The role of V⁴⁺ ions in vanadium oxide catalysts. I. Decomposition of 2-propanol

Abstract

Decomposition of 2-propanol has been studied on vanadium pentoxide with MoO₃ and WO₃ 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 MoO₃, WO₃, and alkali metal oxides to vanadium pentoxide has similar effects on the V⁴⁺ 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 V⁴⁺ ion plays the crucial role in these catalysts.