A complexed initiating system AlCl3• phenetole/TiCl4• H2O with dominant synergistic effect for efficient synthesis of high molecularweight polyisobutylene

Abstract

A complexed initiating system AlCl3phenetole/TiCl4• H2O was prepared by simply compounding AlCl3/phenetole and TiCl4/H2O and used for cationic polymerization of isobutylene. It was found AlCl3phenetole/TiCl4H2O exhibited activities 1.2-3 times higher than those of AlCl3/phenetole, and more than an order of magnitude higher than those of TiCl4/H2O, which indicated a notable synergistic effect produced in the complexed system. In addition, due to the higher activity of AlCl3phenetole/TiCl4 •H2O, lower coinitiator concentration and polymerization temperature, as well as higher monomer concentration were more favored for this complexed initiating system to produce polyisobutylene (PIB) with reasonable molecular weight (Mw) and molecular weight distribution (MWD). Furthermore, high molecular weight polyisobutylene (HPIB) with Mw = 1-3 x 105 gmol-1 could be successfully produced by the complexed catalyst system at Tp =-60 to-40 °C. As a whole, the high activity as well as the simple preparation procedures of the complexed initiating system offer us a unique approach for the production of HPIB with improved efficiency.