化学学报 ›› 2013, Vol. 71 ›› Issue (01): 81-87.DOI: 10.6023/A12110879 上一篇    下一篇

研究论文

烷基环戊烷被羟基自由基夺氢反应类的动力学研究

郑洋a, 朱权a, 李泽荣b, 李象远a   

  1. a 四川大学化工学院 成都 610065;
    b 四川大学化学学院 成都 610065
  • 收稿日期:2012-11-06 出版日期:2013-01-14 发布日期:2012-12-13
  • 通讯作者: 朱权, 李象远 E-mail:qzhu@scu.edu.cn; xyli@scu.edu.cn
  • 基金资助:
    项目受国家自然科学基金(Nos. 91016002, 20903067)资助.

Investigations on Kinetics for the Reaction Class of Hydrogen Abstractions from Substituted Cyclopentane by Hydroxyl Radical

Zheng Yanga, Zhu Quana, Li Zerongb, Li Xiangyuana   

  1. a College of Chemical Engineering, Sichuan University, Chengdu 610065;
    b College of Chemistry, Sichuan University, Chengdu 610065
  • Received:2012-11-06 Online:2013-01-14 Published:2012-12-13
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Nos. 91016002, 20903067).

基于燃烧详细反应机理构建的需要, 采用反应类过渡态理论(RC-TST)研究了OH自由基夺取烷基环戊烷环上和侧链上氢原子的动力学. 在考察侧链氢提取反应类的16个代表反应的基础上, 本工作首次将该方法推广到环上α氢提取反应类的10个代表反应的研究, 分别建立了两类反应的线性自由能(LER)关系式. 计算结果表明, 采用RC-TST/LER方法预测的这两类反应的速率常数与直接应用TST/Eckart方法得到的结果接近, 说明RC-TST/LER方法对预测这两类反应的速率常数非常有效, 且节约了大量计算成本. 而且, 无论是侧链还是五元环, OH·夺取叔碳上的氢原子最易发生.

关键词: 环戊烷, 氢提取, 反应类过渡态理论, 速率常数

In order for the development of the detailed combustion mechanisms, this work applies the reaction class transition state theory (RC-TST) to predict kinetics parameters for hydrogen abstraction reactions from the substituted cyclopentane. 16 Hydrogen abstraction reactions from the side chain and 10 reactions with hydrogen abstraction from the α-carbon atom on the ring have been investigated with RC-TST/LER method. The corresponding linear energy relationship (LER) has also been established. All the geometries of reactants, transition states, and products are optimized at BH&HLYP level of theory with the basis set of cc-pVDZ, and the electronic energy calculation and frequency analyses are also carried out at the same level of theory. Accordingly, the RC-TST factors and LER are derived based on the calculations. For the reference reaction, the minimum energy path of the potential energy surface is obtained at the BH&HLYP/cc-pVDZ level. In order to get the more precise rate constants of the reference reaction, the single-point energies of the selected points along the minimum energy path are calculated at the CCSD(T)/cc-pVDZ level. In the RC-TST/LER method, the other rate constants in this class can be derived from the reference reaction and the RC-TST factors. Our analyses indicate that the rate constants for selected reactions predicted by the RC-TST/LER are in good agreement with those calculated with TST/Eckart method. For the hydrogen abstraction reactions from the side chain and the α-carbon atom on the ring, the maximum error between the two methods is less than 73% and 88%, respectively. Moreover, it is found that the error decreases with the increasing of the temperature. Therefore, the RC-TST/LER method seems to be quite efficient to estimate the rate constants for a large number of reactions in this class and to save a lot of computational resource. In addition, for the two types of reaction classes, the hydrogen at the tertiary carbon can be easily abstracted by hydroxyl radical.

Key words: cyclopentane, hydrogen abstraction, reaction class transition state theory, rate constant