Cyclic arylene sulfides: A novel synthesis and ring-opening polymerization

Oxidative polymerization of aryl disulfides has been carried out under high dilution conditions for the preparation of cyclic arylene sulfides. The readily available diphenyl disulfide and dichloro disulfide with diphenyl sulfide, diphenyl ether, or p-xylene are useful monomers for the synthesis of the corresponding cyclic oligo(thio arylene)s in similar to 69% yield. The cyclization of dichloro disulfide with p-xylene gives cyclic oligo(thio-2,5-dimethyl-1,4-phenylene) (3c) bearing a disulfide bond with the repeating units ranging from 3 to 10. The free radical ring-opening polymerization of the cyclics leads to the formation of linear poly(thio arylene)s. The obtained poly(thio-2,5-dimethyl-1,4-phenylene) (6c) has a melting temperature of 354 degrees C, which is 71 degrees C higher than that of the unsubstituted poly(thio phenylene).