- 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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- METHOD FOR PRODUCING 1-CHLORO-1,2-DIFLUOROETHYLENE
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PROBLEM TO BE SOLVED: To provide a method for efficiently and economically producing 1-chloro-1,2-difluoroethylene that can industrially be performed. SOLUTION: The method for producing 1-chloro-1,2-difluoroethylene comprises bringing 1,2-dichloro-1,2-difluoroethane into contact with an alkali aqueous solution in the presence of a phase transfer catalyst to thereby subject 1,2-dichloro-1,2-difluoroethane to dehydrochlorination reaction. COPYRIGHT: (C)2015,JPO&INPIT
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Paragraph 0082; 0084
(2016/12/22)
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- PROCESS FOR THE SYNTHESIS OF PERFLUOROBUTADIENE
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Process for preparing perfluoro-1,3-butadiene, comprising the following steps : A) preparation of fluoro-halo-butanes of formula : CF2 YI-CFYIICFYIICF2 YI (V) in which YI and YII which may be identical or different, may be H, C1 or Br, with the condition that YI and YII are not simultaneously hydrogen; starting with a chloroolefin having the formula : CY'Y = CY'C1 (II) in which Y, Y', Y', which may be identical or different, are H, C1 or Br, with the condition that Y, Y', Y' are not simultaneously hydrogen; and performing the following steps : - a fluorodimerization, and - a fluorination with elemental fluorine, the order of the two steps also possibly being inverted, - a dehalogenation or dehydrohalogenation step being performed between the two steps, B) dehalogenation or dehydrohalogenation of the fluoro-halo compounds of formula (V) to give the compound perfluoro-1,3-butadiene.
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Page/Page column 13
(2009/09/04)
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- Process for preparing fluorohalogenethers
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A process for preparing perfluorovinylethers having general formula: ???????? RfO-CF=CF2?????(IA) wherein Rf is a C1-C3 alkyl perfluorinated substituent; comprising the following steps: 1a) fluorination with fluorine of olefins of formula: ???????? CY"Y=CY'Cl?????(II) wherein Y, Y' and Y", equal to or different from each other, are H, Cl, Br, with the proviso that Y, Y' and Y" are not contemporaneously hydrogen; and obtainment of fluorohalogencarbons of formula: ???????? FCY"Y-CY'ClF?????(III) wherein Y, Y' and Y" are as above; 2a) dehalogenation or dehydrohalogenation of the fluorohalogencarbons (III) and obtainment of fluorohalogen olefins of formula: ???????? FCYI=CYIIF?????(IV) wherein YI and YII, equal to or different from each other, have the meaning of H, Cl, Br with the proviso that YI and YII are not both H; 3a) reaction between a hypofluorite of formula RfOF and a fluorohalogenolefin (IV), obtaining the fluorohalogenethers of formula: ???????? RfO-CFYI-CF2YII?????(I) wherein YI, YII, equal to or different from each other, are Cl, Br, H with the proviso that YI and YII cannot be contemporaneously equal to H; 4a) dehalogenation or dehydrohalogenation of the compounds (I) and obtainment of the perfluorovinylethers (IA).
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Page/Page column 10
(2008/06/13)
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- Process for preparing fluorohalogenethers
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A process for preparing perfluorovinylethers having general formula: [in-line-formulae]RfO—CF═CF2 ??(IA)[/in-line-formulae] wherein Rf is a C1-C3 alkyl perfluorinated substituent; comprising the following steps: 1a) fluorination with fluorine of olefins of formula: [in-line-formulae]CY″Y═CY′Cl ??(II)[/in-line-formulae]wherein Y, Y′ and Y″, equal to or different from each other, are H, Cl, Br, with the proviso that Y, Y′ and Y″ are not contemporaneously hydrogen; and obtainment of fluorohalogencarbons of formula: [in-line-formulae]FCY″Y—CY′ClF ??(III)[/in-line-formulae]wherein Y, Y′ and Y″ are as above; 2a) dehalogenation or dehydrohalogenation of the fluorohalogencarbons (III) and obtainment of fluorohalogen olefins of formula: [in-line-formulae]FCYI═CYIIF ??(IV)[/in-line-formulae]wherein YI and YII, equal to or different from each other, have the meaning of H, Cl, Br with the proviso that YI and YII are not both H; 3a) reaction between a hypofluorite of formula RfOF and a fluorohalogenolefin (IV), obtaining the fluorohalogenethers of formula: [in-line-formulae]RfO—CFYI—CF2YII ??(I)[/in-line-formulae]wherein YI, YII, equal to or different from each other, are Cl, Br, H with the proviso that YI and YII cannot be contemporaneously equal to H; 4a) dehalogenation or dehydrohalogenation of the compounds (I) and obtainment of the perfluorovinylethers (IA).
