US3906008A
Expired / Lapsed
US
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Method for producing maleic anhydride
Assignee: Kuraray Co Ltd
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Filing: 1972-10-30
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Granted: 1975-09-16
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Expires: 1992-10-30
Abstract
Abstract Maleic anhydride is obtained by oxidizing an unsaturated hydrocarbon having at least four carbon atoms in the presence of a catalyst comprising oxides of phosphorus and tungsten.
Inventors
- 👤 Ryuhei Ueeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:54
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/16; C07C51/21; C07C51/25; C07C51/252; B; B01; B01J; B01J27/00; B01J27/14; B01J27/186; B01J27/188; B01J37/00; B01J37/28; C07C51/31; C07C51/313
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
59 words
A METHOD FOR PREPARING MALEIC ANHYDRIDE WHICH COMPRISES OXIDIZING AN OLEFINIC HYDROCARBON CONTAINING FOUR OR FIVE CARBON ATOMS OR A HYDROCARBON MIXTURE THEREOF IN A REACTION ZONE AT A TEMPERATURE FROM 250* TO 65*C. IN THE PRESENCE OF A CATYLYST CONSISTING OF THE OXIDES OF TUGSTEN AND PHOSPHROUS, THE ATOMIC RATIO OF TUGSTEN TO PHOSPHRUS BEING LESS THAN 30.
Claim 2
Independent Claim
59 words
A METHOD FOR PREPARING MALEIC ANHYDRIDE WHICH COMPRISES OXIDIZING AN OLEFINIC HYDROCARBON CONTAINING FOUR OR FIVE CARBON ATOMS OR A HYDROCARBON MIXTURE THEREOF IN A REACTION ZONE AT A TEMPERATURE FROM 250* TO 65*C. IN THE PRESENCE OF A CATYLYST CONSISTING OF THE OXIDES OF TUGSTEN AND PHOSPHROUS, THE ATOMIC RATIO OF TUGSTEN TO PHOSPHRUS BEING LESS THAN 30.
Claim 3
Dependent Claim
58 words
A method according to claim 1, wherein there is introduced into the reaction zone an additional phosphorus compound selected from the group consisting of phosphine, phosphorus oxides, hydrophosphorous acid, phosphorous acid, diphosphorous acid, hypophosphoric acid, orthophosphoric acid, metaphosphoric acid, salts of phosphorous and phosphoric acid which are decomposed at the reaction temperature, and organophosphorus compounds of the formulae:
Claim 4
Dependent Claim
14 words
A method according to claim 1 wherein the catalyst is supported on a carrier.
Claim 5
Dependent Claim
22 words
A method according to claim 1 wherein the catalyst consists essentially of a complex or a compound of tungsten, phosphorus and oxygen.
Claim 6
Dependent Claim
30 words
A method according to claim 1 wherein the catalyst consists essentially of oxides of tungsten and phosphorus, a complex or a compound of tungsten, phosphorus and oxygen, and mixtures thereof.
Claim 7
Dependent Claim
25 words
A method according to claim 1 wherein oxidation is effected by admixing said olefinic hydrocarbon with an oxidizing agent comprising oxygen or an oxygen-containing gas.
Claim 8
Dependent Claim
23 words
A method according to claim 6 wherein the molar ratio of olefinic hydrocarbon to oxygen is less than one-tenth or more than one-half.
Claim 9
Dependent Claim
24 words
A method according to claim 1 wherein the gaseous hourly space velocity through the reaction zone ranges from 500 to 15, 000 per hour.
Claim 10
Dependent Claim
24 words
A method according to claim 1 in which the olefinic hydrocarbon is selected from the group consisting of butene-1, butene-2, butadiene, cyclopentadiene and pentene-1.
Claim 11
Dependent Claim
21 words
A method according to claim 1 in which the olefinic hydrocarbon is the C4 fraction which is obtained by naphtha cracking.
References Cited (Backward Citations)
US2206377A
Cited
US3156706A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-15 | 1979-03-17 | 1979-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-15 | 1983-03-17 | 1983-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-15 | 1987-03-17 | 1987-09-16 | $7700.00 | Window Closed / Lapsed |