IMPROVED MIXED VANADIUM PHOSPHORUS OXIDE CATALYSTS

摘要

Oxidn. catalysts contg. mixed oxides of V and P are prepared by introducing pentavalent V-contg. Compound and pentavalent P-contg. compound into an organic liq. medium capable of reducing V to a valence state of less than +5; reducing at least a portion of V to a valence state of +4 in the presence of the P-contg. compound; recovering the mixed V-P oxide containing a catalyst precursor; drying the precursor and calcining to form an active oxidn. catalyst. The oxidn. catalysts are esp. effective in oxidn. of n-butane, n-butene, 1,3-butadiene or their mixt. with O2 in a vapor phase to prepare maleic anhydride with good yield and selectivity.