Process for the preparation of polyarylene sulphides

Claim 1

In the process for preparing a polyarylene sulphide by polycondensing at a temperature of from 160°-285° C. for up to 60 hours (a) a p-dihalogenobenzene which consists of 50-100 mol % of a compound of the formula ##STR3## and 0-50 mol % of a compound of the formula ##STR4## wherein X is fluorine, chlorine, bromine or iodine and each R is independently selected from the group consisting of hydrogen, C 1 -C 20 -alkyl, C 5 -C 20 -cycloalkyl, C 6 -C 24 -aryl, C 7 -C 24 -alkaryl and C 7 -C 24 -aralkyl with the proviso that at least one R is other than hydrogen; and (b) 0-2.0 mol %, based on (a), of a compound of the formula ArX n wherein Ar is an aromatic radical having 6 to 24 carbon atoms and at least 3 free valencies, X is as aforesaid and n is at least 3 with (c) an alkali metal sulphide in (d) a polar solvent, the molar ratio of (a) to (c) being from 0.98:1 to 1.02:1 and the molar ratio of (c) to (d) being from 1:2 to 1:10, the improvement wherein said polycondensation is carried out in the presence of 0.05-2.0 mols of tri-alkali metal phosphate per mol of (c).