Catalytic aluminas: surface models and characterization of surface sites

Abstract

Aluminas have been used extensively as adsorbenu and active catalysrs and catalyst supponsm the pas. Already in 1197 the aluminadyzed dehydration of ettllnoi was dtscavered by Dutch chermsts: and S;rbatier [3] remewed the use of dumlnas as active cazaiysrs far vanous reacttons UI the second decade of thu century. She that time the applicazions of aluuuas m dycic pmcesses have mcreased tremendously. In tndustrral cualytic pmcesses, alumuus are mostiy used as catalyst suppons [4]. Oxides a d mued oxides ap well as tracuuion mauls and noble meare supported oa alumma. Thuscb. romaa-elumana catalysts are ktng used for the conversion of parafdns to olailnrc hydrocarbons, 10 hydrodealkplation of aromatics. and to a lesser exzm in catalyzic reforming. The larter process LS also caralyzed by molybdena-alumina, a cavlyst system whid is also active for malang toluene and ocher aromatics from satwed hydrocarc bons. It also dyzes the Isomerhation of pm. Great efions are presently be-made to nudy the surface chemlstry of these molybdena-alumma ysfs [5, 6]. The great mterest LD. ttuS catalyst and its detailed nature and properties are certadp reiated to the enormous imnortance of cobalt oxade-molybdenum omde-nlumlna as a widely u5ed Caulytic system for hydrodesuUunzaim, hydmdeoirrogemion, and hydmcracklng reacttans. Cenaialy one of the most imporrant appllcations of alumbas is its use as a support for nobie met tn cazalpzic reformtng, My, dunsinas may also be used as supports for the immobilt.? tioa of mommuclear complexes and of polynucieu me clusters, a fleld which hs recently begun to attraa the Wrest of cacaiytic chamlsts [7, 8].