Zhang Ji-Dong, Kang Li-Hua, Cheng Xin-Lu
Key Laboratory of Ecophysics and Department of Physics, School of Science, Shihezi University, Shihezi, 832003, People's Republic of China,
J Mol Model. 2015 Jan;21(1):13. doi: 10.1007/s00894-014-2568-y. Epub 2015 Jan 24.
The intriguing decompositions of nitro-containing explosives have been attracting interest. While theoretical investigations have long been concentrated mainly on unimolecular decompositions, bimolecular reactions have received little theoretical attention. In this paper, we investigate theoretically the bimolecular reactions between nitromethane (CH3NO2)-the simplest nitro-containing explosive-and its decomposition products, such as NO2, NO and CO, that are abundant during the decomposition process of CH3NO2. The structures and potential energy surface (PES) were explored at B3LYP/6-31G(d), B3P86/6-31G(d) and MP2/6-311 + G(d,p) levels, and energies were refined using CCSD(T)/cc-pVTZ methods. Quantum chemistry calculations revealed that the title reactions possess small barriers that can be comparable to, or smaller than, that of the initial decomposition reactions of CH3NO2. Considering that their reactants are abundant in the decomposition process of CH3NO2, we consider bimolecular reactions also to be of great importance, and worthy of further investigation. Moreover, our calculations show that NO2 can be oxidized by CH3NO2 to NO3 radical, which confirms the conclusion reached formerly by Irikura and Johnson [(2006) J Phys Chem A 110:13974-13978] that NO3 radical can be formed during the decomposition of nitramine explosives.
含硝基炸药的有趣分解过程一直备受关注。虽然理论研究长期以来主要集中在单分子分解上，但双分子反应在理论上却很少受到关注。在本文中，我们从理论上研究了最简单的含硝基炸药硝基甲烷（CH3NO2）与其分解产物（如在CH3NO2分解过程中大量存在的NO2、NO和CO）之间的双分子反应。在B3LYP/6-31G(d)、B3P86/6-31G(d)和MP2/6-311+G(d,p)水平上探索了反应结构和势能面（PES），并使用CCSD(T)/cc-pVTZ方法对能量进行了优化。量子化学计算表明，本文所研究的反应具有较小的势垒，这些势垒与CH3NO2的初始分解反应势垒相当或更小。考虑到它们的反应物在CH3NO2分解过程中大量存在，我们认为双分子反应也非常重要，值得进一步研究。此外，我们的计算表明，NO2可被CH3NO2氧化为NO3自由基，这证实了Irikura和Johnson [(2006) J Phys Chem A 110:13974-13978]之前得出的结论，即在硝胺炸药分解过程中可形成NO3自由基。
