- 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 9-10
(2010/12/17)
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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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- Process for preparing fluorohalogenethers
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A process for preparing (per)fluorohalogenethers having general formula: wherein: A and A', equal to or different from each other, are selected among Cl, Br, H; m=1, 2; n=0, 1; R1 is a fluorinated substituent, preferably perfluorinated, selected from the following groups: C1-C20 linear or branched alkylic; C3-C7 cycloalkylic; aromatic, C6-C10 arylalkyl; heterocyclic or C5-C10 alkylheterocyclic; preferably perfluoroalkyl; R' is as defined in the application; by reaction of carbonyl compounds having formula: wherein: R1 and n are as above; u=0, 1; R' is as defined in the application; in liquid phase, with elemental fluorine and with olefinic compounds of formula:CAF=CA'F2 wherein A and A' are as above, at temperatures from -120°C to -20°C, preferably from -100°C to -40°C, optionally in the presnece of an inert solvent under the reaction conditions.
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Page/Page column 5-6
(2008/06/13)
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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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- 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 preparing (per) fluorohalogenethers
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A process for preparing (per)fluorohalogenethers containing the —SO2F group, having general formula (I): FSO2—R—CF2OCAF—CA′F2??(I) wherein: A and A′, equal to or different from each other, are Cl or Br; R has the following meanings: a (per)fluorinated, preferably perfluorinated, substituent, optionally containing one or more oxygen atoms; by reaction of carbonyl compounds having formula (II): FSO2—R—COF??(II) wherein 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, operating at temperatures from ?120° C. to ?20° C., optionally in the presence of a solvent inert under the reaction conditions.
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- New perfluorovinylethers through the bis(fluoroxy)difluoromethane (BDM) chemistry
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In the present work we give an overview of the CF2(OF) 2 radical reactivity and report the synthesis of new perfluorovinylethers. CF2=CF-OCF2OCF2 CF3 and CF2=CF-OCF2OCF2 CF2OCF3 are prepared in a semi-continuous methodology starting from CF2(OF)2. These highly reactive vinylethers are characterized by the OCF2O group directly bonded to the insaturation. For this reason they are excellent candidates for the preparation of very low Tg perfluororubbers.
- Navarrini, Walter,Corti, Sandra
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p. 189 - 197
(2007/10/03)
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- Process for preparing (per)fluorohalogenethers
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A process for preparing (per)fluorohalogenethers containing the -SO2F group, having general formula (I):FSO2-R-CF2OCAF-CA' F2 wherein:A and A', equal to or different from each other, are Cl or Br;R has the following meanings: a (per)fluorinated, preferably perfluorinated, substituent, optionally containing one or more oxygen atoms; by reaction of carbonyl compounds having formula (II):FSO2-R-COF wherein 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, operating at temperatures from -120°C to -20°C, optionally in the presence of a solvent inert under the reaction conditions.
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Page column 6-7
(2008/06/13)
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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 5
(2008/06/13)
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- 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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p. 225 - 232
(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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- 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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- Threshold Energies and Substituent Effects for Unimolecular Elimination of HCl (DCl) and HF (DF) from Chemically Activated CF2ClCH3 and CF2ClCD3
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Chemically activated CF2ClCH3-d0 and -d3 were prepared with 101 and 102 kcal/mol of internal energy, respectively, by the combination of CF2Cl with methyl-d0 and -d3 radicals at 300 K.The CF2ClCH3 reacts by loss of HCl and HF with rate constants of (2.5 +/- 0.4) x 109 and (0.10 +/- 0.02) x 109 s-1, respectively, a branching ratio of 25:1 in favor of HCl.The CF2ClCD3 has rate constants of (0.78 +/- 0.12) x 109 for loss of DCl and 0.033 +/- 0.005 x 109 sec-1 for loss of DF.The combined primary and secondary isotope effect was 3.2 +/- 0.9 for HCl/DCl elimination and 3.0 +/- 0.9 for loss of HF/DF.RRKM theory was used to model these unimolecular rate constants to determine the threshold energy barriers, E0's, for the four-centered elimination reactions.The E0's were 55 +/- 2 kcal/mol for dehydrochlorination and 69.5 +/- 2 kcal/mol for dehydrofluorination.These threshold barriers are in sharp disagreement with prediction based on trends in the E0's for a series of mono-, di-, and trisubstituted chloroethanes and a similar series of fluoroethanes.An analysis of the E0's for the chloroethanes, fluoroethanes, and chlorodifluoroethane suggests that the carbon-halogen bond in the transition state changes from a nearly neutral C-Cl bond for HCl loss to a C-F bond that has much greater charge separation when HF is eliminated.
- Jones, Yukari,Holmes, Bert E.,Duke, David W.,Tipton, Debbie L.
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p. 4957 - 4963
(2007/10/02)
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- Kinetics and Mechanisms of the CO2 Laser Induced Decompositions of CFCl3 and CF2Cl2
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The kinetics and reaction mechanisms of the decomposition of CFCl3 and CF2Cl2 induced by a continuous CO2 laser are examined and compared with previous results for CF3Cl.All three compounds exhibit two temperature regimes, with similar reaction mechanisms in the low-temperature regimes and significantly different mechanisms in the high-temperature regimes.
- Zitter, R. N.,Koster, D. F.,Choudhury, T. K.,Cantoni, A.
