- The behaviour of chlorofluoroethanes on β-aluminium(III) fluoride: A [ 36Cl ] radiotracer study
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A [36Cl] radiotracer study of the behaviour of 1,1,2-trichlorotrifluoroethane on β-aluminium(III) fluoride at elevated temperature indicates that the isomerisation of CCl2FCClF2 to CCl3CF3 occurs by an intramolecular process. Isomerisation is followed by dismutation of CCl3CF3 to give CCl2FCF3 and CCl3CClF2. In neither reaction, surface Al-Cl groups are formed. The compound CCl3CClF2 undergoes further reaction, readily, apparently also via dismutation processes.
- Bozorgzadeh, Hamid,Kemnitz, Erhard,Nickkho-Amiry, Mahmood,Skapin, Toma?,Tate, Graeme D.,Winfield, John M.
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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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- 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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- 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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- 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 OF CHLORINATING HYDROCHLOROFLUOROOLEFIN TO PRODUCE CHLOROFLUOROOLEFIN
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The present disclosure provides a process for the preparation of chlorofluoroolefin. The process involves chlorinating a hydrochlorofluoroolefin of the formula R1CH=CCIR2 to produce a product mixture comprising a chlorofluoroolefin of the formula R1CCI=CCIR2; wherein R1 and R2 are perfluoroalkyi groups independently selected from the group consisting of CF3, C2F5, n-C3F7, i-C3F7, n-C4F9, i-C4F9 and t- C4Fg.
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(2013/03/28)
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- PROCESSES FOR THE SYNTHESIS OF 2-CHLORO-1,1,1,3,3,4,4,4-HEPTAFLUORO-2-BUTENE AND HEXAFLUORO-2-BUTYNE
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Disclosed is a process comprising reacting CF3CCl2CF2CF3 (CFC-318ma) with hydrogen in the presence of a dehalogenation catalyst to produce CF3CCl=CFCF3(CFC-1317mx). Also disclosed is a process comprising reacting CF3CCl═CFCF3 (CFC-1317mx) with hydrogen in the presence of a dehalogenation catalyst to produce CF3C≡CCF3 (hexafluoro-2-butyne). Hexafluoro-2-butyne can be used to produce CF3CH═CHCF2CF3 (1,1,1,4,4,5,5,5-octafluoro-2-pentene).
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(2009/07/03)
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- PROCESS FOR THE PRODUCTION OF 1,1,1,3,3,3-HEXAFLUOROPROPANE
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A process for the preparation of 1,1,1,3,3,3-hexafluoropropane is disclosed. The process involves (a) contacting at least one halopropane of the formula CF3CH2CHyX3-y (where each X is independently F, Cl or Br, and y is 3, 2, or 1) with Cl?2#191 in the presence of light or a free radical initiator to produce a mixture comprising CF3CH2CCIyX3-y; (b) contacting the CF3CH2CCIyX3-y produced in step (a) with HF, optionally in the presence of a fluorination catalyst, to produce a product mixture comprising CF3CH2CF3; and (c) recovering CF3CH2CF3 from the mixture produced in step (b).
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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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- 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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- 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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- Generation of radical species in surface reactions of chlorohydrocarbons and chlorocarbons with fluorinated gallium(III) oxide or indium(III) oxide
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The reactions of C1 and C2 chlorohydrocarbons and chlorocarbons have been studied with the Lewis acid catalysts fluorinated gallium(III) oxide and fluorinated indium(III) oxide, respectively. Product analysis shows chlorine-for-fluorine exchange reactions together with the formation of 2-methylpropane and its chlorinated analogues 2-chloromethyl-1,3-dichloropropane and 2-chloromethyl-1,2,3-trichloropropane. Reactivities of the chlorohydrocarbon probe molecules show fluorinated gallium(III) oxide to be a stronger Lewis acid than fluorinated indium(III) oxide. The formation of the symmetrical butyl compounds is consistent with the generation of surface radical species and is also consistent with a 1,2-migration mechanism operating within radical moieties at the Lewis acid surface.
- Thomson
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p. 1881 - 1885
(2007/10/03)
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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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- Stabilization of chlorofluoroalkanes
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A method of stabilizing a composition comprising a chlorofluoroalkane and an amine or amine-based polyol comprising incorporating into said composition an effective stabilization promoting amount of at least one but-3-en-1-ol compound and compositions comprising at least one chlorofluoroalkane and a stabilization promoting but-3-en-1-ol.
