Oxidative dehydrogenation of propane and n-butane over alumina supported vanadium catalysts

Abstract

Structural properties of vanadium dispersed species on γ-A1203 are investigated with the scope to detect changes related with V loading in the oxidative dehydrogenation (ODH) of propane and nbutane. XPS, FTIR, and FTIR of absorbed pyridine were used to study the nature of vanadium supported species. Tetrahedral V5+ and probably V4+ species were detected. For vanadium loadings higher than 4.3 % wt octahedral species were also observed. In the n-butane ODH reaction, the selectivity to ODH products decreases when vanadium content increases. However, for propane ODH, the selectivity seems to be independent of vanadium loadings. Low oxygen/alkane feeding ratios favor selectivity to olefins. It is also shown that low V loading catalysts reach selectivities as good as best reported V-Mg-O catalyst.