Designation:D4824−13(Reapproved2018)StandardTestMethodforDeterminationofCatalystAciditybyAmmoniaChemisorption1ThisstandardisissuedunderthefixeddesignationD4824;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.INTRODUCTIONThistestmethodinvolvesthemeasurementoftotalcatalystaciditybychemisorptionofammoniainastaticvolumetricsystem.Acidityisaveryimportantpropertyindeterminingcatalystactivityandselectivityinmanycommercialreactions.Zeolitebasedcatalystsusedinthepetroleumindustryforcatalyticcrackingareaprimeexample.Thistestmethoddescribesasimpleprocedureemployinginexpensiveequipmentthatcouldreadilybeassembledinmostlaboratories.1.Scope1.1Thistestmethodcoversthedeterminationofacidityofcatalystsandcatalystcarriersbyammoniachemisorption.Avolumetricmeasuringsystemisusedtoobtaintheamountofchemisorbedammonia.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesafterSIunitsareprovidedforinformationonlyandarenotconsideredstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.4Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:2D3766TerminologyRelatingtoCatalystsandCatalysisE691PracticeforConductinganInterlaboratoryStudytoDeterminethePrecisionofaTestMethod3.Terminology3.1Definitions—SeeTerminologyD3766.3.2Symbols:Vk=calibratedexpansionvolume,cm3.T1=temperatureofVkatinitialamm...
