Acta Chimica Sinica ›› 2011, Vol. 69 ›› Issue (21): 2574-2582.DOI: 10.6023/A1012234D Previous Articles     Next Articles

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  1. (1生物流变科学与技术教育部重点实验室 国家“985工程”生物材料与仿生工程研究中心 重庆大学生物工程学院
    重庆 400044)
    (2重庆科技学院化学化工学院 重庆 401331)
  • 投稿日期:2010-12-23 修回日期:2011-05-13 发布日期:2011-06-23
  • 通讯作者: 胡承波
  • 基金资助:


ROP of D,L-Lactide Catalyzed by Bis(alkoxy-imine-phenoxy) Titanium(IV) Complex: Kinetic and Mechanism

Hu Chengbo1 Fu Ya1,2 Xiang Hongzhao1 Sun Jiaoxia1 Ruan Changshun1 Li Xiang1 Xiang Yan1 Peng Qin1 Wang Yuanliang*,1   

  1. (1 Key Laboratory of Biorheological Science and Technology for Ministry of Education, and Center of Bioinspired Materials Science and Engineering of National 985 Project Program”, Bioengineering College of Chongqing University, Chongqing 400044)
    (2 College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331)
  • Received:2010-12-23 Revised:2011-05-13 Published:2011-06-23
  • Contact: Cheng-Bo HU

A bis(alkoxy-imine-phenoxy) titanium(IV) complex was synthesized and characterized by IR, 1H NMR, elemental analysis and single crystal X-ray diffraction method. The crystal of titanium(IV) complex belongs to triclinic system with space group, P , a=14.294(9) ?, b=16.206(10) ?, c=18.458(12) ?, V=3911(4) ?3, Dc=1.098 g•cm-3, μ=0.262 mm-1, F(000)=1589, Z=2, R1=0.081, wR2=0.240. The ring-opening polymerization (ROP) of D,L-lactide catalyzed by the titanium(IV) complex could take place over 130 ℃ and the maximum number-averaged molecular weight (Mn) of poly(D,L-lactic acid) (PDLLA) was 8.8×104 g/mol. Kinetics experiments indicate that the polymerization shows second-order kinetics in D,L-lactide monomer concentration and first-order kinetics in catalyst concentration. The apparent activation energy (Ea) and frequency factor (A) amount to 76.63 kJ/mol and 2.91×1011, respectively. 1H NMR spectroscopy of polymer terminated by benzyl group suggests that the polymerization proceeds via a conventional coordination-insertion mechanism and Ti—O active centers initiate the cleavage of acyl-oxygen bond of D,L-lactide monomer.

Key words: lactide, complex, ring-opening polymerization, kinetic

CLC Number: