Mechanism of acid-catalyzed hydrolysis of formamide from cluster-continuum model calculations: concerted versus stepwise pathway.
Mechanism of acid-catalyzed hydrolysis of formamide from cluster-continuum model calculations: concerted versus stepwise pathway.
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DOI：
10.1021/jp106560s
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发表时间：
2010-12
期刊：
影响因子：
--
通讯作者：
Binju Wang;Z. Cao
中科院分区：
文献类型：
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作者：
Binju Wang;Z. Cao
用从头计算方法研究了甲酰胺在水溶液中的酸催化水解反应。在第一溶剂化壳层中引入水分子的团簇-连续介质模型合理地考虑了溶剂对水解反应的影响，水合团簇的选择对水解反应热力学值的可靠估算起着重要作用.通过大量的计算，O-质子化和N-质子化途径的可能协调和分步机制进行了研究。基于无偏理论处理的所有可能的途径，O-质子化的逐步途径被证明是有利的机制，和预测的速率控制步骤和C-N键断裂的活化自由能分别为21.8和9.4千卡/摩尔，由B3 LYP。本研究结果与实验结果吻合良好，并提供了一个完整的描述酸催化水解甲酰胺。
The acid-catalyzed hydrolysis of formamide in aqueous solutions was investigated by ab initio calculations. Solvent effects on the hydrolysis reaction were reasonably considered by the cluster-continuum model with explicit water molecules in the first solvation shell, and the selection of hydration cluster plays an important role in reliable estimation of thermodynamic values for the hydrolysis reaction. Possible concerted and stepwise mechanisms of the O-protonated and N-protonated pathways were investigated by extensive calculations. On the basis of unbiased theoretical treatments on all plausible pathways, the O-protonated stepwise pathway was shown to be the favored mechanism, and the predicted activation free energies for the rate-determining step and the breaking of the C-N bond are 21.8 and 9.4 kcal/mol by B3LYP, respectively. The present results show good agreement with experiment and provide a complete description of the acid-catalyzed hydrolysis of formamide.