- A study of the gas phase reactions of various cations with two derivatives of SF6; SF5CF3 and SF5Cl
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A selected ion flow tube apparatus was used to investigate the positive ion chemistry of two derivatives of SF6; SF5CF3 and SF5Cl. This represents the first investigation of the positive ion chemistry of SF5Cl, and much of the data on SF5CF3 is being presented here for the first time. Rate coefficients and ion product branching ratios have been determined at room temperature (300 K) for reactions with the following twenty-two cations; Ne+, F+, Ar+, N2+, N+, CO+, CO2+, O+, N2O+, H2O+, O2+, SF4+, CF2+, SF+, SF2+, NO2+, SF5+, NO+, CF+, CF3+, SF3+, and H3O+ (listed in order of decreasing recombination energy). Comparisons are made in the text for the reactions of these ions with SF6. SF2+, NO2+, NO+, SF3+, and H3O+ are found to be unreactive with both of the derivatives. The majority of the other reactions proceed with rate coefficients which are close to the capture value. The exceptions are the reactions of O2+, SF+, SF5+, and CF3+ with SF5CF3, and SF4+ and SF5+ with SF5Cl, all of which have rate coefficients significantly less than the capture mechanism value. Several distinct processes are observed among the large number of reactions studied, including dissociative charge transfer and various abstraction channels. Non-dissociative charge transfer is not observed, implying that any parent ions formed dissociate rapidly to the fragment ions and associated neutrals.
- Atterbury, Clair,Critchley, Andrew D.J.,Kennedy, Richard A.,Mayhew, Chris A.,Tuckett, Richard P.
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Read Online
- Ab Initio/IGLO/GIAO-MP2 Studies of Fluorocarbocations: Experimental and Theoretical Investigation of the Cleavage Reaction of Trifluoroacetic Acid in Superacids
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The structures of a number of fluorocarbocations were calculated at the correlated MP2/6-31G* level. 13C and 19F NMR chemical shifts of fluorocarbocations were calculated for the first time using IGLO and GIAO-MP2 methods.The data showed good correlation of calculated 19F and 13C NMR chemical shifts with the experimental shifts of fluorocarbocations.The correlation for GIAO-MP2-calculated 19F NMR chemical shifts with the experimental data is excellent.Using theoretical calculations as guidance, the protolytic cleavage of trifluoroacetic acid (CF3COOH) in superacid forming CF4 was also investigated experimentally and by ab initio calculations.This reaction is suggested to involve the gitonic CF3C(OH)(OH)2+ dication as an intermediate.
- Prakash, G. K. Surya,Rasul, Golam,Burrichter, Arwed,Laali, Kenneth K.,Olah, George A.
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Read Online
- Synthesis of tetrafluoromethane by graphite fluorination with elemental fluorine
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Formation of high-temperature inverse wave of the filtration combustion of graphite fixed bed in fluorine was studied. Scientific principles of the industrial process of the tetrafluoromethane synthesis from graphite and fluorine were developed.
- Pashkevich,Mukhortov,Petrov,Alekseev,Asovich,Barabanov
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Read Online
- Fluorosulfates and perchlorates of xenon(II) and the salt [(FXeO)2S(O)F]+[AsF6]-
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Each of the fluorine ligands of XeF2 may be substituted by highly electronegative species. Interaction of XeF2 with the appropriate molar quantity of anhydrous acid yields FXeOSO2F (colorless, mp 36.6°), Xe(OSO2F)2 (pale yellow, mp 43-15°), FXeOClO3 (colorless, mp 16.5°), Xe(OClO3)2 (a yellow solid, which decomposes below 0°), and FXeOSO2CF3 and FXeOSO2-CH3 (both of which are colorless solids). All of the compounds are thermodynamically unstable and the last three compounds are known to be detonators. Decomposition of the fluorosulfates provides for the synthesis of high-purity S2O6F2. The acids HCl, HOSO2Cl, and HOC(CF3)3 do not yield Xe derivatives and are oxidized. Vibrational spectroscopic evidence indicates that the xenon atom in the Xe(II) compounds is similarly coordinated to Xe in XeF2 and FXeOSO2F. Attempts to prepare [XeOSO2F]+[MF6]- salts (M = Ru, As, Sb) have not been successful but the new cation [(FXeO)2S(O)F]+ has been isolated in the [AsF6]- salt. Efforts to prepare [(FXe)2L]+ (L- = CF3CO2-, Cl-) resulted in oxidation of L.
- Wechsberg,Bulliner,Sladky,Mews,Bartlett, Neil
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Read Online
- F2 + CF3I Dark Reaction. 1. Stoichiometry and Pressure-Dependent Kinetics
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The reaction between F2 and CF3I has been investigated over a wide range of pressures and flow velocities at 298 K.An induction time precedes a period of CF3I consumption which is well characterized by an exponential decrease in concentration over time.The CF3I disappearance rate as well as the induction time are dependent upon the concentration of the initial species, indicating that a chain reaction is responsible.CF3I and F2 react to give IF5, C2F6, and CF4 as end products (where the principal carbon-containing end product is CF4), suggesting that both IF and CF3 play an important role in the kinetics of the reaction.The apparent discrepancies of the previous studies of this reaction are shown to be related to experimental conditions.
- Johnson, D. E.,Whitehead, J. C.,Walters, E. A.,Dorko, E. A.
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Read Online
- METHOD FOR PRODUCING TETRAFLUOROMETHANE
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Fluorine gas is introduced to a raw material liquid containing a reaction inducer and a fluorinated hydrocarbon represented by CpHqClrFs (in the formula, p is an integer of 3 to 18, q is an integer of 0 to 3, r is an integer of 0 to 9, and s is an integer of 5 to 30) and having no carbon-carbon unsaturated bond to give tetrafluoromethane. The reaction inducer is a halogen-containing carbon compound liquid at room temperature and pressure and is reacted with fluorine gas to induce a reaction of forming tetrafluoromethane from the fluorinated hydrocarbon and the fluorine gas. The reaction inducer is contained at a content of more than 0% by mass and not more than 10% by mass when the total content of the fluorinated hydrocarbon and the reaction inducer contained in the raw material liquid is 100% by mass.
