G型含氟有机磷神经毒剂醇解反应机理研究.PDF

化学通报 2015 年 第 78 卷 w2015002 研究论文 G 型含氟有机磷神经毒剂醇解反应机理研究 李强根 郑 妍 毛 双 刘柳斜 蔡皖飞 李来才 李 权* ( 四川师范大学化学与材料科学学院 成都 610068) 摘 要 含氟有机磷神经毒剂毒性强，危害大，给实验研究带来不便。本文采用 B3LYP/6−311G**和 MP2/6−311G**方法及一个简化计算模型，探讨了 G 型含氟有机磷神经毒剂在中性和碱性条件下的醇解反应机 理。结果显示，中性环境下 G 型含氟有机磷神经毒剂的醇解，不管是气相还是液相反应，3 个甲醇分子参与的 分步路径(Path C)都是最优路径；而 1 个甲醇阴离子参与的碱性条件下的分步路径(Path A)，其气相和液相反应 决速步骤的吉布斯自由能垒分别为 14.6 和 31.4 kJ/mol，比Path C 分别低 87.0 和 59.8 kJ/mol 。因此，强碱催化 下的 G 型含氟有机磷神经毒剂的醇解更高效。 关键词 G 型含氟有机磷神经毒剂 醇解反应 B3LYP 反应机理 Theoretical Studies on the Alcoholysis Reaction Mechanism of G-type Fluoride Organophosphorus Nerve Agents Li Qianggen, Zheng Yan, Mao Shuang, Liu Liuxie, Cai Wanfei, Li Laicai, Li Quan* (College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068) Abstract Fluoride organophosphorus nerve agents are inconvenient to experimental research due to its high toxicity. In present work, we investigate theoretically on the alcoholysis reaction mechanism of G-type fluoride organophosphorus nerve agents in neutral and alkaline conditions by employing the B3LYP/6−311G** and MP2/6−311G** methods through a simplified model. The results indicated that the stepwise path in neutral conditions of three methanol molecules involved (Path C) is the most favorable pathway, due to lower activation energy barrier (ΔG≠) both in the gas phase and in methanol solution. Moreover, for the alcoholysis involving a methanol anion in alkaline conditions (Path A), ΔG≠ of the liquid phase reaction and gas phase reaction is 14.6 and 31.4 kJ/mol, which is lower than that Path C in neutral environment 87.0 and 59.8 kJ/mol, respectively. Thus, alkali catalytic alcoholysis