Preparation of mixed vanadium phosphorus oxide catalysts and their use in oxidative processes
AssigneeThe Standard Oil Company
InventorsNoel J. Bremer, Dennis E. Dria
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Abstract
Vanadium phosphorus mixed oxide containing catalysts are prepared by sequentially forming an alpha-VOPO.sub.4 catalyst precursor in aqueous media, and thereafter partially reducing a portion of the vanadium to a valence state of +4 in an organic liquid reducing media, in the absence of corrosive reducing agents. The catalysts exhibit excellent activity for the production of maleic anhydride from 4 carbon atom hydrocarbons such as n-butane.
Claims10
A process for the preparation of vanadium phosphorus mixed oxide containing catalysts comprising
- (a) introducing a pentavalent vanadium compound and a pentavalent phosphorus compound into an aqueous medium wherein the aqueous medium is free from agents which would substantially reduce the pentavalent vanadium compound;
- (b) forming a substantially pentavalent, alpha-VOPO.sub.4 catalyst precursor in the aqueous medium;
- (c) recovering the pentavalent catalyst precursor from the aqueous medium;
- (d) introducing the pentavalent catalyst precursor into a substantially organic liquid medium capable of reducing at least a portion of the vanadium to a valence state of about +4 in the absence of corrosive reducing agents;
- (e) effecting reduction of the vanadium;
- (f) recovering the resulting partially reduced catalyst precursor from the organic liquid medium;
- (g) drying the partially reduced catalyst precursor;
- (h) calcining the partially reduced catalyst precursor.
An oxidation catalyst containing the mixed oxides of vanadium and phosphorus prepared by
- (a) introducing a pentavalent vanadium compound and a pentavalent phosphorus compound into an aqueous medium wherein the aqueous medium is free from agents which would substantially reduce the pentavalent vanadium compound;
- (b) forming a substantially pentavalent, alpha-VOPO.sub.4 catalyst precursor in the aqueous medium;
- (c) recovering the pentavalent catalyst precursor from the aqueous medium;
- (d) introducing the pentavalent catalyst precursor into a substantially organic liquid medium capable of reducing at least a portion of the vanadium to a valence state of about +4 in the absence of corrosive reducing agents;
- (e) effecting reduction of the vanadium;
- (f) recovering the resulting partially reduced catalyst precursor from the organic liquid medium;
- (g) drying the partially reduced catalyst precursor;
- (h) calcining the partially reduced catalyst precursor.
Dependencies are inferred from the claim text.