- Study on the pyrolysis characteristics of a series of fluorinated cyclopentenes and implication of their environmental influence
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3,3,4,4,5,5-hexafluorocyclopentene (6FE), 1,3,3,4,4,5,5-heptafluorocyclopentene (7FE) and octafluorocyclopentene (8FE) are considered as new generation of potential chlorofluorocarbons substitutes. To investigate the thermostabilities, tubular furnace experiments were designed over temperature range of 500-850℃. The results show that 6FE, 7FE and 8FE are all stable below 650 ℃, thus have good stabilities in common storage and practical use condition. Furthermore, considering the short atmospheric lifetimes (several months), low global warming potentials (GWPs, less than 119) and zero ozone depletion potentials (ODPs), the compounds seem no big influences on the climate change.
- Bi, Fang,Gao, Rui,Ji, Yuanyuan,Li, Hong,Li, Ling,Liu, Chenfei,Wang, Xuezhong,Wu, Zhenhai,Yanqin, Ren,Zhang, Hao,Zhang, Xin
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- Xenon(IV)-carbon bond of [C6F5XeF2]+; Structural characterization and bonding of [C6F5XeF2][BF4], [C6F5XeF2][BF4]·2HF, and [C6F5XeF2][BF4]· n NCCH 3 (n = 1, 2); And the fluorinating properties of [C6F5XeF2][BF4]
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The [C6F5XeF2]+ cation is the only example of a XeIV-C bond, which had only been previously characterized as its [BF4]- salt in solution by multi-NMR spectroscopy. The [BF4]- salt and its new CH3CN and HF solvates, [C6F5XeF2][BF4]·1.5CH3CN and [C6F5XeF2][BF4]·2HF, have now been synthesized and fully characterized in the solid state by lowerature, single-crystal X-ray diffraction and Raman spectroscopy. Crystalline [C6F5XeF2][BF4] and [C6F5XeF2][BF4]·1.5CH3CN were obtained from CH3CN/CH2Cl2 solvent mixtures, and [C6F5XeF2][BF4]·2HF was obtained from anhydrous HF (aHF), where [C6F5XeF2][BF4]·1.5CH3CN is comprised of an equimolar mixture of [C6F5XeF2][BF4]·CH3CN and [C6F5XeF2][BF4]·2CH3CN. The crystal structures show that the [C6F5XeF2]+ cation has two short contacts with the F atoms of [BF4]- or with the F or N atoms of the solvent molecules, HF and CH3CN. The lowerature solid-state Raman spectra of [C6F5XeF2][BF4] and C6F5IF2 were assigned with the aid of quantum-chemical calculations. The bonding in [C6F5XeF2]+, C6F5IF2, [C6F5XeF2][BF4], [C6F5XeF2][BF4]·CH3CN, [C6F5XeF2][BF4]·2CH3CN, and [C6F5XeF2][BF4]·2HF was assessed with the aid of natural bond orbital analyses and molecular orbital calculations. The 129Xe, 19F, and 11B NMR spectra of [C6F5XeF2][BF4] in aHF are reported and compared with the 19F NMR spectrum of C6F5IF2, and all previously unreported J(129Xe-19F) and J(19F-19F) couplings were determined. The long-term solution stabilities of [C6F5XeF2][BF4] were investigated by 19F NMR spectroscopy and the oxidative fluorinating properties of [C6F5XeF2][BF4] were demonstrated by studies of its reactivity with K[C6F5BF3], Pn(C6F5)3 (Pn = P, As, or Bi), and C6F5X (X = Br or I).
- Koppe, Karsten,Haner, Jamie,Mercier, Hlne P. A.,Frohn, Hermann-J.,Schrobilgen, Gary J.
