- 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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- Turnover Rate, Reaction Order, and Elementary Steps for the Hydrodechlorination of Chlorofluorocarbon Compounds on Palladium Catalysts
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The rates of hydrodechlorination catalyzed by Pd supported on carbon for four chlorofluorocarbons spanned a range of 7 orders of magnitude. The rates scaled up to the bond strength of the carbon-chlorine bond for the gas-phase reactant. This finding demonstrates that the rate-determining step involves the scission of the C-Cl bond and suggests, through Polanyi and linear free-energy relationships, that rates for other compounds can be estimated if the C-Cl bond strength is known. The reaction orders for the most abundant products are approximately first-order for the chlorine-containing compound, half-order in H2, and inverse first-order in HCl. The reaction steps consistent with these orders include a rate-determining step involving the adsorption of the chlorofluorocarbon to a single site (which could be a single surface palladium atom) and equilibrated steps between gas-phase H2, gas-phase HCl, and adsorbed hydrogen and chlorine atoms. The rates on the supported catalysts are comparable to the ones reported before on a Pd foil, indicating that the support does not play a role in the reaction. The product distribution is independent of conversion, implying that the various products are formed from a single visit of the reactant on the surface and not from readsorption of gas-phase products. The four compounds studied were chloropentafluoroethane (CF3-CF2Cl), 2-chloro-1,1,1,2-tetrafluoroethane (CF3-CFClH), 1,1-dichlorotetrafluoroethane (CF3-CFCl2), and 1,1,1-trichloro-2,2,2-trifluoroethane (CF3-CCl3).
- Thompson,Rioux,Chen,Ribeiro
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- Hydrodechlorination of 1,1-dichlorotetrafluoroethane and dichlorodifluoromethane catalyzed by Pd on fluorinated aluminas: The role of support material
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The gas phase hydrodechlorination of CF3CFCl2 to CF3CFH2 and CF2Cl2 to CF2H2 catalyzed by Pd supported on Al2O3, a series of fluorinated Al2O3, and AlF3 was investigated. A combination of reaction kinetics investigations and characterization by in situ FTIR spectroscopy has been performed. It has been found that for reactions involving CF3CFCl2, all catalysts exhibit a rapid and significant decrease in activity; however, little change in activity with time on stream occurs with CF2Cl2. FTIR investigations suggest the occurrence of direct reaction between the CFC and the support material, which results in the consumption of hydroxyl groups during the early stages of reaction. The effect of fluorination of support on catalytic behavior of Pd is discussed.
- Early, Kintu,Kovalchuk, Vladimir I.,Lonyi, Ferenc,Deshmukh, Subodh,D'Itri, Julie L.
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- Structure Insensitivity and Effect of Sulfur in the Reaction of Hydrodechlorination of 1,1-Dichlorotetrafluoroethane (CF3-CFCl2 ) over Pd Catalysts
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The kinetics of the hydrodechlorination of 1,1-dichlorotetrafluoroethane (CFC 114a) was studied on Pd(111), Pd(100), and a Pd foil at atmospheric pressure. The three products formed were CF3-CFH2 (HFC 134a), CF3-CFClH (HCFC 124), and CF3-CH3 (HFC 143a) with selectivities independent of conversion. The single crystals and foil (model catalysts) were studied in an apparatus that permitted the direct transfer of samples between a high pressure cell (1 atm) and an ultrahigh vacuum chamber. The reaction rates were measured in the temperature range of 350 to 470 K. The reaction is not sensitive to the structure of the catalyst, as indicated by the similar turnover rates for all catalysts tested. The reaction is inverse first order in the reaction product HCl on all samples. Sulfur adsorbed on the Pd surface depressed the rates of formation of 134a more strongly than the rates of 124 and 143a.
- Ribeiro,Gerken,Rupprechter,Somorjai,Kellner,Coulston,Manzer,Abrams
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- Effects of M-promoter (M = Y, Co, La, Zn) on Cr2O3 catalysts for fluorination of perchloroethylene
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The vapor phase fluorination of perchloroethylene (PCE) to synthesize 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123), 1-chloro-1,2,2,2- tetrafluoroethane (HCFC-124) and pentafluoroethane (HFC-125) was carried out on M-Cr2O3 catalysts with different promoters (M = Y, Co, La, Zn). The catalysts were characterized by X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H2-TPR), Raman spectrum, Ammonia temperature-programmed desorption (NH3-TPD) and X-ray photoelectron spectroscopy (XPS) techniques. It was found that in the pre-fluorination process CrOx (x ≥ 1.5) in M-Cr2O3 catalysts could be transformed into CrOxFy species. The highest activity was obtained on La-Cr2O3(F) catalyst with 90.6% of PCE conversion and 93.7% to total selectivity (HCFC-123 + HCFC-124 + HFC-125) at 300 C. The decline in surface acid sites density of the catalyst could improve the specific reaction rate, and the formation of surface CrOxF y species could enhance the selectivities to HCFC-123, HCFC-124 and HFC-125 for gas phase fluorination of PCE. Copyright - 2013 Published by Elsevier B.V. All rights reserved.
