- Bis(perfluoroorganyl)bromonium salts [(RF)2Br]Y (RF = aryl, alkenyl, and alkynyl)
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Bromonium salts [(RF)2Br]Y with perfluorinated groups RFC6F5, CF3CFCF, C 2F5CFCF, and CF3C≡C were isolated from reactions of BrF3 with RFBF2 in weakly coordinating solvents (wcs) like CF3CH2CHF2 (PFP) or CF3CH2CF2CH3 (PFB) in 30-90% yields. C6F5BF2 formed independent of the stoichiometry only [(C6F5)2Br][BF 4]. 1:2 reactions of BrF3 and silanes C6F 5SiY3 (Y = F, Me) ended with different products - C 6F5BrF2 or [(C6F5) 2Br][SiF5] - as pure individuals, depending on Y and on the reaction temperature (Y = F). With C6F5SiF3 at ≥-30 °C [(C6F5)2Br][SiF5] resulted in 92% yield whereas the reaction with less Lewis acidic C 6F5SiMe3 only led to C6F 5BrF2 (58%). The interaction of K[C6F 5BF3] with BrF3 or [BrF2][SbF 6] in anhydrous HF gave [(C6F5) 2Br][SbF6]. Attempts to obtain a bis(perfluoroalkyl) bromonium salt by reactions of C6F13BF2 with BrF3 or of K[C6F13BF3] with [BrF2][SbF6] failed. The 3:2 reactions of BrF3 with (C6F5)3B in CH2Cl2 gave [(C6F5)2Br][(C6F 5)nBF4-n] salts (n = 0-3). The mixture of anions could be converted to pure [BF4]- salts by treatment with BF3·base.
- Frohn, Hermann-Josef,Giesen, Matthias,Welting, Dirk,Bardin, Vadim V.
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experimental part
p. 922 - 932
(2010/10/03)
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- Reactivite par voie thermique de RFH
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Hydroperfluoroalkanes are well known as being rather inert chemically.Hydroperfluoroalkanes react at high temperature with carbon tetrabromide and carbon tetrachloride to yield bromoperfluoroalkanes and chloroperfluoroalkanes. - Keywords: Hydroperfluoroalkanes; High-temperature reaction; Carbon tetrabromide; Carbon tetrachloride; Bromoperfluoroalkanes; Chloroperfluoroalkanes
- Signe, E.,Blancou, H.,Commeyras, A.
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p. 197 - 200
(2007/10/02)
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- Synthesis of perfluoroalkyl bromides
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The invention relates to the preparation of perfluoroalkyl bromides or bromoperfluoroalkanes Cn F2n+1 -Br (n=1 to 20). A perfluoroalkanesulphonyl chloride Cn F2n+1 -SO2 Cl is reacted with a compound of formula: STR1 in which X represents a nitrogen or phosphorus atom and R1, R2, R3 and R4, which may be identical or different, each represent an optionally substituted hydrocarbon radical, it also being possible for one of these symbols to be a hydrogen atom.
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