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p. 11640 - 11661
(2015/01/16)
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- Explored routes to unknown polyfluoroorganyliodine hexafluorides, R FIF6
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Two routes to RFIF6 compounds were investigated: (a) the substitution of F by RF in IF7 and (b) the fluorine addition to iodine in RFIF4 precursors. For route (a) the reagents C6F5SiMe3, C6F 5SiF3, [NMe4][C6F 5SiF4], C6F5BF2, and 1,4-C6F4(BF2)2 were tested. C 6F5IF4 and CF3CH2IF 4 were used in route (b) and treated with the fluoro-oxidizers IF7, [O2][SbF6]/KF, and K2[NiF 6]/KF. The observed sidestep reactions in case of routes (a) and (b) are discussed. Interaction of C6F5SiX3 (X = Me, F), C6F5BF2, 1,4-C6F 4(BF2)2 with IF7 gave exclusively the corresponding ring fluorination products, perfluorinated cyclohexadiene and cyclohexene derivatives, whereas [NMe4][C6F 5SiF4] and IF7 formed mixtures of C 6FnIF4 and C6FnH compounds (n = 7 and 9). CF3CH2IF4 was not reactive towards the fluoro-oxidizer IF7, whereas C6F 5IF4 formed C6FnIF4 compounds (n = 7 and 9). C6F5IF4 and CF 3CH2IF4 were inert towards [O 2][SbF6] in anhydrous HF. CF3CH 2IF4 underwent C-H fluorination and C-I bond cleavage when treated with K2[NiF6]/KF in HF. The fluorine addition property of IF7 was independently demonstrated in case of perfluorohexenes. C4F9CFCF2 and IF7 underwent oxidative fluorine addition at -30 °C, and the isomers (CF 3)2CFCFCFCF3 (cis and trans) formed very slowly perfluoroisohexanes even at 25 °C. The compatibility of IF7 and selected organic solvents was investigated. The polyfluoroalkanes CF 3CH2CHF2 (PFP), CF3CH 2CF2CH3 (PFB), and C4F9Br are inert towards iodine heptafluoride at 25 °C while CF3CH 2Br was slowly converted to CF3CH2F. Especially PFP and PFB are new suitable organic solvents for IF7.
- Frohn, Hermann-Josef,Bardin, Vadim V.
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experimental part
p. 1000 - 1006
(2010/11/16)
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- Fluorination of tetrafluorobenzenes C6HF4R with XeF2
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Replacement of hydrogen by fluorine and addition of fluorine atoms to the aromatic ring were found in the reaction of XeF2 with 1-R-2,3,4,5-tetrafluorobenzene (R = H, F, Br, NO2) or 1-R-2,3,4,6-tetrafluorobenzene (R = H, CF3) in HF or CH2Cl2-BF3·OEt2. Only fluorine addition took place in the case of 1-R-2,3,5,6-tetrafluorobenzenes (R = H, Br, CF3) or 1-Br-2,3,4,6-tetrafluorobenzene. The role of cation radicals as reactive intermediates is discusseed.
- Bardin,Shchegoleva,Frohn
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p. 153 - 159
(2007/10/03)
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- The Preparation and Characterization of Radical Cation Salts Derived from Perfluorobenzene, Perfluorotoluene, and Perfluoronaphthalene
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The salts C6F6+AsF6- (yellow), C6F5CF3- (lime green), and C10F8+AsF6- (dark green) may be prepared by electron oxidation of the appropriate perfluoro aromatic molecule with O2+AsF6-.Other O2+ salts can be similarly employed as can the more strongly oxidizing transition-metal hexafluorides, but salts of the latter are more labile than their AsF- relatives.C6F6+AsF6- is a convenient electron oxidizer (C6F6AsF6+C10F8 -> C10F8AsF6+C6F6) since that which remains from the reaction decomposes at room temperature to volatile products (2C6F6AsF6 -> C6F6+1,4-C6F8+2AsF5).Magnetic susceptibilities for C6F6AsF6 and C10F8AsF6 approximate to Curie law behavior, and g values are close to free-electron values.X-ray diffraction data (single crystal) show C6F6AsF6 to be primitive rhombohedral with a0=6.60 (1) Angstroem, α=106.0 (1) deg, V=246.1 Angstreom3, Z=1, probable space group R3, and (powder data) C10F8AsF6 to be tetragonal with a0=8.27 (5) Angstroem, c0=18.57 (s) Angstroem, V=1270 Angstoem3, Z=4.Salts derived from the monocyclic perfluoro aromatics are thermally unstable but can be kept below -15 deg C.The perfluoronapthalene salts are indefinitely stable at room temperatures.All hydrolyze rapidly.The products of thermal decomposition of the hexafluoroarsenates of the monocyclic cation salts parallel the products of the attack by F-.The latter reaction products are in the molar ratios indicated by the following equations: 2C6F6+ 2F- -> C6F6+ 1,4-C6F8; 2C6F5CF3+ ->2F- -> C6F5CF3+1,3-C6F7CF3.The 1,3-C6F7CF3 isomerizes to a 1:1 mixture with 1,4-C6F7CF3 over several days in the presence of fluoro acids.Mechanisms for the formation of the dienes are discussed.
