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化学学报
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化学学报 ›› 2007, Vol. 65 ›› Issue (19): 2117-2123. 上一篇    下一篇

研究论文

Criegee自由基CH2O2与H2O反应机理及动力学的理论研究

齐斌*, 晁余涛   

  1. (陕西师范大学化学与材料科学学院 西安 710062)
  • 投稿日期:2006-10-19 修回日期:2007-03-22 发布日期:2007-10-14
  • 通讯作者: 齐斌

Theoretical Study on the Mechanism and Kinetics of the Reaction of Criegee Radical CH2O2 with H2O

QI Bin*; CHAO Yu-Tao   

  1. (School of Chemistry and Materials Sciences, Shaanxi Normal University, Xian 710062)
  • Received:2006-10-19 Revised:2007-03-22 Published:2007-10-14
  • Contact: QI Bin

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在6-311＋G(2d,2p)水平下, 采用密度泛函理论(DFT)的B3LYP方法, 研究了Criegee 自由基CH2O2与H2O的反应. 结果表明反应存在三个通道: CH2O2＋H2O®HOCH2OOH (R1); CH2O2＋H2O®HCO＋OH＋H2O (R2); CH2O2＋H2O®HCHO＋H2O2 (R3), 各通道的势垒高度分别为43.35, 85.30和125.85 kJ/mol. 298 K下主反应通道(R1)的经典过渡态理论(TST)与变分过渡态理论(CVT)的速率常数kTST与kCVT均为2.47×10－17 cm3•molecule－1•s－1, 而经小曲率隧道效应模型(SCT)校正后的速率常数kCVT/SCT为 5.22×10－17 cm3•molecule－1•s－1. 另外, 还给出了200～2000 K 温度范围内拟合得到的速率常数随温度变化的三参数Arrhenius方程.

关键词: Criegee 自由基CH2O2, H2O, 反应机理, 速率常数

The reaction of Criegee radical CH2O2 with H2O was investigated by density functional theory (DFT) at the B3LYP/6-311G＋(2d,2p) level. Three channels were identified: CH2O2＋H2O®HOCH2OOH (R1); CH2O2＋H2O®HCO＋OH＋H2O (R2); CH2O2＋H2O®HCHO＋H2O2 (R3). The energy barriers are 43.35, 85.30 and 125.85 kJ/mol for (R1), (R2) and (R3), respectively. The rate constants of reaction (R1) are both 2.47×10－17 cm3•molecule－1•s－1 for classic transitional state theory (TST) kTST and canonical variational transition state theory (CVT) kCVT. The rate constant with small-curvature tunneling (SCT) correction kCVT/SCT is 5.22×10－17 cm3•molecule－1•s－1. The dependence of the rate constants on temperature is given with a three parameters Arrhenius equation within the temperature range 200～2000 K.

Key words: Criegee radical CH2O2, H2O, mechanism, rate constant