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Paragraph 0059-0064
(2021/03/05)
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- METHOD FOR PRODUCING TETRAFLUOROMETHANE
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Provided is a method for producing tetrafluoromethane, and the method is unlikely to damage a reaction apparatus and can produce tetrafluoromethane safely, inexpensively, and stably. To a raw material liquid (1) containing a reaction inducer and a fluorinated hydrocarbon represented by chemical formula CpHqClrFs (in the chemical formula, p is an integer of 3 or more and 18 or less, q is an integer of 0 or more and 3 or less, r is an integer of 0 or more and 9 or less, and s is an integer of 5 or more and 30 or less) and having no carbon-carbon unsaturated bond, fluorine gas is introduced to give tetrafluoromethane. The reaction inducer is a hydrocarbon polymer solid at normal temperature and pressure and is reacted with fluorine gas to induce a reaction of forming tetrafluoromethane from the fluorinated hydrocarbon and the fluorine gas.
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Paragraph 0062-0071
(2021/11/26)
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- METHOD FOR PRODUCING TETRAFLUOROMETHANE
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A method for producing tetrafluoromethane as follows is unlikely to damage a reaction apparatus and can produce tetrafluoromethane safely, inexpensively, and stably. To a raw material liquid containing a fluorinated hydrocarbon represented by chemical formula CpHqClrFs (wherein p is an integer of 3 to 18, q is an integer of 0 to 3, r is an integer of 0 to 9, and s is an integer of 5 to 30) and having no carbon-carbon unsaturated bond, fluorine gas is introduced, and concurrently a reaction inducer is introduced in a gas state, giving tetrafluoromethane. The reaction inducer is reacted with fluorine gas to induce a reaction of forming tetrafluoromethane from the fluorinated hydrocarbon and the fluorine gas and is at least one reaction inducer selected from a hydrocarbon gaseous at normal temperature and pressure and hydrogen gas.
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Paragraph 0058-0070
(2021/01/19)
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- Decomposition characteristics of C5F10O/air mixture as substitutes for SF6 to reduce global warming
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Sulfur hexafluoride (SF6) is widely used in the power industry but is a serious greenhouse gas. Many researchers committed to achieving sustainable development of the power industry are finding alternatives to SF6 gas. C5F10O performs well in terms of environmental protection, insulation, and safety and is a potential environment-friendly alternative gas. In this paper, the insulation and decomposition characteristics of C5F10O/air gas mixture were examined using gas-insulation performance test platform, and decomposition products were detected by gas chromatography–mass spectrometry. The formation mechanism and distribution of C5F10O decomposition products were analyzed through reactive molecular dynamics method and density functional theory. The influence of air on the decomposition of C5F10O was also evaluated. Results showed that the decomposition of C5F10O/air gas mixture mainly produces CF3[rad], C3F7[rad], C4F7O[rad], CO, CF2[rad], CF[rad], F[rad] and CF4. The breakdown voltage of C5F10O/air gas mixture decreased slightly after repeated breakdown tests, and CF4, C2F6, C3F8, C3F6, C4F10, CF2O were detected. These results can serve as a reference for the systematic comprehension of the decomposition characteristics of C5F10O/air gas mixture and for related engineering applications.
- Li, Yi,Zhang, Xiaoxing,Xiao, Song,Chen, Qi,Wang, Dibo
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- Carbon-Carbon Bond-Forming Reductive Elimination from Isolated Nickel(III) Complexes
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This manuscript describes the design, synthesis, characterization, and reactivity studies of organometallic NiIII complexes of general structure TpNiIII(R)(R1) (Tp = tris(pyrazolyl)borate). With appropriate selection of th
- Bour, James R.,Camasso, Nicole M.,Meucci, Elizabeth A.,Kampf, Jeff W.,Canty, Allan J.,Sanford, Melanie S.
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supporting information
p. 16105 - 16111
(2016/12/22)
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- Preparation of trifluoroiodomethane via vapour-phase catalytic reaction between pentafluoroethane and iodine
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A new route for preparing C33I has been developed via a reaction between C2HF5 and I2. The influence of reaction temperature and active components of the catalysts on the amount of C33I was investigated. The result suggests that the selectivity of the C33I can be controlled by reaction conditions and active component of catalyst. The process for the formation of C33I and by-products is also discussed.
- Mao, Aiqin,Wang, Hua,Tan, Linhua,Nin, Xiangyang,Pan, Renming
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p. 4640 - 4642
(2013/07/19)
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- Evidence for the unimolecular decomposition of CF3OCF 3 to COF2 and CF4 by high energy irradiation
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The decomposition of CF3OCF3 via electron beam irradiation in the gas phase and isolated in an argon matrix at T = 10 K is investigated via infrared spectroscopy. CF3OCF3 produces only COF2 and CF4. In the gas phase irradiation, the G value for CF3OCF3 decomposition is 5.9, and the G values for formation of COF2 and CF4 are 5.0 and 4.9, respectively. In the low temperature matrix isolated irradiation, CF 3OCF3 decomposition and COF2 evolution occur in a 1:1 ratio. The results strongly suggest that a unimolecular mechanism for the formation of COF2 is operative because the product yields in the gas phase and matrix exposures are similar.