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Page/Page column 5
(2008/06/13)
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- Dynamic behaviour of chlorofluoroethanes at fluorinated chromia aerogels and fluorinated zinc(II) or magnesium(II) doped chromia aerogels
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The preparation and characterisation of two series of fluorinated chromia aerogel materials, lightly doped with zinc(II) or magnesium(II), are described. They behave as heterogeneous catalysts for transformations of 1,1,2-trichlorotrifluoroethane under HF
- Bozorgzadeh, Hamid,Kemnitz, Erhard,Nickkho-Amiry, Mahmood,Skapin, Toma?,Winfield, John M.
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- Kinetics and mechanism of the thermal gas-phase oxidation of tetrachloroethene by molecular oxygen in presence of trifluoromethylhypofluorite, CF3OF
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The oxidation of tetrachloroethene by molecular oxygen in presence of CF3OF has been studied at 314.0, 324.2, 334.1 and 344.3 K. The initial pressure of CF3OF was varied between 2.0 and 8.2 Torr, that of CCl2CCl2 between 8.7 and 21.7 Torr, that of O2 between 33.2 and 730.7 Torr. Several runs were made adding N2 at pressure varying between 250.4 and 525.9 Torr. The major products were CCl3C(O)Cl and COCl2. CF3OCCl2C(O)Cl, CCl2FC(O)Cl, CF3OCCl2CCl2F and CCl2FCCl2F were formed in traces. The oxidation is a chain reaction. Its rate increases with total pressure. The following mechanism, where E = CCl2CCl2, R = CCl2FCCl2, CF3OCCl2CCl2 or CCl3CCl2, R′ = CCl2F, CF3OCCl2 or CCl3 and M = effective pressure, explains the experimental results: 1) CF3OF+E → R+CF3O 3, 7) R+O2+M → RO2+M 5) RO → R′C(O)Cl+Cl 9) CCl3CCl2O → CCl3C(O)Cl+Cl 11) CCl3+O2+M → CCl3O2+M 13) CCl3O → COCl2+Cl 15) R+CF3OF → RF+CF3O 2) CF3O+E → R 4, 8) 2RO2 → 2RO+O2 6) Cl+E → CCl3CCl2 10) CCl3CCl2O → CCl3+COCl2 12) CCl3O2+RO2 → CCl3O+RO+O2 14) 2R → recombination products, k9 = (3.0±1.4) × 1013 exp(-9.66±1 kcal mol-1/RT) s-1. by R. Oldenbourg Verlag, Muenchen 1998.
