Chemical Conversion Pathways and Kinetic Modeling for the OH-Initiated Reaction of Triclosan in Gas-Phase

International Journal of Molecular Sciences

Xue Zhang¹  Chenxi Zhang¹  Xiaomin Sun¹  Lingyan Kang¹  Yan Zhao¹ 

[1] Environment Research Institute, Shandong University, Jinan 250100, China; E-Mails:

关键词: triclosan;    reaction mechanism;    kinetic property;    formation of PCDD and PCB;   

DOI  :  10.3390/ijms16048128

来源: mdpi

【 摘 要 】

As a widely used antimicrobial additive in daily consumption, attention has been paid to the degradation and conversion of triclosan for a long time. The quantum chemistry calculation and the canonical variational transition state theory are employed to investigate the mechanism and kinetic property. Besides addition and abstraction, oxidation pathways and further conversion pathways are also considered. The OH radicals could degrade triclosan to phenols, aldehydes, and other easily degradable substances. The conversion mechanisms of triclosan to the polychlorinated dibenzopdioxin and furan (PCDD/Fs) and polychlorinated biphenyls (PCBs) are clearly illustrated and the toxicity would be strengthened in such pathways. Single radical and diradical pathways are compared to study the conversion mechanism of dichlorodibenzo dioxin (DCDD). Furthermore, thermochemistry is discussed in detail. Kinetic property is calculated and the consequent ratio of k_add/k_total and k_abs/k_total at 298.15 K are 0.955 and 0.045, respectively. Thus, the OH radical addition reactions are predominant, the substitute position of OH radical on triclosan is very important to generate PCDD and furan, and biradical is also a vital intermediate to produce dioxin.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.