- Richardson, T. J.,Tanzella, F. L.,Bartlett, Neil
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p. 4937 - 4943
(2007/10/02)
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- FLUORINATION OF POLYFLUOROAROMATIC COMPOUNDS WITH VANADIUM PENTAFLUORIDE
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Fluorination of polyfluoro-derivatives of benzene and diphenyl with vanadium pentafluoride at -25 to -10 deg C afforded fluorinated cyclohexadienes and cyclohexenes.Octafluoronaphthalene was converted under these conditions to perfluoro-1,4-dihydronaphthalene, perfluorotetralin, perfluoro-1,4,5,8-tetrahydronaphthalene and perfluoro-1,2,3,4,5,8-hexahydronaphthalene.
- Bardin, V. V.,Avramenko, A. A.,Furin, G. G.,Yakobson, G. G.,Krasilnikov, V. A.,et al.
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- AROMATIC FLUORINE DERIVATIVES. XCVII. OXIDATIVE FLUORINATION OF PERFLUORINATED AROMATIC COMPOUNDS WITH VANADIUM PENTAFLUORIDE
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Perfluorinated aromatic compounds are converted by the action of vanadium pentafluoride at -25 to -15 deg C into perfluorinated derivatives of cyclohexadiene and cyclohexene.The rate of addition of the two fluorine atoms to the perfluorinated derivatives of 1,3- and 1,4-cyclohexadiene under conditions of competing fluorination depends on the nature of the substituent at the carbon-carbon double bond.
- Bardin, V. V.,Furin, G. G.,Avramenko, A. A.,Krasil'nikov, V. A.,Tushin, P. P.,et all
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p. 307 - 311
(2007/10/02)
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- AROMATIC FLUORINE DERIVATIVES. XCIII. REACTION OF POLYFLUORINATED AROMATIC COMPOUNDS WITH XENON DIFLUORIDE IN THE PRESENCE OF HYDROGEN FLUORIDE AND SALTS OF THE XeF+MFm- (MFm-1 = SbF5, WF6) TYPE
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Under the influence of xenon difluoride in the presence of hydrogen fluoride at 20 deg C hexafluorobenzene, nitropentafluorobenzene, 4-nitroheptafluorotoluene, and octafluoronaphthalene undergo regiospecific fluorination with the formation of polyfluorinated 1,4-cyclohexadienes containing substituents other than fluorine at the C=C bond.Salts of the XeF+MFm- (MFm-1 = Sb5, WF6) type are stronger fluorinating agents and react with polyfluorinated aromatic compounds at -50 to -80 deg C.A possible reaction mechanism, involving one-electron oxidation of the polyfluorinated aromatic compounds, is discussed.
- Bardin, V. V.,Furin, G. G.,Yakobson, G. G.
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p. 525 - 530
(2007/10/02)
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- FLUOROCYCLOHEXANES PART XV. DEHYDROFLUORINATIONS OF UNDECA- DECA- AND NONA- FLUOROCYCLOHEXANES
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An experimental modification has improved dehydrofluorinations of undeca- deca- and nona- fluorocyclohexanes, and enhanced the proportions of dienes and aromatics formed.
