US4178298A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing maleic anhydride
Assignee: Lonza AG
•
Filing: 1977-10-12
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Granted: 1979-12-11
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Expires: 1997-10-12
Abstract
Abstract 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° to 500° 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 4 -hydrocarbons in the gaseous phase.
Inventors
- 👤 Giancarlo Stefani
- 👤 Pietro Fontana
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:20
CPC Classifications
B; B01; B01J; B01J27/00; B01J27/14; B01J27/186; B01J27/195; B01J27/198; C; C07; C07C; C07C51/00; C07C51/16; C07C51/21; C07C51/215
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
110 words
Process which comprises converting a straight-chain C 4 -hydrocarbon in the gaseous phase to maleic anhydride using an activated catalyst, which can be reactivated, for oxidation reactions on the basis of a mixed oxide of vanadium and phosphorus, said vanadium having an average valence of less than +3.9, said catalyst having been activated at a temperature of 300° to 450° C. by passing over the mixed oxide a gaseous hydrocarbon component, which has 2 to 6 carbon atoms, in the absence of molecular oxygen, said catalyst having been calcined before activation, and said catalyst having an atomic ratio of phosphorus to vanadium between 1.05 to 1 and 1.10 to 1.
Claim 2
Dependent Claim
110 words
Process which comprises converting a straight-chain C 4 -hydrocarbon in the gaseous phase to maleic anhydride using an activated catalyst, which can be reactivated, for oxidation reactions on the basis of a mixed oxide of vanadium and phosphorus, said vanadium having an average valence of less than +3.9, said catalyst having been activated at a temperature of 300° to 450° C. by passing over the mixed oxide a gaseous hydrocarbon component, which has 2 to 6 carbon atoms, in the absence of molecular oxygen, said catalyst having been calcined before activation, and said catalyst having an atomic ratio of phosphorus to vanadium between 1.05 to 1 and 1.10 to 1.
Claim 3
Dependent Claim
20 words
Process as claimed in claim 1 wherein said mixed oxide also contains oxides of elements other than vanadium and phosphorus.
Claim 4
Dependent Claim
14 words
Process as claimed in claim 1 wherein said mixed oxide also contains titanium dioxide.
Claim 5
Dependent Claim
15 words
Process as claimed in claim 1 wherein said straight-chain C 4 -hydrocarbon is gaseous n-butane.
Claim 6
Dependent Claim
17 words
Process as claimed in claim 1 wherein said vanadium has an average valence between +3.5 and +3.85.
Claim 7
Dependent Claim
112 words
Process which comprises converting a straight-chain C 4 -hydrocarbon in the gaseous phase to maleic anhydride using an activated catalyst, which can be reactivated, for oxidation reactions on the basis of a mixed oxide of vanadium and phosphorus, said vanadium having an average valence of less than +3.9, said catalyst having been activated at a temperature of 300° to 450° C. by passing gaseous butane or a mixture of gaseous butane and a non-oxidizing inert gas over the mixed oxide in the absence of molecular oxygen, said catalyst having been calcined before activation, and said catalyst having an atomic ratio of phosphorus to vanadium between 1.05 to 1 and 1.10 to 1.
Claim 8
Dependent Claim
112 words
Process which comprises converting a straight-chain C 4 -hydrocarbon in the gaseous phase to maleic anhydride using an activated catalyst, which can be reactivated, for oxidation reactions on the basis of a mixed oxide of vanadium and phosphorus, said vanadium having an average valence of less than +3.9, said catalyst having been activated at a temperature of 300° to 450° C. by passing gaseous butane or a mixture of gaseous butane and a non-oxidizing inert gas over the mixed oxide in the absence of molecular oxygen, said catalyst having been calcined before activation, and said catalyst having an atomic ratio of phosphorus to vanadium between 1.05 to 1 and 1.10 to 1.
Claim 9
Dependent Claim
20 words
Process as claimed in claim 6 wherein said mixed oxide also contains oxides of elements other than vanadium and phosphorus.
Claim 10
Dependent Claim
14 words
Process as claimed in claim 6 wherein said mixed oxide also contains titanium dioxide.
Claim 11
Dependent Claim
15 words
Process as claimed in claim 6 wherein said straight-chain C 4 -hydrocarbon is gaseous n-butane.
Claim 12
Dependent Claim
17 words
Process as claimed in claim 6 wherein said vanadium has an average valence between +3.5 and +3.85.
Claim 13
Dependent Claim
17 words
Process as claimed in claim 6 wherein said inert gas is CO 2 or N 2 .
Claim 14
Dependent Claim
23 words
Process as claimed in claim 6 wherein said inert gas is N 2 and said mixture contains at least 5 percent of butane.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-10 | 1983-06-11 | 1983-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-10 | 1987-06-11 | 1987-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-10 | 1991-06-11 | 1991-12-11 | $7700.00 | Window Closed / Lapsed |