- Unimolecular reactions in the CF3CH2Cl ? CF 2ClCH2F system: Isomerization by interchange of Cl and F atoms
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The recombination of CF2Cl and CH2F radicals was used to prepare CF2ClCH2F* molecules with 93 ± 2 kcal mol-1 of vibrational energy in a room temperature bath gas. The observed unimolecular reactions in order of relative importance were: (1) 1,2-ClH elimination to give CF2=CHF, (2) isomerization to CF 3CH2Cl by the interchange of F and Cl atoms and (3) 1,2-FH elimination to give E- and Z-CFCl=CHF. Since the isomerization reaction is 12 kcal mol-1 exothermic, the CF3CH2Cl* molecules have 105 kcal mol-1 of internal energy and they can eliminate HF to give CF2=CHCl, decompose by rupture of the C-Cl bond, or isomerize back to CF2ClCH2F. These data, which provide experimental rate constants, are combined with previously published results for chemically activated CF3CH2Cl* formed by the recombination of CF3 and CH2Cl radicals to provide a comprehensive view of the CF3CH2Cl* ? CF 2ClCH2F* unimolecular reaction system. The experimental rate constants are matched to calculated statistical rate constants to assign threshold energies for the observed reactions. The models for the molecules and transition states needed for the rate constant calculations were obtained from electronic structures calculated from density functional theory. The previously proposed explanation for the formation of CF2=CHF in thermal and infrared multiphoton excitation studies of CF3CH 2Cl, which was 2,2-HCl elimination from CF3CH 2Cl followed by migration of the F atom in CF3CH, should be replaced by the Cl/F interchange reaction followed by a conventional 1,2-ClH elimination from CF2ClCH2F. The unimolecular reactions are augmented by free-radical chemistry initiated by reactions of Cl and F atoms in the thermal decomposition of CF3CH2Cl and CF 2ClCH2F.
- Enstice, Erin C.,Duncan, Juliana R.,Setser,Holmes, Bert E.
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experimental part
p. 1054 - 1062
(2011/04/18)
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- A mild hydrodehalogenation of fluoroalkyl halides
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A mild hydrodehalogenation reaction of fluoroalkyl halides (RfCF2X, X = Br, I) has been developed under weakly basic conditions, giving the corresponding hydrogenolysis products with moderate to high yields.
- Zhang, Cheng-Pan,Chen, Qing-Yun,Xiao, Ji-Chang,Gu, Yu-Cheng
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experimental part
p. 671 - 673
(2009/12/22)
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- Functionalized Copolymers of Terminally Functionalized Perfluoro (Alkyl Vinyl Ether) Reactor Wall for Photochemical Reactions, Process for Increasing Fluorine Content in Hydrocaebons and Halohydrocarbons and Olefin Production
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A photochemical reaction apparatus including a reactor and a light source situated so that light from the light source is directed through a portion of the reactor wall is disclosed. The apparatus is characterized by the portion of the reaction wall comprising a functionalized copolymer of a terminally functionalized perfluoro(alkyl vinyl ether). Also described is a photochemical reaction process using said reactor. The functional group of the copolymer of the apparatus and the process is selected from —SO2F, —SO2CI, —SO3H, —CO2R (where R is H or C1-C3 alkyl), —PO3H2, and salts thereof. A process for increasing the flourine content of at least one compound selected from hydrocarbons and halohydrocarbons, comprising: (a) photochlorinating said at least one compound, and (b) reacting the halogenated hydrocarbon in (a) with HF. A process for producing an olefinic compound, comprising: (a) photochlorinating at least one compound selected from hydrocarbons and halohydrocarbons containing at least two carbon atoms and at least two hydrogen atoms to produce a halogenated hydrocarbon containing a hydrogen substituent and a chlorine substituent on adjacent carbon atoms; and (b) subjecting the halogenated hydrocarbon produced in (a) to dehydrohalogenation.
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Page/Page column 5
(2008/06/13)
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- PHOTOCHLORINATION AND FLUORINATION PROCESS FOR PREPARATION OF FLUORINE-CONTAINING HYDROCARBONS
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A process is disclosed for increasing the fluorine content of at least one compound selected from halohydrocarbons and hydrocarbons. The process involves (a) directing light from a light source through the wall of a reactor to interact with reactants comprising chlorine and said at least one compound in said reactor, thereby producing a halogenated hydrocarbon having increased chlorine content by photochlorination, and (b) reacting said halogenated hydrocarbon produced by the photochlorination in (a) with HF; and is characterized by the light directed through the reactor wall being directed through a poly(perhaloolefin) polymer.
