Catalytic (amm)oxidation of propane with molecular oxygen over complex metal oxides: Involvement of homogeneous reaction in gas phase

Partial oxidation of propane to acrolein and ammoxidafion to acrylonitrile with molecular oxygen proceed over complex metal oxide catalysts under the restricted conditions of the high partial pressures of both propane and oxygen. The selective formations of acrolein and acrylonitrile also required high reaction temperature around 500°C. Effective catalysts for the selective (amm)oxidation were mostly made up of bismuth oxide and molybdenum oxide and were further modified with another metal oxide. From the studies of the volume effect of pre-catalyst zone on the conversion and the selectivities and of the reactions in the absence of the catalyst, it is suggested that the reactions involve homogeneous reactions in the gas phase where thermally activated propane converts into propene, followed by catalytic oxidation of propene over the metal oxide surface.