ASTM_D_3339_-_12.pdf

Designation:D333912Standard 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 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 or 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 constants 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 oxidizingconditions.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 this 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 additional 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 obscurity 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 thegreater 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 same 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 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 included 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 and health practices and determine the applica-bility of regulatory limitations prior to use.For specificwarning statements,see Sections 7 and 9,A1.1.4,A2.3.1,andA2.10.1.2.Referenced Documents2.1 ASTM Standards:3D664 Test Method for Acid Number of Petroleum Productsby Potentiometric TitrationD943 Test Method for Oxidation Characteristics of InhibitedMineral OilsD974 Test Method for Acid and Base Number by Color-Indicator TitrationD1193 Specification for Reagent Water3.Terminology3.1 Definitions:3.1.1 acid number,nthe quantity of a specified base,expressed in milligrams of potassium hydroxide per gram of1This 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 April 15,2012.Published June 2012.Originallyapproved in 1974.Last previous edition approved in 2011 as D333911.DOI:10.1520/D3339-12.2Use 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 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,10