Study of the oxidative reactions of butenes over mixed tin–antimony oxides

Abstract

Primary selectivities and specific activities for partial oxidation of butene isomers over a range of mixed tin–antimony oxides of varying bulk and surface composition have been obtained using a tubular reactor operating in the differential mode. Reaction rate and product distribution vary with antimony to tin content of the catalyst and with calcination temperature. Reaction mechanisms containing positively charged allylic and vinylic intermediates, operating at specific acid–base and acid surface centres, explain the product distributions of the butene isomers. Reaction rate varies with content of surface antimony associated with the rutile structure and decreases on formation of antimony oxide phases. The influence of catalyst structure and surface composition on determining catalytic and acid–base properties is elucidated.