GB794830A - Production of bis(perhaloacyl) peroxides - Google Patents

Abstract

A mixture of bis-(perhaloacyl) peroxides of the formula: <FORM:0794830/IV (b)/1> (wherein n is an integer from 1 to 10 and X is F, Cl, CFCl2, CF2Cl or CF3) is prepared by rapidly intermixing and reacting at temperatures between - 15 DEG C. and 25 DEG C. an alkali metal peroxide and a mixture of perhaloacyl halides of the formula: <FORM:0794830/IV (b)/2> (wherein Z is F or Cl) in presence of water and an inert water-immiscible organic solvent and recovering the products in solution in the organic solvent. Suitable solvents are perhaloalkanes (or mixtures thereof) preferably containing only chlorine and fluorine atoms attached to the carbon atoms and preferably containing at least one fluorine atom attached to each carbon atom, specific examples being trichlorofluoromethane, 1 : 1 : 2 - trichloro-1 : 2 : 2 - trifluoroethane, dichlorodifluoromethane and decafluorobutane. In examples: (1) a mixture of perhaloacyl chlorides, prepared as described below, is added to an agitated mixture of an aqueous solution of sodium peroxide and 1 : 1 : 2 - tri - chloro - 1 : 2 : 2 - trifluoroethane solvent at 3 DEG C. and the mixture then allowed to separate into 2 layers; the lower solvent layer contains the required product and, for identification and analysis, a portion of this solution is hydrolysed with sodium hydroxide at from - 40 DEG to + 10 DEG C., giving, on removal of the organic solvent, a residue of the sodium salts of perhaloalkanoic acids; (2) to (4) similar experiments with differing perhaloacyl halide starting materials, prepared as described below, are performed. The products are stated to have utility in the polymerization of chlorotrifluoroethylene and other polymerizable compounds. Starting materials. Perhaloacyl halides Perhaloacyl fluorides are prepared by heating a polychlorotrifluoroethylene, which may be a molecular weight commercial moulding grade resin or a wax or oil of lower average molecular weight, or scrap polymer, to 250 DEG C. to about 375 DEG C., passing an oxygen containing gas into the body of molten polymer and removing from the zone of oxidation a gaseous mixture containing unreacted oxygen and oxidation products of the polymer, these being mixtures of perhaloacyl fluorides and perhalocarbon oils. These mixtures may be (1) fractionated, hydrolysed and distilled to give perhaloalkanoic acids, or salts thereof, which may be converted to perhaloacyl chlorides; these may then be used directly in the process of the invention or first distilled and selected fractions, particularly those free from 2 carbon products, used; (2) fractionated and selected fractions, particularly those free from 2 carbon products, used directly in the process of the invention. In examples: (1) polychlorotrifluoroethylene is oxygenated as described above and the volatile products fractionally distilled, the resulting perhaloacyl fluoride containing product of boiling range 110 DEG to 150 DEG C. is hydrolysed with water at 50 DEG to 90 DEG C. and the mixture is vacuum distilled, the perhaloalkanoic acid fractions of boiling range 125 DEG to 175 DEG C. at 50 mm. are heated with benzotrichloride and the product fractionally distilled to give a mixture of perhaloacyl chlorides of boiling range 135 DEG to 146 DEG C. and average molecular weight 318; (2) polychlorotrifluoroethylene is oxygenated as described above and a product of 1- and 2-carbon compound free chlorine-containing perhaloacyl fluorides of average molecular weight 466 isolated; (3) processes similar to those in (1) are carried out, products of somewhat lower boiling range being isolated from each fractionation, and the final perhaloacyl chloride mixture boils at 94 DEG to 100 DEG C. and has an average molecular weight of 214; (4) a polychlorotrifluoroethylene is oxygenated as described above and a product of boiling range 0 DEG C. to 175 DEG C. at 50 mm. isolated. Specification 765,700 is referred to.ALSO:Ethylenically unsaturated monomers are polymerized in the presence of a mixture of bis-(perhaloacyl) peroxides, prepared by rapidly intermixing and reacting at -15 DEG to +25 DEG C. an alkali metal peroxide and a mixture of perhaloacyl halides of formula <FORM:0794830/IV (a)/1> (wherein X is F, Cl, CFCl2, CF2Cl or CF3, Z is F or Cl and n is 1 to 10) (see Group IV (b)). The monomer may be chlorotrifluoroethylene, trichlorofluoroethylene, 1 : 1 - dichloro - 2 : 2 - difluoroethylene, vinyl chloride, vinyl fluoride, vinylidene chloride, vinyl acetate, the lower alkyl esters of acrylic and methacrylic acids, or mixtures. The perhaloacyl halides may be obtained by heating polytrifluorochloroethylene, e.g. scrap, to a temperature between 250 DEG and 375 DEG C., passing air, oxygen, or ozone through the molten mass, and recovering the degraded, oxidation products. Specification 765,700 is referred to.