Process for the production of polyarylene sulphides

A process for the production of optionally branched, high molecular weight polyarylene sulphides, from

• (a) dihalo-benzenes, of which from 0 to 100 mol % correspond to formula (I) ##STR25## and from 0 to 100 mol % correspond to formula (II) ##STR26## wherein each X represents a halogen which is in the meta- or para-position with respect to the other and
• R.sup.1 is the same or different, and represent hydrogen, C.sub.1 -C.sub.20 alkyl, C.sub.5 -C.sub.20 cycloalkyl, C.sub.6 -C.sub.24 aryl, C.sub.7 -C.sub.24 alkaryl or C.sub.7 -C.sub.24 aralkyl, or two radicals R.sup.1 which are in the ortho-position with respect to one another linked to form an aromatic or heterocyclic 5 to 10-membered ring which contains up to three heteroatoms, and at least one radical R.sup.1 is always different from hydrogen, and
• (b) from 0 to 5.0 mol %, based on the total of the dihalogen aromatic compounds corresponding to formulae (I) and (II), of a tri- or tetrahalogen aromatic compound corresponding to formula (III)
• ArHal.sub.n (III),
• wherein
• Ar represents an aromatic or heterocyclic radical which contains up to three heteroatoms, and has from 6 to 24 carbon atoms,
• Hal represents halogen, and
• n represents the number 3 or 4, and
• (c) alkali sulphides, the molar ratio of (a+b):c ranging from 0.85:1 to 1.14,
• (d) in a polar solvent the molar ratio of (c) to (d) ranging from 1:2 to 1:15,
• characterized in that the above-mentioned components are reacted together in the presence of disulphides corresponding to formmula (IV) ##STR27## wherein R and R' which are the same or different, represent C.sub.1 -C.sub.20 alkyl, C.sub.5 -C.sub.20 cycloalkyl, C.sub.6 -C.sub.24 aryl or C.sub.7 -C.sub.24 aralkyl, and in the case of the cycloalkyl, or aryl or aralkyl radicals with from 1 to 3 ring carbon atoms replaced by heteroatoms,
• X and X' which may be the same or different, represent a single bond, O, S or ##STR28## wherein R.sup.2 represents hydrogen and has the meaning stated for R, Z which is the same or different, represents O, S, NR, wherein R is as defined above, and
• n represents 0 or 1.