The role of V<SUP>4+</SUP> ions in vanadium oxide catalysts. I. Decomposition of 2-propanol

Decomposition of 2-propanol has been studied on vanadium pentoxide with MoO<SUB>3</SUB> and WO<SUB>3</SUB> additives. It has been observed that a small amount of the additives increases the dehydration activity of the catalysts, but at 5% or higher concentration, dehydration of 2-propanol decreases. The initial increase followed by a decrease in the dehydration activity with increased amount of additives is due to the change in the rate-determining step. Addition of MoO<SUB>3</SUB>, WO<SUB>3</SUB>, and alkali metal oxides to vanadium pentoxide has similar effects on the V<SUP>4+</SUP> concentration and catalytic activity. Based on the results of the kinetic and ESR spectral studies, a scheme for the reaction has been proposed. It is concluded that the concentration of V<SUP>4+</SUP> ion plays the crucial role in these catalysts