GB601596A - Halogenation of organic fluorine compounds - Google Patents

Abstract

Compounds of the general formula X(CZ2CZ2)nRHb-dYd, wherein the Z substituents are halogen atoms of which at least three are fluorine, n is a positive integer not greater than 12, X is hydrogen or a halogen having an atomic weight of less than 80, Rhb-d is a halogen-free saturated organic radical containing at least two carbon atoms and derived from an aliphatic or cycloaliphatic hydrocarbon or ether and having b-d hydrogen atoms attached directly to carbon, b being a positive integer and d zero or an integer not greater than b and Y is a halogen having an atomic weight less than 80 are prepared by halogenating a compound of the general formula H(CZ2CZ2)nRHb with a halogen having an atomic weight of less than 80. The process may be carried out in the presence or absence of a solvent and a halogenation catalyst such as actinic light, heat or a polyvalent metal halide, for example, ferric chloride may be used. The chlorinated products may be further treated with inorganic fluorinating agents such as antimony fluorides, silver fluoride or hydrogen fluoride. The starting materials may be prepared by heating a tetrahaloethylene containing at least three fluorine atoms, preferably tetrafluoroethylene, with a saturated non-polymerizable aliphatic or cycloaliphatic hydrocarbon or ether of the type RHb + 1 containing at least two carbon atoms and b + 1 hydrogen atoms attached to carbon and as described in Specification 583,874; typical hydrocarbons and ethers are diethyl ether, dioxane, methylal, diethyl acetal, propane, isobutane, iso-octane, cyclohexane and methylcyclohexane. In examples: (1) a tetrafluoroethylene-n-butane reaction product consisting mainly of H(C2F4)4C4H9 is chlorinated in carbon tetrachloride solution in the presence of actinic light to yield a series of products containing 1 to 4 chlorine atoms; the compound is also brominated in the presence of sunlight; (2) a tetrafluoroethylene-isobutane reaction product consisting of H(C2F4)nC4H9, where n varies from 1 to 5 is chlorinated as in (1) yielding chlorinated liquid products. The chlorination of the products from the reaction of tetrafluoroethylene and cyclohexane or dioxane in which the ratio of tetrafluoroethylene to cyclohexane or dioxane is 1 : 1, in carbon tetrachloride in the presence of light, is disclaimed. The products of the invention may be used as solvents, fire extinguishers, hydraulics, insulating oils, lubricators and plasticisers. The Specification as open to inspection under Sect. 91 relates to the halogenation as above of fluorine containing organic compounds of the type H(CZ2CZ2)n-mRHb-1 (CZ2CZ2)mH, where Z, n and b are as defined above, m is zero or a positive integer less than n and RHb-1 is a halogen-free saturated divalent organic radical containing at least two carbon atoms and having b-1 hydrogen atoms attached directly to carbon. In additional examples: (1) cyclohexane is heated with tetrafluoroethylene in the presence of benzoyl peroxide in an autoclave yielding on distillation, three fractions containing compounds corresponding to HCF2CF2C6H11\t H(CF2CF2)2C6H11 and H(CF2CF2)3C6H11 respectively; the first fraction is chlorinated as in (1) above to yield products corresponding to C8H8F4Cl4 and C8H7F4Cl5; (2) dioxane and tetrafluoroethylene are reacted similarly yielding fractions corresponding to H.C2F4.C4H7O2 and H(C2F4)2.C4H7O2 and the first fraction is chlorinated as in (1) yielding a product which is probably C5H6O2F4Cl3. The starting materials, prepared as above, may be derived from aliphatic, cycloaliphatic, aromatic and heterocyclic saturated non-polymerizable compounds including ethers, hydrocarbons, alcohols, acids, anhydrides, esters and ketones and many examples are given; the cycloaliphatic compounds may contain carboxyl, alkoxy, hydroxy, carbonyl and cyano groups. This subject-matter does not appear in the Specification as accepted.