- LASER-INDUCED DECOMPOSITION OF HEPTAFLUORO-2-IODOPROPANE
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CO2 laser-induced homogeneous decomposition of i-C3F7I yields a variety of perfluorinated compounds, which are suggested to be formed by recombinations of carbenes and radicals generated upon the cleavage of the C-1 bond and the fragmentation of the i-C3F7 radical.The decomposition of i-C3F7I in the presence of ethene leads mainly to the formation of (i-C3F7CH2)2 and i-C3F7(CH2)2I.
- Pola, Josef,Horak, Milan
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p. 121 - 124
(2007/10/02)
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- Skeletal Rearrangements during the Fluorination of C6-Hydrocarbons over Cobalt(III) Trifluoride
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Perfluorination of hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, methylcyclopentane and cyclohexane over cobalt(III) trifluoride gave, in each case except perhaps cyclohexane, a mixture of linear, branched and cyclic C6-fluorocarbons: the degree of skeletal rearrangement (excluding cyclohexane) varied from ca. 7percent (methylcyclopentane) to 96percent (2,2-dimethylbutane).A carbocation mechanism, which does not proceed to equilibrium, is suggested.
- Burdon, James,Creasey, Jeremy C.,Proctor, Lee D.,Plevey, Raymond G.,Yeoman, J.R. Neil
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p. 445 - 447
(2007/10/02)
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- Synthesis of Functional Perfluorinated Resins, Branched Perfluorinated Ethers and Perfluoroalkanoyl Fluorides
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Functional-group-containing perfluorinated resins have been prepared by carefully controlled direct fluorination of poly-(3-methyloxetane-3-methanol).Branched perfluorinated ethers such as bis(perfluoroneopentyl) ether and perfluoro-(2,2-dimethylbutyl methyl ether) have also been synthesized by direct fluorination of alkanols.The by-products, perfluoroalkanoyl fluorides, are useful intermediates.
- Huang, Hsu-Nan,Lagow, Richard J.
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p. 871 - 875
(2007/10/02)
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- THE FLUORINATION OF BUTANE OVER COBALT TRIFLUORIDE
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The fluorination of butane over cobalt trifluoride has given a complex mixture of partially fluorinated compounds: 51 of these have been identified, comprising over 99percent of the products.Most were polyfluor-butanes but 1-2percent were polyfluoro-2-methylpropanes.The reaction has no synthetic utility.There was some selectivity in the fluorination: secondary C-H was convertart byed into C-F more easily then primary, and the ease of replacement of a particular H was reduced by geminal vicinal fluorines.A computer model of the fluorination was only partially successful, perhaps because the fluorination proceeded in part by simple F for H replacement and in part via alkenes: the model only allowed for the former.
- Burdon, James,Ezmirly, Saleh T.,Huckerby, Thomas N.
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p. 283 - 318
(2007/10/02)
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- Synthesis of Unusual Perfluorocarbon Ethers and Amines Containing Bulky Fluorocarbon Groups: New Biomedical Materials
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The reactions of elemental fluorine with structually crowded hydrocarbon ethers and amines have been studied.The perfluorinated products are currently of interest in biomedical or electronic industrial applications.The syntheses by direct fluorination of perfluoro(tert-butyl methyl ether), perfluoro(tert-butyl isobutyl ether), perfluoro(1,2-di-tert-butoxyethane), perfluoro(cyclohexyl neopentyl ether), perfluoro(2,2,5,5-tetramethyltetrahydrofuran), perfluoro(2,5-dimethyltetrahydrofuran), bis(perfluoroisopropyl) ether, perfluoro(2-ethyltetrahydrofuran), and perfluoro(1,2,2,6,6-pentamethylpiperidine) are reported.The skeletally rearranged byproducts perfluoro(isobutyl methyl ether), perfluoro(2,2,5-trimethyltetrahydrofuran), perfluoro(2,2,5-trimethyltetrahydropyran), 3-hydropentadecafluoro-2,2,5,5-tetramethyltetrahydrofuran, perfluoro(isopropyl propylether), and perfluoro(ethyl isopropyl ether) were also characterized.The 19F and 13C (19F decoupled) NMR assignments of these perfluorinated chemicals are discussed.
- Huang, Hsu-Nan,Persico, Daniel F.,Lagow, Richard J.,Clark, Leland C.
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- Aerosol Direct Fluorination: Alkyl Halides. 2. Chlorine Shift and the Stability of Radicals
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Unlike alkyl bromides and iodides, alkyl chlorides are shown to be stable to direct fluorination, even under ultraviolett irradiation, at temperatures of 30 deg C and below.Although less reactive than the bromides and iodides, F-alkyl chlorides may be derivatized, presenting another example of direct fluorination-survivable functionality.High (63 percent) to moderate (32 percent) isolated yields of the analogous perfluororalkyl chlorides can be synthesized by aerosol direct fluorination of 1-chloropropane, 1-chlorobutane, 1-chloro-2-methylpropane, 1-chloro-3-methylbutane, 1-chlo-ro-2-methylbutane, and chlorocyclopentane with generally less than 20 percent C-C bond cleavage.Tertiary alkyl chlorides generally undergo intramolecular 1,2-chloride shift in the earliest stages of reaction in a manner characteristic of β-chloro radicals forming principally primary F-alkyl chlorides.Thus 2-chloro-2-methylpropane produces 1-chloro-F-2-methylpropane (47 percent), and 2-chloro-2-methylbutane produces a 16:6.3:1 ratio of 1-chloro-F-2-methylbutane, 1-chloro-F-3-methylbutane, and 2-chloro-F-3-methylbutane, respectively, in 32 percent combined yield.Secondary alkyl chlorides undergo a similar but incomplete rearrangement producing mixtures of primary and secondary F-alkyl chlorides.Thus 2-chloropropane produces a 2:1 mixture of 2-chloro-F-propane and 1-chloro-F-propane in 50 percent combined yield; 2-chlorobutane produces a 1:1.5 mixture of 2-chloro-F-butane and 1-chloro-F-butane in 34 percent combined yield, and 3-chloropentane produces a 2:3:1 mixture of 3-chloro-F-pentane, 2-chloro-F-pentane, and 1-chloro-F-pentane, respectively, in a combined yield of 30 percent.Because secondary alkyl chlorides partially rearrange but primary alkyl chlorides donot rearrange at all on fluorination, doubt is cast on the postulate that the intermediate radicals are equilibrating.
- Adcock, James L.,Evans, William D.
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p. 2719 - 2723
(2007/10/02)
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- Aerosol Direct Fluorination Syntheses: Alkyl Halides, Neopentyl Chloride and Bromide, Free Radicals vs. Carbocations
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Aerosol direct fluorination of neopentyl chloride produces perfluoroneopentyl chloride in 74percent yields.Analogous fluorination of neopentyl bromide produces perfluoroisopentane in 63percent yield.Data are presented that support a carbocation rearrangement in the fluorination of neopentyl bromide.The carbocations are presumed to arise from disproportionation of neopentylbromine fluorides.
- Adcock, James L.,Evans, William D.,Heller-Grossman, Lilly
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p. 4953 - 4957
(2007/10/02)
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