Alain Battais

Etude de la réactivité du fluorure de potassium sur des esters polyhalogénés

Abstract Reactions of polyhalogenated esters with potassium fluoride in polar solvents have been studied. Two kinds of reactions are possible depending on the starting compound: the hydrochlorinated esters RCCl 2 CH 2 CHR′CO 2 CH 3 (R=Cl, -CF 3 ; R′=H, -CH 3 give the corresponding α-β unsaturated derivatives. Moreover when using ethylene glycol as a solvent, a transesterification reaction occurs after the dehydrohalogenation. From perhalogenated esters, mainly decarboxylation products are formed; for example in DMSO as a solvent, the fluorination of the telomers Cl-(CFClCF 2 ) n -CO 2 CH 3 yields the corresponding perfluoroalkenes C 2n F 4n . Some mechanistic interpretations are given in order to explain the formation of the different compounds.

Synthèses de diols fluorés a partir de dérivés des télomères du chlorotrifluoroéthylène et du tétrachlorure de carbone

Abstract Synthesis of fluorinated diols using telomers as starting compounds was studied. Thus chemical transformation of difunctional telomers RO2CCF2(CFClCF2)nCO2R (I,n) (n = 1,2 ; R = H or CH3) leads to the following series of diols: (II,n) HOCH2CF2(CFXCF2)nCH2OH (n = 1,2 ; X = H or Cl) (III,n) et (IV,n) RCOCF2(CFClCF2)nCOR (n = 1,2 ; R = OCH2CH2OH, NHCH2CH2 Addition of 1,1,1,3,3,3 hexachloro 2,2 difluoro propane by redox catalysis on functionalized alkenes of general formula CH2CHG (G = OCOCH3, CH2OCOCH3, CO2CH3, CH2OH, CO2CH2CH2OH) leads to the corresponding difunctional products GCHClCH2CCl2CF2CCl2CH2CHClG (V). Kinetic study shows that the reaction proceeds in two steps: formation of the monoadduct which then reacts with the monomer to give the difunctional compound. Reduction (when G = CH2OCOCH3, -OCOCH3, CO2CH3) or hydrolysis (when G = CH2OCOCH3) of compounds (V) leads to the two following diols: HOCH2CHClCH2CCl2CF2CCl2CH2CHClCH2OH HOCH2CH2CCl2CF2CCl2CH2CH2OH

Determination de la structure de perfluoroalcenes a chaines longues par R.M.N. du 19F 2éme Partie : Perfluoroalcenes 2–3 et 4

Abstract After a review of 1-perfluoroalkene R F CFCF 2 synthesis, with R F C 4 F 9 , C 5 F 11 , C 6 F 13 , we have studied their fine structures by 19 F N.M.R. This study has led us to first generalize the rules set for the chemical shifts and coupling constants of olefinic fluorine atoms of fluoropropene and their derivatives. Then, we have been able to determinate unambiguously the chemical shifts of the difluoromethylene groups of the perfluorinated chains. We have thus shown, by irradiation, that inversions may take place in the chemical shifts of the CF 2 groups at the β and γ position of the double bond.

Calcul a priori des deplacements chimiques en RMN du 19F. 1. Modele previsionnel adapte aux composes aliphatiques fluores lineaires

Abstract A new empirical model for the a priori calculation of the chemical shifts in 19 F NMR spectroscopy for fluorinated linear aliphatic compounds is described. In contrast to previous models, it takes into account the influence of distant atoms (up to 5 bonds). Comparison between measured and calculated chemical shifts in linear saturated molecules containing hydrogen and halogen atoms shows a significantly increased accuracy for the present model with regard to that described previously. Perfluorinated linear saturated carboxylic acids are also studied using the model described.

Telomerisation du tetrafluoroethylene avec le tetrachlorure de carbone par catalyse redox

Abstract The redox telomerization of tetrafluoroethylene with carbon tetrachloride using the FeCl3/benzoīn complex as catalyst has been studied. The CnFe transfer constants of this reaction are measured and compared to the results obtained under other conditions, especially under radical catalysis. We can also evaluate the Ki constant of the reaction rate between telogen and the metal at its lowest oxidation state. The DP n on the reaction conditions, the structure of low molecular weight telomers being established by mass spectrometry and the conditions to obtain the telomers of C2F4 with CCl4 are specified.

Fluoration de telomeres polyhalogenes par le fluorure de potassium: synthese d'olefines perfluorees

Abstract Action of potassium fluoride on chlorofluorinated telomers of general formula Cl-(CFCl-CF 2 ) n -CCl 3 leads to a mixture of perfluorinated cis isomers of internal olefins with the more substitued isomer being preponderant. The influence of temperature and solvant has also been studied. Only reactions carried out in tetramethylene sulfone or preferably in dimethylsulfoxide lead to perfluorinated alkenes. We suggest a mechanism with elimination followed by fluorination.

Synthese d'acides perfluores de hauts poids moleculaires

Abstract Perfluorinated olefins of general formula CF3(CF2)pCFCF(CF2)mCF3 (3 ⩽ m + p ⩽ 25) are oxidized by potassium permanganate or ruthenium tetroxide. The linear high molecular weight perfluorinated carboxylic acids so obtained are characterized by 19F N.M.R. spectroscopy.

Fluoration de telomeres polyhalogenes par le fluorure de potassium (2ème partie). Synthese d'olefines perfluorees de hauts poids moleculaires

Abstract Fluorination of chlorofluorinated telomers of general formula Cl(CFClCF 2 ) n CCl 3 (n ⩾ 7) was studied using potassium fluoride in dimethylsulfoxide as fluorinating agent. The reaction leads to a mixture of perfluorinated linear olefins having 15 to 30 carbon atoms : CF 3 (CF 2 ) p CFCF(CF 2 ) m CF 3 (p + m = 2n−3). We perfected a method to determine molecular weights of the telomers by gel permeation chromatography (G.P.C.). The olefins obtained by fluorination are analyzed both by vapor phase chromatography (V.P.C.) and by 19 F nuclear magnetic resonance (N.M.R.).