Rediscovery of a Broad Array of Lewis Acids for Living Cationic Polymerization in the Presence of an Added Base

  • Kanaoka, Shokyoku (Department of Macromolecular Science, Graduate School of Science, Osaka University) ;
  • Kanazawa, Arihiro (Department of Macromolecular Science, Graduate School of Science, Osaka University) ;
  • Aoshima, Sadahito (Department of Macromolecular Science, Graduate School of Science, Osaka University)
  • 발행 : 2006.10.13

초록

Cationic polymerization of isobutyl vinyl ether using various metal halides was examined in toluene in the presence of an added base at $0^{\circ}C$. In conjunction with an appropriate weak base such as ethyl acetate or 1,4-dioxane, all metal halides but $FeBr_{3}\;and\;GaCl_{3}$ led to living cationic polymerization. The polymerization rates varied as follows: $FeBr_{3},\;GaCl_{3}\;>\;FeCl_{3}\;>\;SnCl_{4}\;>\;InCl_{3}\;>\;ZnCl_{2}\;>>\;AlCl_{3},\;HfCl_{4},\;ZrCl_{4}\;>\;EtAlCl_{2},\;BiCl_{3},\;TiCl4\;>>\;SiCl_{4}\;>\;GeCl_{4}$. This order partially corresponds to that of the equilibrium constant in the formation of a carbocation from a chloroalkane in the presence of a carbonyl compound. With extremely active Lewis acids, such as $FeBr_{3}\;and\;GaCl_{3}$, the use of a stronger base, THF, was required to achieve living polymerization.

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