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化学学报
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化学学报 ›› 2003, Vol. 61 ›› Issue (10): 1524-1527. 上一篇    下一篇

研究论文

CH_2X(X=H,FCI)与臭氧反应机理的最子化学研究

李来才;邹勤;田安民   

  1. 四川师范大学化学系;四川大学化学系
  • 发布日期:2003-10-15

Study on the Quantum Chemistry of CH_2X(X=H,F,CI) and O_3 Reaction Mechanism

Li Laicai;Zou Qin;Tian Anmin   

  1. Department of Chemistry, Sichuan NormalUniversity;Department of Chemistry, Sichuan University
  • Published:2003-10-15

PDF

477

被引次数

5

用量化学UMP2方法，在6-311++G**基组水平上研究了CH_2X(X=H,FCI)与臭氧反 应机理，全参数优化了反应过程中反应物、中间体、过渡态和产物的内何构型，在 UQCISD（T）/6-311++G**水平上计算了它们的能量，并对它们进行了振动分析，以 确定中间体和过渡态的直实性。从CH_2X(X=H,FCI)与O_3的反应机理的研究结果看 ，它们与O_3反应的活性都比较强，相对而言，活性大小顺序为CH_2F＞CH_3＞ CH_2CI，也就是说，CH_2F自由基与臭氧间的反应活性最强，对大气臭氧的损耗将 是最大的。同时研究还发现CH_2X(X=H,FCI)系列自由基与O_3的反应都是强放热反 应。

关键词: 臭氧, 反应机理, 活化能, 卤代烃, 甲烷 P, 游离基

Quantum chemistry UMP2 method was performed to study the reaction mechanism of the reactions of CH_2X (X= H, F, Cl) with O_3. The geometric configurations of reactants, intermediates, transition states and products were optimized by UMP2 method at 6-311+ + G~(* *) level and the energies of stationary points along the pathways were calculated at UQCISD(t)/6-311 + + G~(* *) level. Intermediates and transition states were confirmed by vibration analysis. From the results of the reaction mechanism of the reactions of CH_2X (X = H, F, Cl) with O_3, one can see tlaat they are active radicals depleting ozone and the order of activity is CH_2F > CH_3 > CH_2C1. That is to say, CH2F is the most active chemical of the three radicals depleting the ozone layer. It is also found that the reactions of CH_2X (X= H, F, Cl) with O_3 are strongly exothermic.

Key words: OZONE, REACTION MECHANISM, ACTIVATION ENERGY, HALOHYDROCARBON, METHANE P, FREE RADICAL

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