Superactive and stereospecific catalysts. II. Kinetics of propylene polymerizations

The kinetics of propylene polymerization by superactive CH-catalyst prepared from toluene solution of MgCl₂ · EH/PA/TiCl₄–TEA/PES was investigated. The results are compared with CW-catalyst prepared from crystalline MgCl₂/EB/PC/TEA/TiCl₄–TEA/MPT (abbreviations given in the text). The former is four times more active than the latter and produces more isotactic polypropylene. The CH-catalyst has 25% of the Ti as isospecific sites as compared to 6.7% for the CW-catalysts. These sites have the same rate constant of propagation so that the higher polymerization activity of the CH-catalyst is attributable simply to a greater number of active sites. Differences in the kinetics of deactivation and of chain transfer for the two catalysts are described.