Triclosan (TCS) is a commonly used antimicrobial agent which persists in the environment and may undergo chlorination and/or photodegradation to produce toxic polychlorinated dibenzo-p-dioxins and polychlorinated benzenes. TCS accumulates in wastewater treatment biosolids, which may be used to fuel waste-to-energy plants, although little is known about the fate of TCS at high temperatures. Here, we have studied the thermal decomposition of TCS and chlorinated TCS derivatives in the gas phase using computational chemistry coupled with reaction rate theory calculations to predict rate coefficients and develop a chemical kinetic model to simulate TCS pyrolysis in a plug flow reactor. TCS is shown to interconvert with 4-chloro-2-(2,4-dichlorophenoxy)phenol (TCSi) with a relatively low barrier, achieving equilibrium at temperatures of around 900 K and above. Dissociation of TCS and TCSi proceeds in parallel with barriers of ca. 60–65 kcal/mol to produce dichlorodibenzo-p-dioxin chlorobenzoquinone isomers. Reactor simulations demonstrate that TCS incineration at a temperature of 1100 K or higher leads to the formation of toxic chlorinated aromatics.

中文翻译：

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三氯生（TCS）及其氯化衍生物的热解。

三氯生（TCS）是在环境中通常使用的抗微生物剂，其仍然存在，并且可经历氯化和/或光降解产生有毒多氯联苯二苯并p-二恶英和多氯苯。尽管在高温下TCS的命运知之甚少，但TCS在废水处理过程中会积聚生物固体，可用于为废物转化为能源的工厂提供燃料。在这里，我们使用计算化学方法与反应速率理论计算相结合来预测速率系数，并开发了化学动力学模型来模拟TCS在活塞流反应器中的热解，研究了气相中TCS和氯化TCS衍生物在气相中的热分解。TCS被证明可以与4-氯-2-（2,4-二氯苯氧基）苯酚（TCSi）进行互变，并且具有较低的势垒，可以在900 K左右或更高的温度下达到平衡。TCS和TCSi的解离与ca. 60-65千卡/摩尔以产生dichlorodibenzo- p-二恶英氯苯醌异构体。反应堆模拟表明，在1100 K或更高的温度下进行TCS焚烧会形成有毒的氯化芳烃。