THE OXIDATIVE DEHYDROGENATION OF ETHANE OVER MOLYBDENUM VANADIUM NIOBIUM OXIDE CATALYSTS - THE ROLE OF CATALYST COMPOSITION

The oxidative dehydrogenation rf ethane has been studied at atmospheri c pressure using molybdenum-vanadium-niobium oxide catalysts in the te mperature range of 350-450-degrees-C. The presence of all three oxides together is necessary in order to have active and selective catalysts . The best results have been obtained using a mixture having a Mo : V : Nb ratio of 19 : 5 : 1. Our studies of the variation of oxide compos ition suggest that the active phase is based on molybdenum and vanadiu m. Niobium enhances the intrinsic activity of the molybdenum-vanadium combination and improves the selectivity by inhibiting the total oxida tion of ethane to carbon dioxide. The apparent activation energies for the conversion of ethane to ethylene, carbon monoxide and carbon diox ide were 18, 27 and 17 kcal/mol, respectively. The addition of water v apor to the gas stream does not affect the product distribution on thi s catalyst.