- Cheng, Yong-Xiang,Fan, Jing-Lian,Xie, Zun-Yun,Lu, Ji-Qing,Luo, Meng-Fei
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- Catalytic hydrodechlorination of 1,1-dichlorotetrafluoroethane by Pd/Al2O3
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Palladium supported on γ-alumina displays high activity for the hydrodechlorination of 1,1-dichlorotetrafluoroethane. High H2 partial pressures are needed to avoid deactivation, and steady state is obtained after ~5 h time on stream. Under these conditions (H2/CFC feed ratio = 20) the reaction is zero order in H2 partial pressure and positive (0.65) order in 1,1-dichlorotetrafluoroethane partial pressure. Three main products are formed: 1,1,1,2-tetrafluoroethane, 1-chloro-1,2,2,2-tetrafluoroethane, and 1,1,1-trifluoroethane, with approximately 85% selectivity toward the desired CF3CFH2. The apparent activation energies associated with the formation of each product range from 52 to 68 kJ/mol. All three major products have a nonzero rate of formation in the limit of zero conversion, the implication of which is that all are primary products. The kinetics results are consistent with a reaction mechanism involving a carbene intermediate. Variation of the temperature at which the catalyst is prereduced from 300 to 600°C results in an increase in particle size from 11-53 nm and in an increase in the hydrodechlorination TOF from 2.3 to 5.0 s-1.
- Karpinski, Zbigniew,Early, Kintu,D'Itri, Julie L.
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- Deuterium isotope studies of the hydrofluorination of chloroethenes over chromia catalysts
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The mechanism of the catalytic fluorination of chloroalkenes over a chromia catalyst has been investigated by examining the effects of substituting DF for HF as the fluorine source for reaction with tetrachloroethene and trichloroethene.At a temperature of 250 degC and a HF (DF)/alkene molar ratio of 4.2:1, the rate of conversion of tetrachloroethene is increased by using DF and there is a concomitant increase in the selectivity to some chlorofluoroalkanes and a decrease in the selectivity to chlorofluoroalkenes.The opposite behaviour observed for the halogenated alkenes and alkanes indicates that the alkenes are not important intermediates in the production of the alkanes by a series of hydrofluorination and dehydrochlorination reactions.For tetrachloroethene, the main reaction pathway to the alkanes is a direct chlorine/fluorine exchange over a heavily fluorinated chromia surface with minimal C-H/C-D cleavage of intermediates.Substitution of DF for HF causes no change in the product selectivities from reaction with trichloroethene over chromia catalysts.However, the presence of dideutero - and monodeutero - products shows that both chlorine/fluorine exchange and HF addition / HCl elimination pathways are occurring for the less-substituted alkene.
- Kavanagh, David M. C.,Ryan, T. Anthony,Mile, Brynmor
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- Production Method for 1,2,2,2-Tetrafluoroethyl Difluoromethyl Ether (Desflurane)
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Fluoral is obtained by gas-phase fluorination of chloral in the presence of a catalyst and then reacted with trimethyl orthoformate, thereby readily forming 1,2,2,2-tetrafluoroethyl methyl ether as an intermediate for production of desflurane. 1,2,2,2-Tetrafluoroethyl difluoromethyl ether (desflurane) is produced with high yield from the thus-formed 1,2,2,2-tetrafluoroethyl methyl ether by chlorination and fluorination. This method enables efficient industrial-scale production of desflurane useful as an inhalation anesthetic
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Paragraph 0180-0183
(2019/11/22)
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- PROCESS FOR PRODUCING FLUOROETHANE
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Fluorochromium oxide having a fluorine content of not less than 30 wt.% is used for the fluorination reaction. To provide a manufacturing method for fluorine-containing ethane which contains 1, 1, 1, 2, 2-pentafluoroethane as the main component in which the reaction can be performed while controlling the generation of CFCs to the greatest possible extent by fluorinating at least one selected from the group composed of tetrachloroethylene, 2, 2-dichloro-1, 1, 1-trifluoroethane and 2-chloro-1, 1, 1, 2-tetrafluoroethane with hydrogen fluoride.
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Paragraph 0046
(2015/12/04)
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- Catalytic fluorination of 1,1,1-trifluoro-2-chloro-ethane in the presence of oxygen over chromium based catalyst doped or not by zinc supported over partially fluorinated alumina
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The addition of zinc in low amount to chromium based catalyst supported over partially fluorinated alumina has a positive effect for the fluorination reaction of CF3CH2Cl in the presence of dioxygen in order to prevent the catalyst deactivation. However, under these operating conditions, the Deacon reaction by reaction with HCl produced by Cl/F exchanges could be involved. The formation of various by-products was observed corresponding to the addition of HCl or Cl2 into halogenated double bonds.
