ASTM_D_3766_-_08_2018.pdf

Designation:D376608(Reapproved 2018)Standard Terminology Relating toCatalysts and Catalysis1This standard is issued under the fixed designation D3766;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 terminology covers definitions of terms related tocatalysts and catalysis.NOTE1The Manual of Symbols and Terminology for Physicochemi-cal Quantities and Units presents authoritative descriptions of many termsused in the field of catalysis.21.2 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Terminology2.1 Definitions:activity,nof a catalyst,the measure of the rate of a specificcatalytic reaction conducted in the presence of a catalyst.calcine,vin catalysis,to heat a material to a high temperaturecausing a physical or chemical change,for example,loss ofmoisture and volatile matter,or a phase change,or both.catalyst bed support,nan essentially inert plate,grid,particulate bed,or other structural component designed tohold up or bear a quantity of catalyst in a catalytic reactor.catalyst carrier,na solid,generally porous material upon thesurface or into the voids of which catalytic materials areplaced to create the desired catalyst.DISCUSSIONA carrier may have or contribute to catalytic activity.catalyst substrate,nless preferred alternative term for cata-lyst carrier.catalyst support,nless preferred alternative term for catalystcarrier.crush strength,nin catalysis,a measure of the resistance offormed catalysts or catalyst carriers,either singly or in bulk,to loss of form when subjected to a compressive force.DISCUSSIONFormed catalysts may include tablets,spheres,extrudates,rings,pellets,etc.and should be distinguished frompowders and granules.density,packing(bulk),nthe ratio of the mass of acollection of discrete pieces of solid material to the sum ofthe volumes of:the solids in each piece,the voids within thepieces,and the voids among the pieces of the particularcollection.density,particle(envelope),nthe ratio of the mass of aparticle to the sum of the volumes of:the solid in each pieceand the voids within each piece,that is,within close-fittingimaginary envelopes completely surrounding each piece.density,skeletal,nthe ratio of the mass of discrete pieces ofsolid material to the sum of the volumes of:the solidmaterial in the pieces and closed(or blind)pores within thepieces.density,theoretical,nthe ratio of the mass of a collection ofdiscrete pieces of solid material to the sum of the volumes ofsaid pieces,the solid material having an ideal regulararrangement at the atomic level.envelope,nof a particle in catalysis,a theoretical surfacethat encloses the particle and that bridges openings to theinterior of the particle.pore,nin catalysis,a small opening in a material permittingadmission,adsorption,or passage of a fluid.pore size distribution,n in catalysis,the volume of pores ofa material expressed or displayed as a function of porediameters.pore volume distribution,nin catalysis,an alternative termfor pore size distribution.porosity,nof particles in catalysis,the ratio of the volumesof the pores in the particles to the volumes enclosed by theirenvelopes.selectivity,nof a catalyst,the measure of the distribution ofproducts in a specific reaction conducted in the presence ofa catalyst.1This terminology is under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.92 on Nomenclatureand Definitions.Current edition approved Nov.1,2018.Published December 2018.Originallyapproved in 1979.Last previous edition approved in 2013 as D376608(2013).DOI:10.1520/D3766-08R18.2“The Manual of Symbols and Terminology for Physicochemical Quantities andUnitsAppendix II.Definitions,Terminology and Symbols in Colloid and SurfaceChemistry.Part II:Heterogeneous Catalysis,”Pure and Applied Chemistry,Vol 46,No.1,7390(1976).Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 sintering,nin catalysis,a reduction of the surface area of acatalyst carrier or other solid catalytic material caused byheat.DISCUSSIONSintering may be enhanced by steam or other chemicalspecies and may be accompanied by changes in cryst