- REACTIONS OF PENTAFLUOROTELLURIUM HYPOHALITES WITH FLUOROOLEFINS
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Both pentafluorotellurium hypochlorite, TeF5OCl, and hypofluorite, TeF5OF, react with fluoroolefins to form TeF5O- containing fluorocarbons, a new class of compounds.In the case of TeF5OF, yields of the adducts are high (60-86percent) but are lower (22-30percent) with TeF5OCl.In the latter case extensive chlorofluorination of the olefin occurs.Olefins studied include CF2=CF2, CF3CF=CF2, CF2=CFCl, and perfluorocyclopentene.Details of the synthesis and characterization of these new fluorocarbons are presented.
- Shack, Carl J.,Christe, Karl O.
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Read Online
- From hypochlorites to perfluorinated dialkyl peroxides
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The synthesis and characterization of the new perfluorinated hypochlorite, undecafluoro-tert-pentyl hypochlorite, (C2F5)(F3C)2COCl, is reported. Its gas-phase infrared, UV/Vis and NMR spectra have been recorded and its spectroscopic properties are discussed and compared with quantum-chemical predictions and those of other known perfluorinated hypochlorites such as RFOCl [RF = F3C, (F3C)3C, (C2F5)(F3C)2C]. A synthetic route to otherwise difficult to access perfluorinated dialkyl peroxides, RFOORF, is also provided by low-temperature photolysis of the corresponding hypochlorite.
- Nissen, Jan H.,Wickemeyer, Lucas,Stüker, Tony,Steinhauer, Simon,Beckers, Helmut,Riedel, Sebastian
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- High surface area chromium(III)fluoride – Preparation and some properties
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Reaction of hydrated hydrazinium fluorochromate(III), [N2H6][CrF5]·H2O, with fluorine (F2)in anhydrous hydrogen fluoride (aHF)medium at room temperature yields completely amorphous CrF3-based materials with exceptionally high specific surface areas of 180–420 m2 g?1 (HS-CrF3). The stepwise reaction starts with the oxidative decomposition of the cationic part of the precursor with F2 that gives a CrF3 intermediate with low surface area. In the following step, part of Cr3+ is oxidized to Cr>3+, and in the presence of residual H2O/[H3O]+ species Cr>3+ fluoride oxides are formed. Formation of volatile chromium compounds, mainly CrO2F2, is apparently the key step in HS-CrF3 formation. Removal of these components from the final product reduces the oxygen content, and generates microporosity. The HS-CrF3 materials are completely amorphous with a bulk composition that is close to stoichiometric CrF3. Small amounts of Cr>3+ and oxygen in the final product very likely originate from the retained non-volatile CrOF3. The HS-CrF3 materials are Lewis acids and exhibit a high reactivity towards chlorofluorocarbons (CFCs)evidenced by substantial F/Cl exchange between CFCs and the solid fluoride. High reactivity of these new materials can be ascribed to their nanoscopic nature, exceptionally high surface area, and low levels of impurities. As such, they represent an interesting new class of benchmark fluoride materials applicable in fluorocarbon chemistry.
- Tav?ar, Ga?per,Skapin, Toma?
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- PROCESS FOR PREPARING FLUORINE-CONTAINING PROPANE
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The present invention provides a process for preparing a fluorine-containing propane represented by the formula: CF2XCF2CH3 wherein X is F or Cl, the process including reacting tetrafluoroethylene and methyl chloride in the presence of an antimony halide represented by the formula: SbFxC5-x wherein x is a value of 0 to 5. According to the present invention, the fluorine-containing propane represented by the formula: CF2XCF2CH3 wherein X is F or Cl, which is useful as a starting material of 2,3,3,3-tetrafluoropropene (1234yf), can be obtained by a simple process, using relatively inexpensive starting materials.
