Direct synthesis of highly reactive polyisobutylenes via cationic polymerization of isobutylene co‐initiated with TiCl 4 in nonpolar hydrocarbon media

Living cationic polymerization of isobutylene (IB) with 1‐chlorine‐2,4,4‐trimethyl pentane (TMPCl)/TiCl 4 /isopropanol ( i PrOH) or isoamylol ( i AmOH) has been achieved in the presence of 2,6‐di‐ tert ‐butylpyridine (DtBP) at −80°C. Polyisobutylenes with nearly theoretical M n based on TMPCl molecules and more than 90% of tert ‐chlorine‐end groups could be obtained at high [TMPCl]. The β ‐proton elimination from CH 3 in growing chain ends increased with increasing polymerization temperature and decreasing solvent polarity. A chain‐transfer‐dominated cationic polymerization process with H 2 O/TiCl 4 / i AmOH could be achieved in n ‐hexane at −30°C. The monomer conversion and content of exo ‐olefin end groups increased while molecular weight decreased with increasing [ i AmOH]. To the best of our knowledge, this is the first example to achieve the direct synthesis of highly reactive polyisobutylene with low M n of 1200∼1600, carrying more than 80% of exo ‐olefin terminals by a single‐step process via cationic polymerization co‐initiated by TiCl 4 in nonpolar hydrocarbon. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42232.