- Loustaunau,Fayolle-Romelaer,Celerier,Brunet
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experimental part
p. 1262 - 1265
(2011/12/21)
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- METHOD FOR PRODUCING PENTAFLUOROETHANE
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The present invention aims in a method wherein tetrachloroethylene (PCE) is reacted with HF in a gas phase in the presence of a catalyst to obtain pentafluoroethane (HFC-125), to reduce production of undesirable by-products and maintain a catalytic activity at a high level over a long period of time while achieving a high conversion ratio of PCE and suppressing deterioration of the catalyst. In a method for producing pentafluoroethane wherein tetrachloroethylene is reacted with HF in a gas phase in the presence of a catalyst to obtain pentafluoroethane, characterized in that chromium oxyfluoride is disposed in a reactor as the catalyst, and oxygen is fed into the reactor together with tetrachloroethylene and HF, at a amount of 0.4-1.8% by mole with respect to tetrachloroethylene.
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Page/Page column 5-6
(2010/11/03)
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- PROCESS FOR PRODUCING PENTAFLUOROETHANE
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The present invention relates to a process for producing pentafluoroethane. More particularly, the subject of the invention is a continuous process for producing pentafluoroethane comprising (i) a step of fluorinating perchloroethylene (PER) with hydrofluoric acid, in the gas phase, in the presence of a catalyst, (ii) a step of separating the products issuing from step (i) in order to give a fraction of light products and a fraction of heavy products, comprising hydrofluoric acid, unreacted perchloroethylene and under-fluorinated products, and (iii) a step of pretreating the fraction of heavy products before recycling to step (i).
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Page/Page column 2-3
(2010/08/22)
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- PROCESSES FOR PRODUCING HYDROHALOCARBON AND HALOCARBON COMPOUNDS USING SILICON TETRAFLUORIDE
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Methods and systems for producing hydrohalocarbon and/or halocarbon compounds with an inorganic fluoride (e.g., silicon tetrafluoride (SiF4)) are disclosed herein.
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Page/Page column 5-6
(2009/04/24)
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- PROCESSES FOR PRODUCING HYDROFLUOROCARBON COMPOUNDS USING INORGANIC FLUORIDE
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Methods and systems for producing hydrofluorocarbon with an inorganic fluoride (e.g., germanium tetrafluoride (GeF4)) are disclosed herein.
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Page/Page column 4
(2008/12/04)
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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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- Methane and methyl chloride as selective reducing agent in the transformation of hydrochlorofluorocarbons or chlorofluorocarbons to hydrofluorocarbons
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A gas phase reaction process for producing a hydrofluorocarbon from a hydrochlorofluorocarbon or chlorofluorocarbon reactant by contacting, in the presence of a catalyst, the hydrochlorofluorocarbon or chlorofluorocarbon reactant with a reducing agent selected from methane, methyl chloride and mixtures thereof, to produce the hydrofluorocarbon.
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Page/Page column 6-7
(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 10; 11
(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 4-5
(2008/06/13)
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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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- 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 PRODUCING HEXAFLUOROETHANE AND USE THEREOF
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A process for producing hexafluoroethane, comprising a step of distilling a crude hexafluoroethane containing chlorine compounds each having two carbon atoms to distill out hexafluoroethane as a top flow from the top of a distillation column and separate a hexafluoroethane mixture containing the chlorine compounds as a bottom flow from the bottom, and a step of contacting the bottom flow with hydrogen fluoride in the gas phase at a temperature of 300 to 500 °C in the presence of a fluorination catalyst to fluorinate the chlorine compounds. This process provides hexafluoroethane which can be used mainly as a cleaning gas in the production process of a semiconductor device.
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Page/Page column 17
(2008/06/13)
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- Production and use of hexafluoroethane
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A process for production of high-purity hexafluoroethane, wherein a mixed gas containing hexafluoroethane and chlorotrifluoromethane is reacted with hydrogen fluoride in a gas phase in the presence of a fluorination catalyst at 200-450° C., for fluorination of the chlorotrifluoromethane, or wherein pentafluoroethane containing chlorine compounds with 1-3 carbon atoms is reacted with hydrogen in a gas phase in the presence of a hydrogenation catalyst at 150-400° C., and the product is then reacted with fluorine in a gas phase in the presence of a diluent gas.
