ASTM_E_1788_-_08.pdf

Designation:E178808Standard Test Method forAcidity in Acrylonitrile1This standard is issued under the fixed designation E1788;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 totalacidity as acetic acid in concentrations below 500 g/g inacrylonitrile.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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.Specific hazardstatements are given in Section 8.1.4 Review the current Material Safety Data Sheets(MSDS)for detailed information concerning toxicity,first aidprocedures,and safety precautions.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE200 Practice for Preparation,Standardization,and Storageof Standard and Reagent Solutions for Chemical Analysis3.Summary of Test Method3.1 The acrylonitrile sample is titrated with alcoholic so-dium hydroxide solution to the visual end point.4.Significance and Use4.1 This test method is useful for determining low levels ofacidity,below 500 g/g in acrylonitrile.The total acidity iscalculated as acetic acid.4.2 Acidity may be present as a result of contamination ordecomposition during storage,distribution,or manufacture.5.Apparatus5.1 Buret,10 mL,graduated in 0.05 mL subdivision.6.Purity of Reagents6.1 Use reagent grade chemicals in all tests.Unless other-wise indicated,all reagents shall conform to the specificationsof the Committee on Analytical Reagents of the AmericanChemical Society,where such specifications are available.3Other grades may be used provided it is first ascertained thatthe reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination.6.2 Unless otherwise indicated,references to water meanreagent water conforming to Type II or Type III of Specifica-tion D1193.7.Reagents7.1 Bromthymol Blue Indicator Solution(1 g/L)Weigh100 mg into a 150 mL beaker,add 1.5 mL of 0.1 meq/mLNaOH to aid in dissolving,gradually add 100 mL of methanol.Neutralize to a deep green by dropwise addition of 0.02meq/mL NaOH.7.2 Sodium Hydroxide Standard Solution(0.02 meq/mL)Dissolve 0.800 g NaOH in 500 mL of methanol and dilute to1 L with methanol.Standardize in accordance with the appro-priate sections of Test Method E200.8.Hazards8.1 Acrylonitrile is potentially hazardous to human health ifnot properly handled.Acrylonitrile is a suspected humancarcinogen.Use acrylonitrile in a well ventilated hood.8.2 Acrylonitrile can contribute to a toxic condition insystems of the human body from inhalation,swallowing,orcontact with the eyes or skin.Direct contact with acrylonitrilecan cause skin burns.8.3 Acrylonitrile liquid and vapor are absorbed readily intoshoe leather and clothing and will penetrate most rubbers,1This test method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicalsand is the direct responsibility of SubcommitteeE15.02 on Product Standards.Current edition approved Dec.15,2008.Published January 2009.Originallyapproved in 1996.Last previous edition approved in 2003 as E1788 96(2003).DOI:10.1520/E1788-08.2For 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 barrier fabrics,or creams.Contact lenses should not be worn inareas where eye contact with acrylonitrile could occur.Imper-meable protective clothing must be used.Consult the currentMSDS for recommended materials.9.Procedure9.1 To a 250-mL Erlenmeyer flask,add 0.5 mL of bromthy-mol blue indicator solution.9.2 Pipet 100 mLof the sample into the 250-mLErlenmeyerflask.Titrate with the 0.02 meq/mL NaOH solution to the firstperceptible blue color.10.Calculation10.1 Calculate the acidity of the sample as follows:Acidity as Acetic Acid,mg/g by wt.5A 3N 360000B 3D(1)where:A=NaOH