Organic compounds -- part of the class 532-570 series – Organic compounds – Halogen containing
Reexamination Certificate
1998-07-31
2002-02-26
Davis, Brian J. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Halogen containing
C570S126000, C570S127000, C570S128000, C570S129000, C570S138000, C570S144000
Reexamination Certificate
active
06350925
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a process that comprises reacting CFX
2
CFXI, wherein each X is independently F or Cl, provided that at least one X is Cl and at least one X is F, with an aromatic compound Ar to form (CFX
2
CFX)
n
—Ar, wherein n is 1, 2 or 3. This product may then be dechlorohalogenated to form (CFX=CF)
n
—Ar.
BACKGROUND OF THE INVENTION
Polymers of various &agr;,&bgr;,&bgr;-trifluorostyrenes are used to fabricate ion-exchange membranes and solid polymer electrolytes for use in electrochemical applications such as fuel cells. Polymers containing monomer units based on &agr;,&bgr;,&bgr;-trifluorostyrene sulfonic acid (I) are typically used. Polymers containing monomer units based on other &agr;,&bgr;,&bgr;-trifluorostyrene derivatives are also used. See U.S. Pat. Nos. 4,012,303, 4,107,005 (division) and 4,113,922 (division); and U.S. Pat. No. 5,422,411, 5,498,639 (continuation), U.S. Pat. No. 5,602,185 (CIP), U.S. Pat. No. 5,684,192 (division of CIP) and U.S. Pat. No. 5,773,480 (CIP).
Hodgdon,
Polyelectrolytes Prepared from Perfluoroalkylaryl Macromolecules,
J. Polymer Sci., 6:171-191 (1968) (“Hodgdon”) discloses a many-step synthesis of &agr;,&bgr;,&bgr;-trifluorostyrene starting from trifluoroacetophenone and Grignard reagent phenyl magnesium bromide, followed by polymerization of the monomer and partial sulfonation of the resulting poly-&agr;,&bgr;,&bgr;-trifluorostyrene. U.S. Pat. Nos. 5,602,185 and 5,684,192 (division) disclose a many-step synthesis of p-sulfonyl fluoride-&agr;,&bgr;,&bgr;-trifluorostyrene via p-iodobenzenesulfonylfluoride. U.S. Pat. No. 3,449,449 discloses a synthesis of &agr;,&bgr;,&bgr;-trifluorostyrene from phenyl sodium and tetrafluoroethylene. U.S. Pat. No. 3,489,807 discloses pyrolytic reaction of phenyl chlorofluoromethane and chlorodifluoromethane at very high temperature which results in mixtures of perfluoroethylene, &agr;,&bgr;,&bgr;-trifluorostyrene and difluorostilbene. Cohen et al., &agr;,&bgr;,&bgr;-
Trifluorostyrene and
&agr;-
Chloro
-&bgr;,&bgr;-
Difluorostyrene,
J.Am.Chem.Soc., 71(10):3439-3440 (1949) (“Cohen”) discloses a synthesis of &agr;,&bgr;,&bgr;-trifluorostyrene which begins with a Friedel-Crafts reaction of trifluoroacetyl chloride with benzene in the presence of aluminum chloride.
Addition of perfluoroalkyl groups to aromatic compounds has been demonstrated. Tiers,
Perfluoroalkylation of Aromatic Compounds,
J.Am.Chem.Soc. 82:5513 (1960); U.S. Pat. No. 3,281,426; U.S. Pat. No. 3,271,441; Kamigata et al,
Direct Perfluoroalkylation of Aromatic and Heteroaromatic Compounds,
J. Chem Soc. Perkin Trans. 1:1339-1346 (1994). Addition of C4 or larger dichloroperfluoroalkyl groups to aromatic compounds and subsequent dechlorination to olefins has been demonstrated. Knunyants and Shokina, &ohgr;-
Phenylperfluoro
-&agr;-
Olefins and
&ohgr;-
Phenylperfluoroalkanoic Acids,
J.Acad.Sci.SSSR, Chem.Ser., pp. 68-71 (January, 1967).
SUMMARY OF THE INVENTION
Briefly, the present invention provides a process of reacting CFX
2
CFXI, wherein each X is independently F or Cl, provided that at least one X is Cl and at least one X is F, with an aromatic compound Ar to form (CFX
2
CFX)
n
—Ar, wherein n is 1, 2 or 3. This product may then be dechlorohalogenated to form (CFX═CF)
n
—Ar. The resulting &agr;,&bgr;,&bgr;-difluoro-&bgr;-halo-ethenyl aromatic compounds, which are preferably &agr;,&bgr;,&bgr;-trifluoroethenyl aromatic compounds, may be polymerized or copolymerized and may be derivatized, e.g. by sulfonation, before dechlorohalogenation or after polymerization.
