1、Designation:D788320Standard Test Method forDetermination of 4-Carboxybenzaldehyde and p-Toluic Acidin Purified Terephthalic Acid by Weak Anion Exchange HighPerformance Liquid Chromatography1This standard is issued under the fixed designation D7883;the number immediately following the designation ind
2、icates 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 method2covers the determination of th
3、e4-Carboxybenzaldehyde(4-CBA)and p-Toluic acid(p-TOL)in purified terephthalic acid(PTA)by weak anion exchangehigh performance liquid chromatography(HPLC).Thismethod is applicable for 4-CBA from 2 to 500 mg/kg and forp-TOL from 10 to 500 mg/kg,respectively.1.2 In determining the conformance of the te
4、st results usingthis method to applicable specification,results shall be roundedoff in accordance with the rounding-off method of PracticeE29.1.3 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
5、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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was dev
6、eloped in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Docume
7、nts2.1 ASTM Standards:3D1193 Specification for Reagent WaterD6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE682 Practice for Liquid Chrom
8、atography Terms and Rela-tionshipsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Document:4EN ISO 8213 Chemical products for industrial useSampling techniquesSolid chemical products in theform of particles varying from powders to coarse lumps2
9、.3 Other Document:5OSHA Regulations,29 CFR paragraphs 1910.1000 and1910.12003.Summary of Test Method3.1 Weak Anion Exchange HPLC MethodPTA sample isdissolved in ammonium hydroxide solution.After pHadjustment,a fixed volume of this solution is injected into ahigh performance liquid chromatograph equi
10、pped with a UVdetector.An anion-exchange column is used to separate theimpurities 4-CBAand p-TOL from PTA.The external standardcalibration is used for quantification.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic,Industrial,Specialty and Related Chemicals and is the dir
11、ect responsi-bility of Subcommittee D16.02 on Oxygenated Aromatics.Current edition approved Oct.1,2020.Published December 2020.Originallyapproved in 2013.Last previous edition approved in 2019 as D7883 19.DOI:10.1520/D7883-20.2This standard is based on SH/T 1612.7-1995 Purified terephthalic acid for
12、industrial usedetermination of p-Toluic Acid,4-Carboxybenzaldehyde-HPLC,copyright SINOPEC,22 Chaoyangmen North Street,Chaoyang District,Beijing,China 100728.A copy of SH/T 1612.7-1995 may be obtained from ChinaPetrochemical Press,www.sinopec-.3For referenced ASTM standards,visit the ASTM website,www
13、.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.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.5A
14、vailable from U.S.Government Printing Office Superintendent of Documents,732 N.Capitol St.,NW,Mail Stop:SDE,Washington,DC 20401,http:/www.access.gpo.gov.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,P
15、A 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Te
16、chnical Barriers to Trade(TBT)Committee.14.Significance and Use4.1 The presence of 4-CBA and p-TOL in PTA used for theproduction of polyester is undesirable because they can slowdown the polymerization process,and 4-CBAis also impartingcoloration to the polymer due to thermal instability.4.2 Determining the amount of 4-CBA and p-TOL remain-ing from the manufacture of PTA is often required.This testmethod is suitable for setting specifications and could be usedas an internal quality control tool
