新型二茂锆化合物(1,2-Ph2-4-PrCp)2ZrCl2的合成及催化烯烃聚合反应研究

3,4-二苯基环戊-2-烯-1-酮与丙基锂反应,经酸化脱水得新环戊二烯衍生物1,2-二苯基-4-丙基-1,3-环戊二烯(1).用丁基锂处理1得到相应的环戊二烯基锂,再与ZrCl₄在甲苯中反应,生成大立体阻碍二氯二茂锆化合物(1,2-Ph₂-4-PrCp)₂ZrCl₂(2).化合物1和2均经元素分析和核磁共振谱学表征.经甲基铝氧烷(MAO)活化,化合物2在较低Al/Zr比条件下既可有效地催化乙烯聚合,生成高分子量、高熔化温度聚乙烯.2/MAO体系对丙烯聚合表现出高活性,生成低分子量齐聚物,其分子量随聚合温度的降低而升高.

Synthesis of A Novel Zirconocene Complex (1,2-Ph2-4-PrCp)2ZrCl2 and Catalysis for Olefin Polymerization

A new cyclopentadiene derivative 1,2 diphenyl 4 propyl 1,3 cyclopentadiene(1) was synthesized by reaction of 3,4 diphenyl 2 cyclopentenone with n propyl lithium. 1 was treated with n butyl lithium and then reacted with ZrCl 4 in toluene to give sterically bulky unbridged zirconocene dichloride(1,2 Ph 2 4 PrCp) 2ZrCl 2(2). 1H NMR and 13 C NMR spectroscopic analyses reveal its C 2v symmetric conformation in solution. Upon activation with methylaluminoxane(MAO), 2 effectively polymerizes ethylene and produces high molecular weight polyethylenes with high melting transition temperatures at low Al/Zr ratios. At ambient conditions, 2/MAO system shows high catalytic activity in propylene polymerization and produces oily oligomers.