Preparation of maleic anhydride
AssigneeThe Standard Oil Company (Ohio)
InventorsNoel J. Bremer, Dennis E. Dria
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Abstract
The present invention provides a process for the preparation of oxidation catalysts containing mixed oxides of vanadium and phosphorus, which catalysts are particularly effective in the oxidation of n-butane, n-butenes, 1,3-butadiene or a mixture thereof with molecular oxygen or an oxygen-containing gas in the vapor phase to produce high yields of maleic anhydride with good selectivity. A vanadium compound is introduced into an olefinic oxygenated organic liquid medium, a phosphorus-containing compound is added to the medium, reduction of at least a portion of the vanadium to a +4 valence state is effected either prior to or subsequent to the addition of the phosphorus-containing compound, and the resulting vanadium-phosphorus oxide catalyst precursor is recovered, dried and calcined.
Claims11
A process for the production of maleic anhydride by the oxidation of n-butane, n-butene, 1,3-butadiene or a mixture thereof with molecular oxygen or oxygen-containing gas in the vapor phase at a reaction temperature of 250.degree. C.-600.degree. C. in the presence of a catalyst containing the mixed oxides of vanadium and phosphorus, wherein said catalyst is 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 and 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.
A process for the production of maleic anhydride by the oxidation of n-butane, n-butene, 1,3 butadiene or a mixture thereof with molecular oxygen or oxygen-containing gas in the vapor phase at a reaction temperature of 250.degree. C.-600.degree. C. in the presence of a catalyst containing the mixed oxides of vanadium and phosphorus, wherein said catalyst is prepared by
- (a) introducing a pentavalent vanadium-compound into an olefinic 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;
- (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 resultng from step (c) to form a catatalyst precursor precipitate;
- (e) recovering said catalyst precursor precipitate;
- (f) drying said catalyst precursor precipitate;
- and
- (g) calcining said precipitate.
A process for the production of maleic anhydride by the oxidation of n-butane, n-butene, 1,3 butadiene or a mixture thereof with molecular oxygen or oxygen-containing gas in the vapor phase at a reaction temperature of 250.degree. C.-600.degree. C. in the presence of a catalyst containing the mixed oxides of vanadium and phosphorus, prepared from at least one pentavalent vanadium-containing compound and at least one phosphorus-containing compound, wherein the pentavalent vanadium is reduced to an average valence state of about +3.9 to about +4.6, including the step of effecting reduction of at least a portion of the dispersed or solubilized pentavalent vanadium to a valence state of +4 in an olefinic, oxygenated organic liquid-containing liquid medium and in the absence of a corrosive reducing agent.
Dependencies are inferred from the claim text.