物理化学学报 >> 2004, Vol. 20 >> Issue (05): 483-487.doi: 10.3866/PKU.WHXB20040508

研究论文 上一篇    下一篇

H＋CH2CO反应机理的G2计算

糜骏;冯文林;李会英;刘坤辉;蒲敏   

  1. 北京化工大学可控化学反应科学与技术基础教育部重点实验室,北京　100029
  • 收稿日期:2003-09-17 修回日期:2003-12-17 发布日期:2004-05-15
  • 通讯作者: 蒲敏 E-mail:pumin@mail.buct.edu.cn

Mechanism of the Reaction H＋CH2CO:G2 Calculation

Mi Jun;Feng Wen-Lin;Li Hui-Ying;Liu Kun-Hui;Pu Min   

  1. Key Laboratory of Science and Technology of Controllable Chemical Reaction, Education Ministry, Beijing University of Chemical Technology, Beijing　100029
  • Received:2003-09-17 Revised:2003-12-17 Published:2004-05-15
  • Contact: Pu Min E-mail:pumin@mail.buct.edu.cn

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摘要： 分别在UQCISD/6-311G(d,p)和G2理论计算水平上，对CH2CO和H反应可能存在的四条反应通道进行了研究，详细分析了每个通道的反应机理;通过振动分析的虚频数和内禀反应坐标(IRC)计算,确认了反应涉及的每一个过渡态.通过反应位能剖面的比较，发现经过一个中间体生成CH3＋CO的一条途径是主反应通道，该通道是个放热反应，总焓变为－146.07 kJ•mol－1，速控步骤的位垒为55.09 kJ•mol－1.理论计算结果较好地解释了实验观察到的主要产物和副产物并存的现象。

关键词: 乙烯酮, 原子氢, 从头算法, G2理论

Abstract: The reaction mechanisms and molecular dynamics of the multi-channel reaction H＋CH2CO which might occur through four channels depending on the different initial reaction positions of the reactants CH2CO are detailedly studied. All the calculations are performed at the UQCISD/6-311G (d,p) and G2 theory level. Every transition state is confirmed by the numbers of virtual frequency and the intrinsic reaction coordinate (IRC) paths. The computational results suggest that the reaction channel of forming CH3＋CO through an intermediate is the dominant one. This channel is an exothermic reaction whose enthalpy changes are －146.07 kJ•mol－1 and the calculated potential barrier of the rate-determining step is 55.09 kJ•mol－1. The obtained reaction potential profile can qualitatively explain the experimental coexistence phenomena of the primary products and the other minor products.

Key words: Ketene, Atomic hydrogen, Ab initio study, G2 theory