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Page/Page column 8-9
(2010/12/17)
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- PROCESSES FOR PRODUCING CHLOROFLUOROCARBON COMPOUNDS USING INORGANIC FLUORIDE
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Methods and systems for producing chlorofluorocarbon 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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- PROCESS FOR RECOVERING PENTAFLUOROETHANE, AND PRODUCTION METHOD OF PENTAFLUOROETHANE INVOLVING THE PROCESS
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The process for recovering pentafluoroethane of the invention includes bringing a mixed gas containing pentafluoroethane and a non-condensable gas into contact with a chlorinated solvent, and allowing the chlorinated solvent to absorb pentafluoroethane contained in the mixed gas. The process for the production of pentafluoroethane of the invention uses the recovering process.
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Page/Page column 20-21
(2008/06/13)
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- Catalytic conversion of hydrofluoroalkanol to hydrofluoroalkene
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Methane is used as the selective dehydrating agent for the production of 2,3,3,3-tetrafluoro-1-propene (R1234yf) from 2,2,3,3,3-pentafluoro-1-propanol. Supported transition metal catalysts are prepared and used for this reaction with high activity. Almost 58% selectivity to R1234yf is obtained at an alcohol conversion level of 60% using unsupported Ni-mesh as the catalyst. Pd and Pt show almost similar level of conversion; however, the selectivity to the desired product is low. The activity of the metal catalyst was found to be a function of the type of support material, activated carbon showing better activity than alumina. Different important process parameters such as temperature, pressure, and contact time are studied to optimize the process. High pressure and temperature are deleterious to the rate of 1234yf formation; yet, the highest yield to 1234yf is obtained while performing a reaction at 494° C. with a contact time of 23 sec.
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(2008/06/13)
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- Nitrogen trifluoride as an oxidative co-reagent in high temperature vapor phase hydrofluorinations
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Nitrogen trifluoride (NF3) has proven to be a useful additive in high temperature vapor phase hydrofluorination reactions of chlorocarbons. The activity of chromium-based catalysts is maintained by introducing a co-stream of NF3 into the reagent chlorocarbon and HF stream. NF3 is a desirable additive instead of O2 as there is no water generation due to its use.
- Belter, Randolph K.,Sweval, Mark S.,Iikubo, Yuichi
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p. 816 - 820
(2008/03/27)
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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 11; 16
(2008/06/13)
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- Processes for the purification and use of 2-chloro-1,1,1,2,3,3,3-heptafluoropropane and zeotropes thereof with HF
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A process is disclosed for the separation of a mixture of HF and CF3CClFCF3. The process involves placing the mixture in a separation zone at a temperature of from about ?30° C. to about 100° C. and at a pressure sufficient to maintain the mixture in the liquid phase, whereby an organic-enriched phase comprising less than 50 mole percent HF is formed as the bottom layer and an HF-enriched phase comprising more than 90 mole percent HF is formed as the top layer. The organic-enriched phase can be withdrawn from the bottom of the separation zone and subjected to distillation in a distillation column to recover essentially pure CF3CClFCF3. The distillate comprising HF and CF3CClFCF3can be removed from the top of the distillation column while essentially pure CF3CClFCF3can be recovered from the bottom of the distillation column. The HF-enriched phase can be withdrawn from the top of the separation zone and subjected to distillation in a distillation column. The distillate comprising HF and CF3CClFCF3can be removed from the top of the distillation column while essentially pure HF can be recovered from the bottom of the distillation column. If desired, the two distillates can be recycled to the separation zone. Also disclosed are compositions of hydrogen fluoride in combination with an effective amount of CF3CClFCF3to form an azeotrope or azeotrope-like composition with hydrogen fluoride. Included are compositions containing from about 38.4 to 47.9 mole percent CF3CClFCF3. Also disclosed are processes for producing 1,1,1,2,3,3,3-heptafluoro-propane. One process uses a mixture comprising HF and CF3CClFCF3and is characterized by preparing essentially pure CF3CClFCF3as indicated above, and reacting the CF3CClFCF3with hydrogen. Another process uses an azeotropic composition as described above, and reacts the CF3CClFCF3with hydrogen in the presence of HF. Also disclosed is a process for producing hexafluoropropene. This process is characterized by preparing essentially pure CF3CClFCF3as indicated above, and dehalogenating the CF3CClFCF3.