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- REACTION OF PHOSPHORUS PENTACHLORIDE WITH PERHALO CARBONYL-CONTAINING COMPOUNDS
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The reaction between PCl5 and the carbonyl oxygen in a variety of perfluoro compounds containing the carbonyl functional group, e.g.RfC(O)R'f, RfC(O)X or XC(O)RfC(O)X, where X = Cl, F, OH, NH2, and ONH4 has led to a convenient synthesis procedure for fluorochlorocompounds.Monoketones, e.g.RfC(O)R'f, yield RfCCl2R'f compounds, while the diketones, e.g.RfC(O)(CF2)nC(O)R'f, also react to yield the fluorochloro compounds.When n = 3, RfCCl2(CF2)3CCl2R'f is produced in quite high yields (65 percent); however, when n = 2, the principal product is a cyclic fluorodichloroether compound while the fluorotetrachloro compound is the minor product.The RfC(O)X and XC(O)RfC(O)X compounds produce RfCCl3 and Cl3CRfCCl3 respectively in high yields.Reaction temperature and pressure are important factors for high yield synthesis.
- Chen, Loomis S.,Chen, Grace J.
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p. 371 - 388
(2007/10/02)
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- GAS PHASE REACTION OF CF3CN AND OTHER NITRILES WITH CHLORINE ATOMS
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The photolytically induced reaction of Cl2 with some nitriles was investigated in the gas phase at room temperature.The reaction with CF3CN produced CF3CCl=NCl, CF3CCl=N-N=CClCF3 and CF3CCl3 as well as minor quantities of CF3(Cl)C=N-CCl2CF3, CF3CCl2(CF3)C=N-N=C(Cl)CF3, CF3CCl2-N=N-CCl2CF3, CF3CCl2(CF3)C=N-CCl2CF3 and CF3CCl2(CF3)C=N-N=C(CF3)CCl2CF3. ClCN reacted in a similar way giving CCl2=NCl, CCl2=N-N=CCl2 and CCl4 as principal products. On the other hand, when HCN was allowed to react with chlorine atoms, only ClCN, CCl2=NCl and CCl4 were obtained.No compounds containing C-H bonds were found. Possible reaction schemes taking into account the products obtained are discussed.
- Vohringer, C. M. de,Staricco, E. R. de,Staricco, E. H.
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- Aluminium Chloride Induced Isomerisation of 1,1,2-Trichlorotrifluoroethane and 1,2-Difluorotetrachloroethane
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Under comparable conditions, the isomerisation of 1,1,2-trichlorotrifluoroethane (I) to 1,1,1-trichlorotrifluoroethane (II) is more difficult than the isomerisation of 1,2-difluorotetrachloroethane (III) to 1,1-difluorotetrachloroethane (IV).Advantageously, III was isomerised to IV in the presence of I or II.The degree of isomerisation of the starting compounds I and III was 95-99percent, the preparative yield of IV being 65-74percent.The C-F bond energies in I-IV were derived from correlation diagram and the physico-chemical aspects of the isomerisation are discussed.
- Paleta, Oldrich,Liska, Frantisek,Posta, Antonin,Dedek, Vaclav
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p. 104 - 114
(2007/10/02)
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- DETERMINATION OF HEATS OF VAPORIZATION AND SOME OTHER THERMODYNAMIC QUANTITIES FOR SEVERAL FLUORINATED HALOGEN DERIVATIVES OF ETHANE AND PROPANE
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Some physico-chemical properties were determined for 1,1,1-trichlorotrifluoroethane, 1,1,2-trichlorotrifluoroethane, 1-bromo-1-chloro-2,2,2-trifluoroethane and 1,2-dichlorohexafluoropropane.For all the substances, their heats of vaporization in dependence on temperature were measured and their densities and refractive indices at two temperatures were determined.For 1,1,1-trichlorotrifluoroethane and 1,2-dichlorohexafluoropropane the saturated vapour pressures were measured, too.The temperature dependences of standard heats of vaporization, vaporization internalenergies and cohesive energies were determined on the basis of the experimental data.
- Majer, Vladimir,Svoboda, Vaclav,Posta, Antonin,Pick, Jiri
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p. 3063 - 3068
(2007/10/02)
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