Process for producing maleic anhydride

摘要

Maleic anhydride is produced by the oxidation of a non-aromatic hydrocarbon having at least four carbon atoms in a straight chain with molecular oxygen or a molecular oxygen-containing gas in the vapor phase in the presence of a phosphorus-vanadium mixed oxide oxidation catalyst. Such catalysts are prepared by introducing a substantially pentavalent vanadium-containing compound and a pentavalent phosphorus-containing compound into an alcohol medium capable of reducing the vanadium to a valence state less than +5 in the presence of an alcohol-modifying agent to form a phosphorus-vanadium mixed oxide catalyst precursor. The catalyst precursor is recovered, dried, formed into desired structures, and calcined at temperatures from about 250 DEG C. to about 600 DEG C. The catalysts are highly effective in that they exhibit a weight/weight productivity of at least 70 grams of maleic anhydride per kilogram of catalyst per hour.