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US3818680A
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Maleic anhydride recovery method
Assignee: Chevron USA Inc
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Filing: 1971-12-17
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Granted: 1974-06-25
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Expires: 1991-12-17
Abstract
Abstract Maleic anhydride is recovered from a gaseous mixture containing the anhydride and water by contacting the mixture with a normally liquid intramolecular carboxylic acid anhydride, especially at a temperature in the range 55* C. to 260* C. under sufficient pressure for absorption of the maleic anhydride.
Inventors
- 👤 D Marquis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:52
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/54; C07C51/573
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
27 words
The method as in claim 1 wherein the mixture contains water vapor and the contact temperature is at least 10* C. above the dew point of water.
Claim 2
Dependent Claim
11 words
withdrawing a portion of the resulting solution from said zone; and
Claim 3
Dependent Claim
10 words
separating maleic anhydride from the resulting solution by fractional distillation.
Claim 4
Dependent Claim
9 words
separating maleic aNhydride from said solution by fractional distillation.
Claim 5
Dependent Claim
21 words
The method as in claim 2 wherein the contact temperature is in the range from about 55* C. to 260* C.
Claim 6
Dependent Claim
21 words
THe method as in claim 2 wherein the contact temperature is in the range from about 65* C. to 125* C.
Claim 7
Dependent Claim
46 words
The method as in claim 1 wherein said scrubbing agent contains a diluent, said diluent being selected from the group consisting of ordinary non-aqueous maleic anhydride scrubbing agents, and wherein the intramolecular anhydride content of the resulting diluted agent is at least about 30 mol percent.
Claim 8
Dependent Claim
19 words
The method as in claim 1 wherein said pressure is in the range from about 0.1 to 3.5 atmospheres.
Claim 9
Dependent Claim
35 words
The method as in claim 1 wherein said pressure is about atmospheric pressure, said contact is effected in a multicontact staged column having a number of theoretical stages in the range from 1 to 30.
Claim 10
Independent Claim
128 words
The method for the recovery of maleic anhydride from a gaseous mixture containing maleic anhydride and water, which comprises condensing said maleic anhydride by passing said mixture into contact with a liquid scrubbing agent at a temperature in the range from about 55* C. to 260* C. and at a pressure sufficient to absorb maleic anhydride into the liquid phase, said pressure being in the range from about 0.07 to 7 atmospheres, said contact temperature being at least about 10* C. above the dew point of water, and said agent comprising one or more compounds of the formula R(Z)n wherein R is a substantially inert hydrocarbon group having a carbon atom content in the range from 1 to about 25, wherein Z is a group of the formula
Claim 11
Dependent Claim
20 words
The method as in claim 8 wherein said temperature is in the range from about 65* C. to 125* C.
Claim 12
Dependent Claim
19 words
The method as in claim 8 wherein said pressure is in the range from about 0.1 to 3.5 atmospheres.
Claim 13
Dependent Claim
13 words
The method as in claim 8 wherein said pressure is about atmospheric pressure.
Claim 14
Dependent Claim
29 words
The method as in claim 8 wherein said contacting is effected in a multicontact staged column having a number of theoretical stages in the range from 1 to 30.
Claim 15
Dependent Claim
18 words
The method as in claim 12 wherein said range of theoretical stages is from about 5 to 15.
Claim 16
Dependent Claim
35 words
The method as in claim 8 wherein said agent has a carbon atom content in the range from about 10 to 25 and is a branched or straight chain alkenyl or alkyl substituted succinic anhydride.
Claim 17
Dependent Claim
15 words
The method as in claim 14 wherein said agent is an alkenyl substituted succinic anhydride.
Claim 18
Dependent Claim
15 words
The method as in claim 8 wherein said agent is a bissuccinic anhydride substituted alkene.
Claim 19
Dependent Claim
18 words
The method as in claim 15 wherein R of said formula is in the range C12 to C15.
Claim 20
Dependent Claim
18 words
The method as in claim 15 wherein R of said formula is in the range C15 to C20.
Claim 21
Dependent Claim
17 words
The method as in claim 8 wherein said agent contains a minor amount of inert substituent groups.
Claim 22
Independent Claim
18 words
The method for the recovery of maleic anhydride from a gaesous mixture containing maleic anhydride and water comprising
Claim 23
Dependent Claim
31 words
The method as in claim 20 wherein said mixture is the effluent product stream from an oxidation process, said process being an air or oxygen oxidation of a vaporized hydrocarbon feed.
Claim 24
Dependent Claim
22 words
The method as in claim 20 wherein said agent has a carbon atom content in the range from about 10 to 25.
Claim 25
Independent Claim
33 words
The method for the recovery of maleic anhydride from a gaseous mixture containing water, said mixture being the effluent product stream from a catalyzed air oxidation of n-butane in the vapor phase, comprising:
Claim 26
Dependent Claim
27 words
The method as in claim 1 wherein said agent contains inert substituted groups, said groups being present in an amount in the range from 1 to 5.
Claim 27
Dependent Claim
27 words
The method as in claim 8 wherein said agent contains inert substituted groups, said groups being present in an amount in the range from 1 to 5.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-24 | 1977-12-24 | 1978-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-24 | 1981-12-24 | 1982-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-24 | 1985-12-24 | 1986-06-25 | $7700.00 | Window Closed / Lapsed |