高等学校化学学报 ›› 2022, Vol. 43 ›› Issue (2): 20210563.doi: 10.7503/cjcu20210563

• 物理化学 • 上一篇    下一篇

多环芳烃与不饱和自由基氢提取反应类的动力学研究

邓红日1,2, 曹晓梅3, 王静波1,2(), 李象远1,2   

  1. 1.四川大学化学工程学院, 成都 610065
    2.空天动力燃烧与冷却教育部工程研究中心, 成都 610065
    3.中国空气动力研究与发展中心, 超高速空气动力研究所, 绵阳 621000
  • 收稿日期:2021-08-10 出版日期:2022-02-10 发布日期:2021-11-23
  • 通讯作者: 王静波 E-mail:wangjingbo@scu.edu.cn
  • 基金资助:
    国家自然科学基金(91741201)

Rate Rules for Hydrogen Abstraction Reactions of Polycyclic Aromatic Hydrocarbons and Unsaturated Radicals

DENG Hongri1,2, CAO Xiaomei3, WANG Jingbo1,2(), LI Xiangyuan1,2   

  1. 1.College of Chemical Engineering,Sichuan University,Chengdu 610065,China
    2.Engineering Research Center of Combustion and Cooling for Aerospace Power,Ministry of Education,Sichuan University,Chengdu 610065,China
    3.Hypervelocity Aerodynamic Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China
  • Received:2021-08-10 Online:2022-02-10 Published:2021-11-23
  • Contact: WANG Jingbo E-mail:wangjingbo@scu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(91741201)

摘要:

对2~6个环的多环芳烃的氢提取反应类进行了系统研究, 提取氢原子的不饱和自由基包括丙炔基自由基(C3H3)、 烯丙基自由基(C3H5)、 丁二烯基自由基(nC4H5, iC4H5)、 环戊二烯基自由基(C5H5)以及苯基自由基(C6H5). 采用M06-2X/cc-pVTZ方法得到了多环芳烃的电子结构信息, 利用过渡态理论并结合Eckart隧道校正, 计算了所有反应在500~2500 K范围内的反应速率常数.考察了多环芳烃的大小、 结构对反应速率常数的影响, 对比了不同氢提取自由基及不同氢提取反应类型的速率常数. 结果表明, 多环芳烃的大小对反应速率常数影响不大, 但是多环芳烃的环结构对反应速率常数影响较大. 将不同的氢提取反应类简化为发生在五元环上的C5类和发生在六元环上的C6类两类, 结果表明, C6类的反应活性高于C5类. 研究了nC4H5, iC4H5以及C6H5自由基与多环芳烃的氢提取反应, 它们的氢提取反应活性大小顺序为C6H5>nC4H5>iC4H5. 通过对每类典型反应的速率常数取平均值, 总结出相应类型的速率规则, 可用于构建多环芳烃和碳烟机理.

关键词: 多环芳烃, 不饱和自由基, 氢提取反应, 速率规则

Abstract:

The reaction kinetics for a series of polycyclic aromatic hydrocarbons(PAHs) containing up to six aroma-tic rings by propynyl radical(C3H3), allyl radical(C3H5), butadienyl radical(nC4H5, iC4H5), pentadienyl radical (C5H5) and phenyl radical(C6H5) were systematically investigated via the M06-2X/cc-pVTZ method. Based on the electronic structure calculations, the rate constants of title reactions were calculated by using transition state theory coupled with Eckart tunneling correction at the temperature range of 500—2500 K. The effects of PAH sizes and structures on the rate constants were examined. The results show that the PAH sizes have little effect on the rate constants, while the structures of PAHs influence the rate constant significantly. Hence, the hydrogen abstraction reactions are simplified into C5 and C6 reaction classes depending on the abstraction site on the five-membered or six-membered ring. The simple two classes are conducive to construct the combustion model of PAHs. The results indicate that C6 class possesses a higher activity than the C5 class. Hydrogen extraction reactions classes from PAHs by nC4H5, iC4H5 and C6H5 radicals are studied in a systematic way, and the reactivity of different H-abstraction reactions from PAHs by different radicals shows the following trends: C6H5>nC4H5>iC4H5. The rate rules are summarized by taking the average values of rate constants of a representative set of reactions in each class, which are applicable for the chemical model construction of PAHs.

Key words: Polycyclic aromatic hydrocarbons, Unsaturated radical, Hydrogen abstraction, Rate rule

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