ASTM_D_8045_-_17e1.pdf

Designation:D8045171Standard Test Method forAcid Number of Crude Oils and Petroleum Products byCatalytic Thermometric Titration1This standard is issued under the fixed designation D8045;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.1NOTESubsections 16.1.1 and 16.1.2 were corrected editorially in July 2018.1.Scope*1.1 This test method covers the determination of acidiccomponents in crude oil and petroleum products includingwaxes,bitumen,base stocks,and asphalts that are soluble inmixtures of xylenes and propan-2-ol.It is applicable for thedetermination of acids whose dissociation constants in waterare larger than 109;extremely weak acids whose dissociationconstants are smaller than 109do not interfere.The valuesobtained by this test method may not be numerically equivalentto other acid value measurements.The range of KOH acidnumbers included in the precision statement is 0.1 mg g to16 mgg.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.Some specific hazards statements are given in Section 7 onSafety Precautions.1.4 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:2D664 Test Method for Acid Number of Petroleum Productsby Potentiometric TitrationD974 Test Method for Acid and Base Number by Color-Indicator TitrationD1193 Specification for Reagent WaterD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4175 Terminology Relating to Petroleum Products,LiquidFuels,and LubricantsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD5854 Practice for Mixing and Handling of Liquid Samplesof Petroleum and Petroleum ProductsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance3.Terminology3.1 For general terminology,refer to Terminology D4175.3.2 Definitions:3.2.1 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.3.2.2 catalytic thermometric titration,na method to de-termine the end point of a chemical reaction through the use atemperature measuring device and the addition of a chemical toenhance the detection of the endpoint.3.2.3 crude oil,na naturally occurring hydrocarbonmixture,generally in a liquid state,which may also includecompounds of sulfur,nitrogen,oxygen,metals,and otherelements.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 July 1,2017.Published July 2017.Originally approvedin 2016.Last previous edition approved in 2016 as D8045 161.DOI:10.1520/D8045-17E01.2For 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 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 4.Summary of Test Method4.1 The sample and a fixed mass of paraformaldehyde aredissolved in a mixture of xylenes and propan-2-ol.The mixtureis then titrated with potassium hydroxide using a constant rateof titrant addition.A plot of the temperature of the reactionmixture versus the volume of titrant is generated.An exother-mic reaction between the titrant and sample occurs simultane-ously with the endothermic depolymerization of paraformalde-hyde.After all of the acidic material in the sample has reacted,the slope of the plot changes due to the absence of the