- Synthesis process for bromine-containing hydrofluoroalkane
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The invention discloses a synthesis process for bromine-containing hydrofluoroalkane CnH2n+2-x-y-zFxClzBry. In the presence of halogen gas, hydrofluoroalkane and Br2 react to prepare corresponding bromine-containing hydrofluoroalkane. The method provided by the invention is simple in process, high in yield and low in energy consumption, and is suitable for industrial production.
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Paragraph 0026-0028
(2017/05/12)
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- CONVERSION OF FLUOROCARBONS
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A process is disclosed for the conversion of fluorocarbons into fluorinated unsaturated compounds useful as monomers or other chemical precursors, such as C2H2F2. The process comprises reacting a hydrocarbon feed (20) and a fluorocarbon feed (10) in a high temperature reactor (26), at sufficiently high temperature and sufficiently short resident time to form a reaction product mixture (28) having the fluorinated unsaturated compound as the major reaction product, and cooling (18) to a temperature sufficiently low to inhibit polymerisation of the unsaturated compound. The reaction product may then be processed by removal of higher molecular weight compounds (35) and acids (32) and optionally separated (44) into product components.
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Page column 7-10
(2008/06/13)
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- Environmentally Benign Processes for Making Useful Fluorocarbons: Nickel- or Copper(I) Iodide-Catalyzed Reaction of Highly Fluorinated Epoxides with Halogens in the Absence of Solvent and Thermal Addition of CF2I 2 to Olefins
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Highly fluorinated epoxides react with halogens in the presence of nickel powder or CuI at elevated temperatures to provide a useful and general synthesis of dihalodifluoromethanes (CF2X2) and fluoroacyl fluorides (RFCOF) in the absence of solvent. At 185 °C, hexafluoropropylene oxide and halogens produce CF2X 2 (X = I, Br) in 68-90% isolated yields, along with small amounts of X(CF2)nX, (n = 2, 3). With interhalogens I-X (X = Cl, Br), a mixture of CF2I2, CF2XI, and CF 2X2 was obtained. The fluorinated epoxides substituted with perfluorophenyl, fluorosulfonyl, and chlorofluoroalkyl groups also react cleanly with iodine to give CF2I2 and the corresponding fluorinated acyl fluorides in good yields. The reaction probably involves an oxidative addition of fluorinated epoxides into metal surfaces to form an oxametallacycle, followed by rapid decomposition to difluorocarbene-metal surfaces, which alters the reactivity of the difluorocarbene carbon from electrophilic to nucleophilic. The increase of nucleophilicity of difluorocarbene facilitates the reaction with electrophilic halogens. CF 2I2 reacted with olefins thermally to give 1,3-diiodofluoropropane derivatives. Both fluorinated and nonfluorinated alkenes gave good yields of the adducts. Reaction with ethylene, propylene, perfluoroalkylethylene, vinylidene fluoride, and trifluoroethylene provided the corresponding adducts in 58-86% yields. With tetrafluoroethylene, a 1:1 adduct was predominantly formed along with small amounts of higher homologues. In contrast to perfluoroalkyl iodides, CF2I2 also readily adds to perfluorovinyl ethers to give 1,3-diiodoperfluoro ethers.
- Yang, Zhen-Yu
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p. 2394 - 2403
(2007/10/03)
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- Kinetics and Mechanism of the Gas-phase Thermal Bromination of Difluorochloromethane
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We have studied the kinetics of the gas-phase thermal bromination of difluorochloromethane in the dynamic regime at 613-693 K.The form of the kinetic equation has been established for conversions of the difluorochloromethane not greater than 20percent.The absolute value of the rate constant of the bromination reaction has been determined.The energy of the C-H bond in difluorochloromethane has been calculated.
- Zhdanov, G. F.,Poluektov, V. A.,Belevtsev, E. G.,Orlov, G. D.
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- Infrared Multiphoton Dissociation of Heptafluoropropane
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The dissociation yield and branching ratio in CO2-laser-induced multiphoton dissociation (MPD) of CF3CF2CHF2 were studied as a function of irradiation frequency (979.7, 1037.4, and 1081.1 cm-1) and laser fluence (focal fluence 2).Br2 was successfully employed to reveal the dissociation mechanisms by scavenging a number of primary and secondary dissociation fragments produced in the MPD.At low laser fluences the distributions of scavenged products were the same regardless of irradiation frequencies.The primary dissociation of CF3CF2CHF2 was found to proceed mainly via the higher activation energy channels (i.e., C-C ruptures: CF3CF2CHF2 -> C2F5 + CHF2, and CF3CF2CHF2 -> CF3 + C2HF4) rather than via HF elimination (CF3CF2CHF2 -> C3F6 + HF) in our experimental conditions.The observed branching ratio between the two C-C rupture channels (ca. 2:1) agreed with the results obtained by RRKM calculation.A remarkable difference in product distribution with respect to the irradiation frequency was observed at higher laser fluences.This indicates that the secondary photolysis of primarily produced radicals within the laser pulse occured significantly at higher fluences (i.e., C2F5 -> CF3 + CF2, CHF2 -> CF2 + H, CF3 -> CF2 + F, and C2HF4 -> CF2 + CHF2), depending strongly upon the irradiation frequencies.
- Kato, Shuji,Makide, Yoshihiro,Tominaga, Takeshi,Takeuchi, Kazuo
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p. 4278 - 4284
(2007/10/02)
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- Infrared Multiphoton Dissociation of Pentafluoroethane: Two-Channel Dissociation Process and Secondary Photolysis of Radical Products
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The dissociation yield and branching ratio in CO2 laser-induced multiphoton dissociation (MPD) of C2HF5 were investigated.In order to distinguish the two primary dissociation pathways (C2HF5 -> C2F4 + HF, Ea=71.6 kcal/mol; C2HF5 -> CF3 + CHF2, Ea=93.5 kcal/mol), Br2 was employed as an excellent scavenger of radicals and C2F4.The scavenged products were CBrF3, CHBrF2, CBr2F2, and C2Br2F4.The yield of C2Br2F4 originating from HF elimination was much smaller than those of CBrF3 and CHBrF2 from C-C bond rupture.The pulse energy dependence of the product distribution demonstrates that the primarily produced radicals were further photolyzed within the laser pulse (CF3 + nhν -> CF2 + F, and CHF2 + n'hν -> CF2 + H) to yield CBr2F2.The secondary photolysis of the radicals was also confirmed by real-time monitoring of infrared emission from HF* and DF* generated in the MPD of C2DF5 in the presence of H2 as an F atom scavenger.In the MPD of neat C2HF5, the formation of C2F4 was unexpectedly enhanced with increasing pulse energy; this was explained by assuming that C2F4 was mainly formed via recombination of CF2 radicals originating from the secondary photolysis of primarily produced radicals.
- Kato, Shuji,Makide, Yoshihiro,Takeuchi, Kazuo,Tominaga, Takeshi
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p. 3977 - 3981
(2007/10/02)
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- PREPARATION OF HALO-F-METHANES VIA POTASSIUM FLUORIDE-HALOGEN CLEAVAGE OF HALO-F-METHYLPHOSPHONIUM SALTS
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Treatment of halo-F-methylphosphonium salts with potassium fluoride and halogen (I2, Br2, ICl, IBr) gives modest yields of halo-F-methanes.This method of preparation augments the classical Hunsdiecker approach to these materials.
- Burton, D. J.,Shin-Ya, S.,Kesling, H.S.
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