POLYMERIZATION OF AROMATIC NUCLEI .16. MECHANISM OF CHAIN PROPAGATION IN POLYMERIZATION OF BENZENE BY ALUMINUM CHLORIDE CUPRIC CHLORIDE

In the reported experiments, a study was made of the mechanism of benzene polymerization by aluminum chloride-cupric chloride. the main effort was devoted to propagation with the aim of resolving a literature conflict as to whether a cationic or radical pathway is involved. When equimolar mixtures of benzene and haloarene are polymerized, the resulting copolymers are composed almost exclusively of benzene monomer. The amount of haloaromatic present in the copolymer was determined by elemental analyses and confirmed by infrared spectroscopy. These rresults are strongly indicative of propagation by an electrophilic moiety. The presence of oxygen in the reaction mixture was found to have no significant effect on the rate or yield of the polymerization, in contrast to a previous published report. increased yields of biphenyl and the presence of chlorobenzene point to oxidation of intermediate radicals by cupric chloride. None of the experimental evidence is satisfactorily interpreted by radical propagation.