二氧化氯氧化水中质子态联苯胺的反应机制

联苯胺类化合物是一类具有致基因突变、致癌性且在环境中广泛存在的有毒有害物质。以联苯胺作为代表性有机污染物，采用UV-vis、IR及GC/MS等方法研究了ClO2氧化水中质子态联苯胺的反应机理。指出了溶液pH值与联苯胺存在型体的关系，当pH值低于3.57时，溶液中联苯胺是以双质子态为主要存在形式的；控制溶液pH值2.0，对ClO2氧化水中质子态联苯胺的反应中间产物进行了鉴定。结果表明，该氧化反应中间产物依次为联苯醌二亚胺、联苯醌二肟和联苯醌，联苯醌最终被氧化成不饱和酸；通过分析ClO2与有机物反应特点和联苯胺分子结构的特性，在单电子转移理论的基础上，探讨了ClO2氧化质子态联苯胺可能的反应历程。

Reaction mechanism of protonated benzidine oxidation with chlorine dioxide in water

Benzidine derivatives constitute an important group of toxic and hazardous materials, which are known to be mutagenic, carcinogenic and extensively exsited in the environment. With benzidine as the model organic pollutant, the reaction mechanism of the protonated benzidine-ClO2 reaction in water was studied by gas chromatography-mass spectrometry (GC-MS), ultraviolet–visible spectroscopy (UV-vis) and infrared spectroscopy (IR) techniques. The relationship between presence states of benzidine and the solution pH was proposed. When the pH is lower than 3.57, benzidine presents as bi-proton state. The oxidation immediates and products formed in the reaction of the protonated benzidine with chlorine dioxide (ClO2) in the water were identified at pH 2.0 and the results showed that sequences of the main intermediates were diphenoquinone diimine, diphenoquinone dioxime and diphenoquinone. The end product of the proton state benzidine oxidized by ClO2 was unsaturated organic diacid. Through analyzing the reactions properties of chlorine dioxide with organic compounds and the molecular structure characteristics of benzidine, the possible pathway for the protonated benzidine-ClO2 reaction was proposed based on the theory of single electron transfer (SET).