US4244879A
Expired / Lapsed
US
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Preparation of maleic anhydride
Assignee: Standard Oil Co
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Filing: 1979-12-26
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Granted: 1981-01-13
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Expires: 1999-12-26
Abstract
Abstract The present invention provides a method 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 improved yields of maleic anhydride with good selectivity. A vanadium compound is at least partially solubilized in an organic liquid medium capable of reducing at least a portion of the vanadium to a +4 valence state, and unsolubilized vanadium having a particle size larger than about 0.1 mm diameter is removed from the medium before addition of a phosphorus-containing compound.
Inventors
- 👤 Noel J. Bremer
- 👤 Dennis E. Dria
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:18
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/16; C07C51/21; C07C51/25; C07C51/252; B; B01; B01J; B01J23/00; B01J23/002; B01J27/00; B01J27/14; B01J27/186; B01J27/195; B01J27/198; C07C51/215; B01J2523/00
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
163 words
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° C.-600° 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 organic liquid capable of at least partially solubilizing and capable of reducing vanadium to a valence state less than +5 to form a reaction medium; (b) effecting reduction of at least a portion of vanadium to a valence state of +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 resulting from step (c) to form a catalyst precursor precipitate; (e) recovering said catalyst precursor precipitate; (f) drying said catalyst precursor precipitate; (g) calcining said precipitate to form the active oxidation catalyst.
Claim 2
Dependent Claim
163 words
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° C.-600° 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 organic liquid capable of at least partially solubilizing and capable of reducing vanadium to a valence state less than +5 to form a reaction medium; (b) effecting reduction of at least a portion of vanadium to a valence state of +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 resulting from step (c) to form a catalyst precursor precipitate; (e) recovering said catalyst precursor precipitate; (f) drying said catalyst precursor precipitate; (g) calcining said precipitate to form the active oxidation catalyst.
Claim 3
Dependent Claim
15 words
A process as recited in claim 1 wherein said organic liquid medium is essentially anhydrous.
Claim 4
Dependent Claim
23 words
A process as recited in claim 1 wherein reduction of said vanadium is effected by heating the vanadium-containing reaction medium of step (a).
Claim 5
Dependent Claim
26 words
A process as recited in claim 3 wherein reduction of said vanadium is effected by heating the vanadium-containing reaction medium of step (a) under reflux conditions.
Claim 6
Dependent Claim
16 words
The process as recited in claim 1 wherein said unsolubilized vanadium-containing compounds are removed by filtration.
Claim 7
Dependent Claim
33 words
A process as recited in claim 1 wherein said pentavalent phosphorus-containing compound is added to the reaction medium in the form of a solution of said pentavalent phosphorus-containing compound in said organic liquid.
Claim 8
Dependent Claim
14 words
A process as recited in claim 1 wherein said organic liquid is an alcohol.
Claim 9
Dependent Claim
13 words
A process as recited in claim 7 wherein said organic liquid is isobutanol.
Claim 10
Dependent Claim
14 words
A process as recited in claim 1 wherein said vanadium-containing compound is vanadium pentoxide.
Claim 11
Dependent Claim
14 words
A process as recited in claim 1 wherein said phosphorus-containing compound is orthophosphoric acid.
Claim 12
Dependent Claim
41 words
A process as recited in claim 1 wherein said oxidation catalyst is represented by the empirical formula: V.sub.1 P.sub.a O.sub.x wherein a=1.0 to 1.2 and x is the number of oxygens required to satisfy the valence requirements of the other elements.
Claim 13
Dependent Claim
25 words
A process as recited in claim 1 wherein said oxidation catalyst is represented by the empirical formula V 1 P 1 .1 O x .
Claim 14
Dependent Claim
23 words
A process as recited in claim 1 wherein unsolubilized vanadium-containing compounds having a particle size greater than about 0.06 mm diameter are removed.
Claim 15
Dependent Claim
23 words
A process as recited in claim 1 wherein unsolubilized vanadium-containing compounds having a particle size greater than about 0.04 mm diameter are removed.
References Cited (Backward Citations)
US4132670A
Cited
US4016105A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-13 | 1984-07-14 | 1985-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-13 | 1988-07-14 | 1989-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-13 | 1992-07-14 | 1993-01-13 | $7700.00 | Window Closed / Lapsed |