取代茚基二价稀土配合物催化甲基丙烯酸甲酯的聚合

Polymerization of Methyl Methacrylate Catalyzed by the Substituted Indenyl Lanthanide(Ⅱ) Complexes

较系统地研究了取代茚基二价稀土配合物 ( 1 -C5H9C9H6) 2 Sm(THF)作为单组分催化剂 ,催化MMA的聚合反应。结果表明 ,催化剂在较宽的温度范围显示出较高的催化活性 ,在以甲苯为溶剂的催化体系中加入少量的极性溶剂THF ,聚合活性有显著的提高 ,温度降低MMA的转化率增加 ,所得PMMA的分子量升高 ,分子量分布变窄 ,几种取代茚基二价稀土配合物都显示了较高的催化活性 ,其活性次序为 :( 1 -PhCH2 C9H6) 2 Sm (THF) 2 <( 1 -C5H9C9H6) 2 Yb(THF) 2 <( 1 -C5H9C9H6) 2 Sm(THF) <( 1 -C2 H5C9H6) 2 Sm(THF) 2 。中性取代茚基二价稀土配合物所得聚合物主要为间同立构的PMMA ,而由离子型的二价稀土配合物KSm ( 1 -C5H9C9H6) 3(THF) 3所得到的为无规立构PMMA。

It was studied that the substituted indenyl lanthanide(Ⅱ) complexes as single component catalyst for the polymerization of MMA. The results indicated that these complexes show good catalytic activity and the catalytic activity affected by the temperature and time of polymerization, amount of catalyst used and the solvent as well. The polymerization gives syndiotacticity-rich PMMA.