In another aspect, the present invention provides a reaction intermediate (CFCl
2
CF
2
)
n
—Ar, wherein X is F or Cl, n is 1, 2 or 3 and Ar is unsubstituted benzene.
In another aspect, the present invention provides a reaction intermediate (CFX
2
CFX)
n
—Ar, wherein each X is independently F or Cl, provided that at least one X of each (CFX
2
CFX) group is Cl and at least one X of each (CFX
2
CFX) group is F, wherein n is 1, 2 or 3 and wherein Ar is selected from the group consisting of monosubstituted benzene, disubstituted benzene and polysubstituted benzene bearing three or more substituents.
What has not been described in the art, and is provided by the present invention, is a relatively simple, inexpensive and effective synthetic route to &agr;,&bgr;-difluoro-&bgr;-halo-ethenyl aromatic compounds such as &agr;,&bgr;,&bgr;-trifluorostyrene and derivatives thereof. Furthermore, such a synthetic route involving addition to an aromatic compound bearing electronegative substituents has not been described.
In this application “dechlorohalogenation” refers to removal of a chlorine atom and another halogen atom, which may be chlorine or fluorine, from a molecule, e.g., removal of Cl and F from CF
2
ClCF
2
—Ar to form CF
2
═CF—Ar or removal of Cl and Cl from CF
2
ClCFCl—Ar to form CF
2
═CF—Ar;
“substituted” means substituted by conventional substituents which do not interfere with the desired product, e.g., substituents can be alkyl, alkoxy, aryl, phenyl, halo (F, Cl, Br, I), cyano, nitro, etc; and
“carbonyl-attached”, “sulfonyl-attached” and “phosphonyl-attached” refers to substituents that are attached to the substituted molecule at a carbonyl, sulfonyl or phosphonyl group (respectively) of the substituent.
As used herein, Ar represents an aromatic compound as specified or, where appropriate, a monovalent, divalent or trivalent moiety derived therefrom by removal of one, two or three hydrogens.
It is an advantage of the present invention to provide a relatively simple, inexpensive and low temperature synthetic route to &agr;,&bgr;-difluoro-&bgr;-halo-ethenyl aromatic compounds, including those bearing electronegative substituents and those used to fabricate ion exchange membranes or solid polymer electrolytes for use in electrochemical applications such as fuel cells.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention provides a process of reacting CFX
2
CFXI, wherein each X is independently F or Cl, provided that at least one X is Cl and at least one X is F, with an aromatic compound Ar to form (CFX
2
CFX)
n
—Ar, wherein n is 1, 2 or 3. This product may then be dechlorohalogenated to form (CFX═CF)
n
—Ar. The resulting &agr;,&bgr;-difluoro-&bgr;-halo-ethenyl aromatic compounds, which are preferably &agr;,&bgr;,&bgr;-trifluoroethenyl aromatic compounds, may be polymerized or copolymerized and may be derivatized, e.g. by sulfonation, before dechlorhalogenation or after polymerization.
The aromatic starting compound may be any aromatic compound which will react in the present process. Such aromatic compounds must have at least one hydrogen bound to an aromatic carbon. Preferably, the aromatic compound is based on benzene, naphthalene, thiophene, phenanthrene or biphenyl. Most preferably the aromatic compound is based on benzene. The aromatic starting compound may be unsubstituted, monosubstituted, disubstituted or polysubstituted with three or more substituents. Preferred substituents include halogens, such as fluorine, mono- or polyhalogenated alkyl groups, which preferably contain 1-8 carbons and more preferably 1-3 carbons and are preferably perfluoroalkyl groups, aryl groups, halogenated oxa-alkyl groups, aryl ether groups, carbonyl-attached groups, such as fluorocarbonyl and keto aryl groups, sulfonyl-attached groups, such as fluorosulfonyl, aryl sulfones and aryl sulfonate esters, and phosphonyl-attached groups, such as difluorophosphonyl groups. Most-preferred substituents include phenyl, fluoro, perfluoroalkyl, in particular trifluoromethyl, and fluorosulfonyl (—SO
2
F). The aromatic starting compound may be made by any known process.
The use of aromatic starting compounds that are disubstituted, or polysubstituted with three or more substituents, may lead to syntheses of monomers, polymers and copolymers which were previously difficult or impossible to obtain. These include monomers, polymers and copolymers containing moieties such as 3,5-bis-(fluorosulfonyl)phenyl, 3,5-bis-(trifluoromethyl)phenyl, or 3
3M Innovative Properties Company
Dahl Philip Y
Davis Brian J.
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