ENHANCED PRODUCT SELECTIVITY IN PARTIAL OXIDATION OF PROPANE ON MULTICOMPONENT OXIDE CATALYSTS BY MASKING OF TOTAL OXIDATION SITES

A new method is reported which enables us to effectively poison strong acid sites on multicomponent metal oxide catalysts, responsible for u ndesired total oxidation reactions, by chemical vapor phase deposition of silane and subsequent oxidation, In the partial oxidation of propa ne over VSb2WOx/Al2O3 the selectivity of the primary product propene c ould be enhanced by 10% using a SiOx modified catalyst compared to the unmodified sample, The selectivity towards the consecutive product ac rolein also increased by a factor of 3; however, it remained low, neve r exceeding 6%, The effect of poisioning is explained on the basis of the changes in the physico-chemical bulk and surface properties due to the surface silane/N2O modification and treatment under reaction cond itions. (C) 1997 Academic Press.