Oxidative oligomerization of phenolic endocrine disrupting chemicals mediated by Mn(III)-L complexes and the role of phenoxyl radicals in the enhanced removal: experimental and theoretical studies
Oxidative oligomerization of phenolic endocrine disrupting chemicals mediated by Mn(III)-L complexes and the role of phenoxyl radicals in the enhanced removal: experimental and theoretical studies
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Mn(III)-L配合物介导的酚类内分泌干扰物的氧化低聚以及苯氧基自由基在增强去除中的作用：实验和理论研究
DOI：
10.1021/acs.est.9b05423
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发表时间：
2020
影响因子：
11.4
通讯作者：
Wang Zunyao
中科院分区：
文献类型：
--
作者：
Wang Xinghao;Xiang Wenrui;Wang Siyuan;Ge Jiali;Qu Ruijuan;Wang Zunyao
可溶性锰（III）通过配体稳定为Mn（III）-L络合物，普遍存在于天然沃茨和沃茨中，并且可以潜在地在与有机污染物的单电子转移反应中充当氧化剂和还原剂。在这项研究中，14酚类内分泌干扰物（EDCs）的氧化转化原位形成的Mn（III）-L的配合物，从辐照水含有Mn（II）和腐殖酸，进行了研究。这些酚类化合物的准一级反应速率常数（kobs，h-1）在1.0 × 10- 4 ~ 5.9 × 10-2之间。定量构效关系模型表明，酚类化合物的供电子能力（EHOMO）是Mn（III）-L介导的氧化转化反应最重要的分子特征。苯酚转化是通过电子转移到Mn（III）-L产生苯氧基自由基而开始的。随后的苯氧基自由基之间的自偶联反应导致形成自偶联二聚体和三聚体。随着简单苯酚作为共底物的加入，这些酚类内分泌干扰物的转化增强被清楚地观察到，简单苯酚和底物的交叉偶联产物也被检测到。此外，基于过渡态理论的反应活化能计算表明，在苯酚存在下，交叉偶联反应比自偶联反应更容易发生。这项工作为酚类化合物的环境命运提供了新的见解。
Soluble manganese(III), stabilized by ligands as Mn(III)-L complexes, are ubiquitous in natural waters and wastewaters and can potentially serve as both the oxidant and reductant in one-electron transfer reactions with organic contaminants. In this study, the oxidative transformations of 14 phenolic endocrine disrupting chemicals (EDCs) by in situ-formed Mn(III)-L complexes, generated from irradiated water containing Mn(II) and humic acid, were investigated. The pseudo-first-order rate constants (kobs, h–1) of these phenols varied from 1.0 × 10–4to 5.9 × 10–2. A quantitative structure–activity relationship model was developed, which suggests that the electron-donating ability (EHOMO) of phenolic chemicals was the most important molecular characteristic for the Mn(III)-L-mediated oxidative transformation. Phenol transformation was initiated by the generation of a phenoxyl radical through electron transfer to Mn(III)-L. Subsequent self-coupling reactions between phenoxyl radicals resulted in the formation of self-coupling dimers and trimers. With the addition of simple phenol as a cosubstrate, enhanced transformations of these phenolic EDCs were clearly observed, and cross-coupling products of simple phenol and the substrates were also detected. In addition, a reaction activation energy calculation based on the transition-state theory indicated that the cross-coupling reaction was more likely than the self-coupling reaction to occur in the presence of phenol. This work provides new insights into the environmental fate of phenolic compounds.