Abstract:

In situ infrared spectroscopy was used to systematically study the electro-oxidation reaction information of p-toluenesulfonic acid (p-TSA) on the titanium-based lead dioxide (Ti/PbO₂) electrode. The results of cyclic voltammentry curve indicated that Ti/PbO₂ electrode exhibited a high electrochemical activity for the oxidation of p-TSA, and the direct oxidation potential ranged from 0.55—0.9 V. When the voltage was less than 1000 mV (vs. SCE), the multi-step potential FTIRS (MSFTIRS) and time-resolved FTIRS (TRFTIRS) analysis showed that the p-TSA was in the process of breaking of sulfonic acid group and methyl group oxidation of side-chain of benzene ring . When the voltage was higher than 1000 mV (vs. SCE), the aromatic ring of p-TSA was degradated. Meanwhile, the compounds of acid, alcohol and ketone were generated. The results of the reaction kinetics study showed that the apparent rate constant K of p-TSA electrooxidation has a linear relationship with the current density j, the removal of chemical oxygen demand (COD) increased with the increase of specific charge, and the average current efficiency showed a downward trend.

Key words: p-toluene sulfonic acid, in situ FTIR, titanium-based lead dioxide, electrochemical oxidation, reaction kinetics

摘要：

采用原位红外光谱法系统地研究了对甲基苯磺酸（p-TSA）在钛基二氧化铅（Ti/PbO₂）电极上的电氧化反应信息。循环伏安曲线显示，Ti/PbO₂对p-TSA有良好的电氧化活性，直接氧化电位区间为0.55~0.9 V。多步电位阶跃FTIRS（MSFTIRS）和时间分辨FTIRS（TRFTIRS）分析显示，电压小于1000 mV时，p-TSA主要发生了磺酸基的脱落和苯环侧链甲基的氧化；电压大于1000 mV时，p-TSA的苯环骨架被破坏，同时生成了酸、醇、酮。反应动力学研究结果表明，p-TSA电氧化表观速率常数K与电流密度j呈线性关系，化学需氧量（COD）去除量随比电荷增大而增加，平均电流效率则呈下降趋势。

关键词: 对甲基苯磺酸, 原位红外光谱, 钛基二氧化铅, 电化学氧化, 反应动力学