Study on Catalytic Properties of Cyclopentadienyl Bisphenoxyl Titanium Chloride for Ethylene Polymer

Threemono-cyclopentadienyl metal complexes, [C6H4O2]CpTiCl (Ⅰ), [C12H8O2]CpTiCl (Ⅱ), and [C20H12O2]and 2,2'-bisnaphthol, respectively. In the presence of a moderate amount of methylaluminoxane (MAO), thecomplexes exhibited catalytic activities for ethylene polymerization. Complex I showed the highest activity atAl/Ti molar ratio of 500 at the temperature of 30 ℃. With increasing of polymerization temperature, catalyticactivities and molecular weight of the obtained polyethylene tended to decrease, and molecular weight distri-bution of polyethylene became narrower. With the molecular simulation method, the charges on titanium atomsof complexes Ⅰ, Ⅱ, and Ⅲ, and the bond angles formed by Ti and bisphenoxy ligands were calculated. It wasconcluded that the smaller the net charge on Ti and the smaller the angle of O 1-Ti-32, the higher the activity of the complex.