
Citation: ZHU Ying-Hong, XU Ying-Hua, MA Hao, ZHAO Feng-Ming, MA Chun-An. Selective Dehalogenation of 2,4,6-Tribromophenol in Aqueous Solution on a Silver Cathode[J]. Acta Physico-Chimica Sinica, 2009, 25(06): 1190-1194. doi: 10.3866/PKU.WHXB20090625

水溶液中2,4,6-三溴苯酚在银阴极上的选择性脱卤
采用循环伏安法比较了玻碳、光亮银和粗糙化银电极对2,4,6-三溴苯酚还原脱卤反应的电催化活性, 初步研究了碱性水溶液中2,4,6-三溴苯酚在粗糙化银电极上的还原脱卤历程; 在此基础上, 利用恒电位电解法进一步探索了2,4,6-三溴苯酚在粗糙化银电极上的电还原脱卤历程. 结果表明, 粗糙化银电极对2,4,6-三溴苯酚的选择性还原脱卤反应具有优良的电催化活性, 且其活性优于光亮银和玻碳电极; 2,4,6-三溴苯酚在粗糙化银电极上的还原反应是个逐步脱卤过程, 推测得出其邻位和对位C—Br键的还原断裂所需的活化能非常接近, 而反应中间产物2,4-二溴苯酚的对位C—Br键的还原断裂所需的活化能比邻位要低; 2,4,6-三溴苯酚能实现完全脱卤生成苯酚, 主要路径为2,4,6-三溴苯酚→2,4-二溴苯酚→2-溴苯酚→苯酚.
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关键词:
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选择性脱卤
- / 2,4,6-三溴苯酚
- / 银电极
- / 废水处理
English
Selective Dehalogenation of 2,4,6-Tribromophenol in Aqueous Solution on a Silver Cathode
The electrocatalytic activity of a roughened silver electrode towards the reductive dehalogenation of 2,4,6-tribromophenol was compared to a glassy carbon electrode and a polished silver electrode in basic aqueous solution by cyclic voltammetry (CV). Furthermore, the course of reductive dehalogention of 2,4,6-tribromophenol was studied by CV and controlled-potential electrolysis. Results indicated that roughened silver exhibited more powerful electrocatalytic activity than the glassy carbon electrode and the polished silver electrode for the selective dehalogention of 2,4,6-tribromophenol. The reduction of 2,4,6-tribromophenol was determined to be a stepwise dehalogenation as follows: 2,4,6-tribromophenol→2,4-dibromophenol→2-bromophenol→phenol. In addition, the activity energy needed for the dissociative reduction of the ortho carbon-halogen bond was similar to the para carbon-halogen bond for 2,4,6-tribromophenol and a higher energy was probably required for 2,4-dibromophenol to cleave the ortho carbon-halogen bond compared to the para carbon-halogen bond.

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