Applied Catalysis A: General, Vol.164, No.1-2, 105-117, 1997
Ammoxidation of propane over modified V-Sb-Al-oxides - The role of acidity and redox properties of the catalysts
Vanadium-antimony-oxides are known to be active and selective catalysts for the ammoxidation of propane to acrylonitrile. The performance of these catalysts can be enhanced by doping with different metal ions. However, the catalytic function of these promoters is still unknown. In the present work the influence of promoters (W, Mg, Nh, Te, Ga, Pb, Sm) on the surface acidic and bulk redox properties and on the catalytic performance of VSb5Ox/Al2O3 catalysts was investigated. The freshly prepared catalysts exhibited only small differences in their acidic and redox properties, while dramatic changes occurred under reaction conditions in the first hours-on-stream. The selectivity to acrylonitrile of the modified catalysts in the final state (after 5 h on-stream) increased in the following order of dopants : Sm, Pb