Lonza Inc.

Pietro Fontana

Giancarlo Stefani

Activated catalyst for oxidation reactions on the basis of mixed oxides of vanadium and phosphorus, characterized in that the vanadium has an average valence of less than +3.9. The activated catalyst is produced using a process wherein a mixed oxide, in which the vanadium has an average valence of +3.9 to more than +4, is activated at temperatures of 300.degree. to 500.degree. C. by passing over it a gaseous hydrocarbon component having 2 to 6 carbon atoms with the exclusion of molecular oxygen. The activated catalyst is used for the production of maleic anhydride from straight-chain C.sub.4 -hydrocarbons in the gaseous phase.

Catalyst for oxidation reactions and process for its production

Process for preparing maleic anhydride

The process for the production of a mixed-oxide oxidation catalyst which, based on the vanadium and pentavalent phosphorus, has an atomic ratio of phosphorus to vanadium between 1.05 to 1 and 1.10 to 1. The process involves reacting a salt of tetravalent vanadium, dissolved in a non-oxidizing acid aqueous solution, with orthophosphoric acid. The resultant soluble vanadium salt complex, after concentrating the solution is precipitated by adding water. The precipitate is dried. The dried precipitate is put or formed into the desired form. The formed, dried precipitate is subjected to a heat treatment of at least 300.degree. C. A mixed-oxide oxidation catalyst is obtained.

Process for the production of a mixed-oxide oxidation catalyst

The process for the production of a mixed-oxide oxidation catalyst which, based on the vanadium and pentavalent phosphorus, has an atomic ratio of phosphorus to vanadium between 1.05 to 1 and 1.10 to 1. The process involves a salt of the tetravalent vanadium, dissolved in a non-oxidizing acid aqueous solution, with orthophosphoric acid. After the solution is concentrated the vanadium salt complex is precipitated by adding water. The precipitate is dried. The dried precipitate is put or formed into the desired form. The formed, dried precipitate is subjected to a heat treatment of at least 300.degree. C. A mixed-oxide oxidation catalyst is obtained.

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Schaffhausen, Switzerland

Pietro Fontana