1、Designation:D333921Standard Test Method forAcid Number of Petroleum Products by Semi-Micro ColorIndicator Titration1This standard is issued under the fixed designation D3339;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of
2、 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.Scope*1.1 This test method covers the determination of acidicconstituents in new or used petroleum products and lubricantssoluble o
3、r nearly soluble in mixtures of toluene,and isopropylalcohol.The test method is especially intended for cases inwhich the amount of sample available to be analyzed is toosmall to allow accurate analysis by Test Methods D974 orD664.It is applicable for the determination of acids havingdissociation co
4、nstants in water larger than 109.Extremelyweak acids having dissociation constants smaller than 109donot interfere.Salts titrate if their hydrolysis constants are largerthan 109.1.2 This test method can be used to indicate relative changesin acid number that occur in an oil during use under oxidizin
5、gconditions.Although the titration is made under definiteequilibrium conditions,the method does not measure anabsolute acidic property that can be used to predict perfor-mance of an oil under service conditions.No general relation-ship between bearing corrosion and acid number is known.1.3 Since thi
6、s test method requires substantially less samplethan Test Methods D974 or D664,it provides an advantageousmeans of monitoring an oxidation test by changes in acidnumber by(1)minimizing test sample depletion for acidnumber analyses and thus minimizing the disturbance of thetest or(2)allowing addition
7、al acid number analyses to be madewhile maintaining the same test sample depletion and thusproviding additional data.NOTE1Some oils,such as many cutting oils,rust-proofing oils,andsimilar compounded oils,or excessively dark-colored oils,may be moredifficult to analyze by this test method due to obsc
8、urity of the color-indicator end point.These oils can be analyzed by Test Method D664provided sufficient sample is available.However,this situation is muchless likely using Test Method D3339 than using Test Method D974 due tothe use of a more highly dilute sample during the titration and due to theg
9、reater stability of the end point color change.The acid numbers obtainedby Test Method D3339 may or may not be numerically the same as thoseobtained by Test Method D664 but they should be of the same order ofmagnitude.NOTE2The results obtained using this method have been found to benumerically the s
10、ame as those obtained using Test Method D974,withinthe precision of the two methods,for new or oxidized lubricants of thetype primarily intended for hydraulic or steam turbine type service.Theoxidized lubricants were obtained using the Test Method D943 oxidationtest.This correlation is shown by the
11、correlation coefficient r=0.989 withslope s=+1.017 and intercept y=+0.029,calculated using the acidnumbers obtained using both titration methods for the samples used for theprecision statement(12.2).21.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are in
12、cluded 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 limita
13、tions prior to use.For specific warning statements,see Sections 7 and 9,A1.1.4,A2.3.1,and A2.10.1.1.6 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
14、Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:3D664 Test Method for Acid Number of Petroleum Productsby Potentiometric TitrationD943 Test Method for Oxidation Characteristics of Inhibited
15、Mineral OilsD974 Test Method for Acid and Base Number by Color-Indicator TitrationD1193 Specification for Reagent Water1This 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
16、 of Liquid Fuels and Lubricants.Current edition approved Nov.1,2021.Published November 2021.Originallyapproved in 1974.Last previous edition approved in 2017 as D3339 12(2017).DOI:10.1520/D3339-21.2Use of the correlation coefficient is given in Mack,C.,Essentials of Statisticsfor Scientists and Technologists,Plenum Press,New York,NY,1967,or otherpublications on statistics.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Ann
