Oxydehydrogenation of propane on V2O5/TiO2 catalyst: kinetic and mechanistic aspects

Abstract

Catalytic oxydehydrogenation of propane and work function measurements in similar conditions have been performed on V₂O₅/TiO₂ catalyst. The oxidation mechanism C₃H₈ [graphic omitted] C₃H₆ [graphic omitted] CO_x+ H₂O has been kinetically modelled which permits theoretical evolution of the selectivity as a function of the conversion, for various ratios of K=k₁/k₂. A good correlation is obtained between the experimental and theoretical curves, validating the kinetic modelling. The value obtained for K is 1, so the reactivity of propene is much higher than that of propane and justifies the observed yield limitation. Moreover, the rate-determining step of propane ODH reaction as well as of propene oxidation is attributed to the attack of the oxidized site by the hydrocarbon. The value of K, which depends on the type of catalyst may be used to evalute the selectivity to propene and for classification of oxydehydrogenation catalysts. The work function measurements give the nature and charge of the various oxygen species (O₂ ^–, O^–, O^2–) involved in the reaction, and O^2– is found to react with propane.