- Czarnowski, Joanna
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p. 183 - 197
(2007/10/03)
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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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- Kinetics and mechanism of the thermal gas-phase reaction between trifluoromethylhypofluorite, CF3OF, and tetrachloroethene
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The thermal gas-phase reaction of CF3OF with CCL2CCL2 has been studied between 313.8 and 343.8 K. The initial pressure of CF3OF was varied between 10.8 and 77.5 torr and that of CCl2CCl2 between 3.7 and 26.8 torr. CF3OF was always present in excess, varying the initial ratio of CF3OF to that of CCl2CCl2 from 1.3 to 10. Three products were formed: CF3OCCl2CCl2F, CCl2FCCl2F, and CF3O(CCl2CCl2)2OCF3. The yields of CF3OCCl2CCl2F were 98-99.5%, based on the sum of the products. The reaction was a homogeneous chain reaction not affected by the total pressure. In presence of O2 the oxidation of CCl2CCl2 to CCl3C(O)Cl and COCl2 occurred. The proposed basic reaction steps are: generation of the radicals CF3O· and CCl2FCCl2· (k1) in a biomolecular process between CF3OF and CCl2CCl2, formation of the radical CF3OCCl2CCl2· by addition of CF3O· to CCl2CCl2, chain generation of CF3O· by abstraction of fluorine atom from CF3OF by CF3OCCl2CCl2· (k4), and chain termination by recombination of the radicals CF3OCCl2CCl2·. The expressions obtained for the constants k1 and k4 are: k1 = 3.16 ± 0.6 × 107 exp(- 15.2 ± 1.7 Kcal mol-1/RT) dm3 mol-1 s-1; k4 = 3.7 ± 0.5 × 109 exp(- 6.0 ± 1.1 Kcal mol-1/RT) dm3mol-1s-1.
- Czarnowski
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p. 489 - 495
(2007/10/03)
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- Substituent effects and threshold energies for the unimolecular elimination of HCl (DCl) and HF (DF) from chemically activated CFCl2CH3 and CFCl2CD3
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Combination of CFCl2 and methyl-d0 and -d3 radicals form CFCl2CH3-d0 and -d3 with 100 and 101 kcal/mol of internal energy, respectively. An upper limit for the rate constant ratio of disproportionation to combination, kd/kc, for Cl transfer is 0.07 ± 0.03 for collision of two CFCl2 radicals and 0.015 ± 0.005 for CH3 and CFCl2 radicals. The chemically activated CFCl2CH3 undergoes 1,2-dehydrochlorination and 1,2-dehydrofluorination with rate constants of 3.9 × 109 and 4.9 × 107 s-1, respectively. For CFCl2CD3 the rate constants are 8.7 × 108 s-1 for loss of DCl and 1.1 × 107 s-1 for DF. The kinetic isotope effect is 4.4 ± 0.9 for HCl/DCl and appears to be identical for HF/DF. Threshold energies are 54 kcal/mol for loss of HCl and 68 kcal/mol for HF; the E0's for the deuterated channels are 1.4 kcal/mol higher. Comparison of these threshold energies with other haloethanes suggests that for HF and HCl elimination the transition states are developing charges of different signs on the carbon containing the departing halogen and that chlorine and fluorine substituents exert similar inductive effects.
- McDoniel, J. Bridget,Holmes, Bert E.
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p. 3044 - 3050
(2007/10/03)
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- Catalytic Liquid-phase Fluorination of Tetrachlorethene (PCE) with Titanium Antimony Mixed Halides
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A new catalyst consisting of a TiCl4-SbCl5 mixture with a molar composition Sb : Ti = 4 : 1 makes possible the fluorination of tetrachlorethene with liquid HF at 90 deg C.
- Batiot, Catherine,Brunet, Sylvette,Barrault, Joel,Blanchard, Michel
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p. 867 - 868
(2007/10/02)
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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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- The chlorination of 1,2-difluoroethane (HFC-152)
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The photochlorination of CH2FCH2F yields CH2FCCl2F and CHClFCHClF, both of which were considered to be potential replacements for CFC-113 (CCl2FCF2Cl) based on their boiling points (48 deg C and 59 deg C, respectively).The CHClFCHClF/CH2FCCl2F ratio can be controlled by the choice of solvents.In aromatic solvents, the reactivity of the chlorine radical is reduced, increasing the amount of CH2FCCl2F produced.Relative rates in CCl4 and in the presence of water were compared to rates in aromatic solvents.Both CH2FCCl2F and CHClFCHClF failed in early toxicity tests and will thus not be pursued as HCFC replacements for CFC-113.