- Waltman
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p. 378 - 381
(2014/01/06)
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- Chemical ionization using CF3+: Efficient detection of small alkanes and fluorocarbons
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The trifluoromethyl ion CF3+ is evaluated as a chemical ionization (CI) precursor in a compact Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometer. It reacts with alkanes by hydride abstraction allowing characterization and quantification of alkanes up to C4 and cyclic. With larger alkanes fragmentation occurs. Fluorocarbons react by fluoride abstraction. Rate coefficients have been measured for reaction with alkanes, fluoroalkanes, chlorofluoroalkanes as well as several common VOCs. Use of CF3+ for trace analysis in air has been tested on an air sample containing traces of acetone, toluene, benzene and cyclohexane. The results are consistent with those obtained with H3O+ precursor and allow additional cyclohexane quantification.
- Dehon, Christophe,Lemaire, Jo?l,Heninger, Michel,Chaput, Aurélie,Mestdagh, Hélène
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experimental part
p. 113 - 119
(2011/08/21)
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- CrOx -Y2O3 catalysts for vapor phase fluorination of dichlorodifluoromethane
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A series of CrOx-Y2O3 catalysts has been prepared using a deposition-precipitation method and tested for vapor phase fluorination of dichlorodifluoromethane (CCI2F2) for synthesis of tetrafluoromethane (CF4). A comparative study using CCI2F2 and CCIF3 as the reactants for the fluorination reaction reveals that the conversion of CC12F2 to CC1F3 is very fast, while that of CC1F3 to CF4 is a rate-determining step. Pre-fluorinated CrOx-Y2O3 catalyst calcined at 600 °C (CrYF-6) is found to be the most active for the reaction, (CF4 yield 95%) and is stable during the testing period for the fluorination reaction. The characterization results indicate that the catalytic activity depends on the coordination of active Cr species and Lewis acid sites.
- Jia, Wen-Zhi,Xing, Li-Qiong,Qian, Lin,Chen, Xin,Wang, Yue-Juan,Lu, Ji-Qing,Chen, Ke-Feng,Zhang, Xue-Liang,Luo, Meng-Fei
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body text
p. 1212 - 1216
(2011/01/07)
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- Perfluorocarbon gel formulations
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A perfluorocarbon gel composition is disclosed with numerous uses including topical medical and cosmetic uses.
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- Catalytic pyrolysis of CHF3 over activated carbon and activated carbon supported potassium catalyst
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The catalytic activity of activated carbon (AC) and activated carbon supported potassium for the decomposition of CHF3 was investigated at temperatures between 873 and 1173 K and at a space velocity of 4300 h -1. It is found that activated carbon supported potassium shows high and relatively stable activity during the pyrolysis of CHF3 under the conditions studied. Compared with the gas phase reaction, the conversion of CHF3 increases by up to 10 times between 873 and 1123 K, with the major products being C2F4 and C3F6. Selectivities as high as 55% to C2F4 and 35% to C 3F6 are achieved under optimum conditions. The main byproduct HF readily reacts with K2O in the catalyst, converting the catalyst from K2O/AC into KF/AC. Selectivity to the major products remains relatively constant following this transformation.
- Han, Wenfeng,Kennedy, Eric M.,Liu, Huazhang,Li, Ying,Adesina, Adesoji A.,MacKie, John C.,Dlugogorski, Bogdan Z.
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scheme or table
p. 698 - 703
(2010/09/12)
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- Depolymerization of Fluoropolymers
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A process for depolymerizing fluoropolymers includes continuously feeding a solid fluoropolymer, in particulate form, into a horizontal cylindrical first reaction zone. The fluoropolymer particles enter the first reaction zone at one end. Within the first reaction zone, a central axle from which protrudes at least one paddle, continuously rotates. The rotating paddle serves to advance the fluoropolymer particles along the reaction zone while agitating them. As the fluoropolymer particles pass along the reaction zone, they are subjected to an elevated temperature, thereby depolymerizing the fluoropolymer into a fluoro-containing compound-rich gas phase. A residual solids phase is withdrawn at the other end of the first reaction zone, as is the gas phase. Optionally, the gas phase is passed through a second reaction zone which is also at an elevated temperature. The gas phase is quenched, thereby to recover the fluoro-containing compounds as gaseous products.
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Page/Page column 5-6
(2009/06/27)
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- Investigation of CF2 carbene on the surface of activated charcoal in the synthesis of trifluoroiodomethane via vapor-phase catalytic reaction
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This paper investigates the synthetic mechanism of trifluoroiodomethane (CF3I) in the reaction of trifluoromethane and iodine via vapor-phase catalytic reaction. It is suggested that CF2 carbene is the key intermediate and is formed in the pyrolysis process of CHF3 at high temperature. However, in pyrolysis of CHF3 under activated charcoal (AC) existing conditions, no C2F4 was detected. H2 and 2-methyl-2-butene could not trap the CF2 carbene. When treating the remained compounds on the used AC with H2, CH4 is formed on the process. It is proposed that CF2 carbene combines with AC strongly and transfers into CF3 radical on heat. In addition, it is found that the AC is not only the catalyst supporter to form CF3I, but also a co-catalyst to promote the formation of CF2 carbene and CF3 radical.
- Yang, Guang-Cheng,Lei, Shi,Pan, Ren-Ming,Quan, Heng-Dao
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experimental part
p. 231 - 235
(2009/08/07)
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- Reaction between carbon dioxide and elementary fluorine
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Reactions between carbon dioxide and fluorine were examined at temperatures of 303-523 K under various pressure and mixture ratios of both gases. Reactions were carried out similarly under the existence of NaF, CsF and EuF3. After the reaction, fluorine was removed and the reaction products were analyzed using FT-IR, GC/FT-IR and GC/MS. The major products were CF3OF, COF2, CF4 and CF2(OF)2. The best yield of COF2 was 11.1% under the reaction condition of CO2/F2 = 76 kPa/76 kPa with temperature of 498 K for 72 h in a direct reaction. The formation rate of COF2 in the direct reaction was estimated as 0.232 dm3 mol-1 h-1 under the reaction conditions of CO2/F2 = 76 kPa/76 kPa, at 498 K. In the presence of CsF, it was estimated as 1.88 dm3 mol-1 h-1 at CO2/F2 = 76 kPa/76 kPa at 498 K. The activation energy of the COF2 formation in the direct reaction was estimated as 45.7 kJ mol-1 at CO2/F2 = 76 kPa/76 kPa at 498 K. In addition, 24.2 and 38.9 kJ mol-1 were evaluated at CO2/F2 = 76 kPa/76 kPa at 498 K, respectively, in the presence of CsF and EuF3.
