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US 4,381,254 AGranted
Method for preparing catalysts for production maleic anhydride
AssigneeMonsanto Company
InventorJames T. Wrobleski
Life of this patent
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Abstract
An improvement in a method of preparing catalysts for the manufacture of maleic anhydride by oxidizing a saturated hydrocarbon. The catalyst is prepared by a process in which a catalyst precursor, containing tetravalent vanadium, is formed into agglomerates and calcined, the improvement being quick freezing the catalyst precursor before calcining.
Claims7
In a method for the preparation of a phosphorus-vanadium-oxygen-containing complex catalyst comprising:
- (a) contacting vanadium and phosphorus compounds under conditions which will provide catalyst precursor wherein greater than 50 atom % of the vanadium is in the tetravalent state;
- (b) recovering the catalyst precursor;
- (c) forming the catalyst precursor into agglomerates;
- and
- (d) calcining the catalyst precursor agglomerations at a temperature between about 300.degree. C. and 600.degree. C.
- the improvement wherein the catalyst precursor is subjected and reduced to temperatures less than about -78.degree. C. before calcinating.
3 more elements
In a method for the preparation of a phosphorus-vanadium-oxygen-containing complex catalyst comprising:
- (a) contracting vanadium and phosphorus compounds under conditions which will provide a catalyst precursor wherein greater than 50 atom % of the vanadium is in the tetravalent state;
- (b) recovering the catalyst precursor;
- (c) forming the catalyst precursor into agglomerates;
- and
- (d) calcinating the catalyst precursor agglomerates at a temperature between about 300.degree. C. and 600.degree. C.
- the improvement wherein the catalyst precursor formed by step (a) is a precipitate in an aqueous precipitant which is quick frozen and further cooled by exposure to temperatures less than about -78.degree. C. before being recovered according to step (b).
3 more elements
Dependencies are inferred from the claim text.