Patent GB-839034-A (GB)
Title: Halogenated hydrocarbons and compositions and methods of production thereof
IPC: C07C19/14
Filed: 1946-06-14
Abstract: Halogenated hydrocarbons containing fluorine are prepared by treating a fluorinated hydrocarbon with an elemental halogen, metal halide or hydrogen halide as a halogenating agent such that a different compound is produced having no fewer carbon atoms than the starting material, and in particular by the following processes: (a) fluorinating perfluorohalo - olefines to obtain dimer addition or simple addition products (e.g. CFCl=CFCl+F2 yield CF2Cl-CFCl-CFCl-CF2Cl together with some C2Cl2F4 and C2Cl3F3 and minor amounts of C2ClF5, C2Cl4F2, C4Cl5F5 and C4Cl6F4); (b) fluorinating a saturated perhalogenated hydrocarbon, containing fluorine and one or more other halogens, with elemental fluorine, a metal fluoride or hydrogen fluoride to replace said other halogen or halogens by fluorine (e.g. CFCl2CCl2CCl2-CFCl2+SbF3+SbCl5 give CF2ClCCl2CCl2CF2Cl); (c) chlorinating or brominating perfluorohaloolefines with elemental chlorine or bromine to obtain simple addition products (e.g. CF2ClCFClCF=CF2 yields CF2ClCFClCFClCF2Cl or CF2ClCFClCFBrCF2Br); (d) subjecting products of (a), (b) or (c) to dehalogenation or (when hydrogen is present) dehydrohalogenation to obtain an unsaturated compound (e.g. CF2ClCFClCFClCF2Cl with zinc dust in alcohol or butyl carbitol gives CF2=CF-CF=CF2); (e) replacement of allylic chlorine by a functional group, e.g. one derived from an alkali metal salt (e.g. sodium cyanide) or from ammonia or an amine (allylic fluorine is stated to react analoously but less readily).  Apparatus suitable for the fluorination process and for the dechlorination process is described with the aid of drawings.  The Specification as open to inspection under Sect. 91 of the Patents and Designs Acts, 1907-1946, comprises also the subject-matter of Specification 839,035, and the following further processes: (a) polymerization of perfluorobutadiene by the action of benzoyl peroxide and light; (b) polymerization of trifluorochloroethylene by the action of bis-trichloroacetyl peroxide at 0 DEG  C. or below, or of AlCl3, BF3 or SnCl4 at 30 DEG  C.; (c) pyrolysis of 1 : 2-dichloroperfluorocyclobutane to form trifluorochloroethylene and some 3 : 4-dichloroperfluorobutene-1; (d) thermal depolymerization of high molecular weight polymers, if desired in the presence of CoF3 or fluorine.  This subject-matter does not appear in the Specification as accepted.ALSO:The Specification as open to inspection under Sect. 91 of the Patents and Designs Acts, 1907-1946, comprises the subject-matter of Specification 839,035, and the following further processes: (a) polymerization of perfluorobutadiene by the action of benzoyl peroxide and light; (b) polymerization of trifluorochloroethylene by the action of bis-trichloroacetyl peroxide at 0 DEG  C. or below to produce a white spongy solid which can be hot-pressed, extruded, milled, rolled or formed into fibres; (c) polymerization of trifluorochloroethylene with AlCl3, BF3 or SnCl4 (e.g. by dissolving in CF2ClCF2Cl and warming to 30 DEG  C. with AlCl3 in a sealed tube). This subject-matter does not appear in the Specification as accepted.