- (Re)Investigation of the reactivity of uranium hexafluoride toward several organic functions at room temperature
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The annual worldwide production of UF6 is very large and this compound is not used. Consequently, it could be interesting to find some applications as organic reagent. UF6 could be considered as an oxidizer of various functions. However, it seems also present some possibilities as a fluorinating reagent in mild conditions.
- Roy, Olivier,Marquet, Bernard,Alric, Jean-Paul,Jourdan, Alex,Morel, Bertrand,Langlois, Bernard R.,Billard, Thierry
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- Selective fluorination of substituted trichloromethyl benzenes by HF in liquid phase: Preparation of fluorinated building blocks
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The selective fluorination by successive Cl/F exchanges of α,α,α-trichlorotoluene, substituted or not by a chlorine atom, was studied in the presence of HF as the fluorinating agent. The influence of the presence of a catalyst or a basic solvent (such as dioxane, pyridine, tributylphosphate) in order to control the fluorination was also investigated. In mild conditions (50 °C and after 1 h of reaction), HF in excess was required in order to obtained the trifluoromethylation by Cl/F exchanges. The presence of SbCl5 in small amount activated the Cl/F exchanges and only a stoichiometric amount of HF was required whatever the chlorinated molecules. Selective mono and difluorination could be obtained by using basic solvents.
- Piou, Alexandre,Celerier, Stephane,Brunet, Sylvette
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experimental part
p. 1241 - 1246
(2011/01/12)
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- Activation of nucleophilic fluorination by salts in ionic liquids and in sulfolane
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The nucleophilic substitution of PhCCl3 by KF in imidazolium-type RTILs is faster than in classical organic solvents but it is strongly dependent upon the nature of the counteranion. The addition of bromide salts in substoichoimetric amounts to the [bmim][PF6] solvent strongly accelerates this reaction. Furthermore, it has been discovered that addition of KPF6 to the reaction mixtures strongly activates the nucleophilic fluorination by KF, not only in the [bmim][NTf2] or [bmim][PF6] ionic liquids but also for the reactions performed in sulfolane.
- Anguille, Stephane,Garayt, Maxime,Schanen, Vincent,Gree, Rene
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p. 1149 - 1153
(2007/10/03)
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- Selective aliphatic fluorination by halogen exchange in mild conditions
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HF-Base media, in particular (HF)10-pyridine or (HF) 3-triethylamine, allow aliphatic chlorine-fluorine exchanges on acid-sensitive molecules. Depending on the nature (pyridine or triethylamine), stoichiometry of the base and temperature, selective mono-, di-, or tri-chlorine-fluorine exchanges on trichloromethyl groups alpha to sulfur, oxygen and carbon atoms can be obtained.
- Saint-Jalmes, Laurent
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- Fluorination agent and preparation and use of same
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The invention disclose a hydrogen fluoride containing composition comprising hydrogen fluoride and a compound which is liquid in the standard state (25° C., 1 atmosphere) and has a boiling point of 120° C. or more and pka of 12 or more at 25° C., and use of the composition for a fluorination agent. The compound which can be preferably used is represented by the formula (1): wherein R1 to R4 are a substituted or unsubstituted alkyl or aryl group and can be the same or different, and R1 or R2 or R3 and R4 can bond to form a ring having a nitrogen atom or a nitrogen atom and other hetero atom, or R1 and R3 can bond to form a ring having a nitrogen atom or a nitrogen atom and other hetero atom. The fluorination agent of the invention exerts effect with a similar reaction mechanism to hydrogen fluoride, can be applied to the halogen exchange reaction of a halogen containing organic compound, and can produce a fluorine containing compound with safety and ease without specific equipment or technique.
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