1、Designation:D473911Standard Test Method forBase Number Determination by Potentiometric HydrochloricAcid Titration1This standard is issued under the fixed designation D4739;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of l
2、ast revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONCurrently,there are two ASTM test methods under the jurisdiction of Committee D02 used fordetermining base number by potent
3、iometric titration:Test Method D2896 and Test Method D4739.They are both used throughout the petroleum industry.Test Method D2896 is for new oils and is usedin setting specifications since it is more accurate than Test Method D4739.Test Method D4739 shallbe used exclusively for the purpose of tracki
4、ng base number loss as an oil proceeds in service.In manycases,the test methods will provide different results.Some comparisons are given in the Scope andthe Significance and Use sections of this test method to distinguish between the two standards and toprovide guidance to users.1.Scope*1.1 This te
5、st method covers a procedure for the determina-tion of basic constituents in petroleum products and new andused lubricants.This test method resolves these constituentsinto groups having weak-base and strong-base ionizationproperties,provided the dissociation constants of the morestrongly basic compo
6、unds are at least 1000 times than that ofthe next weaker groups.This test method covers base numbersup to 250.1.2 In new and used lubricants,the constituents that can beconsidered to have basic properties are primarily organic andinorganic bases,including amino compounds.This test methoduses hydroch
7、loric acid as the titrant,whereas Test MethodD2896 uses perchloric acid as the titrant.This test method mayor may not titrate these weak bases and,if so,it will titratethem to a lesser degree of completion;some additives such asinhibitors or detergents may show basic characteristics.1.3 When testing
8、 used engine lubricants,it should berecognized that certain weak bases are the result of the servicerather than having been built into the oil.This test method canbe used to indicate relative changes that occur in oil during useunder oxidizing or other service conditions regardless of thecolor or ot
9、her properties of the resulting oil.The valuesobtained,however,are intended to be compared with the othervalues obtained by this test method only;base numbersobtained by this test method are not intended to be equal tovalues by other test methods.Although the analysis is madeunder closely specified
10、conditions,this test method is notintended to,and does not,result in reported basic propertiesthat can be used under all service conditions to predictperformance of an oil;for example,no overall relationship isknown between bearing corrosion or the control of corrosivewear in the engine and base num
11、ber.1.4 This test method was developed as an alternative for theformer base number portion of Test Method D664(lastpublished in Test Method D66481).1.4.1 Colorimetric test methods for base number are TestMethod D974,IP 139,and 5102.1 on acid and base number byextraction(color-indicator titration)of
12、Federal Test MethodStandard No.791b.Test results by these methods may or maynot be numerically equivalent to this test method.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all o
13、f thesafety concerns,if any,associated with its use.It is the1This 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 M
14、ay 15,2011.Published July 2011.Originallyapproved in 1987.Last previous edition approved in 2008 as D4739081.DOI:10.1520/D4739-11.*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 Sta
15、tes1 responsibility 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 TitrationD9
16、74 Test Method for Acid and Base Number by Color-Indicator TitrationD1193 Specification for Reagent WaterD2896 Test Method for Base Number of Petroleum Productsby Potentiometric Perchloric Acid TitrationD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum Products2.2 IP Standard:3IP 139 Petroleum products and lubricants Determinationof acid and base number Colour-indicator titrationmethod2.3 U.S.Federal Test Method:4
