高等学校化学学报

高等学校化学学报

• 研究论文 • 上一篇    下一篇

硝基苯在离子液体EMimBF4中的选择性电还原

陈松1,2, 马淳安1, 褚有群1, 毛信表1   

    1. 浙江工业大学化工与材料科学学院, 绿色化学合成技术国家重点实验室培育基地, 杭州 310032;
    2. 盐城工学院应用化学研究所, 盐城 224002
  • 收稿日期:2007-03-01 修回日期:1900-01-01 出版日期:2007-10-10 发布日期:2007-10-10
  • 通讯作者: 马淳安

Selective Electrochemical Reduction of Nitrobenzene in Ionic Liquid EMimBF4

CHEN Song1,2, MA Chun-An1*, CHU You-Qun1, MAO Xin-Biao1   

    1. College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310014, China;
    2. Institute of Applied Chemistry, Yancheng Institute of Technology, Yancheng 224002, China
  • Received:2007-03-01 Revised:1900-01-01 Online:2007-10-10 Published:2007-10-10
  • Contact: MA Chun-An

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摘要： 采用循环伏安法和恒电位电解法研究了离子液体EMimBF4中硝基苯在微铂电极上的选择性电还原特性. 研究结果表明, 硝基苯在铂电极上的电还原反应为双分子八电子三步骤电化学过程: 第一步反应为准可逆单电子转移步骤, 产生阴离子自由基; 第二步为二电子转移步骤, 并伴有随后的双分子不可逆自由基偶合反应和快速质子化及脱水反应, 主要产物为氧化偶氮苯; 第三步是二电子转移产生偶氮苯的过程. 通过控制电位, 可以选择性地合成氧化偶氮苯和偶氮苯; 在EMimBF4中, 硝基苯和水的浓度变化对电化学行为产生较大影响.

关键词: 硝基苯, EMimBF4, 电还原, 绿色化学, 选择性

Abstract: The electroreduction of nitrobenzene in room temperature ionic liquidEMimBF4 on Pt electrode was investigated. The experimental results from cyclic voltammetry and constant-potential electrolysis show that the mechanism of the reaction was two molecules and three steps electrochemical process with eight-electrons transferred: anion radical arose in the first step; two-electrons were transferred in the second step and accompanied with coupling reaction of radicals and protonation and dehydrate, the main product was azoxybenzene; two-electrons were transferred in the third step, and azobenzene was achieved. The stronge interaction between EMimBF4 and nitrobenzene, and its intermediates yielded in the process of electroreduction caused the selective reaction. By controlling the reduction potential, the electroreduction of nitrobenzene to azoxybenzene and azobenzene had a high selectivity and high conversion. The concentrations of nitrobenzene and water in EMimBF4 have great effect on the electrochemical behavior. With the increasing of nitrobenzene concentration, the electroreduction peak potential of cyclic voltammogram around -1.47 V was shifted to negative value, and the current density was increased, as well as the water had reversed effect on the electroreduction peak potential, and increased current density.

Key words: Nitrobenzene, EMimBF4, Electroreduction, Green chemistry, Selectivity

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