- Nappa, Mario J.,Sievert, Allen C.
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p. 111 - 118
(2007/10/02)
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- FLUORINATION OF POLYHALOGENATED UNSATURATED COMPOUNDS WITH VANADIUM PENTAFLUORIDE
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Vanadium pentafluoride reacts with polyfluorinated and polychlorinated olefins, alkadienes, cycloalkenes and cyclodienes in CFCl3 or without a solvent at -25 deg C to 100 deg C, forming products of addition of two fluorine atoms across the C=C bond.
- Bardin, V. V.,Avramenko, A. A.,Furin, G. G.,Krasilnikov, V. A.,Karelin, A. I.,et al.
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p. 385 - 400
(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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- 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 POLYHALOGENATED UNSATURATED COMPOUNDS WITH VANADIUM PENTAFLUORIDE
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Terminal polyhalogenoalkenes are fluorinated by vanadium pentafluoride at -20 to -30 deg C, whereas internal polyfluoroalkenes only react with vanadium pentafluoride when heated. 2-Chloropentafluoro-1,3-butadiene adds fluorine atoms predominantly at positions 1,4 under the influence of vanadium pentafluoride, but only the isomeric tetrafluorohexachlorobutanes are formed from perchloro-1,3-butadiene.Fluorination of perfluoroallylbenzene and perfluoro-β-methylstyrene takes place more rapidly in the side chain than in the aromatic ring.
- Petrov, V. A.,Bardin, V. V.,Furin, G. G.,Avramenko, A. A.,Galakhov, M. V.,et al.
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- Methyl-halogenated Allyl Methyl Sulfoxides and Sulfones and the Synthesis of Halogenated Sulfines
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Allyl methyl sulfoxides R1R2R3C-S(O)-CH2CH=CH2 1a-7a (R1, R2, R3 = H, F, Cl, CF3) as well as the corresponding sulfones 1b-7b were synthesized.The sulfoxides substituted at the methyl group are in equilibrium with the allyl sulfenates R1R2R3-S-OCH2CH=CH2 depending on temperature and kind of substitution.By pyrolysis of the sulfoxides 2a, 3a, 4a, and 7a the sulfines Cl2C=SO and (CF3)2C=SO could be prepared, and evidence for the existence of the sulfines ClFC=SO and F2C=SO could be obtained.The new pentenes 12 and 14 are described.
- Holoch, Jan,Sundermeyer, Wolfgang
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p. 269 - 278
(2007/10/02)
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- REACTIONS OF CHLORINE MONOFLUORIDE. REGIOSPECIFICITY AND STEREOCHEMISTRY OF THE SUBSTITUTION OF BROMINE ATOMS BY FLUORINE IN HALOGEN-SUBSTITUTED ALKANES AND ESTERS
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Under mild conditions without catalysts chlorine monofluoride substitutes bromine atoms for fluorine in bromine-substituted alkanes and esters.Electron-donating substituents promote the substitution reaction.The following sequence is observed in the reactivity of the bromine atoms at the carbon: tertiary > secondary > primary.Halogen atoms (Cl, F) at a carbon containing a bromine also promotes substitution of the latter by fluorine.The reactivity of the bromine atoms decreases in the following order: CCl2Br(CClFBr) > CHClBr(CHFBr) > CH2Br.An alkoxycarbonyl group at a carbon containing bromine prevents substitution.In a number of cases substitutive fluorination is accompanied by skeletal rearrangements and by migration of chlorine atoms.The stereochemistry of substitutive fluorination was studied for the case of the reaction of erythro- and threo-1-bromo-2-fluoro-1,2-dichloroethanes and 1,2-dibromo-1,3-dichloropropanes with chlorine monofluoride.The probable mechanism of the reaction is discussed.
- Boguslavskaya, L. S.,Chuvatkin, N. N.,Panteleeva, I. Yu.,Ternovskoi, L. A.
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p. 814 - 820
(2007/10/02)
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