ASTM_D_4046_-_14_2019.pdf

Designation:D404614(Reapproved 2019)Standard Test Method forAlkyl Nitrate in Diesel Fuels by Spectrophotometry1This standard is issued under the fixed designation D4046;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.Scope1.1 This test method covers a procedure for the determina-tion of 0.03%to 0.30%by volume of alkyl nitrate in dieselfuels.1.2 This test method can be used for the determination ofany alkyl nitrate in diesel fuel provided that standards used forcalibration contain the same alkyl nitrate ester as the testspecimens to be analyzed.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 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.For specific hazard statements,see Section 7.1.5 This international standard was developed 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 Documents2.1 ASTM Standards:2D1193 Specification for Reagent Water3.Summary of Test Method3.1 The determination is based on the simultaneous hydro-lysis of the ester in 65%sulfuric acid solution and nitration ofm-xylenol by the nitric acid liberated.The nitroxylenol isextracted from the reaction mixture and reacted with sodiumhydroxide to form the yellow salt.The color is measuredspectrophotometrically at 452 nm,and the concentration ofalkyl nitrate is determined by reference to the slope of thecalibration curve.4.Significance and Use4.1 In diesel fuel,the presence of alkyl nitrates such as amylnitrate,hexyl nitrate,or octyl nitrate causes a higher residuevalue than observed in untreated fuel,which can lead toerroneous conclusions as to the coke forming propensity of thefuel.The presence of such alkyl nitrate in the fuel can bedetermined using this test method.This test method can beused to determine the amount of alkyl nitrate that has beenadded to diesel fuel to improve Cetane Number.The testmethod is applicable as a basis for judging compliance withspecifications covering any alkyl nitrate.5.Interferences5.1 Other nitrate esters,inorganic nitrate ions,and nitrogenoxides will interfere.6.Apparatus6.1 Absorption Cells,matched,having a 1.000 cm 60.002 cm path length.6.2 Separatory Funnel,Squibb-type glass stoppered withTFE-fluorocarbon stopcock,125 mL capacity.6.3 Shaking Machine,automatic,capable of multiplesamples and 250 oscillations min.6.4 Spectrophotometer,capable of measuring absorption inthe region of 452 nm 6 5 nm.6.5 Volumetric Flask,10 mL and 100 mL capacity.6.6 Measuring Pipet,1 mL,3 mL,4 mL,and 10 mL.6.7 Buret,10 mL capacity.7.Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents conform to the specifications of the committee onAnalytical Reagents of the American Chemical Society,where1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved April 15,2019.Published April 2019.Originallyapproved in 1981.Last previous edition approved in 2014 as D4046 14.DOI:10.1520/D4046-14R19.2For 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.Copyright 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 theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 such specifications are available.3Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water conformingto Type II of Specification D1193.7.3 Acetic Acid,reagent grade.7.4 Alkyl Nitrate.7.5 Alkyl Nitrate,Standard SolutionPipet 3.0 mL of thealkyl nitrate to b