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Page column 7
(2008/06/13)
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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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- Materials and methods for the conversion of hydrofluorocarbons
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Methods and materials are disclosed for the recovery of valuable hydrofluorocarbons and subsequent conversion to environmentally inert compounds. More specifically methods and materials are provided for recovering hydrofluorocarbons such as HFC-227, HFC-236, HFC-245, HFC-125, HFC-134, HFC-143, HFC-152, HFC-32, HFC-23 and their respective isomers. Processes are provided for converting hydrofluorocarbons such as these to fluoromonomer precursors such as CFC-217, CFC-216, CFC-215, CFC-115, CFC-114, CFC-113, CFC-112, HCFC-22, CFC-12, CFC-13 and their respective isomers. Materials, methods and schemes are provided for the conversion of these fluoromonomer precursors to fluoromonomers such as HFP, PFP, TFP, TFE, and VDF.
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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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- Preparation of 1-X-2,2-Difluoroethenylxenon(II) Tetrafluoroborates [CF 2=CXXe][BF4]
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The new type of alkenylxenon(II) salts [CF2=CXXe] [BF 4] (X = H, Cl, CF3) was prepared by reacting the corresponding alkenyldifluoroboranes CF2=CXBF2 with XeF2 in 1,1,1,3,3-pentafluoropropa
- Frohn, Hermann-Josef,Bardin, Vadim V.
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p. 2465 - 2469
(2008/10/09)
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- Process for producing 1,1,1,2,2-pentafluoroethane
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A process for producing 1,1,1,2,2-pentafluoroethane by fluorinating with hydrogen fluoride at least one of 2,2-dichloro-1,1,1-trifluoroethane and 2-chloro-1,1,1,2-tetrafluoroethane as a starting material, the process being characterized by separating the reaction mixture resulting from the fluorination into a product portion A mainly containing 1,1,1,2,2-pentafluoroethane and a product portion B mainly containing 2,2-dichloro-1,1,1-trifluoroethane, 2-chloro-1,1,1,2-tetrafluoroethane and hydrogen fluoride, removing a fraction mainly containing 2,2-dichloro-1,1,1,2-tetrafluoroethane from the product portion B, and recycling the rest of the product portion B as part of feedstocks for fluorination. According to the process of the invention, the amount of CFC-115 contained in the target HFC-125 can be remarkably reduced through a simplified procedure.
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(2008/06/13)
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- Conversion of 1,1,2-trichlorotrifluoroethane to 1,1,1-trichlorotrifluoroethane and 1,1-dichlorotetrafluoroethane over aluminium-based catalysts
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Conversion of CCl2FCClF2 to CCl2FCF3 is achieved in the temperature range, 593-713 K, under flow conditions by using the catalysts, β-AlF3 or γ-alumina, prefluorinated with CCl2F2/sub
- Bozorgzadeh,Kemnitz,Nickkho-Amiry,Skapin,Winfield
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- FTIR spectroscopic and reaction kinetics study of the interaction of CF3CFCl2 with γ-Al2O3
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The interaction of CF3CFCl2 with γ-Al2O3 has been investigated by a combination of reaction kinetics experiments and FTIR spectroscopic studies. The reaction of fresh γ-Al2O3 with CF3CFCl2 at 573 K resulted in the fluorination of the γ-Al2O3 surface. The reaction also resulted in dehydroxylation of the γ-Al2O3 and an increase in both the number and strength of Lewis acid sites on the surface. The fluorinated γ-Al2O3 was catalytically active for the disproportionation of CF3CFCl2 to CF3CCl3 and CF3CF2Cl at 353 K. Adsorption of CF3CFCl2 on γ-Al2O3 at temperatures between 298 and 523 K resulted in the formation of surface trifluoroacetate species, which were stable up to 573 K. These species are likely to be the intermediates for the complete oxidation of CF3CFCl2 to CO and CO2. The transformation of γ-Al2O3 as a result of the CF3-CFCl2 adsorption and reaction is discussed.
