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采用密度泛函理论和MP2方法研究了3-甲基环状乙撑磷酸二酯(MEP)与甲醇的反应途径:(I)CH3O-+MEP;(II)CH3OH+MEP;(III)CH3O-+HMEP(MEP的质子化形式);(IV)CH3OH+HMEP.在B3LYP/6-31++G(d,p)水平上优化了四条反应途径的反应物、中间体、过渡态及产物的几何构型,并在同水平上进行了自然电荷分析,然后在MP2/6-311++G(3df,2p)水平上计算了各驻点的单点能.采用极化连续介质模型(PCM)研究了各途径在苯、甲醇和水溶液中的溶剂化效应.计算结果表明,溶剂效应使途径(I)的自由能垒降低,而使途径(II)和(IV)的决速步骤的自由能垒升高.在气相和苯溶剂中途径(IV)是反应的优势途径,在甲醇和水溶剂中途径(I)则成为最优.研究结果进一步表明实验条件下途径(II)与(IV)对总醇解反应的贡献相当.
The reaction pathway of 3-methyl cyclic ethylene phosphate diester (MEP) with methanol was studied by using density functional theory and MP2 method: (I) CH3O- + MEP; (II) CH3OH + MEP; + HMEP (protonated form of MEP); (IV) CH3OH + HMEP. The reactants, intermediates, transition states and product of the four reaction pathways were optimized at the B3LYP / 6-31 ++ G (d, Geometry configuration and natural charge analysis at the same level, and then calculate the single point energy of each stagnation point at the level of MP2 / 6-311 ++ G (3df, 2p) .Using the polarization continuum model (PCM ) Studied the solvating effects of various routes in benzene, methanol and aqueous solutions. The calculated results show that the solvent effect reduces the free energy barrier of route (I) and the free route of route (II) and (IV) (IV) is the predominant route of reaction in gas phase and benzene solvent, and route (I) is the best in methanol and water solvent.The results further demonstrate that under the experimental conditions, route (II) and (IV) ) Contributed substantially to the overall alcoholysis reaction.