ASTM_D_4365_-_13.pdf

Designation:D436513Standard Test Method forDetermining Micropore Volume and Zeolite Area of aCatalyst1This standard is issued under the fixed designation D4365;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 This test method covers the determination of totalsurface area and mesopore area.From these results are calcu-lated the zeolite area and micropore volume of a zeolitecontaining catalyst.The micropore volume is related to thepercent zeolite in the catalyst.The zeolite area,a numberrelated to the surface area within the zeolite pores,may also becalculated.Zeolite area,however,is difficult to intepret inphysical terms because of the manner in which nitrogenmolecules pack within the zeolite.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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.For a specificprecautionary statement,see Note 3.2.Referenced Documents2.1 ASTM Standards:2D3663 Test Method for Surface Area of Catalysts andCatalyst CarriersD3906 Test Method for Determination of Relative X-rayDiffractionIntensitiesofFaujasite-TypeZeolite-Containing MaterialsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 mesopore(matrix)area of a catalystthe area deter-mined from the slope of the t-plot.3.1.2 micropore volume of the catalystthe pore volume inpores having radii less than 1 nm,usually associated with thezeolite portion of the catalyst,and determined from theintercept of the t-plot.3.1.3 surface area of a catalystthe total surface of thecatalyst pores.It is expressed in square metres per gram.3.1.4 zeolite area of a catalystthe difference between totalsurface area and mesopore area.3.2 Symbols:PH1=initial helium pressure,torrPH2=helium pressure after equilibration,torrSB=slope of BET plot,11.7IB=intercept of BET plot,11.7St=slope of t-plot,11.13It=intercept of t-plot,11.13TH1=temperature of manifold at initial helium pressure,CTH2=temperature of manifold after equilibration,CTx(i)=extra volume bulb temperature,CTx(i)=extra volume bulb temperature,KP1(i)=initial N2pressure,torrT1(i)=manifold temperature at initial N2pressure,KT1(i)=manifold temperature at initial N2pressure,CP2(i)=pressure after equilibration,torrT2(i)=manifold temperature after equilibration,KT2(i)=manifold temperature after equilibration,CP0(i)=liquid nitrogen vapor pressure,torrTs(i)=liquid nitrogen temperature,KX=relative pressure,P2/P0Vd=volume of manifold,cm3Vx=extra volume bulb,cm3Vs=effective void volume,cm3Ws=weight of sample,gW1=tare weight of sample tube,gW2=weight of sample+tare weight of tube,gVds=volume of nitrogen in the dead-space,cm3V1=see 11.4.31This test method is under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.01 on Physical-Chemical Properties.Current edition approved April 1,2013.Published August 2013.Originallyapproved in 1984.Last previous edition approved in 2008 as D4365 95(2008).DOI:10.1520/D4365-13.2For 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 V2=see 11.4.4Vt=see 11.4.5Va=see 11.4.7Vm=see 11.8BET(i)=see 11.4.8t(i)=see 11.104.Summary of Test Method4.1 The volume of nitrogen gas adsorbed by the catalyst atliquid nitrogen temperature is measured at various low-pressure levels by the catalyst sample at liquid nitrogentemperature.This is done by measuring pressure differentialsresulting from introducing a fixed volume of nitrogen to thedegassed catalyst in the test apparatus.This procedure is thesame as Test Method D3663,that gives total surface area,butextends the pressure range to permit calculation of microporevolume and matrix surface area,by the t-plot method.Zeolitearea is the difference between total area and matrix area.5.Significance and Use5.1 This gas adsorption method complements the X-rayprocedure of Test Method D3906.This test method will beuseful to laboratories that do not have X-ray diffractometers.Each test method can be calibrated by use of an appropriateseri