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Page/Page column 12
(2008/06/13)
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- PYROLYSIS PROCESS
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The present invention relates to the pyrolysis of hydrochlorofluorocarbons to form fluoromonomers such as tetrafluoroethylene, the pyrolysis being carried out in a reaction zone lined with nickel and mechanically supported by a jacket of other corrosion resistant metal, the nickel lining providing an improved yield of valuable reaction products.
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Page/Page column 4
(2008/06/13)
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- Process for activation of AIF3 based catalysts and process for isomerising hydrochlorofluorocarbons
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An activated AlF3 based catalyst is produced by treating a crude AlF3 for more than 5 hours with a gas stream at a temperature from 300°C to 450°C.
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- Process for preparing fluorohalogenethers
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A process for preparing (per)fluorohalogenethers having general formula (I): (R)nC(F)mOCAF—CA′F2??(I) wherein: A and A′, equal to or different the one from the other, are Cl or Br or one is selected from A and A′ and hydrogen and the other is halogen selected from Cl, Br; R═F, or a fluorinated, preferably perfluorinated, substituent, selected from the following groups: linear or branched C1-C20 alkyl more preferably C1-C10; C3-C7 cycloalkyl; aromatic, C6-C10 arylalkyl, alkylaryl; C5-C10 heterocyclic or alkylheterocyclic; when R is fluorinated or perfluorinated alkyl, cycloalkyl, arylalkyl, alkylaryl, it can optionally contain in the chain one or more oxygen atoms; when R is fluorinated it can optionally contain one or more H atoms and/or one or more halogen atoms different from F: n is an integer and is 1 or 2; m=3-n; by reaction of carbonyl compounds having formula (II): (R)pC(F)q(O)??(II) wherein: p is an integer and is 1 or 2; q is an integer and is zero or 1, R is as above; in liquid phase with elemental fluorine and with olefinic compounds having formula (III): CAF═CA′F??(III) wherein A and A′ are as above, at temperatures in the range from ?120° C. to ?20° C.
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- PROCESS FOR THE PREPARATION OF 1,1,1,2,2-PENTAFLUOROETHANE
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A process for the preparation of pentafluoroethane is disclosed which involves contacting a mixture comprising hydrogen fluoride and at least one one starting material selected from haloethanes of the formula CX3191CHX2 and haloethenes of the formula CX2=CX2, where each X is independently selected from the group consisting of F and Cl (provided that no more than four of X are F), with a fluorination catalyst in a reaction zone to produce a product mixture comprising HF, HCl, pentafluoroethane, underfluorinated halogenated hydrocarbon intermediates and less than 0.2 mole percent chloropentafluoroethane based on the total moles of halogenated hydrocarbons in the product mixture. The process is characterized by the fluorination catalyst comprising (i) a crystalline cobalt-substituted alpha-chromium oxide where from about 0.05 atom % to about 6 atom % of the chromium atoms in the alpha-chromium oxide lattice are replaced by trivalent cobalt (Co+3) and/or (ii) a fluorinated crystalline oxide of (i).
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- Process for preparing fluorohalogenethers
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A process for preparing (per) fluorohalogenethers having general formula (I):(R)nC(F)mOCAF-CA'F2 wherein:A and A', equal to or different the one from the other, are Cl or Br or one is selected from A and A' and hydrogen and the other is halogen selected from Cl, Br; R = F, or a fluorinated, preferably perfluorinated, substituent, selected from the following groups: linear or branched C1-C20 alkyl more preferably C1-C10; C3-C7 cycloalkyl; aromatic, C6-C10 arylalkyl, alkylaryl; C5-C10 heterocyclic or alkylheterocyclic; when R is fluorinated or perfluorinated alkyl, cycloalkyl, arylalkyl, alkylaryl, it can optionally contain in the chain one or more oxygen atoms;when R is fluorinated it can optionally contain one or more H atoms and/or one or more halogen atoms different from F:n is an integer and is 1 or 2; m = 3-n; by reaction of carbonyl compounds having formula (II):(R)pC(F)q(O) wherein:p is an integer and is 1 or 2; q is an integer and is zero or 1, R is as above; in liquid phase with elemental fluorine and with olefinic compounds having formula (III):CAF=CA'F wherein A and A' are as above, at temperatures in the range from -120°C to -20°C.
