Designation:D5559−95(Reapproved2011)StandardTestMethodforDeterminationofAcidityasFreeFattyAcids/AcidNumberintheAbsenceofAmmoniumorTriethanolamineSoapsinSulfonatedandSulfatedOils1ThisstandardisissuedunderthefixeddesignationD5559;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationoftheacidityasfreefattyacidsexistinginasampleofsulfonatedorsulfatedoil,orboth,bytitratingthesampledissolvedinasolvent.Itisnotapplicableinthepresenceofammoniumortriethanolaminesoapsorsaltsorothercompoundsthatdonotreactneutraltophenolphthaleinwhendissolvedinalcohol.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.SignificanceandUse2.1Thistestmethodisintendedforuseinthedeterminationoftheacidityasfreefattyacidsintheabsenceofammoniumortriethanolaminesoapsinsulfonatedandsulfatedoilsforthepurposeofqualityassurance.3.ApparatusandReagents3.1Alcohol-EtherMixture—Mix50mLofneutralalcoholwith25mLofether.3.2PhenolphthaleinIndicatorSolution(10g/L)—Dissolve1gofphenolphthaleinin100mLofethanol(95%).3.3SodiumHydroxide,StandardSolution(0.5N)—Prepareandstandardizea0.5Nsolutionofsodiumhydroxide(NaOH).Potassiumhydroxide(KOH)maybesubstitutedforNaOH.4.Procedure4.1Theprocedureconsistsoftitratingasolutionofthesampleinamixtureofalcoholandetherinthepresenceofphenolphthaleinindicator.Dissolve10gofthesampleinanalcohol-ethermixture,addfivedropsofphenolphthaleinindi-catorsolution,andtitratethesolutionwith0.5NNaOHorKOHsolutionuntilthepinkcolorpersistsaftervigorousshaking.5.Calcu...
