US4191616A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification process
Assignee: Imperial Chemical Industries Ltd
•
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 17:56
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)
US2398485A
Cited
US3036126A
Cited
US3036127A
Cited
US3180878A
Cited
US3511757A
Cited
US3551300A
Cited
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 |