甲苯异构体在石墨电极上的直接电氧化

通过循环伏安法、电化学原位红外光谱和恒电位电解法研究了甲苯异构体在0.05 mol/L硫酸体系中的直接电氧化行为. 结果表明, 对甲氧基甲苯、对甲基甲苯、对氯甲苯和对叔丁基甲苯4种含不同取代基的甲苯异构体具有相似的电氧化行为, 均在1710 cm^-1左右出现向下的羰基伸缩振动峰(υ_C=O), 在1130 cm^-1左右出现向上的甲基消耗峰. 通过气相色谱-质谱法(GC-MS)对恒电位电解产物进行检测, 进一步证实了在石墨电极、硫酸水溶液体系中甲苯异构体直接电氧化主要产物为相应的芳香醛, 40 ℃时, 对甲氧基苯甲醛的产率为70.9%.

Direct Electro-oxidation of Toluene Derivations on Graphite Electrode

Direct electro-oxidation behaviors of toluene derivations(p-methoxy methylbenzene, p-xylene, p-chloro methylbenzene, p-tert-butyl methylbenzene) were studied by cyclic voltammetry(CV), in situ Fourier transform infrared spectroscopy(in situ FTIR), and constant potential electrolysis on graphite electrode in sulfuric acid and acetone solutions. The direct electro-oxidation behaviors of the four toluene derivations were similar. The negative-going band at 1710 cm^-1 is the stretching vibration peak of carboxyl group of aromatic aldehydes, and the positive-going band at 1130 cm^-1 shows the consumption peak of methyl of toluene derivations. The main electro-oxidation products are aromatic aldehydes detected by gas chromatography-mass spectrometry(GC-MS). The yield of p-methoxy benzaldehyde could reach up to 70.9% in the sulfuric acid system at 40 ℃.