Patent US4250331A successfully refreshed from Google Patents.
US4250331A
Expired / Lapsed
US
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Removal of organic acids from dilute aqueous solutions of salts of organic acids by supercritical fluids
Assignee: EIDP Inc
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Filing: 1979-10-09
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Granted: 1981-02-10
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Expires: 1999-10-09
Abstract
Abstract Process for recovering carboxylic acids from dilute aqueous solutions of alkali metal salts of such carboxylic acids by mixing such solutions with from 10 to 1000% of a supercritical solution comprising at least 10 mole % carbon dioxide at a pressure from 80 to 500 atm and preferably 100 to 350 atm and at a temperature of from 35° to 200° C. and preferably from 35° to 100° C. whereby the salt reacts with the carbon dioxide to form the carboxylic acid which dissolves in the supercritical fluid. The aqueous phase is allowed to separate from the supercritical fluid phase. The pressure of the supercritical phase is lowered which lowers the solubility of the carboxylic acid in the supercritical fluid so that an acid phase is formed separate from the supercritical fluid phase whereby recovery of the acid is effected.
Inventors
- 👤 Edward J. Shimshick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:37
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/02; B; B01; B01D; B01D11/00; B01D11/04; B01D11/0403; B01D11/0407; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/54
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
110 words
A process comprising contacting an aqueous solution of at least one metal salt of a carboxylic acid with a supercritical fluid comprising at least 10 mole % carbon dioxide at from 35° to 200° C. and from 80 to 500 atm, whereby the carbon dioxide reacts with the metal salt of a carboxylic acid to release the free carboxylic acid, forming an aqueous phase and a separate supercritical fluid phase and recovering one or more carboxylic acids derived from a salt or salts of a carboxylic acid contained in the original dilute aqueous solution from the supercritical phase by lowering the pressure of the supercritical fluid from 5 to 85%.
Claim 2
Dependent Claim
110 words
A process comprising contacting an aqueous solution of at least one metal salt of a carboxylic acid with a supercritical fluid comprising at least 10 mole % carbon dioxide at from 35° to 200° C. and from 80 to 500 atm, whereby the carbon dioxide reacts with the metal salt of a carboxylic acid to release the free carboxylic acid, forming an aqueous phase and a separate supercritical fluid phase and recovering one or more carboxylic acids derived from a salt or salts of a carboxylic acid contained in the original dilute aqueous solution from the supercritical phase by lowering the pressure of the supercritical fluid from 5 to 85%.
Claim 3
Dependent Claim
19 words
The process of claim 1 wherein the pressure used in the contacting step is from 100 to 350 atm.
Claim 4
Dependent Claim
19 words
The process of claim 2 wherein the temperature used in the contacting step is from 35° to 100° C.
Claim 5
Dependent Claim
28 words
The process of claim 3 wherein the amount of supercritical fluid in the contacting step is from 10 to 1000 wt % of the amount of salt solution.
Claim 6
Dependent Claim
33 words
The process of claim 1 wherein the supercritical fluid contains from 10 to 90 mole percent of material which has a dipole moment and has a T c of less than 200° C.
Claim 7
Dependent Claim
19 words
The process of claim 5 wherein the pressure used in the contacting step is from 100 to 350 atm.
Claim 8
Dependent Claim
19 words
The process of claim 6 wherein the temperature used in the contacting step is from 35° to 100° C.
Claim 9
Dependent Claim
29 words
The process of claim 7 wherein the amount of supercritical fluid in the mixing step is from 50 to 200 mole % of the amount of dilute salt solution.
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) | 1984-02-10 | 1984-08-11 | 1985-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-10 | 1988-08-11 | 1989-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-10 | 1992-08-11 | 1993-02-10 | $7700.00 | Window Closed / Lapsed |