- PROCESS FOR PREPARING OCTAFLUOROCYCLOHEXADIENE
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Disclosed herein is a process of preparing octafluorocyclohexadiene using hexafluorobenzene as a raw material. The hexafluorobenzene reacts with an activated fluorinating agent at 60-200° C. in an inert gas atmosphere. The activated fluorinating agent is prepared by mixing 1-10 wt % of cobalt difluoride with 90-99 wt % of other metal fluoride selected from the group of calcium fluoride, magnesium fluoride, aluminum fluoride, sodium fluoride and potassium fluoride. The mixture reacts with fluorine gas at 200-400° C.
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Page/Page column 3
(2010/06/11)
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- The Perfluoro-1,3,5-hexatrienes
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trans-Perfluoro-1,3,5-hexatriene was obtained by catalytic isomerization of the cis isomer, and their configurations were confirmed by a photochemical method.Equilibration of these isomers with iodine and light at 13 deg C revealed that the cis isomer is slightly more stable than the trans (Kc-t = 0.83).The trienes undergo reactions under the influence of heat and light which contrast with those of their hydrocarbon counterparts.Cis triene cyclizes reversibly to perfluoro-3-vinylcyclobutene at 160 deg C (Keq = 12.2), and at higher temperatures perfluoro-1,3-cyclohexadiene is formed irreversibly.Cyclization of trans triene to the vinylcyclobutene is much slower than that of the cis isomer, as required by the finding that thermal ring opening of the vinylcyclobutene gives cis triene cleanly.Ultraviolet irradiation of the trienes with and without mercury sensitization yields the same two cyclization products, but the cyclohexadiene undergoes a further rapid photocyclization to give perfluorobicyclohex-2-ene, as reported recently by Dedek's group.Mercury photosensitization of the vinylcyclobutene proceeds smoothly to yield this same bicyclic olefin.
- Jing, Naiyong,Lemal, David M.
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p. 1844 - 1848
(2007/10/02)
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- Thermal and UV-induced isomerisation of fluorinated hexatrienes
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Irradiation of octafluoro-1,3,5-hexatriene (I) in the gas phase with a high-pressure mercury lamp gave a mixture of octafluoro-2-vinyl-cyclobutene (III) and octafluorobicyclohex-2-ene (V).The analogous photolysis of hexatriene I in the liquid phase led to an equilibrium mixture of the starting compound I (cis-isomer) and the trans-isomer II, respectively.Photolysis of 2,3,4,5-tetrafluro-1,3,5-hexatriene (VI) gave a mixture of cis- and trans-isomers, both in the vapour and liquid phases.Thermal reaction of hexatriene I gave octafluoro-1,3-cyclohexadiene (IV) as the sole product.
- Hrabal, R.,Chvatal, Z.,Dedek, V.
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p. 185 - 192
(2007/10/02)
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- FLUOROCYCLOHEXANES PART XV. DEHYDROFLUORINATIONS OF UNDECA- DECA- AND NONA- FLUOROCYCLOHEXANES
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An experimental modification has improved dehydrofluorinations of undeca- deca- and nona- fluorocyclohexanes, and enhanced the proportions of dienes and aromatics formed.
- Coe, Paul L.,Mott, Andrew W.,Tatlow, John Colin
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p. 167 - 172
(2007/10/02)
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- THE THERMAL ISOMERIZATION OF HEPTAFLUOROCYCLOHEXADIENES
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The evidence for the involvement of sigmatropic fluorine migrations in the isomerizations of fluorinated polyenes is reviewed and the difficulties inherent in providing satisfactory rationalizations are discussed.The thermal isomerizations of heptafluorocyclohexadienes under various reaction conditions are described.It is established that such isomerizations occur by a mechanism which does not involve catalysis by fluoride ion, however the exact mechanistic pathway remains uncertain.
- Feast, W. J.,Morland, J. B.
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- THE SIGMATROPIC MIGRATION OF FLUORINE
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Pyrolysis of polyfluorocyclohexadienes at 475-480 deg C over new quartz or Pyrex glass gave products derived from 1,5-sigmatropic migrations of fluorine; 1,3-migrations occurred to only a small degree.As the quartz or glass aged, other processes - 1,3-migrations and defluorinations to aromatics - began to occur; these appear to be due in some way to fluoride ion, since pyrolysis over sodium fluoride gave similar products.
- Burdon, J.,Childs, A.,Parsons, I. W.,Rimmington, T. W.
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- Conversion of conjugated diolefins to diacyloxy olefins
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A catalyst comprising a uranium compound, an alkali metal ion, and a halide, is effective to convert conjugated dienes in carboxylic acid media to diacyloxy olefins.
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