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化学学报
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化学学报 ›› 2011, Vol. 69 ›› Issue (21): 2574-2582.DOI: 10.6023/A1012234D 上一篇    下一篇

研究论文

双(烷氧-亚胺芳氧)基钛(IV)配合物催化D,L-丙交酯开环聚合、动力学及机理

胡承波1，傅亚1,2，向鸿照1，孙娇霞1，阮长顺1，李香1，向燕1，彭琴1，王远亮*,1   

  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 E-mail:bch1002@126.com
  • 基金资助:

    MGF调控骨和韧带组织修复的力生物学基础研究;用力生长因子构建新型生物活性骨修复材料

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 E-mail:bch1002@126.com

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合成了双(烷氧-亚胺芳氧)基钛(IV)配合物, 通过IR, 1H NMR和元素分析对其进行表征, X射线单晶衍射测定了其晶体结构. 单晶结构分析表明, 该晶体属于三斜晶系, 空间群为P , a＝14.294(9) Å, b＝16.206(10) Å, c＝18.458(12) Å, V＝3911(4) Å3, Dc＝1.098 g•cm－3, μ＝0.262 mm－1, F(000)＝1589, Z＝2, R1＝0.081, wR2＝0.240. 实验结果表明该配合物在130 ℃以上能引发D,L-丙交酯单体开环聚合, 可得数均分子量(Mn)为8.8×104 g/mol的聚(D,L-乳酸)(PDLLA). 动力学研究表明该聚合反应对D,L-丙交酯单体浓度和催化剂浓度分别呈2级和1级, 表观活化能和频率因子分别为76.63 kJ/mol和2.91×1011. 通过苄基封端聚合物1H NMR谱的研究, 表明钛配合物引发D,L-丙交酯开环聚合是基于以Ti—O键为活性中心引发D,L-丙交酯单体酰氧键断裂开环聚合的“配位-插入”机理.

关键词: 丙交酯, 配合物, 开环聚合, 动力学

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

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