Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1998-09-08
2000-11-21
Richter, Johann
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
570134, 570137, 570172, C07C 4311, C07C 1908
Patent
active
06150565&
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to diiodofluorinated compounds and their production, and more particularly to using CF.sub.2 I.sub.2 and olefinic compounds as reactants for producing diiodofluorinated compounds.
BACKGROUND
Diiodoperfluoroalkanes are useful as chain transfer reagents for fluoroelastomers and in the free radical polymerization of fluorinated vinyl monomers. See U.S. Pat. Nos. 4,243,770 and 4,361,678. The reaction of CF.sub.2 I.sub.2 with olefins allows the stepwise addition to the chain, thereby providing controlled chain growth. The production of these diiodoperfluoroalkanes at relatively high yields has been hampered in the past by the lack of a method by which to produce relatively high yield and purity CF.sub.2 I.sub.2. However, as described in commonly held U.S. patent application Ser. No. 60/012,160, filed Feb. 23, 1996, a priority document listed for PCT International Publication No. WO 97/30957, CF.sub.2 I.sub.2 can be produced in sufficiently high yields to facilitate the reactions described below.
Commonly held U.S. Pat. No. 5,504,248 describes the production of diiodofluoroalkanes by reacting I.sub.2 with hexafluorocyclopropane. This process involves a relatively complex ring-opening reaction, and uses relatively expensive starting materials.
Elsheimer, et al., J. Org. Chem. 1984, 49, pp. 205-207, discloses reactions of CF.sub.2 1.sub.2 with hydrocarbon olefins to produce iododifluoroalkenes viaphotolysis, or diiododifluoroalkanes via reactions catalyzed by peroxide at temperatures less than 100.degree. C. The use of peroxides to form the diiododifluoroalkanes could result in the production of other reaction products, which would have to be separated from the desired products, thus adding an additional step, as well as the associated costs involved with such purification.
Many citations are found throughout the literature describing diiodofluorinated compounds, but interest continues in developing new, efficient processes for producing selected diiodofluorinated compounds.
SUMMARY OF THE INVENTION
A process is provided for making diiodofluorinated compounds of the formula ICF.sub.2 (A).sub.n I wherein n is an integer of at least 1 and each A is CXYCQZ wherein each X, Y, Q, and Z are each independently selected from the group consisting of H, F, Cl, R.sub.F and OR.sub.F, and R.sub.F is a perfluoroalkyl group containing 1 to 20 carbon atoms or a perfluorinated polyether group containing from 2 to 20 carbon atoms wherein one or more of the fluorines of said perfluoroalkyl or perfluorinated polyether group is optionally replaced by a substituent selected from the group consisting of chlorine, bromine, iodine, hydrogen, sulfonyl fluoride, nitrile, ester, acyl chloride and acyl fluoride. The process comprises reacting an olefin of the formula CXY=CQZ with CF.sub.2 I.sub.2 at a temperature in the range of from about 120.degree. C. to 240.degree. C.
Diiodofluorinated compounds of the formula ICF.sub.2 CH.sub.2 CHR.sub.F I, where RF is as indicated above, are also provided in accordance with this invention.
DETAILED DESCRIPTION
This invention provides a process by which CF.sub.2 I.sub.2 is reacted with olefins to produce diiodofluorinated compounds, generally described in Equation (I) below: independently H, F, Cl, R.sub.F or OR.sub.F, and preferably at least one of X, Y, Q and Z is F. The number of repeat units of A, as represented by n in Equation (I) is 1 or greater and is preferably from 1 to about 5, more preferably from 1 to 3. Of note are embodiments where n is 1; embodiments where n is 2; and embodiments where n is 3.
The process represented by Equation (I) takes place at an elevated temperature. It has been found in accordance with this invention that when conducted at temperatures of about 120.degree. C. or above, the reaction needs no chemical catalyst or initiator to proceed. Indeed, the process of this inveniton is typically conducted in the substantial absence of a catalyst or initiator. By "substantial absence of catalyst or initiator" is meant that t
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Elsheimer et al., Difluorodiiodomethane: its prep . . . free-radical reactions, J. Org. Chem., 49(1), 205-7., 1984. No month provided.
Sloan et al., Free Radical Addition to Olefins., J. Chem. Soc., 15, pp. 1841-1845, Apr., 1975.
Dolbier, Jr. et al., New Zinc Difluorocarbenoid Reagent, J. Org. Chem. , 55, pp. 5420-5422, 1990. No month provided.
Yang et al., Ring-Opening Reactions of Fluorocyclopropanes with Halogens: A General and Useful Route to 1,3-Dihalofluoropropane Derivatives , J. American Chemical Society, pp. 5397-5398, vol. 117, 1995. No month provided.
Elsheimer et al., Difluorodiiodomethane: Its Preparation, Properties, and Free-Radical Reactions , J. Org. Chem., 49, pp. 205-207, 1984. No month provided.
J. Balague et al., Synthesis of fluorinated telomers. Part 1, Telomerization of vinylidene fluoride with perfluoroalkyl iodides, Journal of Fluorine Chemistry, 70, pp. 215-223, 1995. No month provided.
E. I. Du Pont de Nemours and Company
Keys Rosalynd
Richter Johann
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