Living Carbocationic Polymerization. LVII. Kinetic Treatment of Living Carbocationic Polymerization Mediated by the Common Ion Effect

The effect of anion concentration on the apparent rate constant of polymerization kA p of isobutylene (IB) induced by the 2-chloro-2,4,4-trimethylpentane (TMPCl)/TiCl4 initiating system using the CH2Cl2/nC6H14 (60/40 v/v) solvent system at −40 and −80°C was studied by the use of nBu4NCl. Computer simulation has shown that kA p decreases several orders of magnitude upon the addition of even a very small amount of common anion TiCl−- 5 to the charge. The rate of change is reduced in the concentration range of experimental interest. It was concluded that the decrease of kA p with increasing TiCl −- 5 concentration is mainly due to the decreasing contribution of propagation by free ions. The contribution (%) of propagation by free ions to the apparent rate of propagation was calculated.