α-氰基丙烯酸乙酯阴离子聚合的密度泛函理论研究  

Density Functional Theory Study on the Anionic Polymerization of Ethyl α-Cyanoacrylate

作　　者：周亚红[1,2] 卑凤利[1] 杨绪杰[1] 陆路德[1] 汪信[1] 

机构地区：[1]南京理工大学化工学院 [2]江苏警官学院南京210012

出　　处：《化学学报》2004年第24期2369-2373,共5页Acta Chimica Sinica

基　　金：国家自然科学基金 (No.50 372 0 2 8);国家教育部博士点基金 (No .2 0 0 30 2 880 1 9)资助项目

摘　　要：运用密度泛函理论DFT B3LYP方法 ,在 6 3 1G 基组水平上 ,首次全优化计算了α 氰基丙烯酸乙酯与羟基反应势能面上的反应物、过渡态的分子几何、电子结构、能量、IR光谱和热力学性质 ,求得气相中反应的活化能为 13 83kJ·mol-1,引发速率常数数量级为 10 10 s-1,从热力学和动力学两方面阐明了阴离子聚合机理 .通过自洽反应场 (SCRF)B3LYP/ 6 3 1G 计算 ,系统研究了相对介电常数分别为 2 0 2 ,2 3 8,7 5 8和 12 3的溶剂对反应物和过渡态的结构和反应机理的影响 ,发现溶剂效应使过渡态的活化能随极性增大而下降 ,并使引发反应在极性溶剂中接近于无垒反应 .Density functional theory (DFT) at the B3LYP level with 6-31G * basis set was employed to optimize the reactant and the transition state on the potential surface of the ethyl α-cyanoacrylate with water for the first time. The charge, energies, IR spectra and thermodynamic properties were obtained. The activation energy of 13.83 kJ/mol in the gas phase and the order of 10 10 s -1 of initiating rate constant were obtained for the reaction. The results both in thermodynamics and kinetics illustrate anionic polymerization mechanism. The impacts of solvent effect on the geometries of reactant and transition state as well as the reaction mechanism were systematically studied for the α-cyanoacrylate with water by self-consistent reaction field (SCRF) technique with different dielectric constants of 2.02, 2.38, 7.58 and 12.3. It was found that the solvent effect would depress the activation energy and finally make the initiation reaction without energy barrier in polar solvents.

关 键 词：过渡态 B3LYP 密度泛函理论 反应势能面 基组 自洽 反应物 阴离子聚合 Α-氰基丙烯酸乙酯 引发 

分 类 号：O631.5[理学—高分子化学]