GB869922A - Omega-chloro-polyfluoroalkane sulphonyl fluorides and derivatives thereof - Google Patents

Abstract

The invention comprises omega-chloro polyfluoroalkane sulphonyl fluorides corresponding to the formula: <FORM:0869922/IV (b)/1> wherein the free valencies on the carbon atoms of the olefinic monomer unit are satisfied by hydrogen, fluorine or chlorine atoms at least two such free valencies being satisfied by fluorine atoms and wherein n is an integer from 1 to 150 or a corresponding sulphonic acid or metal or ammonium salt thereof, acid chloride or sulphonamide and a process for the preparation thereof in which sulphuryl chlorofluoride is reacted in the presence of a free radical initiator with a polyfluorinated olefinic compound copolymerisable with sulphur dioxide. Free radical initiators specified include organic peroxides e.g. benzoyl peroxide and hydroperoxides, aliphatic azo compounds and ultraviolet light. Polyfluorinated olefinic compounds specified for use as starting materials include 1,1-difluoro-, 1,1-dichloro-2-chloro-, 1,1-difluoro-2,2- dichloro-, trifluoro-, trifluorochloro- and tetrafluoroethylenes. The process may be carried out batchwise or continuously. In examples: Compounds of the formula CI(CF2CH2)nSO2F in which n has an average value of 4 or 5 are obtained by reacting 1,1-difluoroethylene and sulphuryl chlorofluoride (1); compounds of the formula CI(CFCICF2)nSO2F in which n has an average value of 18 or 110 are obtained by reacting trifluoroethylene with sulphuryl chlorofluoride (2); compounds of the formula Cl(C2F4)nSO2F in which n has an average value between 4 and 5 are obtained by reacting tetrafluoroethylene with sulphuryl chlorofluoride (3), and similar compounds in which n has a value of 8, 9, 12 or 52 are similarly obtained (4). The number of olefinic monomer units in the products are varied by varying the proportions of reactants. The products of the examples are converted to the corresponding sulphonic acids, metal and ammonium salts thereof, acid chlorides and sulphonamides. Thus the product of Example (3) is converted to the calcium salt of the corresponding sulphonic acid by heating with calcium oxide and water and the zinc, potassium, lithium, ammonium or sodium salt with the appropriate metal or ammonium sulphates. The corresponding free sulphonic acid is obtained by distilling the calcium salt with sulphuric acid. The sulphonyl chlorides Cl(C2F4)nSO2Cl are obtained by reacting the acids with phosphorus pentachloride or the salts with a phosphorus pentachloride-zinc chloride complex. The sulphonamides of the formula Cl(C2F4)nSO2NH2 are prepared by reacting the acid fluorides with liquid ammonia. Specification 758,467 is referred to.