Key Words:Titanium；Homogeneous c atalysis；Polymerization；UHMWPE；LLDPE
Abstract:A series of titanium amido complexes ( 1 Ti(NMe 2 2 to 4 Ti(NMe 2 2 ) bearing NNO tridentate ligands was synthesized from the rea c- tions of phenoxy imine amine ligands with one equivalent of Ti(NMe 2 4 . Subsequently, titanium dichloride complexes 1 TiCl 2 to 4 TiCl 2 ) were prepared by treatment of titanium amido complexes with excess M e 3 SiCl in toluene. All metal complexes were chara c- terized by 1 H and 13 C NMR spectroscopy, and the molecular structures of complexes of 2 Ti(NMe 2 2 , 2 TiCl 2 , and 4 TiCl 2 in the solid state were determined by single crystal X ray diffraction. Upon activation with MAO, titanium dichloride complexes as single site catalysts were extremely active toward ethylene homopolymerization with great control on molecular weight and distribution. I n particular, 3 TiCl 2 /MAO exhibited an activity as high as 1.35 × 10 8 g(PE)·mol 1 (Ti)·h 1 at 70 °C and produced polyethylene with high molecular weight ( 41.7 × 10 4 g∙mol 1 ) and very narrow distribution Đ = 1.23). In the presence of 1 octene as comonomer, lin ear low density polyethylenes (LLDPEs) with ultrahigh molecular we ights ( M w = 136 326 × 10 4 g∙mol 1 ) and narrow distributions ( Đ = 1.20 1.50 ) were successfully synthesized
Volume:
Issue:23
Translation or Not:no