Disinfection is critical for ensuring water safety; however, the potential risks posed by disinfection byproducts (DBPs) have raised public concern. Previous studies have largely focused on low-molecular-weight DBPs with one or two carbon atoms, leaving the formation of high-molecular-weight DBPs (HMW DBPs, with more than two carbon atoms) less understood. This study explores the formation of HMW DBPs during the chloramination of phenolic compounds using a novel approach that combines high-resolution mass spectrometry with density functional theory (DFT) calculations. For the first time, we identified nearly 100 previously unreported HMW nitrogenous DBPs (N-DBPs), with nearly half of those being halogenated N-DBPs. These N-DBPs were tentatively identified as heterocyclic (e.g., pyrrole and pyridine analogs) and coupling heterocyclic N-DBPs. Through detailed structure analysis and DFT calculations, the key formation steps of heterocyclic N-DBPs (monochloramine-mediated ring-opening reactions of halobenzoquinones) and new bonding mechanisms (C–N, C–O, and C–C bonding) of the coupling heterocyclic N-DBPs were elucidated. The selective formation of these novel N-DBPs was significantly influenced by factors such as contact time, monochloramine dosage, pH, and bromide concentration. Our findings emphasize the occurrence of diverse HMW heterocyclic N-DBPs, which are likely toxicologically significant, underscoring the need for further research to evaluate and mitigate their potential health risks in water disinfection.

中文翻译：

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重新审视酚类化合物的氯胺化：新型高分子量含氮消毒副产物的形成


消毒对于确保用水安全至关重要;然而，消毒副产物 （DBP） 带来的潜在风险引起了公众的关注。以前的研究主要集中在具有一个或两个碳原子的低分子量 DBP，而对高分子量 DBP（HMW DBP，具有两个以上的碳原子）的形成知之甚少。本研究使用一种将高分辨率质谱与密度泛函理论 （DFT） 计算相结合的新方法探索了酚类化合物氯胺化过程中 HMW DBP 的形成。我们首次鉴定了近 100 个以前未报道的 HMW 含氮 DBP （N-DBP），其中近一半是卤化 N-DBP。这些 N-DBPs 被初步鉴定为杂环 （例如，吡咯和吡啶类似物） 和偶联杂环 N-DBPs。通过详细的结构分析和 DFT 计算，阐明了杂环 N-DBPs 的关键形成步骤（一氯胺介导的卤代苯醌开环反应）和偶联杂环 N-DBP 的新键合机制（C-N、C-O 和 C-C 键）。这些新型 N-DBPs 的选择性形成受接触时间、一氯胺用量、pH 值和溴化物浓度等因素的显著影响。我们的研究结果强调了多种 HMW 杂环 N-DBP 的存在，这可能具有毒理学意义，强调需要进一步研究以评估和减轻它们在水消毒中的潜在健康风险。