- Deshmukh, Subodh S.,Kovalchuk, Vladimir I.,Borovkov, Victor Yu.,D'Itri, Julie L.
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p. 1277 - 1284
(2007/10/03)
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- vic-difluorination of fluoroalkenes with xenon difiuoride: The effect of fluorine substituents on the reaction of alkenes with xenon difluoride
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vic-Difluorination proceeds by the reaction of fluoroalkenes with xenon difluoride to afford the corresponding fluorinated compounds. From the reaction with polyfluoroalkenes, the products are obtained in high to excellent yields. In this reaction, the fluorine atom substituent of alkene stabilizes the cation intermediate and suppresses side-reactions such as rearrangement.
- Tamura, Masanori,Quan, Heng-Dao,Sekiya, Akira
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p. 3151 - 3153
(2007/10/03)
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- DIRECT GAS-PHASE CATALYTIC FLUORINATION OF PARTIALLY FLUORINATED ORGANIC COMPOUNDS
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The fluorination of a wide range of polyfluorinated organic compounds with molecular fluorine in the gas phase in a layer of NiF2/support as catalyst was investigated.It was shown that the selectivity of fluorination of the series of fluoroolefins, acid fluorides, polyfluoroalkanes, and hydrogen-containing ethers can be greatly increased.The developed method was used on an industrial scale in the production of perfluorinated liquids.
- Zakharov, V. Yu.,Denisov, A. K.,Novikova, M. D.
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p. 1942 - 1945
(2007/10/03)
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- OPTIMIZATION OF PHYSICOCHEMICAL PROPERTIES AND CONDITIONS OF PREPARATION OF CATALYSTS USED FOR THE SYNTHESIS OF FLUORINATED ORGANIC COMPOUNDS
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The physicochemical properties of magnesium fluoride and chromium-magnesium fluoride catalyst, and their activities in dehydrochlorination and fluorination of chlorinated aliphatic hydrocarbons have been studied as functions of preparation conditions.The optimal characteristics of the catalysts (Ssp, VΣ, Vmi, Vma, P) with respect to dehydrochlorination of tetrachloropropane and fluorination of trifluorotrichloroethane have been found.The dependence of the activities of MgF2 and CrF3/MgF2 on their porous structure has been revealed.The optimal technological parameters have been determined, which ensure preparation of magnesium fluoride and chromium-magnesium fluoride catalysts with required physicochemical properties.
- Kramerova, G. E.,Dul'tseva, Z. A.,Yurchenko, E. N.
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- Synthesis of functionalized polyfluoroalkyl hypochlorites and fluoroxy compounds and their reactions with some fluoroalkenes
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Several new polyfluoroalkyl hypochlorites and fluoroxy compounds containing Cl, H and Br in the alkyl group have been prepared and characterized by 19F NMR, 1H NMR and IR spectroscopies and by their reactions with fluoroalkenes to produce new polyfluoroethers.The novel compounds are prepared by the CsF-catalyzed addition of F2 or ClF to the C=O bond in CF3C(O)CF2Cl, ClCF2C(O)CF2Cl, and their derivatives HCF2C(O)CF3 and HCF2C(O)CF2Cl.Compounds containing an α-CF3 group exhibit enhanced thermal stability.New fluoroxy compounds and hypochlorites have also been prepared from the acid fluorides CF3-CFX-C(O)F (X = Cl, Br), which are obtained by the ring-opening reaction of hexafluoropropene oxide with (CH3)3SiCl, LiBr and (C2H5)3SiBr.These -OX compounds behave similarly to previously known materials with two α-F atoms, decomposing quickly at room temperature to COF2 and haloalkanes.
