ASTM_D_3242_-_11.pdf

Designation:D324211Designation:354/98Standard Test Method forAcidity in Aviation Turbine Fuel1This standard is issued under the fixed designation D3242;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 This test method covers the determination of the acidityin aviation turbine fuel in the range from 0.000 to 0.100 mgKOH/g.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.2.Referenced Documents2.1 ASTM Standards:2D664 Test Method for Acid Number of Petroleum Productsby Potentiometric TitrationD1193 Specification for Reagent Water3.Terminology3.1 Definitions:3.1.1 acid number,nthe quantity of a specified base,expressed in milligrams of potassium hydroxide per gram ofsample,required to titrate a sample in a specified solvent to aspecified endpoint using a specified detection system.3.1.1.1 Discussionin this test method,the solvent is atoluene-water-isopropanol mixture and the end point is deter-mined when a green/green brown color is obtained using thespecified p-naphtholbenzein indicator solution.4.Summary of Test Method4.1 The sample is dissolved in a mixture of toluene andisopropyl alcohol containing a small amount of water.Theresulting single phase solution is blanketed by a stream ofnitrogen bubbling through it and is titrated with standardalcoholic potassium hydroxide to the end point indicated by thecolor change(orange in acid and green in base)of the addedp-naphtholbenzein solution.5.Significance and Use5.1 Some acids can be present in aviation turbine fuels dueeither to the acid treatment during the refining process or tonaturally occurring organic acids.Significant acid contamina-tion is not likely to be present because of the many check testsmade during the various stages of refining.However,traceamounts of acid can be present and are undesirable because ofthe consequent tendencies of the fuel to corrode metals that itcontacts or to impair the water separation characteristics of theaviation turbine fuel.5.2 This test method is designed to measure the levels ofacidity that can be present in aviation turbine fuel and is notsuitable for determining significant acid contamination.6.Apparatus6.1 BuretA25-mLburetgraduatedin0.1-mLsubdivisions,or a 10-mL buret graduated in 0.05-mL subdivi-sions.NOTE1An automated buret capable of delivering titrant amounts in0.05 mL or smaller increments can be used,but the stated precision datawere obtained using manual burets only.7.Reagents and Materials7.1 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,1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.06 on Analysis of Liquid Fuels and Lubricants.Current edition approved May 1,2011.Published July 2011.Originally approvedin 1973.Last previous edition approved in 2008 as D324208.DOI:10.1520/D3242-11.This test method has been approved by the sponsoring committees and acceptedby the cooperating societies in accordance with established procedures.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.*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 where such specifications are available.3Other 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.NOTE2Commercially available reagents may be used in place oflaboratory preparations when they are certified in accordance with 7.1.7.2 Purity of Water References to water shall be under-stood to mean distilled water as defined by Type III water ofSpecification D1193.7.3 p-Naphtholbenzein4,5IndicatorSolutionThep-naphtholbenzein must meet the specifications given in AnnexA1.Prepare a solution of p-naphtholbenzein in titration solventequal to 10 6 0.01 g/L.7.4 Nitrogen,dry-type,carbon dioxide-