Polymer Bulletin, Vol.72, No.1, 49-60, 2015
The polymerization of isobutylene catalyzed by FeCl3 center dot i-Pr2O complex prepared in non-halogenated solvents
The synthesis of highly reactive polyisobutylene (HR PIB) using FeCl3 center dot diisopropyl ether (i-Pr2O) as catalyst prepared in dichloromethane (DCM), to produce polyisobutylene with high exo-olefin content (HR PIB), has been previously reported . The use of chlorinated solvent for complex preparation is a major disadvantage for industrial-scale production of HR PIB. In an effort to replace DCM, an undesirable chlorinated solvent, we have studied the feasibility of using non-chlorinated solvents. Polymerization was absent when the complex preparation was attempted in hexanes, nitrobenzene or acetonitrile. When the complex was prepared in benzene the conversion was similar to that observed with DCM. Conversions decreased when a complex was prepared in toluene or o-xylene, due to a side reaction involving chlorination of the aromatic ring by FeCl3. This side reaction was suppressed by changing the addition order, i.e., adding an equivalent amount of FeCl3 to i-Pr2O dissolved in toluene.
Keywords:Motor oil and fuel additives;Highly reactive polyisobutylene;FeCl3;diisopropyl ether complex;Non-chlorinated solvents