| 炔雌醇氯化反应的动力学和机制研究 |
| 摘要点击 2636 全文点击 1456 投稿时间：2012-09-02 修订日期：2012-11-07 |
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| 中文关键词 EE2 氯化 动力学 反应机制 |
| 英文关键词 EE2 chlorination kinetics reaction pathway |
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| 中文摘要 |
| 对典型内分泌干扰物炔雌醇(EE2)在模拟饮用水氯化过程中的反应行为进行了深入研究. 结果发现,EE2的氯化反应符合二级反应动力学. 表观速率常数kapp随pH的变化规律证明EE2分子中的酚环是氯原子攻击的首选位置. EE2的转换是由不同形态的EE2和HClO之间的3个基元反应控制. 去质子化的EE2阴离子明显比其中性共轭体更具活性. 高效液相色谱/质谱(HPLC/MS)分析表明氯原子可以通过亲电取代反应接到EE2分子中的酚羟基的邻位,先后生成一氯和二氯代EE2,第三个氯原子的取代导致苯环结构的破坏,分子不稳定发生水解. 本研究的结果对全面了解EE2在饮用水氯化消毒过程中的反应规律,为评价EE2对人体的潜在暴露提供了依据. |
| 英文摘要 |
| The objective of this research is to explore the fundamentals of reactions between chlorine and ethynyl estradiol (EE2), which is expected to occur during the drinking water treatment. The first step of EE2 chlorination was shown to follow the second-order kinetics with the first order to concentrations of both target compound and chlorine, respectively. Apparent rate constants of EE2 chlorination exhibit the pH-dependent profile which indicates that the phenolic ring is the preferred site of attack by Cl. The transformation of EE2 is governed by 3 elementary reactions between different species of EE2 and HClO. The deprotonated EE2 anion is significantly more reactive than its neutral conjugate. HPLC/MS analysis revealed that several Cl atoms can be incorporated into this site via complex multi-step pathways, resulting in the formation of mono and di-chlorine substituted EE2. The incorporation of the third Cl is accompanied by immediate broken down of the ring via hydrolysis. The results of this study are helpful to fully understand the behavior of EE2 in chlorinated drinking water disinfection, provide the basis for evaluating the potential exposure of this contaminant to human. The data of this work also give insights to the formation of chlorinated drinking water disinfection by-products (DBPs). |
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