Preparation of vanadium phosphorous catalysts using olefinic oxygenated media

A process for the preparation of oxidation catalysts containing the mixed oxides of vanadium and phosphorus which comprises

• (a) introducing a pentavalent vanadium-compound into an oxygenated organic liquid containing liquid medium capable of at least partially solubilizing the vanadium;
• (b) effecting reduction of at least a portion of said vanadium to a valence state of about +4 in the absence of a corrosive reducing agent;
• (c) removing unsolubilized vanadium-containing compounds having a particle size greater than about 0.1 mm diameter;
• (d) adding a pentavalent phosphorus-containing compound to the reaction medium resulting from step (c) to form a catalyst precursor precipitate;
• (e) recovering said catalyst precursor precipitate;
• (f) drying said catalyst precursor precipitate;
• and
• (g) calcining said precipitate.

An oxidation catalyst containing the mixed oxides of vanadium and phosphorus prepared by

• (a) introducing a pentavalent vanadium-containing compound into an olefinic, oxygenated organic liquid-containing liquid medium,
• (b) effecting reduction of at least a portion of said vanadium to a valence state of about +4 in the absence of a corrosive reducing agent;
• (c) adding a phosphorus-containing compound to said medium prior to or subsequent to effecting said reduction to form a catalyst precursor;
• (d) recovering the catalyst precursor;
• (e) drying the catalyst precursor;
• (f) calcining the catalyst precursor.