Environmental Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS 39180, USA.
Environ Pollut. 2010 Oct;158(10):3048-53. doi: 10.1016/j.envpol.2010.06.033. Epub 2010 Jul 24.
Extensive studies have been conducted in the past decades to predict the environmental abiotic and biotic redox fate of nitroaromatic and nitramine explosives. However, surprisingly little information is available on one-electron standard reduction potentials (Eo(R-NO2/R-NO2-)). The Eo(R-NO2/R-NO2-) is an essential thermodynamic parameter for predicting the rate and extent of reductive transformation for energetic residues. In this study, experimental (linear free energy relationships) and theoretical (ab initio calculation) approaches were employed to determine Eo(R-NO2/R-NO2-) for nitroaromatic, (caged) cyclic nitramine, and nitroimino explosives that are found in military installations or are emerging contaminants. The results indicate a close agreement between experimental and theoretical Eo(R-NO2/R-NO2-) and suggest a key trend: Eo(R-NO2/R-NO2-) value decreases from di- and tri-nitroaromatic (e.g., 2,4-dinitroanisole) to nitramine (e.g., RDX) to nitroimino compound (e.g., nitroguanidine). The observed trend in Eo(R-NO2/R-NO2-) agrees with reported rate trends for reductive degradation, suggesting a thermodynamic control on the reduction rate under anoxic/suboxic conditions.
在过去几十年中，已经进行了广泛的研究来预测硝 基芳香族和硝胺炸药的环境非生物和生物氧化还原命运。然而，关于单电子标准还原电位 (Eo(R-NO2/R-NO2-)) 的信息却非常有限。Eo(R-NO2/R-NO2-) 是预测含能残留物还原转化速率和程度的重要热力学参数。在这项研究中，采用了实验（线性自由能关系）和理论（从头计算）方法来确定在军事设施中发现或新兴污染物中的硝 基芳香族、（笼状）环状硝胺和硝基亚氨基炸药的 Eo(R-NO2/R-NO2-)。结果表明，实验和理论 Eo(R-NO2/R-NO2-) 之间非常吻合，并表明了一个关键趋势：Eo(R-NO2/R-NO2-) 值从二硝 基芳香族（例如 2,4-二硝 基苯甲醚）降低到硝胺（例如 RDX）再到硝基亚氨基化合物（例如硝胍）。Eo(R-NO2/R-NO2-) 的观察趋势与还原降解的报告速率趋势一致，表明在缺氧/亚缺氧条件下还原速率受热力学控制。
