Catalysis of the Propagation Reaction in Ziegler-Natta Polymerization

The results on the catalytic action of counterions of homogeneous ionic polymerizations are reviewed. By analogy, positively charged counterious play an important role in the heterogeneous system TiCl3–AlR3. This is illustrated by the influence of “defects” in the TiCl3 on the course of a given reaction. Counterions of different structures act in the polymerization as centers of different stereospecificity.