Department of Earth Sciences, University of Delaware, Newark, DE, 19716, USA.
Reston Stable Isotope Laboratory, U.S. Geological Survey, Reston, VA, 20192, USA.
J Hazard Mater. 2020 Sep 5;396:122627. doi: 10.1016/j.jhazmat.2020.122627. Epub 2020 Apr 6.
The environmental fate of insensitive munitions compounds, such as 2,4-dinitroanisole (DNAN), has drawn increasing attention because of their growing use in military activities. One of the main attenuation mechanisms of DNAN degradation in aqueous environments is alkaline hydrolysis. We investigated the pathway for alkaline hydrolysis of DNAN at pH 12 by a combined approach of experiment and theory. An experiment using O-labeled water was performed to verify the reaction pathway. Calculated free energies for two putative reaction pathways by density-functional theory optimized at the SMD(Pauling)/M06-2X/6-311++G(2d,2p) level including explicit solvation of DNAN by 10 HO molecules and one OH ion gave a prediction in agreement with the experimental result. The verified reaction pathway for alkaline hydrolysis of DNAN is a S2Ar nucleophilic aromatic substitution with a methoxy leaving group (OCH) at the C1 site.
由于在军事活动中越来越多地使用钝感弹药化合物（如 2,4-二硝基苯甲醚（DNAN）），其在环境中的归宿引起了越来越多的关注。DNAN 在水相环境中降解的主要衰减机制之一是碱性水解。我们通过实验和理论相结合的方法研究了 pH 值为 12 时 DNAN 碱性水解的途径。使用 O 标记水进行了实验，以验证反应途径。通过密度泛函理论计算，在 SMD（Pauling）/M06-2X/6-311++G（2d，2p）水平上对两种可能的反应途径进行了优化，包括 10 个 HO 分子和一个 OH 离子对 DNAN 的显式溶剂化，给出的预测结果与实验结果一致。验证的 DNAN 碱性水解反应途径是 S2Ar 亲核芳香取代反应，具有 C1 位上的甲氧基离去基团（OCH）。