- Hasegawa, Yasuo,Otani, Reiko,Yonezawa, Susumu,Takashima, Masayuki
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- CF3 oxonium salts, O-(trifluoromethyl)dibenzofuranium salts: In situ synthesis, properties, and application as a real CF3+ species reagent
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(Chemical Equation Presented) We report in situ synthesis of the first CF3 oxonium salts, thermally unstable O-(trifluoromethyl)- dibenzofuranium salts, which furthermore have different counteranions (BF 4-, PF6-, SbF6 -, and Sb2F11-) and ring substituents (tert-butyl, F, and OCH3), by photochemical decomposition of the corresponding 2-(trifluoromethoxy)biphenylyl-2′- diazonium salts at -90 to -100°C. The yields markedly increased in the order of BF4- 6- 6- 2F11-. The CF3 oxonium salts were fully assigned by means of 1H and 19F NMR spectroscopy at low temperature. The CF3 salts decomposed to form CF4 and dibenzofurans. The half-life times at -60°C of the 2-tert-butyl salts having different counteranions were 29 min for BF4- salt 2d, 36 min for PF6- salt 2c, 270 min for SbF6- salt 2a, and 415 min for Sb2F11- salt 2b. Those at -60°C of the Sb2F11- salts having different 2-substituents were 13 min for F salt 3b, 63 min for H (unsubstituted) salt 1b, and 415 min for tert-butyl salt 2b. Thus, the stability of the CF3 oxonium salts increased in the order of BF4- 6 - 6- 2F 11- and F 3+ species source to the direct O- and N-trifluoromethylations of alcohols, phenols, amines, anilines, and pyridines under very mild conditions. The thermal decomposition method with a mixture of diazonium salt 17a and aryl- or alkylsulfonic acids, pyridine, or pyridines having an electron-withdrawing group also afforded CF3O or CF 3N products. The trifluoromethylation mechanism is discussed and an SN2 mechanism containing the transient formation of free CF 3+ is proposed. Thus, the present study has demonstrated that the exceedingly reactive CF3+ species can be generated much easier than the CH3+ species, contrary to the common sense that CF3+ is extremely difficult to generate in solution.
- Umemoto, Teruo,Adachi, Kenji,Ishihara, Sumi
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p. 6905 - 6917
(2008/02/11)
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- Perfluoroethanesulfonyl fluoride: Preparation from sultone
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A procedure was developed for preparing perfluoroethanesulfonyl fluoride by synthesis of hexafluoropropane-2-β-sultone from sulfuric anhydride and perfluoropropene, followed by hydrolysis of the sultone to α- tetrafluoroethanesulfonyl fluoride and fluorination of the latter with elemental fluorine.
- Nurgalieva,Bispen,Il'in,Moldavskii,Rozhkova
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p. 1562 - 1565
(2008/03/18)
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- Fluorination reactor
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Fluorination reactions in which an organic compound to be fluorinated is contacted with elemental fluorine and HF is produced as a byproduct are disclosed, wherein the elemental fluorine is contacted with the organic compound in the presence of a fluoride-adsorbing composition so that the amount of HF or another hydrogen-containing byproduct is reduced or eliminated. Reactor embodiments for the fluorination reactions are also disclosed.
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Page/Page column 3
(2008/06/13)
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- POTASSIUM PERFLUOROALKANESULFONATES AND PROCESS FOR PRODUCTION THEREOF
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A process for the production of potassium perfluoroalkane- sulfonates which comprises the electrolytic fluorination step of electrofluorinating an alkanesulfonyl halide in anhydrous hydrofluoric acid to obtain a gas containing a perfluoro- alkanesulfonyl fluoride as the main component. The process may further comprise the gas absorption step of reacting the gas with an aqueous solution of potassium hydroxide to form a solution containing a potassium perfluoroalkanesulfonate, the purification step of removing contaminant potassium fluoride, potassium hydroxide and potassium sulfate from the solution, and the concentration/recovery step of subjecting the purified aqueous solution to concentration and drying. In the electrolytic fluorination, the formation of by-products can be inhibited by keeping the proton concentration of the electrolytic solution within the range of 150 to 1500ppm.
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Page/Page column 17
(2008/06/13)
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- Synthesis of perfluoroalkanes in high-temperature fluorination of graphite with fluorine in a reactor with a free-falling graphite bed
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Reaction between fluorine and graphite in a reactor with a free-falling bed of graphite was studied in relation to the temperature in the reaction zone, ratio of the feeding rates of fluorine and graphite, and dilution of fluorine with an inert gas. Pleiades Publishing, Inc., 2006.
- Shelopin,Pashkevich,Alekseev,Mukhortov,Petrov,Asovich
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p. 1031 - 1034
(2008/02/05)
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- Process for producing carbonyl fluoride
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The process for producing carbonyl fluoride according to the invention is a process for safely and easily producing high-purity carbonyl fluoride having a low content of carbon tetrafluoride, and comprises feeding carbon monoxide and fluorine to a reactor and allowing carbon monoxide to react with fluorine under the conditions of a reactor internal pressure of less than atmospheric pressure.
