ASTM_D_4471_-_10.pdf

Designation:D447110Standard 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 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 pyridineand other basic nitrogen impurities in crude and refinedcresylic acids streams,including 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 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 and health practices and determine the applica-bility of regulatory limitations prior to use.For specific hazardstatements,see Section 8.2.Referenced Documents2.1 ASTM Standards:2D3852 Practice for Sampling and Handling Phenol,Cresols,and Cresylic AcidD4790 Terminology of Aromatic 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 1910.1000 and1910.120033.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 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 should 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 purposes 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 nonaqueous medium signifi-cantly deadens response.6.2 Buret,50-mL capacity.6.3 Magnetic Stirrer,with TFE-fluorocarbon or glass cov-ered stirring bar.6.4 Autotitration Equipment may be used if available.7.Reagents1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.02 on Oxygenated Aromatics.Current edition approved Jan.1,2010.Published January 2010.Originallyapproved in 1985.Last previous edition approved in 2004 as D4471 00(2004).DOI:10.1520/D4471-10.2For 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.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 appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.1 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 of the American Chemical Society,where such specifications are available.4Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Perchloric Acid Titrant(0.02 N in glacial acetic acid)Add 1.8 mL of 70%perchloric acid(HClO4)to 1 L of glacialacetic acid and mix well.To standardize,weigh accurately0.0800 to 0.0950 g of primary standard potassium acidphthalate in glacial acetic acid and titrate potentiometrically orto the indicator endpoint,as described in 10.2.Calculate thenormality,N,of the perchloric acid solution as follows:N 5WV 30.2041where:W=weight of potassium acid phthalate,g,andV=volume of perchloric acid titrant consumed,mL.7.3 Potassium Acid Phthalate(