Isobutylaluminum aryloxides as metallocene activators in Homo- and copolymerization of olefins

The article describes that sterically hindered isobutylaluminum aryloxides with bulky Bu-t substituents at 2,6- positions of aryl fragment, i.e. (2,6-di-Bu-t,4-R-C6H2O)(AlBu2)-Bu-i (R=H (1-DTBP), Me (1-BHT), Bu-t (1-TTBP)) and (2,6-di-Bu-t,4-R-C6H2O)(2)(AlBu)-Bu-i (R=H(2-DTBP), Me(2-BHT)) can serve as cocatalysts for metallocene complexes. Isobutylaluminum aryloxides have been applied for activation of rac-Et(2-MeInd)(2)ZrMe2 in homopolymerization of ethylene, propylene, copolymerization of ethylene and propylene, and terpolymerization of ethylene, propylene, and 5-ethylidene-2-norbornene at Al/Zr=300 mol/mol. The type of R substituent at 4-position has a significant effect on catalyst activity. The catalytic system with 1-TTBP showed the highest activity in all homo- and copolymerization processes. Diisobutylaluminum aryloxides provide much higher activity to the systems in all polymerization processes and stronger ability for propylene incorporation in copolymer than diaryloxides. The activities of the systems with isobutylaluminum aryloxides are similar or exceed that of the system with MAO as activator as have shown for propylene polymerization. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43276.