GB581405A - Preparation of organic fluorine compounds - Google Patents

Abstract

Organic fluorine compounds are prepared by pyrolyzing one or more fluoro-halogeno alkanes, fluoro-halogeno alkenes and fluoro-alkenes, in which the halogen, other than fluorine, is chlorine, bromine or both. Atmospheric, sub-atmospheric or elevated pressure may be used and heavy metal halides, mixtures thereof with heavy metals or their alloys, halides of the alkaline earth metals, e.g. BaCl2 or CaCl2 and active carbon may be used as catalysts. In the examples, the following compounds are pyrolyzed by passing through a heated tube of inert material such as carbon or the noble metals; CHClF2, CHClF2+CHCl2F, CCl2F2, CF3CH2Cl, CClF2CClF2, CF2BrCClFBr, CCl3F+ CHClF2, CHClF2+C2F4, CHCl2F, CHClF2+ CCl2F2, CHF2Br, CH3CClF2, CH3CF3, CF3CH2Cl, CClF2CHF2, H(CF2)3Cl H(CF2)3 Cl+CHClF2, CH2CClF and CH2CF2. Chlordiflormethane is also pyrolysed in the presence, separately, of activated carbon, iron and its halides, deoxidized copper and its halides and an alloy of Ni, Fe, Mo and Mn and their halides. Other starting materials mentioned are: CH2ClF, CH3CCl2F, CH2ClCClF2, CHF2CClF2, C2HCl2F3 and CCl2FCClF2. The process, which can be carried out in a continuous or stepwise manner and in the presence or absence of an inert gas, e.g. nitrogen or helium as diluent or buffer, is applicable to the production of C2F4 which is an intermediate for refrigerants and plastics, and compounds of the formula H(CF2)nCl, where n is at least 3. Other compounds are also formed and in general have uses as refrigerants, an sthetics, solvents and intermediates in the production of alcohols, esters, halides and alkyl derivatives.