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Page/Page column 5-6
(2008/06/13)
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- The kinetics of the CF3 + CF3 and CF3 + F combination reactions at 290 K and at He-pressures of ≈ 1-6 Torr
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The rate constants for the combination reactions CF3 + CF 3 and CF3 + F at 290 K and helium pressures of ≈ 1-6 Torr have been determined, using clean chemical sources of CF3, by means of discharge flow-molecular beam sampling-threshold ionisation mass spectrometry (DF/MB-TIMS). For the mutual reaction of CF3, no pressure dependence could be observed over the 1-6 Torr pressure range, indicating that the obtained rate constant of k1∞ = (1.8 ± 0.6) × 10-12 cm3 s-1 is the high pressure limit. This result, which agrees with the lowest values in literature but is ca. five times smaller than the most recent data, is fully in line with the known trend in the mutual reaction rate constant for the series CH3; CH2F; and CHF2. The reaction of CF 3 with F was found to exhibit a clear pressure dependence in the 0.5 to 6 Torr range. Using a Troe fall-off formalism, the low-pressure limit rate constant was determined as k20(He) = (1.47 ± 0.24) × 10-28 cm6 s-1 differing substantially from the only available previous determination; a variational transition state theoretical treatment is shown to support our data. The Owner Societies 2005.
- Dils, Bart,Vertommen, Johan,Carl, Shaun Avondale,Vereecken, Luc,Peeters, Jozef
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p. 1187 - 1193
(2007/10/03)
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- PROCESS FOR PRODUCTION OF 1,1,1,2-TETRAFLUOROETHANE AND/OR PENTAFLUOROETHANE AND APPLICATIONS OF THE SAME
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A process for producing high purity 1,1,1,2-tetrafluoroethane and/or pentafluoroethane by the step of purifying a crude product obtained by reacting trichloroethylene and/or tetrachloroethylene with hydrogen fluoride comprised of a main product including 1,1,1,2-tetrafluoroethane and/or pentafluoroethane, hydrogen fluoride as an azeotropic component with the main product, and impurity ingredients including at least an unsaturated compound, wherein said purifying step includes a step of bringing a mixture obtained by newly adding hydrogen fluoride into said crude product into contact with a fluorination catalyst in the vapor phase to reducing the content of the unsaturated compound contained in said crude product and a distillation step.
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Page/Page column 10-16
(2008/06/13)
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- Separation of C2F6 from CF4 by adsorption on activated carbon
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This invention relates to an improvement in a process for removing C2F6 as an impurity from a CF4 containing gas, preferably CF4 produced by the reaction of F2 with carbon. The improvement in the process comprises the steps:contacting said CF4 containing gas, containing C2F6 impurity, with an activated carbon having a CCl4 activity from 43 to 55 in an adsorption bed to effect adsorption of said C2F6 impurity; and,recovering purified CF4 product in the effluent from said adsorbent bed.
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- Synthesis of perfluoroalkanes by high-temperature reaction of graphite with fluorine in a fluidized bed
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Synthesis of lower perfluoroalkanes (tetrafluoromethane, hexafluoroethane, octafluoropropane, decafluorobutane) by high-temperature reaction of graphite with fluorine in a fluidized bed was studied.
- Pashkevich,Shelopin,Mukhortov,Petrov,Alekseev,Asovich
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p. 1847 - 1853
(2007/10/03)
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- METHOD OF A SIMULTANEOUS PREPARATION OF HEXAFLUOROPROPYLENE AND OCTAFLUOROCYCLOBUTANE
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A method of simultaneous and selective perpararation of hexafluoropropylene and octafluorocyclebutane comprising the steps of: (a) thermally decomposing difluorochloromethane to obtain tetrafluoroethylene and then supplying the resulting tetrafluoroethylene into a bed reactor equipped with a distributor for supplying steam; and (b) supplying steam into a flow of tetrafluoroethylene supplied into the fluidized bed reactor, through a distributor for supplying steam at a certain molar ratio of tetrafluoroethylene/stream, and then performing dimerization of tetrafluoroethylene in the fluidized bed reactor under an atmospheric pressure.
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- The possibility of carbonyl fluoride as a new CVD chamber cleaning gas
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Carbonyl fluoride (COF2) has been investigated as an alternative gas for plasma-enhanced chemical vapor deposition (PECVD) chamber cleaning in order to reduce greenhouse gases emitted from the cleaning process in semiconductor manufacturing. The cleaning performance of COF2 and the environmental impact of its exhaust gases were evaluated using an experimental plasma tool. The results indicated that the cleaning performance of COF 2 was equivalent to that of conventional C2F6. Furthermore, it was confirmed that the use of COF2 would enable the reduction of global warming emissions by over 95% relative to the use of C 2F6, and thus COF2 is considered to be a promising alternative cleaning gas.
- Mitsui, Yuki,Ohira, Yutaka,Yonemura, Taisuke,Takaichi, Tsuyoshi,Sekiya, Akira,Beppu, Tatsuro
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p. G297-G301
(2008/10/09)
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- The radiation chemistry of acyclic hydrofluoro and perhalogenated ether and hydrocarbon compounds
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The radiolytic stability of some hydrofluoroethers and hydrofluorocarbons was investigated and compared with those of perfluoropolyethers (PFPEs) and the CCl2FCClF2 (CFC 113). The experimental results indicate that stability depends mainly on the relative abundance of hydrogen atoms in the molecule; however, a significant role is played also by the chemical structure (i.e. the relative positions of the hydrogen atoms in the molecule). As a result, molecules containing hydrogen atoms as -OCF2H chain ends show a higher stability compared with the other hydrofluoro compounds. Based on the analysis of the end products and on the nature of radicals detected by EPR, radiolysis mechanisms are proposed and discussed. Due to their high dipole moments the hydrofluoro compounds and CCl2FCClF2 degrade mainly through an ionic mechanism.
- Marchionni, Giuseppe,Guarda,Buttafava,Faucitano, Antonio
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p. 153 - 162
(2007/10/03)
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- Electrochemical fluorination of unsaturated sulfides and sulfones
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Electrochemical fluorination of some unsaturated sulfides and sulfones and their reactions with anhydrous HF were studied.
