Controlled Chain-Walking Ethylene Oligomerization in Gas-Phase for Hyperbranched Ethylene Oligomers

Abstract

Gas-phase polymerization is typically employed for the synthesis of high-molecular-weight crystalline polyolefin materials, yet the production of low-molecular-weight hyperbranched ethylene oligomers via this method is seldom reported. In this study, we utilized flexible bulky iminopyridyl Pd(II) catalysts to catalyze the gas-phase oligomerization of ethylene, resulting in the preparation of hyperbranched ethylene oligomers. These catalysts demonstrated higher activity and stability comparable to those observed in solution polymerization, yielding hyperbranched ethylene oligomers with lower branching density and higher molecular weights. Most notably, 13C NMR analysis and viscosity measurements revealed that these hyperbranched ethylene oligomers fulfill the requirements for application as low-viscosity lubricating base.