1、Designation:D447122Standard Test Method forPyridine Bases in Cresylic Acid by Direct Titration1This standard is issued under the fixed designation D4471;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A numb
2、er 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 pyridineand other basic nitrogen impurities in crude and refinedcresylic acids streams,including
3、mixtures.1.2 This test method is applicable for pyridine base levels of0.001%to 0.5%.1.3 In determining the conformance of the test results usingthis method to applicable specifications,results shall berounded off in accordance with the rounding-off method ofPractice E29.1.4 The values stated in SI
4、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 of this standard to establish appro-priate safety,health,and envir
5、onmental practices and deter-mine the applicability of regulatory limitations prior to use.For specific hazard statements,see Section 8.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principle
6、s 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:2D3852 Practice for Sampling and Handling Phenol,Cresols,and Cresylic AcidD4790 Terminology of Aromatic
7、 Hydrocarbons and RelatedChemicalsD6809 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 Specifications2.2 Other Document:OSHA Regulations,29 CFR paragraphs 19
8、10.1000 and1910.1200 Air Contaminates Table of Exposure Limitsand Hazard Communication33.Terminology3.1 For definitions of terms used in this test method seeTerminology D4790.4.Summary of Test Method4.1 This test method is a direct,nonaqueous titration tech-nique utilizing perchloric acid in acetic
9、acid as titrant and thecresylic acid itself as titration solvent.Endpoints may beestablished potentiometrically as well as by indicator so thatthe method is applicable to highly colored as well as lightercolored materials.This test method will detect basic compo-nents other than pyridine bases shoul
10、d they be present.Allbasic compounds detected by this procedure are calculated andexpressed as percent pyridine.5.Significance and Use5.1 The pyridine base content of cresylic acids is importantin certain applications.This test method may be used as a toolfor quality control and specification purpos
11、es by producers andusers.6.Apparatus6.1 Titrimeter or pH meter,equipped with half cell orcombination glass pH and Ag/AgCl reference electrodes.Thepair of electrodes shall be mounted to extend well below theliquid level.Storage in water between titrations is essentialbecause prolonged immersion in no
12、naqueous medium signifi-cantly deadens response.6.2 Buret,50-mL capacity.For low pyridine base concen-trations:10 mL burette that reads to 0.05 mL.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic,Industrial,Specialty and Related Chemicals and is the direct responsi-bility
13、 of Subcommittee D16.02 on Oxygenated Aromatics.Current edition approved May 1,2022.Published June 2022.Originallyapproved in 1985.Last previous edition approved in 2018 as D4471 18.DOI:10.1520/D4471-22.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Servic
14、e at serviceastm.org.For Annual 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.*A Summary of Changes section app
15、ears 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
16、for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.16.3 Magnetic Stirrer,with TFE-fluorocarbon or glass cov-ered stirring bar.6.4 Autotitration Equipment may be used if available.7.Reagents7.1 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
