ChemInform Abstract: THE CHEMISTRY OF CATALYSTS BASED ON VANADIUM‐PHOSPHORUS OXIDES. PART IV. CATALYTIC BEHAVIOR OF CATALYSTS PREPARED IN ORGANIC MEDIUM IN OXIDATION OF C4 FRACTION

Abstract

Abstract Vanadium-phosphorus mixed oxides, catalysts for C4 oxidation to maleic anhydride, were prepared in organic medium and tested in n-butane and butene-1 selective oxidation. These catalysts were compared with those prepared in aqueous medium. Before calcination, the two methods of preparation gave rise to the same phase, but the catalysts prepared in organic medium were characterized by higher surface area and lower oxidability in air. The latter characteristic makes it possible to obtain the selective compound of vanadium(IV) B-phase, (after calcination in air), in the full 0.95–1.15 P:V ratio range without the phases of vanadium(V) obtained in the case of catalysts prepared in aqueous medium. Unlike catalysts prepared in aqueous medium, an excess of phosphorus with respect to the ratio 1.0 led to a decrease both in activity and selectivity to maleic anhydride. The higher surface area of catalysts prepared in organic medium makes it possible to oxidize n-butane at lower temperatures than with catalysts prepared in aqueous medium.