芳二酚-茂型钛配合物[O,O]CpTiCl的合成及其催化乙烯聚合性能研究

制备了含二元芳香酚类配体 O ,O]的茂型钛配合物 O ,O]CpTiCl,并通过元素分析、IR、1 H NMR表征了其组成与结构 .结果表明 ,二元芳香酚类配体中两个O原子同时与金属中心原子Ti相连 ,形成环状结构 .研究表明 ,茂型钛配合物 O ,O]CpTiCl在助催化剂甲基铝氧烷 (MAO)作用下 ,于 30℃、1 0 1× 10 5 Pa乙烯压力下即可催化乙烯聚合 ,并显示较高的活性 ,远高于未引入配体 O ,O]的CpTiCl3的活性 ,并且 O ,O]CpTiCl的催化活性依非茂酚类配体中芳香环的增大而下降 (C6 H4O2 ) >(C1 2 H8O2 ) >(C2 0 H1 2 O2 ) .此外 ,O ,O]CpTiCl MAO体系催化活性随铝 钛比的增加呈上升而后衰减型 ,当铝 钛比为 5 0 0到 30 0 0之间时活性最高 ,所得聚乙烯具有双峰分布特征 ,其重均分子量Mw =12 5× 10 4,分子量分布为Mw Mn =7 4

SYNTHESIS OF NOVEL HALF-METALLOCENE COMPLEXES (［O，O］CpTiCl) CONTAINING BISPHENOXY LIGANDS AND THEIR CATALYTIC PROPERTIES FOR ETHYLENE POLYMERIZATION

Synthesis of half\|metallocene complexes (O,O]CpTiCl) containing bisphenoxy ligands is discribed,while their composition and structure are characterized by elemental analysis,IR and 1H NMR,suggesting that the ring structure is formed by the combination of the two oxygen atoms in the biphenol ligand O,O] and the titanium atom.It is proved by the experiments that O,O]CpTiCl is active for ethylene polymerization at 30℃ and latm with MAO activation,and exibits much higher activity that CpTiCl\-3,and the results show that the activity decreases successively with increase in the aromatic rings (C 6H 4O 2)>(C 12 H 8O 2)>(C 20 H 12 O 2).For the (C 6H 4O 2)CpTiCl/MAO system,the activity is a “up and down” type with increase in the Al/Ti molar ratio, and up to the highest value around 1×10 5?gPE/molTi·h when the Al/Ti molar ratio is 500 to 3000.The polyethylene obtained is characteristic of bi\|model distribution with an average molecular weight M w=12\^5×10 4 and molecular weight distribution M w/ M n=7 4.