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p. 2374 - 2377
(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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- 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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- DEPENDENCE OF THE UNIMOLECULAR DISSOCIATION PRODUCTS ON THE FLUENCE OF THE CO2 LASER BEAM
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The dissociation products of CF2Cl2 irradiated in the line P20 at 9.17 μm with pulses of fluence as high as 60E4 J*m-2 depend on the pressure of the gas, giving rise to C2F4 only when the pressure is of the order of 2 mb.At remarkably lower fluence (2E4 J*m-2) this product appears however in a wide range of pressures. For CF2HCl, C2F4 is the only product that appears at fluences as high as 60E4 J*m-2).At lower fluences (2.5E4 J*m-2), less C2F4 is produced and another product, probably a halogenated derivative of butane, is obtained.
- Santos, M.,Hernandez-Vara, R.,Herreros, J. M.,Gonzales-Diaz, P. F.
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p. 533 - 536
(2007/10/02)
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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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- Photochemistry of Anhydrides. Part 6.-Photolysis of Chlorodifluoroacetic Anhydride, (CF2ClCO)2O
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The photolysis of the vapour of chlorodifluoroacetic anhydride, (CF2ClCO)2O, has been studied over the range 19-201 deg C using 248 nm radiation.Quantum yields of the products CO, CO2, CF2ClCF2Cl and CF2Cl2 were measured with and without added quencher.The effective primary process is which is followed by .The ratio kc/kd is equal to 7.6 at 19 deg C and 4.7 at 201 deg C, both independent of pressure of anhydride and of perfluoromethylcyclohexane added as a quencher.The reactions of CF2Cl radicals from various photolytic sources are compared.
- Watkins, Paul E.,Whittle, Eric
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p. 2323 - 2330
(2007/10/02)
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- REACTIONS OF CHLORINE MONOFLUORIDE. SUBSTITUTION OF CHLORINE ATOMS BY FLUORINE IN CHLORINE-SUBSTITUTED ALKANES AND ESTERS
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In anhydrous hydrogen fluoride under mild conditions chlorine monofluoride selectively substitutes the chlorine atoms in chlorine-substituted alkanes and esters by fluorine with the formation of high yields of the corresponding fluorides.The presence of an alkoxycarbonyl group or difluoromethylene group at the α position to the CHCl group deactivates the chlorine atom, and substitution by fluorine does not occur.In chloroalkanes, from which elimination of the chloride ion leads to sufficiently stable carbocations, substitution by fluorine can be realized in the absence of hydrogen fluoride at temperatures between -20 and -60 deg C.The fluorinating capacity of chlorine monofluoride is increased in the presence of catalytic amounts (3-5percent) of antimony pentachloride.Here the reaction is less selective than in hydrogen fluoride.In certain cases substitution is accompanied by hydride transfers.
- Chuvatkin, N. N.,Panteleeva, I. Yu.,Boguslavskaya, L. S.
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p. 821 - 827
(2007/10/02)
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- Carbon-13 isotopic selectivity in the infrared multiphoton photolysis of CF2Cl2-O2 mixtures
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The infrared multiphoton chemistry of CF2Cl2-O2 mixtures has been studied at laser frequencies where the product CF2O is highly enriched in carbon-13.Yield enhancements with no loss of isotopic selectivity are attributed to suppression of radical-atom recombination reactions.It is demonstrated that addition of up to 60 Torr of either excess O2 or N2 suppresses a thermal, non-selective channel important at higher fluences.A selectivity factor greater than 30 is observed for 4 Torr CF2Cl2 in the presence of 80 Torr of oxygen.
- Nip, W. S.,Hackett, P. A.,Willis, C.
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p. 2703 - 2707
(2007/10/02)
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- Heterocyclic Polyfluoro-compounds. Part 31. Photochemical Oxetan Formation from Fluoroketones and Perfluoroaldehydes and 1,2-Difluoroethylene
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The photochemical addition of five fluoroketones (hexafluoro-, chloropentafluoro-, 1,3-dichlorotetrafluoro-, 1,1,3-trichlorotrifluoro-, and 1,1,1-trifluoro-propan-2-one) and the perfluoroaldehydes RFCHO (RF=CF3, C2F5, or n-C3F7) to (Z)- or (E)-1,2-difluoroethylene at λ > 300 nm has been studied.Oxetan formation dominates with hexafluoropropan-2-one, but there is increasing competition from reactions involving free radicals arising from photolysis of the ketone as the chlorine content is increased.Oxetan formation occurs with little stereospecificity.The aldehydes give r-2-perfluoroalkyl-t-3,c-4-, and -c-3,t-4-, and -t-3,t-4-difluoro-oxetans, in the ratio 1.0 : 1.7 +/- 0.2 : 1.3 +/- 0.1, respectively, and in high yield (78-94percent).A small amount of olefin isomerisation occurred. Flow pyrolysis of the oxetans from hexafluoroacetone yields (Z)- and (E)-1,2-difluoroethylene and the olefin (CF3)2C=CHF, the oxetan yields the olefins (Z)- and (E)-CHF=CHF and (CF2Cl)2C=CHF, and r-2-pentafluoroethyl- or heptafluoro-n-propyl-c-3,t-4-difluoro-oxetans yield mainly the olefins (Z)- and (E)-RFCHC=CHF (RF=C2F5 or n-C3F7).
- Barlow, Michael G.,Coles, Barrie,Haszeldine, Robert N.
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p. 2258 - 2267
(2007/10/02)
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