【摘要】 用量子化学中密度泛函B3LYP方法在6-31G*水平上,对单嘧磺隆的水解机理进行了理论研究.优化了反应过程中反应物、中间体、过渡态及产物的几何构型,并对各个过渡态和中间体进行了振动分析确认其真实性.结果表明:在碱性条件下,水解反应主要经历一个五元环的过渡态TS1,该反应速控步骤的能垒为25.7kJ/mol;在中性条件下,水解反应涉及到一个三元环的过渡态和两个四元环的过渡态,反应的速控步骤为M3’+H2O→TS2’,能垒为236.5kJ/mol.从能量上看,碱性条件更有利于水解反应的进行,与实验结果吻合.同时,我们还考虑了溶剂效应对水解反应的影响.更多还原

【Abstract】 In this paper, the hydrolysis mechanism of monosulfuron herbicide was studied by B3LYP method at the level of 6-31G*. The geometric configurations of reactants, products, intermediates, and transition states in the reaction have been optimized and vibrational analysis has been performed. The results of calculation show that in the basicity, the reaction channel has one five-membered ring transition state TS1, with the activation energy of the controlling step during the reaction of 25.7 kJ/mol, while in the neutrality, the reaction channel has one three-membered and two four-membered ring transition states, and the controlling step is M3’+H2O→TS2’ during the reaction with the activation energy of 236.5 kJ/mol. That is to say, the hydrolysis reaction of monosulfuron herbicide proceeded more easily in the basicity than neutrality, which is essentially consistent with the experimental result. Besides, the influence of the solvation effect was also discussed.更多还原