- Grigor'eva,Shainyan,Kaurova,Gracheva,Lesnevskaya,Barabanov
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p. 1095 - 1100
(2007/10/03)
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- On the reaction of perfluoro-aza-propene with oxygen difluoride and fluorination of bis(trifluoromethyl)-hydroxylamine
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The reactions of perfluoro-aza-propene CF3NCF2 with an excess of oxygen difluoride OF2 and the fluorination of bis(trifluoromethyl)-hydroxylamine (CF3)2NOH are discussed. Additionally, we present density functional calculations (B3LYP/6-31G*) on bis(trifluoromethyl)-hypofluorite (CF3)2NOF, which clearly show that this molecule is a model substance for the discussion of negative hyperconjugation.
- Minkwitz, Rolf,Reinemann, Stefan,Ludwig, Ralf
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p. 145 - 149
(2007/10/03)
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- Technology for the preparation of perfluoro-organic compounds
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Fluorination by elemental fluorine of fluorine-containing alkenes, alkanes, ethers and tertiary amines was investigated, aimed at obtaining the perfluorinated analogs. The factors affecting yield of the target compounds were studied. Elements of technology were elucidated.
- Moldavskii, Dmitrii D.,Bispen, Tatjana A.,Kaurova, Galina I.,Furin, Georgii G.
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p. 157 - 167
(2007/10/03)
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- Innovative surface wave plasma reactor technique for PFC abatement
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Application of surface wave plasmas as an innovative technology for the destruction and removal of perfluorocompounds (PFC) emanating from semiconductor fabrication tools is demonstrated. The destruction of parts per thousand (ppt) concentrations of hexafluoroethane, C2F6, in oxygen and natural gas mixtures has been investigated as a function of microwave power in a low-pressure plasma reactor at 11.3 Torr. Effluent analysis included the determination of destruction and removal efficiencies (DRE) and product distributions by Fourier transform infrared spectroscopy and mass spectrometry. Destruction and removal efficiences of up to 99.6% for C2F6 were achieved using applied microwave powers from 500 to 2000 W, which corresponded to millisecond range residence times within the plasma. Product analysis indicated that hexafluoroethane conversion was limited to low molecular weight gases such as CO2, CO, COF2, H2O, and HF. CF4 was not produced as a plasma byproduct in any significant quantities. These investigations indicate that surface wave plasma destruction of perfluorocompounds at the point of use is a viable nonintrusive abatement technology for application to semiconductor manufacturing tools. Application of surface wave plasmas as an innovative technology for the destruction and removal of perfluoro-compounds (PFC) emanating from semiconductor fabrication tools is demonstrated. The destruction of parts per thousand (ppt) concentrations of hexafluoroethane, C2F6, in oxygen and natural gas mixtures has been investigated as a function of microwave power in a low-pressure plasma reactor at 11.3 Torr. Effluent analysis included the determination of destruction and removal efficiencies (DRE) and product distributions by Fourier transform infrared spectroscopy and mass spectrometry. Destruction and removal efficiencies of up to 99.6% for C2F6 were achieved using applied microwave powers from 500 to 2000 W, which corresponded to millisecond range residence times within the plasma. Product analysis indicated that hexafluoroethane conversion was limited to low molecular weight gases such as CO2, CO, COF2, H2O, and HF. CF4 was not produced as a plasma byproduct in any significant quantities. These investigations indicate that surface wave plasma destruction of perfluorocompounds at the point of use is a viable nonintrusive abatement technology for application to semiconductor manufacturing tools.
- Hartz, Chris L.,Bevan, John W.,Jackson, Marc W.,Wofford, Bill A.
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p. 682 - 687
(2007/10/03)
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- Production of perfluorinated organic compounds
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Fluorination of a series of perfluoroolefins and their alkoxy and diethylamino derivatives with elemental fluorine in the gas and liquid phases was studied. The possibility of fluorinating these compounds with pure fluorine was demonstrated. The fluorination parameters were determined, and separate stages of processes for preparing a series of practically important products were developed. The heats of fluorination of the compounds studied were calculated.
- Bispen,Moldavskii,Furin
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p. 1409 - 1417
(2007/10/03)
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- Synthesis of perfluorinated paraffins, esters, and tertiary amines by direct fluorination with elemental fluorine
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Fluorination of partially fluorinated olefins, paraffins, ethers, and tertiary amines with elemental fluorine at the gas-liquid interface under various conditions was studied.
- Bispen,Moldavskii
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p. 1009 - 1013
(2007/10/03)
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- Atmospheric Chemistry of CF2BrH: Kinetics and Mechanism of Reaction with F and Cl Atoms and Fate of CF2BrO Radicals
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A pulse radiolysis technique was used to investigate the kinetics and products of the reaction of CF2BrH with fluorine atoms at 296 K.This reaction forms an adduct which is in dynamic equilibrium with CF2BrH and fluorine atoms.The UV absorption spectrum of the adduct was measured relative to the UV spectrum of the CH3O2 radical over the range 230-380 nm.At 280 nm, an absorption cross section of (1.3 +/- 0.3)E-17 cm2 molecule-1 was determined.From the absorption at 280 nm the equilibrium constant K5 = /() was measured to be (1.59 +/- 0.13)E-17 cm3 molecule-1.In 1 atm of SF6, the forward rate constant k5 = (1.4 +/- 0.5)E-11 cm3 molecule-1 s-1 and the backward rate constant k-5 = (8.8 +/- 3.0)E5 s-1 were determined by monitoring the rate of formation and loss of the adduct.As part of the present work a relative rate technique was used to measure k(Cl + CF2BrH) = (5.8 +/- 1.0)E-15 cm3 molecule-1 s-1 at 296 K and 700 Torr of N2.The fate of the oxy radical, CF2BrO, in the atmosphere is bromine atom elimination and formation of COF2.
