离子液体RMimBF_4中硝基苯电还原传荷特性

Transfer electron characteristic of nitrobenzene electrochemical reduction in ionic liquids RMimBF_4

采用循环伏安法研究了离子液体RMimBF_4中硝基苯在微铂电极上电还原动力学特性参数——传递系数a的变化规律。研究结果表明,离子液体中,硝基苯电还原过程的第2个电子转移反应是速度控制步骤。该反应的传递系数α随硝基苯浓度增加而减小;相同浓度时,温度升高,α迅速增大。在离子液体EMimBF_4-水-硝基苯体系中,相同硝基苯浓度下,随水含量增加,α先减小,后增大。不同离子液体中,α的变化规律为:EMimBF_4>BMimBF_4>HMimBF_4。

The transfer coefficient a of nitrobenzene electrochemical reduction in RMimBF_4 was investigated by cyclic voltammetry.It is showed that with the increasing of the concentration of nitrobenzene in RMimBF_4,a decreases,while temperature make reversed effect at the same nitrobenzene concentration,a decreases in the order EMimBF_4>BMimBF_4>HMimBF_4,at equal nitrobenzene concentration,the value ofαis reduced in EMimBF_4-H_2O at low water concentration and has reversed effect at high water concentration.