GB753304A - Polyfluorinated polyethers - Google Patents

Abstract

The invention comprises polyfluorinated polyethers of general formula <FORM:0753304/IV(a)/1> where RF is a polyhalogenated hydrocarbon substituent having at least two fluorine atoms on the carbon atom adjacent to the CH2 group, R and R1 are hydrocarbon or substituted hydrocarbon, and R11 is hydrogen, hydrocarbon or substituted hydrocarbon (other than fluorine substituted). The polyethers are prepared by an addition reaction, in the presence of a base, between an alcohol ROH and an unsaturated ether of formula <FORM:0753304/IV(a)/2> The polyethers may be hydrolysed in the presence of an acid to produce the corresponding carbonyl compounds of formula <FORM:0753304/IV(a)/3> The polyfluorinated hydrocarbon group RF is preferably a C1 to C20 perfluoroalkyl group. R and R1 are alkyl, halogenoalkyl, alkenyl, halogenoalkenyl, cycloalkyl, halogenocycloalkyl, aryl or halogenoaryl groups preferably containing not more than 20 carbon atoms. R and R1 may have the formula R11F(CH2)n where R11F is a C1 to C20 perfluoroalkyl group and n is 1 to 6. R11 is preferably hydrogen or alkyl, but may be halogenoalkyl other than fluoroalkyl, alkenyl or halogenoalkenyl, other than fluoroalkenyl, and preferably contains not more than 20 carbon atoms. The polyethers may be prepared by subjecting the reactants to elevated temperature and pressure in the presence of an alkali metal or alkaline earth metal alcoholate of the alcohol used in the reaction. The polyethers may be converted by warming with an acid, such as sulphuric acid, to the carbonyl compounds i.e. aldehydes when R11 is hydrogen and ketones when R11 is a hydrocarbon or substituted hydrocarbon. In examples (1) ethanol is added to 1-ethoxy-3,3,3-trifluoropropene to obtain 1,1 - diethoxy - 3,3,3 - trifluoropropane, which is then hydrolysed to trifluoropropionaldehyde; (2) methanol is added to 2 - methoxy - 1,1,1,4,4,4 - hexafluorobutane - 2 to form 2,2 - dimethoxy - 1,1,1,4,4,4 - hexafluorobutane, which is then hydrolysed to hexafluorobutanone-2; (3) 2,2 - diethoxy - 1,1,1,4,4,4 - hexafluorobutane is prepared as in (2) but using ethanol, and is hydrolysed to 1,1,1,4,4,4-hexafluoro-2-butanone. Lists are given of ether starting materials, alcohol starting materials, and of polyfluorinated polyethers of the invention.