College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, P. R. China.
Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Hangzhou, P. R. China.
Sci Rep. 2017 May 10;7(1):1710. doi: 10.1038/s41598-017-01945-4.
The effects of external electric field (Efield) on chemical reactions were studied with the reactive molecular dynamics (ReaxFF MD) simulations by using the oxidation of toluene as a model system. We observed that Efields may greatly enhance the oxidation rate of toluene. The initial reaction time of toluene is also reduced remarkably in Efields. A stronger Efield leads to a faster oxidation rate of toluene. Further studies reveal that the applying of a Efield may result in the oxidation of toluene at 2100 K which is otherwise not able to happen when the Efield is not present. The oxidation rate of toluene at 2100 K in a Efield is comparable with the oxidation rate of toluene at 2900 K when the Efield is not applied. In addition, Efields were observed to significantly enhance the occurrence of the initial radical generation for different pathways of toluene oxidation but they do not seem to favor any of the pathways. Finally, Efields do not seem to enhance the polarization of toluene during its transition state, which suggests that a polarizable charge equilibration method (PQEq) method might be needed to take the effects of Efields into consideration.
采用反应分子动力学（ReaxFF MD）模拟方法，通过甲苯氧化反应模型体系研究了外加电场（Efield）对化学反应的影响。结果表明，Efield 可能显著提高甲苯的氧化速率，使甲苯的初始反应时间明显缩短。Efield 越强，甲苯的氧化速率越快。进一步的研究表明，在外加电场作用下，甲苯在 2100 K 时发生氧化反应，而在没有外加电场时则不能发生。在外加电场作用下，甲苯在 2100 K 时的氧化速率与无外加电场时在 2900 K 时的氧化速率相当。此外，Efield 显著促进了甲苯氧化不同途径初始自由基生成的发生，但似乎并不有利于任何一种途径。最后，Efield 似乎并没有在外加电场作用下增强甲苯在过渡态时的极化，这表明可能需要使用可极化电荷平衡（PQEq）方法来考虑 Efield 的影响。