- Bilde, Merete,Sehested, Jens,Mogelberg, Trine E.,Wallington, Timothy J.,Nielsen, Ole J.
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p. 7050 - 7059
(2007/10/03)
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- The dark reactions F2 + CF3I, C2F5I, and n-C3F7I
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The reactions between F2 and the lowest members of the homologous series of perfluoroalkyl iodides (CF3I, C2F5I, and n-C3F7I) have been studied. For these compounds, an exponential decrease
- Johnson,Walters,Dorko
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- A new approach to the synthesis of 2,2-difluoro-1,3-dioxolanes
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A direct and versatile way to prepare halogenated 2,2-difluoro-1,3-dioxolanes through the addition of bis(fluoroxy)difluoromethane (BDM) to halogenated alkenes (CF2=CFCF3, CF2=CFOCF2CF3, CF2=CHCF3, CF3CF=CFCF3, CFCl=CFCl, CFBr=CFBr, CCl2=CCl2, CHCl=CCl2, CHCl=CHCl, CH2=CHCl, CF2=CFCl, (CF3)2CFCF=CFCF3, CF2=CFBr, CF2=CF2) has been discovered. - Keywords: Synthesis; Difluorodioxolanes; NMR spectroscopy; IR spectroscopy; Mass spectrometry
- Navarrini, W.,Bragante, L.,Fontana, S.,Tortelli, V.,Zedda, A.
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p. 111 - 118
(2007/10/02)
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- Adsorption and Reaction of Trifluoromethyl Iodide on Ni(111)
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We have investigated the surface chemistry of trifluoromethyl iodide adsorbed on Ni(111) under ultrahigh-vacuum conditions using temperature-programmed desorption, reflection absorption infrared spectroscopy, and Auger electron spectroscopy.Ni(111) activates both carbon-iodine and carbon-fluorine bonds in adsorbed CF3I.Atomic iodine desorbs from the surface near 975 K, and nickel fluoride, NiF2, desorbs near 820 K.Although the desorption temperatures for iodine and nickel fluoride are high, there is evidence that carbon-iodine and carbon-fluorine bonds are actived below room temperature.A small amount of fluorocarbon products containing CF2 and CF3 fragments desorb from the surface between 200 and 375 K.At higher temperatures, fluorine atoms recombine with adsorbed carbon to form CF4, which desorbs near 780 K.CF3I molecularly desorbs from the surface at high coverages with desorption rate maxima of 162 and 122 K for the monolayer and multilayer, respectively.Coadsorption of D atoms and CF3I results in the desorption of CD2F2 near 230 K and DF between 260 and 460 K.After desorption of the monolayer, the bands in the infrared spectrum are quite weak.The IR data suggest that very few fluorocarbon fragments are stabilized on the surface.In general, the data indicate that a large fraction of adsorbed CF3I decomposes to form atomic carbon, fluorine and iodine.A comparison of the reactions of CF3I on Ni to Ag, Pt and Ru shows that only Ni is etched under ultrahigh-vacuum conditions by CF3I.
- Myli K. B.,Grassian, V. H.
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p. 5581 - 5587
(2007/10/02)
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- ROLE OF HYDROGEN FLUORIDE AND COBALT DIFLUORIDE IN FLUORINATION OF HYDROCARBONS WITH COBALT TRIFLUORIDE
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Fluorinatiuon of difluoromethane (CF2H2), trifluoromethane (CF3H), and pentafluoroethane (C2F5H) with cobalt trifluoride has been experimentally studied.The catalytic and inhibiting role of hydrogen fluoride (HF) has been examined.A catalysis mechanism has been proposed.The temperature interval in which HF influence the process has been determined.The role of diffusion of the reactants through the bed of the forming solid reaction product, cobalt difluoride, has been examined.
- Kostyaev, R. A.,Pashkevich, D. S.
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p. 1759 - 1763
(2007/10/03)
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- FLUORINATION OF ORGANIC COMPOUNDS IN THE PRESENCE OF HEXAFLUOROPROPYLENE OLIGOMERS
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Unsaturated perfluorinated compounds, polyfluorinated ethers, and aromatic and heterocyclic compounds were fluorinated by fluorine in the hexafluoropropylene trimer.A mechanism including the formation of the stable C9F19 radical is proposed.
- Zabolot-skikh, V. F.,Kochanov, A. S.,Tiunov, A. V.,Markin, I. V.
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p. 1282 - 1283
(2007/10/02)
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- FLUORINATION OF METHANE AND ITS FLUORINE DERIVATIVES BY COBALT TRIFLUORIDE
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Fluorination of methane is studied with the aim of using difluoromethane and trifluoromethane as promising ozone-safe refrigerants.Principal kinetic features of fluorination of methane, difluoromethane, and trifluoromethane is gas phase are determined.Activation energies and preexponential factors of the rate constants of the main reactions are presented.The process studied is shown to be promising for industrial production of fluoromethanes.
- Asovich, V. S.,Kornilov, V. V.,Kostyaev, R. A.,Maksimov, V. N.
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- Perfluorination of Allene Derivatives by Direct Fluorination
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Perfluoropropane was prepared from allene with elemental fluorine in the presence of sodium fluoride in 84percent yield for the first time.The reaction of allene with elemental fluorine afforded 2,2-difluoropropane in the absence of sodium fluoride.Methoxyallene and cyanoallene were perfluorinated with elemental fluorine in the presence of sodium fluoride to give heptafluoropropyl trifluoromethyl ether and heptafluoropropyl cyanide in good yields respectively.In addition, the direct fluorination of cyanoallene in the presence of cesium fluoride afforded N,N-difluorononafluorobutylamine in 95percent yield.
