催化学报

催化学报 ›› 2011, Vol. 32 ›› Issue (1): 189-196.DOI: 10.3724/SP.J.1088.2011.00739

• 研究论文 • 上一篇    

单脒基铝络合物催化己内酯聚合及己内酯/丙交酯共聚

钱峰, 刘克印, 马海燕   

  1. 华东理工大学应用化学研究所金属有机研究室, 上海 200237
  • 收稿日期:2010-07-28 修回日期:2010-11-18 出版日期:2011-01-13 发布日期:2014-05-22

Polymerization of ε-Caprolactone and Copolymerization with rac-Lactide Catalyzed by Mono(amidinate) Aluminum Complexes

QIAN Feng, LIU Keyin, MA Haiyan*   

  1. Laboratory of Organometallic Chemistry, Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, China
  • Received:2010-07-28 Revised:2010-11-18 Online:2011-01-13 Published:2014-05-22

PDF

847

被引次数

27

摘要： 将单脒基铝络合物用于催化 ε-己内酯 (ε-CL) 开环聚合反应, 结果表明, 该类铝络合物表现出很高的催化活性: 25 ºC 时络合物 [{PhC(N-2,6-iPr2C6H3)2}AlMe2] (C1) 催化ε-CL 聚合 1 h, 单体转化率为 91%; 70 ºC 时络合物[{PhC(N-2,6-iPr2C6H3)-(N-2,6-Me2C6H3)}AlMe2] (C2)催化ε-CL 聚合 15 min, 单体转化率达 100%. 脒基 N-芳环上取代基的引入能明显提高催化剂活性, N-芳环邻位双取代的单脒基铝络合物的催化活性高于邻位单取代的. 所得聚合物的分子量大于理论值, 且分子量分布较宽 (PDI = 1.43~1.85), 说明聚合的可控度不高. 单脒基铝络合物可通过先催化ε-CL 聚合, 再引发外消旋丙交酯聚合, 得到聚己内酯和聚丙交酯的两嵌段共聚物.

关键词: 脒基铝络合物, ε-己内酯, 外消旋丙交酯, 开环聚合, 共聚

Abstract: Mono(amidinate) aluminum complexes showed high catalytic activity for the ring-opening polymerization of ε-caprolactone in toluene at ambient temperature. Monomer conversion up to 91% could be reached within 1 h when using [{PhC(N-2,6-iPr2C6H3)2}AlMe2] (C1) as initiator at 25 ºC. The electron-donating groups on the ortho-positions of the N-substituted phenyl ring were superior to the electron-withdrawing groups for the enhancement of the catalytic activity, but both brought an increase in activity when compared with the un-substituted complex C7. The complexes bearing two ortho-substitutents on one of the N-phenyl rings were more active than the analogues bearing one ortho-substitutent. Although high molecular weight poly(ε-caprolactone)s were obtained by using these aluminum catalysts, the polymerization of ε-caprolactone was not well controlled as indicated by the broad molecular weight distributions (PDI = 1.43~1.85) and the deviation of the number average molecular weight from the theoretical values. Sequential copolymerization of ε-caprolactone and rac-lactide using mono(amidinate) aluminum complexes afforded poly(ε-caprolactone)-poly(rac-lactide) diblock copolymer, which was characterized well by NMR spectroscopy and gel permeation chromatography analysis.

Key words: aluminum amidinate complex, ε-caprolactone, rac-lactide, ring-opening polymerization, copolymerization