- Randolph, Bruce B.,DesMarteau, Darryl D.
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p. 129 - 150
(2007/10/02)
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- REACTION OF ORGANIC COMPOUNDS WITH SF4-HF-HALOGENATING SYSTEM VII. REACTIONS OF OLEFINS WITH THE SF4-HF-Cl2(Br2) SYSTEM
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Under the influence of the SF4-HF-Cl2(Br2) system halogen-containing olefins undergo conjugate halogenofluorination.It was shown for the case of (Z)- and (E)- 1,2-dichloroethenes that these reactions take place anti-stereospecifically through the formation of the bromonium ions.The accumulation of chlorine atoms in the olefin molecule hinders electrophilic addition of stoichiometric equivalents of ClF and BrF at the double bond.The SF4-HF-Br2 system is an effective agent for substitutive fluorination of organic compounds containing bromine.Only the bromine atoms situated at the secondary carbon atom are substituted by fluorine.
- Kunshenko, B. V.,Mokhamed, Nagib Mukhtar,Omarov, V. O.,Muratov, N. N.,Yagupol'skii, L. M.
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p. 511 - 518
(2007/10/02)
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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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- SYNTHESIS OF PENTAFLUOROSELENIUMOXIDE FLUOROCARBONS
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The reaction of xenon bis-pentafluoroseleniumoxide, Xe(OSeF5)5, with the haloolefins, CF2=CF2, CF3CF=CF2, CF2=CFCl, and CF2=CFH, results in the low to moderate yield addition of two SeF5O- groups to the double bond.These are the first examples of this type of addition.From c-C5F8 and the above olefins these same reactions also gave as products, C2F5OSeF5, n-C3F7OSeF5, c-C5F9OSeF5, and SeF5OCF2COCl in higher yields than the bis SeF5O- compounds.Surprisingly, those olefins capable of forming thermally stable epoxides, i.e.C3F6 and c-C5F8, were found to produce significant yields of the corresponding epoxides as a by-product in these reactions, while the remaining olefins gave significant amounts of acid fluorides instead.Characterizing data are presented for all of these new RfOSeF5 compounds.
- Schack, Carl J.,Christe, Karl O.
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p. 163 - 172
(2007/10/02)
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- Kinetics of C2F5 Radical Reactions with HCCl3 and DCCl3 in tha Gas Phase
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The kinetics of pentafluoroethyl radical reactions with trichloromethane and d-trichloromethane have been studied in the static system using perfluoropropionic anhydride as a photolytic source of C2F5 radicals.The Arrhenius parameters for C2F5 radical reactions with HCCl3 and DCCl3 , based on log A 3 mol-1 s-1> = 13.40 and E=0 for the recombination reaction of C3F5 radicals, are: .The magnitude of the primary kinetic isotope effect, i.e. kH/kD=6.7 +/-4.3 at 400 K is shown to be slightly larger than might be expected on the basis of standard zero-point energy model.
- Drys, Andrzej,Ratajczak, Emil
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p. 569 - 575
(2007/10/02)
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- Continuous process for the gaseous-phase preparation of trichlorotrifluoroethane, dichlorotetrafluoroethane and monochloropentafluoroethane in controlled proportions
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This invention relates to a continuous gaseous-phase process for the preparation of trichlorotrifluoroethane, dichlorotetrafluoroethane and monochloropentafluoroethane, in predetermined proportions, from tetrachloroethylene, chlorine and hydrofluoric acid in the presence of a catalyst. The process is characterized by the combination of two chlorination-fluorination reactors in sequence, a parallel fluorination-dismutation reactor, and a separation unit for extracting the desired products and recycling recovered hydrofluoric acid and non-fluorinated or insufficiently fluorinated products. The process advantageously yields dichlorotetrafluoroethane containing less than 7% asymmetric isomer, and trichlorotrifluoroethane containing less than 2% asymmetric isomer.
