Nickel-based ethylene oligomerization catalysts supported by PNSiP ligands

GRAPHICAL ABSTRACT

ABSTRACT

A series of nickel (II) complexes bearing silicon bridged diphosphines ligands (PNSiP) have been synthesized and characterized. All nickel precatalysts, activated with ethylaluminum dichloride (EtAlCl₂), exhibited moderate to high activities for ethylene dimerization to butylene. The in situ nickel precatalysts formed by mixing N-cyclopentyl-N-((diphenylphosphanyl)dimethylsilyl)-1,1-diphenylphosphanamine (L2) with NiBr₂(DME) showed high catalytic activity (2.40 × 10⁸ g/(mol_Ni·h)) and high product selectivity (88.6%) towards butene using methylcyclohexane as solvent at 1.0 MPa ethylene pressure and 45°C temperature, no polyethylene(PE) was observed. Ligand backbone tuning of PNSiP-based catalytic systems help in precise understanding of steric bulk variation effects on catalytic performance.

KEYWORDS:

• Butene
• ethylaluminum dichloride
• ethylene dimerization
• nickel complexes

Acknowledgments

This study was supported by the National Key Research and Development Program of China (2017YFB0306700). The Natural Science Foundation of Tianjin City (14JCYBJC23100, 15JCYBJC48100 and 16JCZDJC31600).

Supplementary Material

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Additional information

Funding

The National Key Research and Development Program of China (2017YFB0306700). The Natural Science Foundation of Tianjin City (16JCZDJC31600).