含8-羟基喹啉类配体的新型钛配合物[O,N]CpTiCl_2的合成及其催化乙烯聚合研究

茂金属催化烯烃聚合的活性中心被认为是1 4电子结构的金属阳离子配合物 Ｃｐ2 ＭＲ]+ (Ｒ为烷基 ) ,并且金属中心的Ｌｅｗｉｓ酸性和周围茂配体的空间构型对其催化活性及聚合产物的结构有直接的影响1,2 ] .然而 ,茂金属须大量ＭＡＯ存在下才能显示高活性 ,并且其稳定性较差 ,这都一定程度上限制了茂金属催化剂的实际应用 .近几年来 ,将含非环戊二烯基配体的金属配合物应用于烯烃均相聚合的研究大量出现3] ,其中非环戊二烯基配体有含氮化合物4～ 9] 和含氧化合物10～ 15] 等 ,这些非茂配合物可催化乙烯或丙烯聚合 ,但活性一般较低 .茂金…

SYNTHESIS OF THE NOVEL TITANIUM COMPLEX ([O,N]CpTiCl_2) CONTAINING 8-HYDROXY-QUINOLINE LIGAND AND ITS CATALYSIS FOR ETHYLENE POLYMERIZATION

Synthesis of half metallocene complexes (O,N]CpTiCl 2) containing 8 hydroxy quinoline ligand is described.The results indicate that O,N]CpTiCl 2 is active for ethylene polymerization at 30℃ and 0.1?mPa with MAO activation,and exhibits much higher activity than CpTiCl\-3.The results show that when there is an electron donor substituent next to N,such as a methyl,the activity of O,N]CpTiCl 2 increases greatly; however,if there is an electron acceptor substituent,such as nitro in the benzene ring,it is inactive.For the O,N]CpTiCl 2/MAO system,the polymerization rate is “up and down” type with increasing the Al/Ti molar ratio.The activity reaches its maximum at molar ratio of Al/Ti = 500,which is over 1×10 5?gPE/molTi·h.The activity decreases as the polymerization time is longer.The polyethylene obtained is characteristic of narrow molecular distribution with molecular weight M w around 40×10 4 and molecular weight ratio M w/ M n=2 8.