ETHANE OXYDEHYDROGENATION OVER SUPPORTED VANADIUM-OXIDES

Ethane oxydehydrogenation to produce ethylene was studied over vanadium oxides supported on either silica gel, HZSM-5, silicalite, or AlPO4-5. Characterization of the catalysts was carried out by X-ray photoelectron spectroscopy for the vanadium binding energy, temperature-programmed desorption of ammonia for the number of chemisorption sites on vanadium oxides. The results of kinetic studies showed that the ethane oxydehydrogenation rates over vanadium oxide were enhanced by the presence of acidic sites on the supports. The rate equations thus derived suggested that the reduction of vanadium oxide sites by adsorbed ethane was the rate-determining step. It is likely that the support acidity can either promote the vanadium oxide reduction activity or increase the equilibrium constant of ethane adsorption on the catalyst.