Ethylene Polymerization with A Nickel(II) Acenaphthenequinonediimine Complex and Its Combination with TiCl_4

A new nickel(Ⅱ) bis(2-biphenylyl)acenaphthenequinonediimine complex was synthesized.It was examined for ethylene polymerization in combination with different alkylaluminium co-catalysts. In the presence of AlEt_2Cl,this complex exhibited high catalystic activity for ethylene oligomerization. Three catystic systems were obtained by combinating it with TiCl_4 by different ratios and supporting on SiO_2/MgCl_2.Results showed that these combined catalysts could catalysize ethylene polymerization to produce branching polyethylene. The influences of various polymerization conditions, including the temperature, [Al]/([Ni]+[Ti]) molar ratio on the catalytic activity, degree of branching and branch length of PE were investigated.