- Coe, Paul L.,Mott, Andrew W.,Tatlow, John Colin
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p. 167 - 172
(2007/10/02)
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- THE SIGMATROPIC MIGRATION OF FLUORINE
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Pyrolysis of polyfluorocyclohexadienes at 475-480 deg C over new quartz or Pyrex glass gave products derived from 1,5-sigmatropic migrations of fluorine; 1,3-migrations occurred to only a small degree.As the quartz or glass aged, other processes - 1,3-migrations and defluorinations to aromatics - began to occur; these appear to be due in some way to fluoride ion, since pyrolysis over sodium fluoride gave similar products.
- Burdon, J.,Childs, A.,Parsons, I. W.,Rimmington, T. W.
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- THE THERMAL ISOMERIZATION OF HEPTAFLUOROCYCLOHEXADIENES
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The evidence for the involvement of sigmatropic fluorine migrations in the isomerizations of fluorinated polyenes is reviewed and the difficulties inherent in providing satisfactory rationalizations are discussed.The thermal isomerizations of heptafluorocyclohexadienes under various reaction conditions are described.It is established that such isomerizations occur by a mechanism which does not involve catalysis by fluoride ion, however the exact mechanistic pathway remains uncertain.
- Feast, W. J.,Morland, J. B.
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- SUBSTITUTION AND ADDITION REACTIONS OF NF4BF4 WITH AROMATIC COMPOUNDS
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Benzene, toluene, and nitrobenzene interact rapidly with NF4BF4 in anhydrous HF to give, almost exclusively, fluorine substituted aromatic derivatives.Up to four hydrogens can be replaced in a rapid reaction, before a much slower addition reaction takes over.The direction of the substitution in C6H6, C6H5CH3 and C6H5NO2 and the lack of side chain fluorination in C6H5CH3 support an electrophilic substitution mechanism.These rapid substitution reactions are followed by much slower fluorine addition reactions to give the corresponding cyclo-hexadienes and -hexenes.These addition reactions were also studied separately using tetra-, penta-, and hexa- fluorobenzene as the starting materials.In these addition reactions, almost no hydrogen substitution occurred.The addition of the first pair of fluorines always gave 1,4-cyclohexadienes in which the CF2 group was adjacent to hydrogen on the ring.The addition of the second pair of fluorines resulted in the formation of cyclohexenes.These reactions occured in high yield and offer a controlled, high yield path to dienes.All products were characterized spectroscopically and by comparison to literature data.
- Schack, Carl J.,Christe, Karl O.
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p. 363 - 374
(2007/10/02)
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- AROMATIC FLUORINE DERIVATIVES. XCI. REGIOSPECIFIC FLUORINATION OF POLYFLUORINATED AROMATIC COMPOUNDS BY SALTS OF THE DIFLUOROBROMONIUM CATION BrF2+
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The reaction of polyfluorinated aromatic compounds with difluorobromium tetrafluoroborate BrF2+*BF4- leads to the products from regiospecific fluorination.Polyfluorinated derivatives of benzene, toluene, and naphthalene are fluorinated to form 1,4-cyclohexadienes, whereas pentafluoropyridine and 3-chlorotetrafluoropyridine are converted into the corresponding 1-aza-1,3-cyclohexadienes.
- Bardin, V. V.,Furin G. G.,Yakobson, G. G.
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p. 879 - 884
(2007/10/02)
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- BF3-Catalyzed Fluorine Addition to Fluoro-Substituted Benzene Derivatives Using Xenon Difluoride
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BF3-catalyzed room-temperature reaction of xenon difluoride with pentafluoro-substituted benzene derivatives resulted in 1,4- and 1,2-fluorine addition with regiospecificity depending on the substituent.Reaction with 1-substituted (H, Cl, Br, C6F5) pentafluorobenzene resulted in the formation of 1-substituted heptafluorocyclohexa-1,4-dienes, and reactions with n-alkoxy-substituted pentafluorobenzenes resulted in two types of 1,4-adducts, while reaction with isopropoxypentafluorobenzene resulted in the formation of hexafluorocyclohexa-2,5-dien-1-one and hexafluorocyclohexa-2,4-dien-1-one.
- Stavber, Stojan,Zupan, Marko
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p. 300 - 302
(2007/10/02)
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