GB591383A - The preparation of alpha-methylene carboxylic acid fluorides - Google Patents

Abstract

Alpha-methylene carboxylic acid fluorides are produced by reacting an alpha-methylene carboxylic acid chloride of the general formula CH2 : CR.CO.Cl in which R is hydrogen or a monovalent aliphatic hydrocarbon radical with antimony trifluoride or an alpha-methylene carboxylic acid anhydride with an alkali metal fluoride. The products may be polymerized, or interpolymerized with polymerizable compounds containing at least one ethylenic linkage, by means of peroxide polymerisation catalysts, ultraviolet light, heat, &c. The products include acrylyl fluoride, alpha-ethyl-, alpha-propyl- and alpha-isobutyl acrylyl fluoride. In the polymerization process the bulk and solution processes are preferred and the polymerizable mixture should contain at least 5 per cent and preferably more than 25 per cent by weight of an a -methylene carboxylic acid fluoride or admixture of said fluorides, the temperature being preferably from 30 DEG C. to 60 DEG C. Compounds which may be employed for the production of interpolymers include ethylene, isobutylene, styrene; 1.1-dichloroethylene, 1,1-difluoroethylene, trifluoroethylene, trifluoro - chloro - ethylene, tetrafluoroethylene; vinyl esters of inorganic and organic acids, such as vinyl formate, vinyl acetate and vinyl benzoate; acrylic acid and methacrylic acid and their esters, nitriles and amides; vinyl ethers, e.g. vinyl ethyl ether and vinyl butyl ether; vinyl ketones, e.g. vinyl methyl ketone and methyl isopropenyl ketone; N-vinyl imides, e.g. N-vinyl succinimide and N-vinyl phthalimide; esters of dicarboxylic acids such as dimethyl fumarate, diethyl maleate and diethyl itaconate; the dienes, e.g. butadiene-1,3; isoprene; 2-chlorobutadiene-1,3; 2-fluorobutadiene-1,3 and 2-cyanbutadiene-1,3; the polyhydric alcohol esters of acrylic and methacrylic acids, e.g. ethylene glycol dimethacrylate, ethylidene glycol dimethacrylate and hexamethylene glycol diacrylate; dimethallyl carbonate and hexamethylene dimethylacrylamide. In examples: (1) and (2) methacrylyl fluoride is obtained from methacrylyl chloride and antimony trifluoride and from methacrylic anhydride and potassium fluoride respectively; (3) methacrylyl fluoride is polymerized in the presence of benzoyl peroxide and benzoin the mixture being exposed to a mercury vapour lamp at room temperature; (4) methyl methacrylate and methacrylyl fluoride are polymerized by heating in an atmosphere of nitrogen with benzoyl peroxide; (5) a solution of petroleum ether, vinyl chloride, methacrylyl fluoride and benzoyl peroxide is heated to form an interpolymer; (6) a mixture of acrylonitrile, methacrylyl fluoride and benzoyl peroxide is heated to yield a hard opaque solid interpolymer. The polymer products may be usefully applied as film forming materials and may be moulded by heat and pressure. The Specification as open to inspection under Sect. 91 states that any alpha-methylene carboxylic acid halide other than the fluoride may be used as starting material and that R in the above formula may be halogen or a monovalent hydrocarbon radical. This subject-matter does not appear in the Specification as accepted.