US4503206A
Expired / Lapsed
US
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α,ω-Perfluorodicarboxylic acids
Assignee: Indiana University Research and Technology Corp
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Filing: 1982-12-22
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Granted: 1985-03-05
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Expires: 2002-12-22
Abstract
Abstract Tetrafluoroethylene is reacted in an aqueous environment with hydroxyl radicals, generating a mixture of water soluble and water insoluble alpha , omega -perfluorodicarboxylic acids.
Inventors
- 👤 Ivan M. Robinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:04
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/16; C07C51/305; C07C51/347; C07C51/353
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
44 words
A method for producing oligomeric α,ω-perfluorodicarboxylic acids of even- and odd-numbered chain lengths, of the general formula HOOC(CF 2 ) n COOH, wherein n=1 to about 1000, comprising the step of: reacting tetrafluorethylene with an inorganic source of hydroxyl radicals in an aqueous environment.
Claim 2
Independent Claim
44 words
A method for producing oligomeric α,ω-perfluorodicarboxylic acids of even- and odd-numbered chain lengths, of the general formula HOOC(CF 2 ) n COOH, wherein n=1 to about 1000, comprising the step of: reacting tetrafluorethylene with an inorganic source of hydroxyl radicals in an aqueous environment.
Claim 3
Dependent Claim
16 words
The method of claim 1 in which the source of hydroxyl radicals is a peroxydisulfate salt.
Claim 4
Dependent Claim
17 words
The method of claim 2 in which a metal ion promoter is used to assist peroxydisulfate decomposition.
Claim 5
Dependent Claim
18 words
The method of claim 3 carried out in the temperature range of about 35° to about 100° C.
Claim 6
Dependent Claim
21 words
The method of claim 2 in which the initial concentration of peroxydisulfate in water is greater than about 0.5% by weight.
Claim 7
Dependent Claim
10 words
Perfluorodicarboxylic acid oligomers formed by the method of claim 1.
Claim 8
Dependent Claim
22 words
A composition comprising a water soluble homologous series of perfluorodicarboxylic acids of the general formula HOOC(CF 2 ) n COOH, wherein n=1-9.
Claim 9
Dependent Claim
22 words
A composition comprising a water soluble homologous series of perfluorodicarboxylic acids of the general formula HOOC(CF 2 ) n COOH, wherein n=1-9.
Claim 10
Dependent Claim
18 words
The composition of claim 7 wherein the composition possesses a neutralization equivalent of about 95 to about 200.
Claim 11
Dependent Claim
26 words
A composition comprising a water insoluble homologous series of perfluorodicarboxylic acid oligomers of the general formula HOOC(CF 2 ) n COOH, wherein n=10 to about 1000.
Claim 12
Dependent Claim
26 words
A composition comprising a water insoluble homologous series of perfluorodicarboxylic acid oligomers of the general formula HOOC(CF 2 ) n COOH, wherein n=10 to about 1000.
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) | 1988-03-04 | 1988-09-03 | 1989-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-04 | 1992-09-03 | 1993-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-04 | 1996-09-03 | 1997-03-05 | $7700.00 | Window Closed / Lapsed |