1、Designation:D577621Standard Test Method forBromine Index of Aromatic Hydrocarbons by ElectrometricTitration1This standard is issued under the fixed designation D5776;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last re
2、vision.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 determines the amount of bromine-reactive material in aromatic hydrocarbons and is thus ameasure of trace amount
3、s of unsaturates in these materials.1.2 This test method is applicable to materials havingbromine indexes below 35.Materials with a higher bromineindex can be analyzed by this method;however,the precisionsection does not apply.1.2.1 This test method is applicable to aromatic hydrocar-bons containing
4、 no more than trace amounts of olefins and thatare substantially free from material lighter than isobutane andhave a distillation end point under 288 C.1.3 In determining the conformance of the test results usingthis method to applicable specifications,results shall berounded off in accordance with
5、the rounding-off method ofPractice E29.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user
6、 of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For a specific hazard statement see Section 8.1.6 This international standard was developed in accor-dance with internationally recognized pri
7、nciples 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 Documents2.1 ASTM Standards:2D1159 Test Method for Bromine Numb
8、ers of PetroleumDistillates and Commercial Aliphatic Olefins by Electro-metric TitrationD1193 Specification for Reagent WaterD3437 Practice for Sampling and Handling Liquid CyclicProductsD6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE
9、29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Other Document:OSHA Regulations,29 CFR paragraphs 1910.1000 and1910.120033.Terminology3.1 Definitions:3
10、.1.1 bromine index,nthe number of milligrams of bro-mine consumed by 100 g of sample under given conditions.4.Summary of Test Method4.1 The specimen dissolved in a specified solvent is titratedwith standard bromide-bromate solution.The end point isindicated by a fixed end-point electrometric titrati
11、on apparatus,when the presence of free bromine causes a sudden change inthe polarization voltage of the system.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic,Industrial,Specialty and Related Chemicals and is the direct responsi-bility of Subcommittee D16.04 on Instrumen
12、tal Analysis.Current edition approved Nov.1,2021.Published November 2021.Originallyapproved in 1995.Last previous edition approved in 2014 as D5776 14a.DOI:10.1520/D5776-21.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annua
13、l Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available 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
14、at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for t
15、heDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1?5.Significance and Use5.1 This test method is suitable for setting specifications,foruse as an internal quality control tool,and for use in develop-m
16、ent or research work on industrial aromatic hydrocarbons andrelated material.This test method gives a broad indication ofolefinic content.It does not differentiate between the types ofaliphatic unsaturation.6.Apparatus6.1 Fixed End Point Electrometric Titration ApparatusAny fixed end-point apparatus may be used incorporating ahigh resistance polarizing current supply capable of maintain-ing approximately 1 to 50 A across two platinum plateelectrodes or a combination platinum electrode and with a
