EFFECT OF THE PREPARATION CONDITIONS ON THE STRUCTURE OF THE ACTIVE SITES AND ACTIVITY OF VANADIUM-ALUMINUM-OXYNITRIDE PROPANE AMMOXIDATION CATALYST

PRADA S., R.; BLANGENOIS, N.; FLOREA, M.; LUIS EDUARDO CADUS; BARBERO, BIBIANA P; GRANGE, P.

Mons, Belgium

Congreso; ISN’T IT 2003 FOURTH INTERNATIONAL SYMPOSIUM ON NITRIDES; 2003

Vanadium-aluminum oxide catalysts for propane oxidative dehydrogenation are investigated with respect to their physico-chemical properties and catalytic activity as a function of the co-precipitation pH. Modifications of the specific surface area, the particle size distribution, and the chemical nature of the active phase are found. At co-precipitation pH=5.5, an amorphous V-Al-Ox mixed phase was formed by condensation of tetrahedral polymeric [VOx]n n- and amorphous aluminum hydroxide species. At pH between 7.5 and 8.5, the catalyst consists of [VOx]n n- species supported on amorphous alumina hydroxide. At pH=10, V2O7 4- ions are presumably adsorbed on boehmite surface. The propane conversion and propylene production gram-atom of vanadium and per hour are higher for the samples prepared at pH³ 8.5. A correlation exists between the reduction temperature of the vanadium species and the catalytic activity for the propane oxidative dehydrogenation reaction.