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- PROCESS FOR PURIFYING PENTAFLUOROETHANE, PROCESS FOR PRODUCING THE SAME, AND USE THEREOF
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ABSTRACT A process comprising bringing crude pentafluoroethane containing at least one compound selected from the group consisting of hydrofluorocarbons containing one carbon atom, hydrochlorofluorocarbons containing one carbon atom and hydrochlorocarbons containing one carbon atom, into contact with an adsorbent comprising a zeolite having an average pore size of 3 to 6 ? and a silica/aluminum ratio of 2.0 or less and/or a carbonaceous adsorbent having an average pore size of 3.5 to 6 ?, to reduce the content of the compound. The purified gas can be used as a low temperature refrigerant or an etching gas.
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- PROCESS FOR THE PRODUCTION OF FLUORINATED HYDROCARBONS
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A process of exchanging at least one heavier halogen in a halogenated hydrocarbon is described. It comprises reacting a perhaloethylene or pentahaloethane, with at most three fluorine atoms with anhydrous hydrofluoric acid in the liquid phase in the presence of an antimony halogenide, the reaction being carried out in a substantially inert vessel.
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Page column 6-7
(2008/06/13)
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- Method for purifying tetrachloroethylene and process for producing hydrofluorocarbons
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Tetrachloroethylene containing a stabilizer is contacted with a zeolite having an average pore size of 3.4 to 11 ? and/or a carbonaceous adsorbent having an average pore size of 3.4 to 11 ? in a liquid phase to obtain a high purity tetrachloroethylene. A halogenated alkene and/or a halogenated alkane are reacted with hydrogen fluoride in the presence of a fluorination catalyst to produce a first hydrofluorocarbon, a halogenated alkene and/or a halogenated alkane are reacted with hydrogen fluoride in the presence of a fluorination catalyst to produce a second hydrofluorocarbon, and the products are joined and then distilled to obtain the first and second hydrofluorocarbons.
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Page/Page column 7-10
(2008/06/13)
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- SEPARATION PROCESS OF 1,1,1,2-TETRAFLUORO-2-CHLOROETHANE (HCFC-124) FROM 1,1,2,2-TETRAFLUORO-1-CHLOROETHANE (HCFC-124A)
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A process for the separation of HCFC-124 from its isomer HCFC-124a, comprising the continuous feeding of a mixture of the two isomers on molecular sieves having sizes comprised between 4? and 10?, and the desorption of HCFC-124 by heating the molecular sieves at a temperature preferably in the range 50° C-200° C.
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Page/Page column 3-5
(2008/06/13)
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- A study of trichloroethylene hydrofluorination using a kinetic model
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The kinetic features of catalytic hydrofluorination of trichloroethylene and 2-chloro-1,1,1-trifluoroethane on chromium fluoride/magnesium fluoride catalyst were studied. The effect of pressure and addition of various components of the reaction mixture at the reactor inlet was studied using the developed model.
- Dmitriev,Trukshin,Smykalov
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p. 771 - 776
(2007/10/03)
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- Hydrodechlorination of 1,1-dichlorotetrafluoroethane over Pd/Al2O3 catalyst. Effect of hydrogen pressure and catalyst pretreatment
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An alumina-supported palladium catalyst has been studied in CF3CFCl2 hydrodechlorination at 100°C using a static-circulation system. At higher partial pressures of H2, when the existence of the β-PdH phase is awaited, the reaction occurs similarly as at lower hydrogen pressures. This indicates that either the β-PdH formation does not have any special effect on active sites of this reaction, or the presence of CF3CFCl2 in the system inhibits this phase transformation. Various pretreatments of the 2 wt.% Pd/Al2O3 influence markedly its catalytic behavior. In particular, reoxidation and subsequent low temperature reduction of the catalyst, prereduced at 600°C, generates a very high activity, however, the selectivity towards CF3CFH2 is not much altered.
- Karpinski,D'Itri
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p. 1421 - 1452
(2007/10/03)
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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 Novel Hydrodechlorinative Dimerization of Chlorofluorocarbons over Supported Ni Catalysts
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1,1,1-Trichloro-2,2,2-trifluoroethane or 1,1-dichloro-1,2,2,2-tetrafluoroethane, both of which have CF3 group, dimerizes over supported Ni catalysts at an elevated temperature (723 K) into corresponding C4-compounds in good to moderate yields.
- Tomioka, Satoshi,Mori, Tohru,Ueda, Wataru,Morikawa, Yutaka,Ikawa, Tsuneo
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p. 1825 - 1826
(2007/10/02)
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- THE VIBRATIONAL SPECTRA OF 1-CHLORO-1-HYDRO-F-ETHANE, CF3CHFCl, AND 1-BROMO-1-HYDRO-F-ETHANE, CF3CHFBr
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Infrared and Raman spectra were obtained for the fluorinated ethanes, CF3CHFCl and CF3CHFBr, and their deuterated isotopomers.A vibrational assignment of these molecules is reported.
- Noftle, R. E.,Ellis, Charles,Johnson, Gary,Bush, S. F.
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