ASTM_D_5974_-_15.pdf

Designation:D597415Standard Test Methods forFatty and Rosin Acids in Tall Oil Fractionation Products byCapillary Gas Chromatography1This standard is issued under the fixed designation D5974;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.Scope1.1 These test methods cover the determination of theamounts of the individual fatty acids and rosin acids infractionated tall oil products,using capillary gas chromato-graphic separation of the volatile methyl esters of these acids.1.2 Four methods for forming the methyl esters,and twomethods for determining the amounts of the individual fattyacids and rosin acids are described.1.2.1 The classic method for the formation of methyl estersis through the use of diazomethane,but diazomethane is ahazardous and toxic material,and so is no longer the preferredreagent.The use of diazomethane is detailed in the Appendix.Methyl esters may be formed through the use of tetramethyl-ammonium hydroxide(TMAH),trimethylphenylammoniumhydroxide(TMPAH),or N,N-dimethylformamide dimethylacetal(DMF-DMA).1.2.2 The two methods for determining the amount of theindividual fatty acids and rosin acids are the“internal standard”method,which yields absolute values,and the“area percent”method,which yields relative values.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D509 Test Methods of Sampling and Grading RosinD804 Terminology Relating to Pine Chemicals,IncludingTall Oil and Related ProductsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Significance and Use3.1 Tall oil fractionated products derived from tall oil areimportant commercial materials,primarily composed of fattyacids and rosin acids,but also containing some neutral material(see Terminology D804).For many applications,it is necessaryto know the level of the individual fatty acids and rosin acidspresent in these products.Gas chromatography has proven tobe a useful tool for such determinations(see Test MethodsD509),and capillary chromatography,described in these testmethods,is considered to be the most effective gas chromato-graphic technique currently available.In particular situations,other techniques may be more suitable than gas chromatogra-phy.For example,the presence of fatty acid esters in thesample would result in transesterification during the derivati-zation step that may affect the results.3.2 Due to hydrogen bonding,unmodified tall oil fatty acidsand rosin acids cannot be volatilized at atmospheric pressurewithout undergoing decomposition.So,it is necessary toconvert the free acids to the more volatile and more stablemethyl esters,prior to chromatographic separation.3.3 These test methods describe four ways to preparemethyl esters.The classic method is through the use ofdiazomethane,but diazomethane is a hazardous and toxicmaterial,and so is no longer the preferred agent.The use ofdiazomethane is detailed in Appendix X1.3.3.1 TMAH causes isomerization of a samples di-andpolyunsaturated fatty acids,when it is used in even a slightexcess.This leads to inaccurate results for the individual fattyacid components.TMAH should be used for materials contain-ing only rosin acids,or when the identification or quantitationof individual fatty acid components is not important.3.3.2 TMPAH is the recommended methylating agent whenthe identification or quantitation of individual di-and polyun-saturated fatty acids is required.TMPAH produces results thatare very similar to those of diazomethane,but without thehazards that are associated with diazomethane.A considerableexcess of TMPAH may cause isomerization of conjugatedcompounds similar to that encountered with TMAH.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.34 on Pine Chemicals and HydrocarbonResins.Current edition approved July 1,2015.Published August 2015.Originallyapproved in 1996.Last previous edition approved in 2010 as D5974 00(2010).DOI:10.1520/D5974-15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.3.3 DMF-DMA gives results comparable to TMPAH andis easy and safe to use.However,the reagent is moi