摘要
This contribution reports ethylene polymerization behavior of titanium complexes incorporating bis（phenoxyimine） ligands. Six phenoxy-imine Ti（IV） complexes {6-R^1-2-[CH=N（2,6-difluoro-3,5-diR^2-4-R^3Ph）]C6H30}2TiCl2 （1： R^1 = H, R^2 = H, R^3 = H; 2： R^1 = H, R^2 = H, R%3 = 4-vinylphenyl; 3： R^1 = CH3, R^2 = H, R^3 = H; 4： R^1 = CH3, R^2 = H, R^3 = 4-vinylphenyl; 5： R^1 = CH3, R^2 = F, R^3 = H; 6： R^1 = CH3, R^2 = F, R^3 = 4-vinylphenyl） have been synthesized and evaluated for ethylene polymerization using dried MAO （simplified as DMAO） as cocatalyst. An obvious catalytic heterogeneity of Cat 2 （Complex 2/DMAO） towards ethylene polymerization was observed, which was illustrated by decreased activity, multi- modal molecular weight distribution and partially improved particle morphology comparing with Cat 1. Moreover, Cat 3 exhibits ＂living＂ characteristics in the process under certain conditions （25 ~C, less than 20 min）. Otherwise, the moderate to high ethylene polymerization activity of ca. 105-106 g PE/（mol Ti＇h） and high molecular weight （Mw = 105-106） of polyethylene can be obtained by changing the skeleton structure of these complexes.
This contribution reports ethylene polymerization behavior of titanium complexes incorporating bis（phenoxyimine） ligands. Six phenoxy-imine Ti（IV） complexes {6-R^1-2-[CH=N（2,6-difluoro-3,5-diR^2-4-R^3Ph）]C6H30}2TiCl2 （1： R^1 = H, R^2 = H, R^3 = H; 2： R^1 = H, R^2 = H, R%3 = 4-vinylphenyl; 3： R^1 = CH3, R^2 = H, R^3 = H; 4： R^1 = CH3, R^2 = H, R^3 = 4-vinylphenyl; 5： R^1 = CH3, R^2 = F, R^3 = H; 6： R^1 = CH3, R^2 = F, R^3 = 4-vinylphenyl） have been synthesized and evaluated for ethylene polymerization using dried MAO （simplified as DMAO） as cocatalyst. An obvious catalytic heterogeneity of Cat 2 （Complex 2/DMAO） towards ethylene polymerization was observed, which was illustrated by decreased activity, multi- modal molecular weight distribution and partially improved particle morphology comparing with Cat 1. Moreover, Cat 3 exhibits ＂living＂ characteristics in the process under certain conditions （25 ~C, less than 20 min）. Otherwise, the moderate to high ethylene polymerization activity of ca. 105-106 g PE/（mol Ti＇h） and high molecular weight （Mw = 105-106） of polyethylene can be obtained by changing the skeleton structure of these complexes.
基金
financially supported by the National Natural Science Foundation of China(Nos.20936006 and 20976152)
National Basic Research Program of China(2011CB606001)
Doctoral Program of Higher Education of China(No.20100101110041)
Program for Changjiang Scholars and Innovative Research Team in Zhejiang University
