采用循环伏安法研究了邻碘苯甲酸在NaOH溶液中的电化学还原反应,与Pt和Ti等电极相比,Ag和Cu电极对邻碘苯甲酸具有较好的电还原活性,还原电位向正电位方向移动。通过原位红外光谱技术研究了邻碘苯甲酸在Ag和Cu电极上的电还原机理。结果表明,在电位高于"800mV时,邻碘苯甲酸在Ag电极表面先形成吸附中间态R…I…Ag,而在Cu电极表面以负离子形式存在。随着电位的进一步负移,邻碘苯甲酸在Ag和Cu电极上均发生脱碘加氢反应,经还原得到最终产物苯甲酸。
Electrochemical reduction of 2-iodobenzoic acid(OIBA) in NaOH solution was investigated by cyclic voltammetry.To compared with Pt and Ti electrodes,Ag and Cu electrodes exhibited good electrocatalytic activity for the electroreduction of OIBA,and the electrochemical deiodination reaction could take place at more positive potentials on Ag and Cu electrodes.The study on the mechanism of OIBA by in situ FTIR spectroscopy showed that there were different between Ag and Cu electrodes during electrocatalytic reductive deiodination reaction of OIBA at the potentials positive than -800 mV,the absorption state of R…I…Ag was formed on Ag electrode initially,while OIBA existed as negative ions on Cu electrode.Then OIBA was processed by a series of deiodination and hydrogenation reactions at more negative potentials at Ag and Cu electrodes,and benzoic acid was obtained finally.