Synthesis,structure and ethylene polymerization behavior of titanium complexes [C3H6(N = CH-Ar-O)2]T

The reaction of C3H-6(N=CH-Ar-OH)2 (Ar =5-tert-butyl-C6H3 (2a), 3-tert-butyl-C6H3 (2b), 3-methyl-Call3(2c)) with 2 equiv, of BuLi followed by 1 equiv TiCh yields the dichloride complexes [C3H6(N=CH-Ar-O)2]TiCI2[Ar =5-tert-butyl-C6H3 (3a), 3-tert-butyl-C6H3 (3b), 3-methyl-C6H3 (3c)]. The structure of compound 3a has been confirmed by X-ray crystallographic analysis. These Ti (IV) dichloride complexes are active catalysts for the polymerization of ethylene with methylaluminoxane (MAO) as a cocatalyst. Activities up to 4.14 × l05 g (mol Ti h)-1 were obtained in dried toluene. And the molecular weights of polyethylene are in the range 1.53 × 104-16.4 × 104. Catalyst activity, polymer yield,and polymer molecular weight can be controlled over a wide range by changing the ligand structure and variation of reaction parameters such as Al-Ti ratio and polymerization reaction temperature.