Abstract The electrochemical oxidation of vanillic acid (VA) in acetone–water mixtures, was studied by electro-Fenton (EF) process in an undivided electro-chemical cell equipped with a carbon fiber cloth as cathode and Pt anode. The objective was the conversion of VA into protocatechuic acid (PCA) well known by its high added value. To our knowledge, the EF method was not used in organic electrosynthesis. The influence of several operating parameters, such as applied current, initial VA concentration and volumic percentage of acetone was investigated. The evolution of the concentrations of VA and its main oxidation product PCA during electrolyses was monitored by means of high performance liquid chromatography (HPLC). The experimental data indicated that the kinetics of VA disappearance follow a pseudo first and zero orders for initial VA concentrations respectively equals to 6.5 and (10, 20, 30) mmol L −1 . The maximum PCA concentration increases with volumic percentage of acetone and initial VA concentration. Under optimal experimental conditions of applied current (20 mA) and volumetric percentage of acetone (20%), the increase in the initial VA concentration leads to a linear increase in the maximum of PCA concentration. The very good selectivity rate of the oxidation of VA to PCA by the EF process, was interpreted by the stabilizing effects of acetone and especially the complexation of PCA by the iron ions.

中文翻译：

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电芬顿法电化学氧化香草酸：原儿茶酸电合成新途径

摘要 在配备有碳纤维布作为阴极和 Pt 阳极的未分隔电化学电池中，通过电芬顿 (EF) 工艺研究了香草酸 (VA) 在丙酮-水混合物中的电化学氧化。目标是将 VA 转化为以其高附加值而闻名的原儿茶酸 (PCA)。据我们所知，EF 方法未用于有机电合成。研究了几个操作参数的影响，例如施加的电流、初始 VA 浓度和丙酮的体积百分比。通过高效液相色谱 (HPLC) 监测电解过程中 VA 及其主要氧化产物 PCA 的浓度变化。实验数据表明，对于初始 VA 浓度分别等于 6.5 和 (10, 20, 30) mmol L -1 ，VA 消失的动力学遵循伪一级和零级。最大 PCA 浓度随着丙酮的体积百分比和初始 VA 浓度而增加。在施加电流（20 mA）和丙酮体积百分比（20%）的最佳实验条件下，初始VA浓度的增加导致PCA浓度最大值的线性增加。通过 EF 过程将 VA 氧化为 PCA 的非常好的选择性可以通过丙酮的稳定作用，尤其是铁离子对 PCA 的络合来解释。最大 PCA 浓度随着丙酮的体积百分比和初始 VA 浓度而增加。在施加电流 (20 mA) 和丙酮体积百分比 (20%) 的最佳实验条件下，初始 VA 浓度的增加导致 PCA 浓度最大值的线性增加。通过 EF 工艺将 VA 氧化为 PCA 的非常好的选择性可以通过丙酮的稳定作用，尤其是铁离子对 PCA 的络合作用来解释。最大 PCA 浓度随着丙酮的体积百分比和初始 VA 浓度而增加。在施加电流（20 mA）和丙酮体积百分比（20%）的最佳实验条件下，初始VA浓度的增加导致PCA浓度最大值的线性增加。通过 EF 过程将 VA 氧化为 PCA 的非常好的选择性可以通过丙酮的稳定作用，尤其是铁离子对 PCA 的络合来解释。