Patent GB-1534903-A (GB)
Title: Process for the preparation of arylene sulphide polymers
IPC: C08G75/02
Filed: 1976-05-26
Abstract: 1534903 Arylene sulfide polymers PHILLIPS PETROLEUM CO 26 May 1976 [27 May 1975 19 Jan 1976] 21882/76 Heading C3R Arylene sulfide polymers are prepared by a process which comprises reacting together: (i) one or more p-dihalo-benzenes or substituted pdihalobenzenes of the formula where X is Cl, Br or I, and R is hydrogen or a saturated or aromatic hydrocarbyl radical, e.g. alkyl, cycloalkyl, aryl, alkaryl or aralkyl radicals, the total number of carbon atoms in each molecule being from 6-24, with the proviso that at least 50 mol. per cent of the reactant is constituted by p-dihalobenzene, i.e. compounds of the above formula where each R is hydrogen; (ii) an alkali metal sulfide; and (iii) lithium acetate; the reaction being performed in the presence of an N-alkyl-2-pyrrolidone of the formula  where R<SP>1</SP> is H or C 1 -C 3  alkyl, and R<SP>11</SP> is C 1 -C 3  alkyl, the total number of carbon atoms in the molecule being from 5-8, and at a temperature of 125 to 450 C.; wherein the reactants are brought together in the following sequence: (a) forming a first mixture containing lithium acetate, N-alkyl-2-pyrrolidone and water in free form or as water of hydration; (b) dehydrating the mixture generally by distillation; (c) adding to the dehydrated mixture an aqueous composition containing the alkali metal sulfide, and optionally an alkali metal hydroxide or alkali metal carbonate, and up to 50% wt. based on the weight of said aqueous composition, of water in free form and/or as water of hydration; (d) dehydrating the mixture generally by distillation, and (e) adding the dihalobenzene to the dehydrated mixture formed in step (d). There may optionally be added to the reaction mix in step (e) up to 0À6 p.b.w. per 100 p.b.w. of reactant (i) of a polyhaloaromatic compound of the formula R<SP>111</SP>X n  where X is Cl, Br or I, n is 3-6, and R<SP>111</SP> is a polyvalent aromatic radical of valence n, having one or more aromatic rings, which may be fused together or separate and may contain up to 4 methyl substituents, the total number of carbon atoms in the compound being from 6-16. At the end of the polymerization reaction the N-alkyl-2-pyrrolidone may be distilled from the reaction mixture, in which case carbon dioxide is preferably introduced into the reaction mixture during or after the polymerization reaction but before the distillation of the N-alkyl-2-pyrrolidone. Alternatively the arylene sulfide polymers may be separated from the reaction mixture by filtration, or by dilution of the reaction mixture with water, followed by filtration. The polymers may be blended with fillers, pigments, extenders and other polymers and cured through crosslinking and/or chain extension, e.g. by heating up to 480 C. in the presence of a free-oxygen containing gas. In the Examples poly(p-phenylene sulphides) are prepared as above by first dehydrating a mixture of lithium acetate dihydrate and N-methyl-2-pyrrolidone, then adding thereto sodium sulfide, sodium hydroxide and water, and then dehydrating the resultant mixture, and then adding p-dichlorobenzene and N-methyl-2-pyrrolidone and optionally 1,2,4-trichlorobenzene and then polymerizing. Uses.-Coatings, films, fibres and moulded objects.