770-11-6Relevant academic research and scientific papers
A 4 - ( chlorine two fluorine methoxy ) method for preparing aniline
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Paragraph 0016; 0026; 0027; 0028; 0029, (2018/02/04)
The invention relates to a preparation method for 4-(chlorodifluoromethoxy)aniline. The method includes: taking trichloromethoxybenzene as the raw material, employing hydrogen fluoride to conduct selective fluorination to obtain chlorodifluoromethoxybenze
Examples of catalytic and selective routes for fluorinated building blocks
Brunet, Sylvette
, p. 1067 - 1071 (2014/11/27)
Examples are presented for the catalytic fluorination of chlorinated starting materials in order to produce building blocks or HFCs. The fluorination of CF3CH2Cl, of CCl2=CCl2, of trichloromethoxylbenzenes and trichloromethoxybenzene involving nucleophilic substitution are reported. In all cases, HF was the fluorinating agent. Depending on the chlorinated substrate and the degree of fluorination required, liquid- or gas-phase processes were involved. Usually, catalysts were SbCl 5 in liquid phase and chromium oxide in gas phase. In the presence of SbCl5, at 90 °C under an initial pressure of 10 bar, the fluorination of CCl2=CCl2 leads mainly to the formation of CClF2CHCl2, and the active catalyst is an antimony mixed halide (SbCl3F2). In the same way, the presence of SbCl5 favored the formation of 1-trifluoromethyl-3- trichloromethylbenzene from bis-1,3-trichloromethylbenzene at low temperature (50 °C) and in the presence of a low amount of HF. Moreover, trichloromethoxybenzene was totally transformed into trifluoromethoxybenzene. At 380 °C and at atmospheric pressure, the transformation of CF 3CH2Cl into CF3CH2F was favored over chromium oxide-based catalyst modified by zinc (corresponding to a (Zn/Zn + Cr) molar ratio of 0.22).
Selective fluorination of substituted trichloromethyl benzenes by HF in liquid phase: Preparation of fluorinated building blocks
Piou, Alexandre,Celerier, Stephane,Brunet, Sylvette
experimental part, p. 1241 - 1246 (2011/01/12)
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.
Selective aliphatic fluorination by halogen exchange in mild conditions
Saint-Jalmes, Laurent
, p. 85 - 90 (2007/10/03)
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.
Synthesis conditions and activity of various Lewis acids for the fluorination of trichloromethoxy-benzene by HF in liquid phase
Salomé,Mauger,Brunet,Schanen
, p. 1947 - 1950 (2007/10/03)
The experimental conditions (temperature, reaction time, amount of hydrogen fluoride (HF)) for the comparison of the performances of various Lewis acids in the liquid phase fluorination by HF of the trichloromethoxy-benzene were determined by using SbCl5 as the reference catalyst. After 1h reaction at 50°C, C6H5OCCl3 was totally converted into C6H5OCF3 requiring only 2mol% of SbCl5 and a stoichiometric amount of HF. The most efficient catalysts were found to be chlorinated Lewis acids in which the metal is at the state of oxidation +V (SbCl5, MoCl5, TaCl5 and NbCl5). The appropriate catalyst has to be able to form a nucleophilic complex with HF, which constitutes the actual fluorinating agent and is more efficient than HF alone.
Photochemical chlorination of α,α-difluoroanisole
Shipilov,Kolpashchikova
, p. 274 - 276 (2007/10/03)
Chlorination of α,α-difluoroanisole was performed. The yield of chlorodifluoromethoxybenzene was studied in relation to the mode of reaction initiation.
Process for the α-chlorination of aryl ethers
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, (2008/06/13)
Aryl ethers are chlorinated in the α-position by a process in which they are metered into a reaction vessel at the same time as chlorine, the reaction being carried out at temperatures in the range from 60° to 150° C.
SYNTHESIS AND REACTIONS OF DIFLUOROMETHOXY- AND DIFLUOROCHLOROMETHOXY DERIVATIVES OF BENZENE
Shelyazhenko, S. V.,Fialkov, Yu. A.,Yagupol'skii, L. M.
, p. 1317 - 1324 (2007/10/02)
Difluoromethoxybenzaldehydes were synthesized by difluoromethylation of aromatic o- and p-hydroxyaldehydes by chladone-22 in alkaline medium.Chlorination of the difluoromethoxybenzene derivatives under illumination gave difluorochloromethoxy benzene with various function groups (F, Cl, CN, COCl, COOH).The values of the ?-constants of the OCF2Cl group have been determined.In its electronic characteristics it is similar to the OCF3 group.
