Efficient incorporation of a polar comonomer for direct synthesis of hyperbranched polar functional ethylene oligomers

Abstract

A series of iminopyridyl Pd(II) catalysts containing bulky diarylmethyl substituents with various remote nonconjugated electron-withdrawing or -donating groups were synthesized and characterized. These catalysts possessing high catalytic activities and long half-life at 50 °C are capable of producing hyperbranched ethylene oligomers in ethylene oligomerization. More importantly, hyperbranched polar functional ethylene oligomers with very high incorporation can be accessible from ethylene–MA co-oligomerization in the presence of iminopyridyl Pd(II) catalysts. In terms of catalysts, the remote nonconjugated electronic substituents of bulky diarylmethyl moieties have a significant effect on the molecular weight and branching density of ethylene oligomers/ethylene–MA co-oligomers, as well as the incorporation of MA in ethylene (co)oligomerization.