Polymerisation by Stable Halides and Esters

In 1962 Tokura and Kawahara reported that styrene could be polymerised by various alkyl and aryl chlorides in sul ur dioxide. The solvent did not participate in the polymerisation as drown by the absence of polysul one copolymers among the products. Benzyl, 1-phenylethyl, propyl and Ixxtyl chlorides were all modestly active initiators in these experiments. Typically about 10% polystyrene, DP = 100—300, was obtained in 150 minutes with 0.37 M of initiator at 25°C. Under these same conditions, both trityl chloride and hydrogen diloride failed to give any polymer. We do not know if these results have ever been repeated and confirmed by other workers. If they are genuine and do not arise from some unknown artifact, they could be interpreted in terms of specific solvation of the chlorides by the solvent to give a C—Cl polarisation sufficient to induce the pseudo cationic polymerisation of styrene. However, more work would be necessary to confirm these proposals. 

N-Vinylcarbazole has been polymerised by a whole series of organic halides by Otsu and coworkers In view of the extreme sensitivity of this monomer to traces of 

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