1、Designation:D779515(Reapproved 2022)1Standard Test Method forAcidity in Ethanol and Ethanol Blends by Titration1This standard is issued under the fixed designation D7795;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of las
2、t revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEEditorially updated references in Section 3 and 19.2 in May 2022.1.Scope1.1 This test method covers the determination of acidity asa
3、cetic acid(see Specification D4806)in commonly availablegrades of denatured ethanol,and ethanol blends with gasolineranging from E95 to E30.This test method is used fordetermining low levels of acidity,below 200 mg kg(ppmmass),with the exclusion of carbon dioxide.1.1.1 Procedure ADeveloped specifica
4、lly for measure-ment of acidity by potentiometric titration.This is the refereemethod.1.1.2 Procedure BDeveloped specifically for measure-ment of acidity by color end point titration.1.2 The ethanol and ethanol blends may be analyzed di-rectly by this test method without any sample preparation.1.3 R
5、eview the current and appropriate Material Safety DataSheets(MSDS)for detailed information concerning toxicity,first aid procedures,and safety precautions and proper personalprotective equipments.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are includ
6、ed 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 environmental practices and deter-mine the applicability of regulatory limitation
7、s prior to use.Some specific hazards statements are given in Section 7 onHazards.1.6 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
8、and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D770 Specification for Isopropyl AlcoholD1193 Specification for Reagent WaterD4175 Terminology Relating to Petroleum Products,LiquidFuels,and LubricantsD4806
9、 Specification for Denatured Fuel Ethanol for Blend-ing with Gasolines for Use as Automotive Spark-IgnitionEngine FuelD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6708 Practice for Statistical Assessment
10、 and Improvementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a MaterialE200 Practice for Preparation,Standardization,and Storageof Standard and Reagent Solutions for Chemical Analysis3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in thi
11、s test method,referto Terminology D4175.3.1.2 acidity,nthe quality,state,or degree of being acid.3.1.2.1 DiscussionThe amount of acid titrated with a base(NaOH or KOH)in a sample of ethanol or ethanol blend withgasoline,calculated as acetic acid in mg/kg(ppm mass).3.2 Abbreviations:3.2.1 KHC8H4O4KHP
12、-Potassium Acid Phthalate4.Summary of Test Method4.1 Samples are purged with nitrogen prior to and duringtitration for the elimination of carbon dioxide and then a knownamount of ethanol or ethanol blend sample is analyzed poten-tiometrically either using a monotonic or dynamic end pointtitrant addi
13、tion,as specified in Procedure A,or by color endpoint titration,as specified in Procedure B,using a base1This 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 Fuel
14、s and Lubricants.Current edition approved April 1,2022.Published May 2022.Originallyapproved in 2012.Last previous edition approved in 2015 as D7795 15.DOI:10.1520/D7795-15R22E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For
15、 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 re
16、cognized 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(NaOH)solution.Acid content is calculated as milligrams ofacetic acid per kilogram of sample.5.Significance and Use5.1 This test method measures acidity in ethanol or ethanolblends quantitatively.Denatured fuel ethanol may containadditives such as corrosion inhibi
