US3891680A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Maleic anhydride recovery using nonaqueous medium
Assignee: Chevron USA Inc
•
Filing: 1972-11-29
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Granted: 1975-06-24
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Expires: 1992-11-29
Abstract
Abstract A process for the recovery of maleic anhydride from gaseous mixtures containing the anhydride and water vapor by contacting the mixture with dialkyl phthalate esters having 4 to 8 carbon atom alkyl groups and a total of 10 to 14 carbon atoms in both alkyl groups, at a temperature in the range of 55*C. to 260*C. under sufficient pressure for absorption of the maleic anhydride.
Inventors
- 👤 Kiyoshi Katsumoto
- 👤 Wilton H Lind
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:46
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/54; C07C51/573
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
93 words
THE METHOD FOR THE RECOVERY OF MALEIC ANHYDRIDE FROM A GASEOUS MIXTURE CONTAINING THE ANHYDRIDE, WHICH COMPRISES CONTACTING SAID MIXTURE WTH A SCRUBBING AGENT IN THE LIQUID PHASE AT A TEMPERATURE BELOW ABOUT 260*C. AND AT A PRESSURE SUFFICIENT TO EFFECT MALEIC ANHYDRIDE ABSORPTION INTO THE LIQUID PHASE, SAID AGENT BEING ONE OR MORE DIALKYL PHTHALATES HAVING FROM 4 TO 8 CARBON ATOMS IN EACH ALKYL GROUP AND A TOTAL OF 10 TO 14 CARBON ATOMS IN BOTH ALKYL GROUPS, AND SAID PRESSURE BEING IN THE RANGE FROM ABOUT 0.07 TO 7 ATMOSPHERES.
Claim 2
Independent Claim
93 words
THE METHOD FOR THE RECOVERY OF MALEIC ANHYDRIDE FROM A GASEOUS MIXTURE CONTAINING THE ANHYDRIDE, WHICH COMPRISES CONTACTING SAID MIXTURE WTH A SCRUBBING AGENT IN THE LIQUID PHASE AT A TEMPERATURE BELOW ABOUT 260*C. AND AT A PRESSURE SUFFICIENT TO EFFECT MALEIC ANHYDRIDE ABSORPTION INTO THE LIQUID PHASE, SAID AGENT BEING ONE OR MORE DIALKYL PHTHALATES HAVING FROM 4 TO 8 CARBON ATOMS IN EACH ALKYL GROUP AND A TOTAL OF 10 TO 14 CARBON ATOMS IN BOTH ALKYL GROUPS, AND SAID PRESSURE BEING IN THE RANGE FROM ABOUT 0.07 TO 7 ATMOSPHERES.
Claim 3
Dependent Claim
11 words
withdrawing a portion of the resulting solution from said zone; and
Claim 4
Dependent Claim
11 words
withdrawing a portion of the resulting solution from said zone; and
Claim 5
Dependent Claim
26 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 6
Dependent Claim
11 words
withdrawing a portion of the resulting solution from said zone; and
Claim 7
Dependent Claim
11 words
withdrawing a portion of the resulting solution from said zone; and
Claim 8
Dependent Claim
10 words
separating maleic anhydride from the resulting solution by fractional distillation.
Claim 9
Dependent Claim
10 words
separating maleic anhydride from the resulting solution by fractional distillation.
Claim 10
Dependent Claim
19 words
The method as in claim 2 wherein the contact temperature is in the range from about 55*C. to 260*C.
Claim 11
Dependent Claim
9 words
separating maleic anhydride from said solution by fractional distillation.
Claim 12
Dependent Claim
9 words
separating maleic anhydride from said solution by fractional distillation.
Claim 13
Dependent Claim
19 words
The method as in claim 2 wherein the contact temperature is in the range from about 65*C. to 135*C.
Claim 14
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 dialkyl phthalate content of the resulting diluted agent is at least about 30 mol percent.
Claim 15
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 16
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 17
Dependent Claim
22 words
The method as in claim 1 wherein said agent is a dialkyl phthalate having both alkyl groups of the same carbon content.
Claim 18
Dependent Claim
14 words
The method as in claim 8 wherein said alkyl groups have 6 carbon atoms.
Claim 19
Dependent Claim
13 words
The method as in claim 1 wherein said agent is a dialkyl orthophthalate.
Claim 20
Dependent Claim
17 words
The method as in claim 10 wherein both alkyl groups have the same number of carbon atoms.
Claim 21
Dependent Claim
14 words
The method as in claim 11 wherein said alkyl groups have 6 carbon atoms.
Claim 22
Independent Claim
18 words
The method for the recovery of maleic anhydride from a gaseous mixture containing maleic anhydride and water comprising:
Claim 23
Independent Claim
18 words
The method for the recovery of maleic anhydride from a gaseous mixture containing maleic anhydride and water comprising:
Claim 24
Dependent Claim
31 words
The method as in claim 13 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 25
Dependent Claim
13 words
The method as in claim 13 wherein said agent is a dialkyl orthophthalate.
Claim 26
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 27
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:
References Cited (Backward Citations)
US2574644A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-23 | 1978-12-23 | 1979-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-23 | 1982-12-23 | 1983-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-23 | 1986-12-23 | 1987-06-24 | $7700.00 | Window Closed / Lapsed |