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化学学报
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化学学报 ›› 2006, Vol. 64 ›› Issue (9): 923-929. 上一篇    下一篇

研究论文

CH3•自由基和HNCO反应机理的理论研究

尚静1，查东1，李来才*,1，田安民2   

  1. (1四川师范大学化学与材料科学学院 成都 610066)
    (2四川大学化学学院 成都 610064)
  • 投稿日期:2005-08-03 修回日期:2006-01-05 发布日期:2006-05-15
  • 通讯作者: 李来才

Theoretical Study on the Reaction Mechanism of CH3• Radical with HNCO

SHANG Jing1, ZHA Dong1, LI Lai-Cai*,1, TIAN An-Min2   

  1. (1 Department of Chemistry and Material Science, Sichuan Normal University, Chengdu 610066)
    (2 Department of Chemistry, Sichuan University, Chengdu 610064)
  • Received:2005-08-03 Revised:2006-01-05 Published:2006-05-15
  • Contact: LI Lai-Cai

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采用密度泛函理论的B3LYP方法, 在6-311＋＋G(d,p)基组水平上研究了CH3•自由基与HNCO的微观反应机理, 优化了反应过程中的反应物、中间体、过渡态和产物, 为了获得更精确的能量信息, 还计算了体系在反应途径上各驻点的能量. 振动分析和IRC分析结果证实了中间体和过渡态的真实性, 计算所得的键鞍点电荷密度的变化情况也确认了反应过程. 对于CH3•自由基与HNCO反应, 找到了七条可行的反应通道, 对结果的分析表明: 通道CH3•＋HNCO→TS7→IM4→TS9→IM5, 控制步骤活化能最低, 是该反应的主要通道. 在该反应体系中质子迁移过程反应活化能不高, 也是能发生的.

关键词: CH3•, 自由基, HNCO, 反应机理, 活化能

The reaction mechanism of CH3• radical with HNCO has been investigated by B3LYP method of density functional theory, while the geometries and harmonic frequencies of reactants, intermediates, transition states and products have been calculated at the B3LYP/6-311＋＋G(d,p) level. To obtain more accurate energy result, stationary point energies were calculated. The vibration analysis and the IRC analysis testified the authenticity of intermediates and transition states. Seven feasible reaction pathways of this reaction have been studied. The results indicate that the pathway CH3•＋HNCO→TS7→IM4→TS9→IM5 is the most energetically favorable and the major pathway. In the reaction system, the activation energy of the proton transfer process is not very high, and it can also happen.

Key words: CH3•, radical, isocyanic acid, reaction mechanism, activation energy