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US4751027A
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Process for the preparation of perfluorocarboxylic acids
Assignee: Hoechst AG
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Filing: 1986-12-09
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Granted: 1988-06-14
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Expires: 2006-12-09
Abstract
Abstract A process is described for the preparation of perfluorocarboxylic acids by oxidizing perfluoroalkylalkenes with permanganate in aqueous solution, catalytic amounts of at least one quaternary ammonium salt containing alkyl and/or arylalkyl groups being added. It is possible by these means to prepare even perfluorocarboxylic acids having a fairly long chain in a high state of purity in a readily controllable reaction and in a good space-time yield.
Inventors
- 👤 Konrad von Werner
- 👤 Anton Probst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:03
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/16
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
168 words
A process for the preparation of perfluorocarboxylic acids by oxidizing perfluoroalkylethylenes with permanganate in aqueous solution, at normal temperature or at an elevated temperature, which comprises reacting 1/p mol of a compound of the formula ##STR4## in which R f denotes a linear or branched perfluoroalkylene group having 6 to 18 carbon- atoms; Z denotes F, Cl, Br or ##STR5## and R 1 , R 2 , R 3 and R 4 each denote a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and moreover p is the number of double bonds in the molecule of the formula I, in the presence of 0.001 to 0.1 mol of at least one quaternary ammonium salt containing alkyl and/or arylalkyl groups at 10° to 100° C., acidifying the mixture after the completion of the reaction, removing the manganese-IV oxide formed or bringing it into solution by reduction to give the manganese-II salt, and separating off and, if required, purifying further, the resulting perfluoromonocarboxylic or perfluorodicarboxylic acid.
Claim 2
Dependent Claim
168 words
A process for the preparation of perfluorocarboxylic acids by oxidizing perfluoroalkylethylenes with permanganate in aqueous solution, at normal temperature or at an elevated temperature, which comprises reacting 1/p mol of a compound of the formula ##STR4## in which R f denotes a linear or branched perfluoroalkylene group having 6 to 18 carbon- atoms; Z denotes F, Cl, Br or ##STR5## and R 1 , R 2 , R 3 and R 4 each denote a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and moreover p is the number of double bonds in the molecule of the formula I, in the presence of 0.001 to 0.1 mol of at least one quaternary ammonium salt containing alkyl and/or arylalkyl groups at 10° to 100° C., acidifying the mixture after the completion of the reaction, removing the manganese-IV oxide formed or bringing it into solution by reduction to give the manganese-II salt, and separating off and, if required, purifying further, the resulting perfluoromonocarboxylic or perfluorodicarboxylic acid.
Claim 3
Dependent Claim
15 words
The process as claimed in claim 1, wherein sodium permanganate and/or potassium permanganate is employed.
Claim 4
Dependent Claim
47 words
The process as claimed in claim 1, wherein a compound of the formula I in which Z denotes F, Cl or Br and R 1 and R 2 denote H is employed, at least 10 mol of permanganate ions being used for 3 mol of this compound.
Claim 5
Dependent Claim
45 words
The process as claimed in claim 1, wherein a compound of the formula I in which Z denotes --CH═CH 2 and R 1 and R 2 denote H is employed, at least 20 mol of permanganate ions being used for 3 mol of this compound.
Claim 6
Dependent Claim
53 words
The process as claimed in claim 1, wherein a compound of the formula I in which Z denotes F, Cl or Br and R 1 and R 2 denote alkyl having 1 to 5 carbon atoms is employed, at least 2 mol of permanganate ions being used for 1 mol of this compound.
Claim 7
Dependent Claim
64 words
The process as claimed in claim 1, wherein a compound of the formula I in which Z denotes ##STR6## and R 1 , R 2 , R 3 and R 4 are identical with one another or different and denote alkyl having 1 to 5 carbon atoms is employed, at least 4 mol of permanganate ions being used for 1 mol of this compound.
Claim 8
Dependent Claim
153 words
The process as claimed in claim 1, wherein at least one compound of the formula [(R.sup.5).sub.2 (R.sup.6).sub.2 N].sup.+ X.sup.- and [(R.sup.5).sub.3 R.sup.6 N].sup.+ X.sup.- in which R 5 denotes an alkyl or arylalkyl radical having 8 to 20 carbon atoms, R 6 denotes an alkyl radical having 1 to 3 carbon atoms and X - denotes the 1/mth part of an m-valent ion selected from the group comprising: Cl - , Br - , R 8 SO 4 - ; SO 4 -- ; PO 4 --- ; R 8 PO 4 -- , (R 8 ) 2 PO 4 -- ; R 7 SO 3 - , R 7 PO 3 -- or (R 7 ) 2 PO 3 - in which R 7 denotes alkyl having 1 to 4 carbon atoms and R 8 denotes H or alkyl having 1 to 4 carbon atoms, is employed as the quaternary ammonium salt.
Claim 9
Dependent Claim
37 words
The process as claimed in claim 1, wherein, after the completion of the reaction, the manganese-IV oxide formed is reduced at a pH of 0 to 6.5 in the reaction mixture to give a water-soluble manganese-II compound.
Claim 10
Dependent Claim
38 words
The process as claimed in claim 1, wherein the reducing agent used for the manganese-IV oxide is sulfur dioxide, which is added in the form of gas to the reaction mixture or is formed in the reaction mixture.
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) | 1991-06-14 | 1991-12-14 | 1992-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-14 | 1995-12-14 | 1996-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-14 | 1999-12-14 | 2000-06-14 | $7700.00 | Window Closed / Lapsed |