- Reaction of i-Heptafluoropropyl Radicals with Cyanogen Chloride
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The gas-phase reaction of i-C3F7 radicals with cyanogen chloride has been studied between 70 and 330 deg C, using heptafluoro-2-iodopropane as the free-radical source.The main product, 2-chloroheptafluoropropane, is formed via chlorine-atom abstraction by i-C3F7: i-C3F7 + ClCN -> C3F7Cl + CN (6) for which log106/k1/2/c)/cm3/2mol-1/2s-1/2> = 6.27-14.41/2.303 RT was obtained.At lower temperatures the Arrhenius plot shows curvature.This was interpreted as the occurence of another reaction producing C3F7Cl, wich could be i-C3F7 + ClCN C3F7ClCN (9.-9) C3F7ClCN -> C3F7Cl + CN (10).The results are compared with those for the reaction of other perfluoroalkyl radicals with ClCN.
- Voehringer, Cecilia M. de,Staricco, Eduardo H.
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- Coupling reactions of chlorofluoro and perfluoroalkyl iodides
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Coupling reactions of chlorofluoro- and perfluoroalkyl iodides R f-I with Rf = ClCF2CFCl-(CF2) 3CF2-, ClCF2CFClO(CF2) 3CF2-, ClCF2CFCl-, (CF3) 2CF- , (CF3)2CFCF2CF2- in the presence of a zinc/solvent system give dimers in good yields. Both homodimerizations (one iodide) and heterodimerizations (two different iodides) have been studied. The effect of temperature and solvent is shown. The zinc mediated dechlorination of vicinal chlorine atoms in the dimers afforded terminal alkenes and dienes.
- Wlassics, Ivan,Tortelli, Vito
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scheme or table
p. 1719 - 1728
(2009/06/05)
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- Thermal decomposition of branched-chain perfluoroalkanes
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The pyrolysis of some branched perfluoroalkanes has been studied.Homolytic cleavage of the most hindered carbon-carbon bond occurs, followed by coupling and rearrangement of the radicals so formed.This mechanism accounts for all the reaction products.Some kinetic and thermodynamic data are presented.
- Tortelli, V.,Tonelli, C.,Corvaja, C.
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p. 165 - 174
(2007/10/02)
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- 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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- THERMOLYSIS AND UV-PHOTOLYSIS OF PERFLUORINATED IODO-ALKANES AND IODO-OXAALKANES: THERE IS A PREFERRED REACTION CHANNEL
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The thermal stability of perfluorinated iodides depends on their structure and decreases in the order of RFCF2CF2I>RFCF2CF(CF3)I>RFOCF(CF3)I=RFCF2C(CF3)2I.The major decomposition path consists of the elimination of an unsaturated compound (CF2=CF2, CF2=CF-CF3, O=CF-CF3, CF2=C(CF3)2, respectively) with concomitant formation of RFI.The highest selectivities were found for tertiary iodides and 2-iodo-3-oxaalkanes, whose decomposition is virtually irreversible.UV-photolysis of the iodo-compounds gave the same products as the thermolysis reactions.
- Probst, Anton,Werner, Konrad von
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p. 163 - 173
(2007/10/02)
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- Photoinduced Fluorination of Hexafluoropropene Trimers: Synthesis of Branched Perfluoroalkanes
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Hexafluoropropene trimers, perfluoro-3-ethyl-2,4-dimethylpent-2-ene (1) and perfluoro-3-isopropyl-4-methylpent-2-ene (2) reacted with fluorine under u.v. irradiation to give the new and highly branched perfluoroalkanes perfluoro-2,3,3,4-tetramethylpentane (7) and perfluoro-2,3,4-trimethylpentane (8) through a mechanism involving the elimination-readdition of CF3 groups.Compound (7), which is very bulky, can be easily cleaved at 200 deg C to give two perfluoro radicals capable of initiating the polymerization of vinylic monomers.
- Tonelli, Claudio,Tortelli, Vito
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- Inorganic chemistry of fluorocarbenes. 1. Reactions of tetrafluoroethylidene with fluorine-containing phosphines
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The interactions of tetrafluoroethylidene with three fluorine-containing phosphines have been investigated. The source of the carbene is the pyrolytic decomposition of C2F5SiF3 at 200°C. The reaction of CF3CF with PF3 generates CF2=CFPF4 and PF5; reaction with (CF3)3P leads to (CF3)2PCF(CF3)2; and reaction with (CF3)2PCF(CF3)2 produces the fluorocarbon (CF3)2CFCF(CF3)2. The possibility that the vinylphosphorane product of the PF3 reaction results from fluorine-transfer rearrangement of C2F5PF2 as an intermediate product was discredited by a demonstration that C2F5PF2 is thermally stable under the reaction conditions. Other mechanistic pathways are discussed.
- Sharp, Kenneth G.,Schwager, Irving
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p. 1697 - 1701
(2007/10/13)
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