GB608111A - Improvements in or relating to the production of organic fluorine compounds - Google Patents

Abstract

Monofluoro derivatives of saturated halohydrocarbons are prepared by reacting a saturated aliphatic halogenated hydrocarbon not containing fluorine but having at least two halogen atoms other than fluorine attached to the same terminal carbon atom, at a temperature of at least 30 DEG C. and at elevated pressure, with at least the stoichiometric equivalent of anhydrous hydrogen fluoride in the presence of at least 2.5 per cent by weight of stannic chloride, based on the halo-hydrocarbon starting material, as catalyst. Temperatures of 50 DEG to 150 DEG C. and pressures of 100 to 200 lbs. per sq. in. are preferred. To minimise formation of difluoro compounds, the monofluoro compound should be removed as formed; thus, in a continuous process, the p hydrogen fluoride is fed into a reaction vessel whilst the monofluoro compound is continuously removed. Examples describe the interaction of hydrogen fluoride with (1) ethylidene dichloride, both batchwise and continuous, yielding 1-fluoro-1-chloro-ethane and 1 : 1-difluoroethane; (2) asym.-tetrachlorethane yielding 1-fluoro-1 : 1 : 2-trichlorethane and some 1 : 1-difluoro-1 : 2-dichloroethane; (3) 1 : 1 : 2- trichlorethane yielding 1-fluoro-1 : 2-dichlorethane. Reference is made to Specifications 391,168 and 428,361 and U.S.A. Specification 2,005,711. The Provisional Specification is not limited to the use of the above amounts of hydrogen fluoride and stannic chloride.