Abstract
The rate of polymerization of isobutylene catalyzed by AlBr3 in the presence of some Friedel‐Crafts halogenides (TiCl4, TiBr4, and SnCl4) in nonpolar medium and in the absence of H2O is much higher than in polymerization catalyzed by AlBr3 alone. The catalytic activity increment decreases in the order TiCl4, SnCl4, and TiBr4. In the system AlBr3TiCl4 the conversion is dependent only on the concentration of AlBr3. A new mechanism of initiation by complex compounds is proposed.