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- RADIOTRACERS IN FLUORINE CHEMISTRY. PART IX FLUORINATION OF CHLOROFLUOROETHANES BY CHROMIA CATALYSTS TREATED WITH HYDROGEN FLUORIDE OR HYDROGEN -FLUORIDE
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Passage of dichlorotetrafluoroethane isomers or 1,1,2-trichloro-1,2,2-trifluoroethane at temperatures >/= 623 K over chromia catalysts, previously treated with hydrogen fluoride at 623 K, leads to the formation of fluorinated and chlorinated products.Incorporation of fluorine-18 radioactivity in the products is observed when hydrogen -fluoride is used in the catalyst pretreatment, indicating the involvement of a surface fluorinecontaining species.The reactions observed are described in terms of series of F-for-Cl and Cl-for-F halogen exchange reactions occurring at the catalyst surface.
- Kijowski, Jerzy,Webb, Geoffrey,Winfield, John W.
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p. 213 - 230
(2007/10/02)
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- The preparation of bis(perfluoroethyl) tellurium difluoride and dichloride, trans perfluoroethyl tellurium monochloride tetrafluoride, trans bis(perfluoroethyl) tellurium tetrafluoride; and the preparation and X-ray crystal structure of perfluoroethyl tellurium trifluoride
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The reaction of (C2F5)2Te and XeF2 in a slurry of SO2ClF yielded (C2F5)2TeF2 essentially quantitatively.Chlorine and (C2F5)2Te gave (C2F5)2TeCl2.Both (C2F5)2TeF2 and (C2F5)2TeCl2 were assigned a trigonal bipyramidal geometry, on the basis of their 19F nmr and vibrational spectra, with the lone pair and C2F5 groups in equatorial, and the halogens in the axial positions.Perfluoroethyl tellurium trifluoride was prepared essentially quantitatively by the reaction of C2F5TeTeC2F5 and XeF2 in liquid SO2F2.The generally inert SO2ClF was found to react with C2F5TeTeC2F5 to give C2F5TeClxF3-x and sulphur dioxide.The structure of C2F5TeF3 was determined by X-ray diffraction.The crystals are tetragonal with a=10.129(4), c=25.561(6) Angstroem, and Z=16.The structure was refined in space group I41/a to a conventional R factor of 0.051 for 901 observed reflections with I>/=3?(I).Each tellurium atom is surrounded by two terminal fluorine atoms and two bridging fluorine atoms and a C2F5 group in an axial position around the apex of a distorted square pyramid.The square-pyramidal units are linked by symmetrical cis bridging atoms into endless chains with bridging angles of 180o and 177o.The geometry of the (C2F5TeF4) group is consistent with steric activity of the non-bonded electron pair.The 19F nmr and Raman spectra of C2F5TeF3 were recorded and the Raman spectrum assigned.Trans-C2F5TeClF4 was prepared by the reaction of C2F5TeTeC2F5, and an excess of ClF.The trans octahedral geometry of C2F5TeClF4 was unambiguously assigned from its 19F nmr and vibrational spectra.A mixture of trans-(C2F5)2TeF4 and trans-C2F5TeClF4 was obtained from the reaction of (C2F5)2Te and an excess of ClF.Trans geometry of (C2F5)2TeF4 was unambiguously assigned from its 19F nmr spectrum.
- Lau, Clement,Passmore, Jack,Richardson, E. Keith,Whidden, Tom K.,White, Peter S.
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p. 2273 - 2280
(2007/10/02)
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- THERMOLYSE DES HALOGENURES DE PERFLUOROALCANESULFONYLE
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Perfluoroalkanesulfonyl chlorides FSO2Cl; RF= CF3, C2F5, C4F9>, decompose thermally to give the corresponding perfluoroalkyl chlorides with evolution of SO2.The latter retards the reaction, but it is catalysed by copper which also inhibits the SO2 effect. 2-methyl-2-nitrosopropane traps the perfluoroalkyl free radicals.In the presence of a perfluoroalkyl iodide FI; R'not equal RF>, other products, RFI and RFCl, are obtained.A free radical chain-mechanism is then suggested.On the other hand, perfluorobutanesulfonyl fluoride is very stable thermally.
