水溶液中2,4,6-三溴苯酚在银阴极上的选择性脱卤  

Selective Dehalogenation of 2,4,6-Tribromophenol in Aqueous Solution on a Silver Cathode

作　　者：朱英红[1] 徐颖华[1] 马昊[1] 赵峰鸣[1] 马淳安[1] 

机构地区：[1]浙江工业大学化学工程与材料学院,绿色化学合成技术国家重点实验室培育基地,杭州310032

出　　处：《物理化学学报》2009年第6期1190-1194,共5页Acta Physico-Chimica Sinica

基　　金：国家基础研究重大项目前期研究专项基金(2003CCA01300);浙江工业大学校级科学研究基金(X1018103)资助

摘　　要：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.The electrocatalytic activity of a roughened silver electrode towards the reductive dehalogenation of 2,4,6-tdbromophenol 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-tdbromophenol. 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.

关 键 词：选择性脱卤 2 4 6-三溴苯酚 银电极 废水处理 

分 类 号：O646.54[理学—物理化学]