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Page column 9
(2008/06/13)
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- Selective reduction of halopolyfluorocarbons by organosilicon hydrides
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It is demonstrated that silicon hydrides can be used for reduction of polyfluorinated halocarbons. For example, the reaction between CF3CCl2F and excess triethylsilane, catalyzed by benzoyl peroxide, leads to the formation of a mixture containing CF3CHClF (major), CF3CH2F, and ClSi(C2H5)3. On the other hand, the reaction of chlorofluoroalkanes, containing an internal -CCl2- group readily proceeds with reduction of both chlorines, leading to compounds such as (CF3)2CH2 and CF3CH2C2F5. In contrast to chlorofluoroalkanes, bromofluoroalkanes are much more reactive and reaction with hydrosilane rapidly proceeds without the catalyst at elevated temperature.
- Petrov, Viacheslav A.
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p. 7294 - 7297
(2007/10/03)
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- A FACILE METHOD FOR FLUOROALKYLATION OF ANILINE AND ITS DERIVATIVES
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In the presence of tetrakis(triphenylphosphine)nickel, fluoroalkylation reactions of aniline and its derivatives occur under mild conditions, giving good yields of the corresponding o- and p-fluoroalkylaniline.The reaction shows regioselectivity.The hydrolytic behaviors of the products are also described.
- Zhou, Qi-Lin,Huang, Yao-Zeng
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- FLUORINATION OF HYDROGEN-CONTAINING OLEFINS WITH ELEMENTAL FLUORINE
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The hydrohalo-olefins cis and trans CHCl=CHCl, CHCl=CCl2, CHCl=CH-CH2Cl and CH2=CCl-CH2Cl have been fluorinated with elemental fluorine to give good yields of hydrohalofluoroalkanes.The best operational conditions for F2 addition to the double bond rather than hydrogen and/or chlorine atom substitution, dimerization and oligomerization of radical intermediates have been studied.Pleriminary studies on the reaction of Freon 12 and Freon 22 towards elemental fluorine have also been carried out.
- Conte, L.,Gambaretto, G. P.,Napoli, M.,Gervasutti, C.
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p. 319 - 326
(2007/10/02)
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- Nickel-, Palladium-, and Platinum-Catalyzed Reactions of Perfluoro- and Polyfluoroalkyl Iodides with Tertiary Amines
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The relative catalytic activities of Ni group metals in the reactions of perfluoroalkyl and polyfluoroalkyl iodides with tertiary amines to give enamines were compared, giving a reactivity order Ni > Pd > Pt, which parallels the order of the first ionization potential of the three metals.In comparing the Ni-catalyzed reaction of iodide 1 with tertiary amines containing zero to three methyl groups, it was found that in the case of trimethylamine only the reduced product 4 was formed, while the other three types of tertiary amines produced enamines (19, 21, 23) as wellas 4.The chemoselectivity of this reaction was studied.A mechanism is proposed for the reaction.Acid hydrolysis of (fluoroalkyl)enamines afforded enaminones or aldehydes depending upon the presence or absence of an alkyl group at the β-carbon.
- Huang, Yao-Zeng,Shou, Qi-Lin
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p. 3552 - 3558
(2007/10/02)
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- HYDROGENOLYSIS OF DICHLOROTETRAFLUOROETHANE ISOMERIC MIXTURES FOR THE FORMATION OF 1,1,1,2-TETRAFLUOROETHANE
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1,1,1,2-tetrafluoroethane was prepared from isomeric mixtures of dichlorotetrafluoroethanes through selective hydrogenolysis of CF3-CCl2F catalyzed by Pd/C.The other isomer CClF2-CClF2 appeared more stable to hydrogenolysis and was only converted partially to the monohydrogenated derivative CHF2-CClF2.The influences of the three most important operating parameters were defined on the basis of a statistical testing program.The mathematical elaboration of the experimental data allowed definition of the relationships by which it is possible to foresee conversion of CF3-CCl2F, yield of CF3-CH2F and concentration of reaction products, such as CF3-CH3, CF3-CH2F, CF3-CHClF and CClF2-CHF2 in terms of the above parameters.
- Gervasutti, C.,Marangoni, L.,Marra, W.
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