1,4-二氯苯在乙腈-水两相系统中的电化学氧化降解途径

Degradation pathways of 1,4-dichlorobenzene by electrochemical oxidation on platinum electrodes in acetonitrile-aqueous two-phase system

研究了乙腈-水两相中Pt电极上1,4-二氯苯的降解途径和氧化特性。实验结果表明,1,4-二氯苯在乙腈-水两相中的氧化电位区间约为2.0～2.3 V(vs SCE),且氧化反应是受扩散控制的不可逆过程。液相色谱、液相色谱-质谱联用、离子色谱等的分析结果表明,乙腈-水两相中1,4-二氯苯氧化中间产物包括对氯苯酚、对苯醌、2,5-二氯对苯醌、草酸根离子、乙酸根离子、甲酸根离子、顺丁烯二酸根离子和氯离子,最终产物为H_2O和CO_2。得出了1,4-二氯苯主要的降解途径有两种。

The anodie oxidation of 1,4-dichlorobenzene in acetonitrile-aqueous solution was investigated on a platinum electrode. The cyclic voltammetric （CV） profiles showed that the oxidation potential region of 1,4-dichlorobenzene was about 2.0--2.3 V （vs SCE） . Moreover, the effect of different scan rates on CV curves implied that oxidation reaction of 1,4-dichlorobenzene was controlled by diffusion process. Additionally, the major intermediates detected by liquid chromatography （LC） and liquid chromatography/mass spectrometry （LC/MS） were parachlorophenol, 1,4-benzoquinone and 2,5-dichloro- p-benzoquinone. The variation of the concentrations of related anions （oxalate, acetate, formate, maleate and chloride ion） during the reaction process was ascertained by ion chromatography （IC） . On the basis of these findings, two tentative degradation pathways, hydroxyl radical attacking of the atom of carbon inbenzene ring and dechlorination of 1,4-dichlorobenzene were described.