US5591877A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the recovery of fluorinated carboxylic acids
Assignee: Hoechst AG
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Filing: 1995-05-03
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Granted: 1997-01-07
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Expires: 2015-05-03
Abstract
Abstract Fluorinated carboxylic acids can be recovered from materials which contain them by releasing, if necessary, the carboxylic acids with sufficiently strong acids, esterifying the released acids and distilling off the esters. The esters can be advantageously directly hydrolyzed with aqueous ammonia solution to give the corresponding ammonium salts.
Inventors
- 👤 Reinhold Obermeier
- 👤 Gunter Stefaniak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:16
CPC Classifications
C; C07; C07C; C07C67/00; C07C67/08; C07C51/00; C07C51/02; C07C51/09; C07C51/42; C07C51/487; C07C51/493; C08; C08F; C08F14/00; C08F14/18
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
26 words
A process for preparing an ammonium salt of a fluorinated carboxylic acid emulsifier, which comprises hydrolyzing an ester of the fluorinated carboxylic acid in aqueous ammonia.
Claim 2
Dependent Claim
26 words
A process for preparing an ammonium salt of a fluorinated carboxylic acid emulsifier, which comprises hydrolyzing an ester of the fluorinated carboxylic acid in aqueous ammonia.
Claim 3
Dependent Claim
30 words
The process of claim 1, wherein the crude ester has been obtained from the reaction of a fluorinated carboxylic acid emulsifier with an alcohol, with distillation to obtain the ester.
Claim 4
Dependent Claim
13 words
The process of claim 1, wherein the aqueous ammonia comprises about 25% ammonia.
Claim 5
Dependent Claim
15 words
The process of claim 1, wherein the hydrolysis reaction is carried out at 70°-95° C.
Claim 6
Dependent Claim
19 words
The process of claim 2, wherein the ammonium salt is recovered after removal of alcohol and water by distillation.
Claim 7
Dependent Claim
12 words
The process of claim 1, wherein the ester is a methyl ester.
Claim 8
Dependent Claim
14 words
The process of claim 1, wherein the fluorinated carobxylic acid emulsifier is perfluorooctanoic acid.
Claim 9
Dependent Claim
48 words
A process for purifying a crude solution of a fluorinated carboxylic acid emulsifier in which the emulsifier is present in the form of an ester, which comprises hydrolyzing the crude solution containing said ester with aqueous ammonia and recovering the emulsifier in the from of an ammonium salt.
Claim 10
Dependent Claim
48 words
A process for purifying a crude solution of a fluorinated carboxylic acid emulsifier in which the emulsifier is present in the form of an ester, which comprises hydrolyzing the crude solution containing said ester with aqueous ammonia and recovering the emulsifier in the from of an ammonium salt.
Claim 11
Dependent Claim
33 words
The process of claim 8, wherein the crude ester solution has been obtained from the reaction of a fluorinated carboxylic acid emulsifer with an alcohol, with distillation to obtain the crude ester solution.
Claim 12
Dependent Claim
13 words
The process of claim 8, wherein the aqueous ammonia comprises about 25% ammonia.
Claim 13
Dependent Claim
15 words
The process of claim 8, wherein the hydrolysis reaction is carried out at 70-95° C.
Claim 14
Dependent Claim
19 words
The process of claim 9, wherein the ammonium salt is recovered after removal of alcohol and water by distillation.
Claim 15
Dependent Claim
12 words
The process of claim 8, wherein the ester is a methyl ester.
Claim 16
Dependent Claim
14 words
The process of claim 8, wherein the fluorinated carboxylic acid emulsifier is perfluorooctanoic acid.
References Cited (Backward Citations)
CA559182A
Cited
US3818074A
Cited
US4730082A
Cited
DE3829409A1
Cited
JPH01153654A
Cited
WO1995000469A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-01-07 | 2000-07-08 | 2001-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-01-07 | 2004-07-08 | 2005-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-01-07 | 2008-07-08 | 2009-01-07 | $7700.00 | Window Closed / Lapsed |