- Oudrhiri-Hassani, M.,Brunel, D.,Germain, A.,Commeyras, A.
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p. 491 - 504
(2007/10/02)
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- PREPARATION OF CHLOROPENTAFLUOROETHANE FROM DICHLOROTETRAFLUOROETHANE
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Gaseous fluorination with hydrogen fluoride at atmospheric pressure of the two isomers CClF2-CClF2 and CCl2F-CF3 was carried out continuously on a chromic oxide based catalyst.The fluorinated derivative, obtained in a yield greater than 90percent, was chloropentafluoroethane.Hexafluoroethane and an isomeric mixture of trichlorotrifluoroethane were obtained as by-products.The latter was recycled with unconverted C2Cl2F4 for further fluorination.Both conversion of C2Cl2F4 and selectivity to the formation of C2ClF5 were affected by temperature, contact time and molar ratio of the reagents.The catalytic activity of chromic oxide was adversely affected by small amounts of water in the hydrogen fluoride.A difference was also observed in the reactivity of the two isomers CCl2F-CF3 and CClF2-CClF2.The formation of C2Cl3F3 as a by-product was due to the disproportionating activity of chromic oxide upon C2Cl2F4.
- Marangoni, L.,Gervasutti, C.
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- Reaction of Pentafluoroethyl Radicals with Cyanogen Chloride
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The reaction of C2F5 radicals with cyanogen chloride was studied between 293 and 573 K, using perfluoroethyl iodide as the free-radical source. The main product, C2F5Cl is formed via an addition reaction or by abstraction of a chlorine atom by C2F5.The reactions involved are C2F5+ClCN->C2F5Cl+CN (2) C2F5+ClCN->/C2F5Cl+CN (4) C2F5+C2F5->C4F10 The Arrhenius plot shows pronounced curvature.The following rate constants were obtained for reactions (2) and (4) where kc is the rate constant for C2F5 combination. The results are compared with those for the reaction of CF3 with ClCN.
- Voehringer, Cecilia M. de,Staricco, Eduardo H.
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p. 3493 - 3498
(2007/10/02)
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- DIE ELEKTROFLUORIERUNG VON Α-CHLORETHYLSULFOCHLORID
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The electrochemical fluorination of CH3CHClSO2Cl was studied at different conditions.Besides methane- and ethane-derivates, SO2F2 and SF6, the products formed are the two sulfonylfluorides C2F5SO2F and CF3CFClSO2F.The yield of CF3CFClSO2F was greater at l
- Sartori, P.,Habel, W.
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p. 131 - 142
(2007/10/02)
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- HALOGEN FLUOROSULFATE REACTIONS WITH FLUOROCARBONS
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The scope of the reaction of simple fluorocarbon halides with chlorine fluorosulfate and mixtures of chlorine and bromine fluorosulfate to produce RfOSO2F compounds has been investigated.It is shown that in many cases even primary chlorine in -CF2Cl groups can be replaced by -OSO2F.Primary bromine or iodine in -CF2X are more readily replaced.The mechanism of this replacement reaction has been established by the isolation of the metastable iodine III intermediate RfI(OSO2F)2.Neither secondary chlorine nor bromine in -CFX- groups is affected.With the secondary iodide, i-C3F7I, the salt + - is formed.Furthermore, it has been found that ClOSO2F is capable of converting fluorocarbon acids or their derivatives into fluorocarbon halides.A combination of these two ClOSO2F reactions with the known conversion of RfCF2OSO2F to the corresponding fluorocarbon acid offers a novel, high yield chain shortening reaction for the otherwise unreactive fluorocarbon halides according to:
- Shack, Carl J.,Christe, K. O.
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