This standard may involve hazardous
5、materials,oper-ations,and equipment.This standard does not purport toaddress allofthe safetyproblems associated with itsuse.It isthe responsibilityofthe userofthis standard to establishappropriate safety and health practices and determine theapplicabilityofregulatory limitations prior touse.Forspeci
6、fic hazard statements,seeSection7.2.Referenced Documents2.1ASTMStandards:D1193SpecificationforReagentWateD3437Practice for Sampling and Handling Liquid CyclicProducts22.2Other Documents:OSHA Regulations,29CFR,paragraphs 1910.1000 and1910.120033.Summary of Test Method3.1The styrene monomerisextracted
7、 with aqueoussodium hydroxide and the aqueous layer,containing thep-tert-butylcatecholasthe colored quinone,isseparated andthe color measured.4.Significance and Use4.1This test methodissuitablefordetermining thequantity of inhibitor,both for the protection against po-lymerization while in transit an
8、d storage,andforinternalquality control.1This test methodisunder the jurisdictionofASTM Committee D-16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibilityofSubcommitteeD16.0Hon Styrene,Ethylbenzene,Cumene,and Naphthalene.Current edition approved May 29,1987.Published July
9、1987.Originallypublished as D 2120-62 T.Last previous edition D 2120-82.2Annual BookojASTMStandards,Vol 06.03.3Available from SuperintendentofDocuments,U.S.Government PrintingOffice,Washington,DC 20402./.fr-.5.Apparatus5.1Separatory Funnels,125mL.5.2Pipets,1,2,5,10,and25mL.5.3Photoelectric Colorimet
10、er or Spectrophotometer,ca-pableofabsorbance measurementsinthe wavelength regionof485 nm.5.4SampleCell-Usethe cell with the maximum lightpath available for the instrument being used.6.Reagents and Materials6.1PurityofReagents-Reagent grade chemicals shall beused in all tests.Unless otherwise indicat
11、ed,itisintendedthat all reagents conform to the specificationsofthe Com-mitteeonAnalytical Reagentsofthe American ChemicalSociety where such specifications are available.4Othergradesmaybeused,provided itisfirst ascertained that the reagentisofsufficiently high purity to permit its use withoutlesseni
12、ng the accuracyofthe determination.6.2 PurityofWater-Unless otherwise indicated,refer-ences to water shall be understood to mean reagent waterasdefined by Type IIIofSpecification D1193.6.3Sodium HydroxideSolution-40giL.6.4 Styrene Monomer,inhibitor-free(Warning-see 7.3).Wash styrene monomer three ti
13、mes with equal volumesofNaOH solution.Wash the monomer with water until thewashings are neutral to litmus.NOTE2-UnhibitedstyrenemonomershouldbekeptrefrigeratedatotoSOCtopreventpolymerization.6.5p-tert-Butylcatechol,Standard Solution(125ppm(mgjkg)-Dissolve 0.113 gofp-tert-butylcatechol in1000mLofinhi
14、bitor-free styrene monomer at20C.(Warning-See 7.2.)7.Hazards7.1Consult the latest OSHA regulations and suppliersMaterial Safety Data Sheets regarding all materials used inthe procedure.7.2Handling Precautions-p-tert-butylcatechol,particu-larly when molten or in concentrated solution,isverycorrosive
15、to the skin.Itisalso a systemic poison when takenorally or absorbed in quantity through the skin.7.3 Flammable Precautions-Styrene monomerisflam-mable and polymerizes exothermally in the presenceofperoxide,mineral acids,and aluminum chloride.4Reagent Chemicals,American Chemical Society Specification
16、s,AmericanChemical Society,Washington,DC.For suggestionsonthe testingofreagents notlisted by the American Chemical Society,see Reagent Chemicals and Standards,by Joseph Rosin,D.Van Nostrand Co.,Inc.,New York,NY,and the UnitedStates Pharmacopeia.NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.tD 2120Reproducibility,mgJkg2.468.Sampling8.1Collect the sampleasdirected in Practice D 3437.9