- Arimura, Takashi,Shibakami, Motonari,Tamura, Masanori,Kurosawa, Shigeru,Sekiya, Akira
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p. 588 - 598
(2007/10/02)
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- Room-temperature Catalytic Fluorination of C1 and C2 Chlorocarbons and Chlorohydrocarbons on Fluorinated Fe3O4 and Co3O4
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A study of the room-temperature reactions of a series of C1 and C2 chlorohydrocarbon and chlorocarbon substrate molecules with fluorinated iron(II,III) oxide and cobalt(II,III) oxide has been conducted.The results show that fluorinated iron(II,III) oxide exhibits an ability to incorporate fluorine into the following substrates in the order: Cl2C=CCl2 > H2C=CCl2 > CH3CCl3 > CHCl3 > CH2Cl2 > CH2ClCCl3 > CCl4 > CHCl2CHCl2.The fluorinated cobalt(II,III) oxide gave the reactivity series CHCl3 > CCl4 > H2C=CCl2 > CHCl2CHCl2 > CH2Cl2 > CH3CCl3 > CCl2CCl2 > CH2ClCl3.Reactions of C1 chlorohydrocarbon or chlorocarbon probe molecules with fluorinated Fe3O4 gave predominately C1 chlorofluorohydrocarbon and chlorofluorocarbon products, respectively, whereas fluorinated cobalt(II,III) oxide produced predominately C2 chlorofluorohydrocarbon and chlorofluorocarbons.For fluorinated Co3O4 the distribution of C2 products obtained from C1 chlorohydrocarbon precursor molecules is consistent with the formation of radical intermediates at strong Lewis acid surfaces.C2 chlorohydrocarbons exhibit a fluorine for chlorine (F-for-Cl) exchange reaction through the catalytic dehydrochlorination of the substrate to the alkenic intermediate.The F-for-Cl exchange process was dependent upon the ability of the substrate material to undergo dehydrochlorination; the inability of a substrate to undergo dehydrochlorination results in the fluorination process proceeding through the formation of chlorocarbon or chlorohydrocarbon radical intermediates.
- Thomson, James
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p. 3585 - 3590
(2007/10/02)
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- Kinetics of the Reactions of F- with CF3Br and CF3I as a Function of Temperature, Kinetic Energy, Internal Temperature, and Pressure
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The reactions of F- with CF3Br and CF3I have been studied at several temperatures as functions of pressure and ion-neutral average center-of-mass kinetic energy (cm>).Rate constants and product branching fractions were measured by using a variable temperature-selected ion flow drift tube apparatus.Both title reactions involve two product pathway: displacement and association, the latter being the major channel under most experimental conditions.The rate constants for displacement are governed by total energy, regardless of the relative contributions by translational and internal energy, indicating that the displacement reactions behave statistically.In contrast, the rate constants for association depend strongly on the internal energy of CF3X (rotations and vibrations) compared with the relatively weak effect of translational collision energy.For CF3Br the rate constants for the association channel increase with increasing pressure while those for displacement are independent of pressure, indicating that the additional reactivity leading to more association at higher pressure appears not to compete with the displacement pathway.This lack of competition may be the result of two different reaction intermediates.The more efficient CF3I reaction is at or near the high-pressure limit for association, showing no pressure dependence in both the association and displacement channels.Therefore, there appears to be no competition between these channels for CF3I as well, but the data are less definitive in this case.
- Morris, Robert A.,Viggiano, A. A.
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p. 3740 - 3746
(2007/10/02)
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- Rates of processes initiated by pulsed laser production of F atoms in the presence of HCl, CH4, and CF3H
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Time-resolved vibrational chemiluminescence from HF has been recorded following the production of F atoms by the pulsed laser photolysis (λ = 266 nm) of F2 in the presence of HCl, CH4, and CF3H. In the first two cases, experiments have been conducted by observing emission from HF(ν = 3) at four temperatures from 295 to 139 K. Rate constants have been determined over this range of temperature for the reactions of F atoms with HCl and CH4 and of CH3 radicals with F2, and for the relaxation of HF(ν = 3) by HCl and CH4. The reaction of F atoms with CF3H is slower than those with HCl and CH4 and measurements on the emission from HF(ν = 2) have been used to infer rate constants for reaction and relaxation only at 295 K.
- Moore,Smith,Stewart
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p. 813 - 825
(2007/10/03)
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- INVESTIGATIONS IN THE REGION OF INDUSTRIAL FLUORINATED COMPOUNDS
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The synthesis and properties of ozone-friendly fluorohydrocarbons, fluoroolefins, and fluorinated compounds with functional groups (acids, alcohols, esters, and others), used for the creation of effective surfactants, ion-exchange membranes for various purposes, heat-resistant oils, and greases, were investigated.A technology was developed for the production of highly pure fluorinated compounds for microelectronics, fiber optics, and medicine.
- Maksimov, B. N.
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p. 1935 - 1940
(2007/10/03)
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- KINETIC RELATIONS IN THE THERMODECOMPOSITION OF CALCIUM AND STRONTIUM F-SUBSTITUTED β-DIKETONATES
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Kinetic relations in the thermodecomposition of calcium and strontium substituted β-diketonates (acetylacetonates, trifluoroacetylacetonates, pivaloyltrifluoroacetylacetonates, dipivaloylmethanates) and their volatilities were studied by the manometric technique under static conditions.
- Tsyganova, E. I.,Titova, O. M.,Faerman, V. I.,Stepanova, L. V.,Aleksandrov, Yu. A.
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p. 195 - 198
(2007/10/02)
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- On the electrochemical fluorination of quaternary ammonium compounds. Part 1. Tetraalkyl ammonium salts
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Tetraalkylated ammonium compounds, which are known to be very stable towards oxidative attack, can be electrofluorinated readily to yield perfluoro tertiary amines.Other than the enhanced formation of gaseous cleavage products, the electrofluorination proceeds similarly to that of other tertiary amines.
- Dimitrov. A.,Radeck, W.,Ruediger, St.,Bechstein, O.
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