邻苯二甲酸正丁酯给电子体构象分析及在Ziegler-Natta丙烯聚合中作用机理研究  

Conformational Analysis of Donor DNBP in Ziegler-Natta Propylene Polymerization

作　　者：王亭亭[1] 程瑞华[1] 刘振[1] 刘柏平[1] 

机构地区：[1]华东理工大学化学工程联合国家重点实验室,上海市多相结构材料化工重点实验室,上海200237

出　　处：《分子催化》2016年第1期88-97,共10页Journal of Molecular Catalysis(China)

基　　金：国家自然科学青年基金(基金号21304033);中央高校科研业务重大交叉项目

摘　　要：首次采用TINKER构象搜索和DFT结构优化相结合方法,基于对Ziegler-Natta丙烯聚合催化体系邻苯二甲酸正丁酯(DNBP)给电子体快速搜索出的1 023种构象,筛选出其优势构象,减少了给电子体初始稳定结构搭建模型的盲目性和随机性.采用DFT方法,对DNBP两种构象与MgCl_2载体相互作用及丙烯插入立体选择性机理进行了研究.结果表明,DNBP构象影响其在Mg Cl2表面的吸附,s-顺、反式构象可以单齿、桥连和螯合方式吸附在MgCl_2(110)表面;s-顺、顺式仅存在桥连吸附.双氯原子缺陷载体模型上Ti Cl4吸附的稳定性高于DNBP,成为可能的活性中心;给电子体对活性位的作用与其吸附方式有关,DNBP以桥连方式吸附在Ti的邻位,可将无规活性中心有效转化为等规活性中心,而螯合方式不能改善催化剂的立体结构和区域选择性.A combination method of TINKER and DFT structure was firstly optimized for the conformational searches of di-n-butyl phthalate（ DNBP）,which is a commercial electron donor in Ziegler-Natta catalyst for the propylene polymerization. 1 023 DNBP conformations were quickly found,suggesting it is an effective method to reduce the blindness and randomness in the initial modeling. Geometry optimization of various conformations,as well as the interaction between DNBP and MgCl_2 support and the effect of DNBP on the propylene enantioselective insertion have been studied by DFT method. The results indicated that the conformation played an important role on the absorption of DNBP on Mg Cl2 surface. The s- cis,trans conformation adsorbed on MgCl_2（ 110） surface in the monodentate,bridge and chelate modes,while the s-cis,cis one only adsorb in the bridge mode. The defective site with more stable adsorption of TiCl_4 than that of DNBP might be the active center. DNBP adsorption with bridge mode on the vicinal position of Ti could effectively transform the atactic active site into the isotactic one. However,when DNBP adsorbed in the chelate mode,the isospecificity and regioselectivity of catalyst could not be improved.

关 键 词：密度泛函 给电子体 Ziegler-Natta聚丙烯催化 构象分析 立构选择性 

分 类 号：O643.32[理学—物理化学]