Electrochemical oxidation of 3-bromobenzoic acid (3-BBA) on a Pt electrode in alkali solution was studied by cyclic voltammetry and in situ Fourier transform infrared (FTIR) spectroscopy. The Pt electrode exhibited good performance for the electrooxidation of 3-BBA. At low oxidation potential (1000 mV), one electron was removed from the 3-BBA radical anion and the corresponding free radical was generated. A Bbromobenzene free radical cation and carbon dioxide were obtained after decarboxylation. The bromobenzene cation was then attacked by the hydroxyl radical, which was adsorbed on the anode, and the bromobenzene cation intermediate product was debrominated to form phenol. When the potential shifted to more positive values, phenol was electrooxided to produce dihydroxybenzene and benzoquinone. Maleic acid and fumaric acid were also detected as the reaction products of the ring-opening reaction.% 采用循环伏安法和原位傅里叶变换红外(FTIR)光谱法研究了碱性介质中间溴苯甲酸(3-BBA)在Pt电极上的电化学氧化反应.3-BBA在Pt电极上有良好的电化学活性.在较低的氧化电位作用下(1000 mV),3-BBA自由基负离子先在Pt电极上失去一个电子,生成对应的自由基,继而发生脱羧反应生成溴苯自由基阳离子和二氧化碳.随着电位的正移,吸附在电极表面的羟基自由基进攻溴苯阳离子,发生脱溴反应,生成苯酚.随着电位的升高,苯酚继续氧化生成苯二酚以及苯醌等,部分苯环还可经开环得到马来酸和富马酸.
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