Synthesis of novel titanium complex bearing two naphthyloxy-imine chelate ligands and its catalytical performance for ethylene polymerization

Reaction of 2-hydroxyl-1-naphthaldehyde with 2, 6-di-isopropyle-aniline via Schiff base condensation in ethanol afforded the corresponding naphthyloxy-imine ligand 1a. Ligand 1a was characterized by mass spectra. Treatment of this ligand with NaH and TiCl4·2THF in THF respectively, a new titanium complex 1 was obtained of which the structure was characterized by 1H NMR and elemental analyses. Activated by MAO, Complex 1 displayed a very high activity for ethylene polymerization Under the conditions of T = 30-70°C and P = 0.6 MPa, the activities achieve 2.66 × 105-7.24 × 105 g PE (mol Ti)-1h-1 and the viscometric average molecular weight (Mv) of polyethylene was from 35000 to 255000. The activities and the Mv increase with the pressure from 0.1 MPa to 1.0 MPa. The temperature effect on activity of complex 1 is very strong. The data characterized by GPC and DSC showed the synthesis of linear polyethylene (LPE).