Designation:D3238−95(Reapproved2015)StandardTestMethodforCalculationofCarbonDistributionandStructuralGroupAnalysisofPetroleumOilsbythen-d-MMethod1ThisstandardisissuedunderthefixeddesignationD3238;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthecalculationofthecarbondistributionandringcontent(Note1)ofolefin-freepetroleumoilsfrommeasurementsofrefractiveindex,density,andmolecularweight(n-d-M).2Thistestmethodshouldnotbeappliedtooilswhosecompositionsareoutsidethefollowingranges:1.1.1Intermsofcarbondistribution—upto75%carbonatomsinringstructure;percentageinaromaticringsnotlargerthan1.5timesthepercentageinnaphthenicrings.1.1.2Intermsofringcontent—uptofourringspermoleculewithnotmorethanhalfofthemaromatic.Acorrectionmustbeappliedforoilscontainingsignificantquantitiesofsulfur.NOTE1—Thecompositionofcomplexpetroleumfractionsisoftenexpressedintermsoftheproportionsofaromaticrings(RA),naphthenerings(RN),andparaffinchains(CP)thatwouldcompriseahypotheticalmeanmolecule.Alternatively,thecompositionmaybeexpressedintermsofacarbondistribution,thatis,thepercentageofthetotalnumberofcarbonatomsthatarepresentinaromaticringstructures(%CA),naphtheneringstructures(%CN),andparaffinchains(%Cp).1.2ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesinparenthesesareforinformationonly.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:3D1218TestMethodforRefractiveIndexandRefractiveDispersionofHydrocarbonLiquidsD1480TestMethodforDensityandRelativeDensity(Spe-cificGravity)ofViscousMaterialsbyBinghamPycnom-eterD1481TestMeth...
