Organoaluminum chemistry and its application to the initiation of carbenium ion polymerization

Abstract

Organoaluminum compounds are weak Lewis acids, which specifically react with a number of reagents (or bases) and generate an electrophile (initiator)gegenion pair, reminiscent of classical Friedel-Crafts complexes. These complexes, under suitable reaction conditions, initiate polymerization of cationically polymerizable monomers producing useful high molecular weight polymers. In recent years a number of such organoaluminum-initiator systems have been systematically explored and their chemistry unravelled. As a consequence new insights have been gained which has led to newer applications of organoaluminum compounds in organic as well as new polymer synthesis. The present paper briefly summarizes the results in this area, especially from the point of view of initiator generation. Some recent results on the initiation of carbenium ion polymerizations using the oxyhalides of sulfur and phosphorous in conjunction with organoaluminum compounds are discussed.