The synthesis of hyperbranched ethylene oligomers by nickel catalysts with oxazole structure

Abstract

Since the discovery of Shell-Higher-Olefin-Process (SHOP), ethylene oligomerization has been one of the most significant processes of homogenous transition-metal catalysts. And the structure designing of catalysts is always the key issue for ethylene oligomerization. In this contribution, a series of oxazole-based nickel complexes were synthesized to prepare the hyperbranched ethylene oligomers. The catalytic performance could be modulated by adjusting the electronic and steric effects of the nickel catalysts. And DFT calculations were also performed to reveal the electronic and steric effects of the ligand structures. Specially, these nickel complexes could catalyze the copolymerization of ethylene and polar monomers (6-chlorohex-1-ene, undecenoic acid and 10-undecen-1-ol, etc.), generating polar hyperbranched oligomers. And the incorporation ratio of polar monomers could be adjusted by using different catalysts (0.1–1.0 mol%). The generated hyperbranched oligomer materials will exhibit some potential applications as lubricants or surface modifiers.