Patent US4191616A successfully refreshed from Google Patents.
US4191616A
Expired / Lapsed
US
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Purification process
Assignee: Imperial Chemical Industries Ltd
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Filing: 1978-12-14
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Granted: 1980-03-04
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Expires: 1998-12-14
Abstract
Abstract Alkane dicarboxylic acids of at least 4 carbon atoms particularly the mixture of succinic, glutaric and adipic acids obtained as byproduct in the manufacture of adipic acid are purified by co-distillation with an alkylbenzene having an atmospheric pressure boiling point of 300 DEG to 350 DEG C. especially dodecylbenzene.
Inventors
- 👤 Brian Baker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:22
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/42; C07C51/43; C07C51/44
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
37 words
A process for the purification of an alkane dicarboxylic acid having at least 4 carbon atoms which comprises co-distilling said acid with an alkylbenzene having an atmospheric pressure boiling point within the range 300° to 350° C.
Claim 2
Dependent Claim
37 words
A process for the purification of an alkane dicarboxylic acid having at least 4 carbon atoms which comprises co-distilling said acid with an alkylbenzene having an atmospheric pressure boiling point within the range 300° to 350° C.
Claim 3
Dependent Claim
15 words
A process according to claim 1 in which the alkylbenzene is a mono- or di-alkylbenzene.
Claim 4
Dependent Claim
16 words
A process according to claim 2 in which the alkylbenzene is dodecylbenzene, undecylbenzene, tridecylbenzene or dodecyltoluene.
Claim 5
Dependent Claim
37 words
A process according to claim 1 in which the alkane dicarboxylic acid is succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, methylglutaric acid, ethylsuccinic acid or a mixture of two or more of such acids.
Claim 6
Dependent Claim
16 words
A process according to claim 1 in which the co-distillation is carried out under reduced pressure.
Claim 7
Dependent Claim
23 words
A process according to claim 1 in which the proportion of alkylbenzene to dicarboxylic acid in the co-distillation is about 1:1 by weight.
Claim 8
Dependent Claim
22 words
A process according to claim 1 in which the distillate from the co-distillation is mixed with water to dissolve the dicarboxylic acid.
Claim 9
Dependent Claim
83 words
A process according to claim 1 for the purification of a mixture of acids containing adipic, glutaric and succinic acids which is obtained as a byproduct of the manufacture of adipic acid in which the mixture of acids is added to the co-distillation in a molten condition at a temperature in the range 120° to 160° C., the co-distillation being carried out at a pressure of about 133 mbar in a still in which the still contents are held at about 230° C.
Claim 10
Dependent Claim
39 words
A process according to claim 8 in which the condensed azeotrope from the co-distillation is run into water the temperature of which is 50° to 150° C. and the ratio of water to azeotrope is about 5:1 by weight.
Claim 11
Dependent Claim
38 words
A process according to claim 9 in which the alkylbenzene is separated from the water and returned to the co-distillation and the aqueous solution of dicarboxylic acids is concentrated and cooled to allow the dicarboxylic acids to crystallise.
References Cited (Backward Citations)
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US3036127A
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US3180878A
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US3511757A
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US3551300A
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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) | 1983-03-04 | 1983-09-03 | 1984-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-04 | 1987-09-03 | 1988-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-04 | 1991-09-03 | 1992-03-04 | $7700.00 | Window Closed / Lapsed |