Permanganate oxidation of diclofenac: The pH-dependent reaction kinetics and a ring-opening mechanism
文献类型：期刊论文
| 作者 | Cheng, Hanyang; Song, Dean; Liu, Huijuan; Qu, Jiuhui |
| 刊名 | CHEMOSPHERE
 |
| 出版日期 | 2015-10 |
| 卷号 | 136期号:0页码:297-304 |
| 关键词 | Permanganate Diclofenac pH-dependent kinetics Ring-opening mechanism |
| 英文摘要 | In this work, the fate of diclofenac (DCF) during permanganate (Mn(VII)) oxidation was investigated at environmentally relevant pH conditions (from 5 to 9). The batch experiments showed that the kinetics of the Mn(VII)/DCF reaction follows a second-order rate law with an apparent rate constant of 1.57 +/- 0.02 M-1 s(-1) at pH 7 and 20 degrees C. The half-value of DCF was calculated to be 37.5 min, when the concentration of Mn(VII) (0.4 mM) was 20-fold excess of DCF. The pH-dependence of the reaction kinetics was investigated, and the DCF reactivity with Mn(VII) was found to decrease with increasing pH. The second-order rate constants were then quantitatively described by incorporating the species distribution of DCF. A lower reactivity of the anionic DCF (DCF-) in comparison with its neutral counterpart (DCF0) was most likely attributable to the interaction between the ionized carboxylate group and amine nitrogen position, which can reduce the nucleophilicity of amine nitrogen by inductive and resonance effects. Moreover, a range of degradation products and the corresponding structures were proposed on the basis of the LC-Q-TOF-MS analysis. A detailed ring-opening reaction mechanism was proposed as follows: Mn(VII) acts as an electrophile to attack the amine moiety, leading to the formation of the primary intermediate products 2,6-dichloroaniline and 5-hydroxy-diclofenac, which can be further transformed. The further degradation proceeded through a multistep process including ring-opening, decarboxylation, hydroxylation, and cyclation reactions. (C) 2014 Elsevier Ltd. All rights reserved. |
| 研究领域[WOS] | Environmental Sciences |
| WOS记录号 | WOS:000357235400039 |
| 公开日期 | 2016-03-15 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/32817]  |
| 专题 | 生态环境研究中心_环境水质学国家重点实验室 |
| 推荐引用方式 GB/T 7714 | Cheng, Hanyang,Song, Dean,Liu, Huijuan,et al. Permanganate oxidation of diclofenac: The pH-dependent reaction kinetics and a ring-opening mechanism[J]. CHEMOSPHERE,2015,136(0):297-304. |
| APA | Cheng, Hanyang,Song, Dean,Liu, Huijuan,&Qu, Jiuhui.(2015).Permanganate oxidation of diclofenac: The pH-dependent reaction kinetics and a ring-opening mechanism.CHEMOSPHERE,136(0),297-304. |
| MLA | Cheng, Hanyang,et al."Permanganate oxidation of diclofenac: The pH-dependent reaction kinetics and a ring-opening mechanism".CHEMOSPHERE 136.0(2015):297-304. |
入库方式： OAI收割
来源：生态环境研究中心
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