二氧化氯氧化水中苯胺的反应动力学及机理研究

Kinetics and Mechanism of Aniline Oxidation with Chlorine Dioxide in Water

采用高效液相色谱技术检测苯胺浓度随时间的变化 ,对二氧化氯氧化苯胺的动力学规律进行了系统的研究 .结果表明 ,ClO2 氧化苯胺的反应对于ClO2 和苯胺均为一级反应 ,总反应级数为二级 .在pH6 86和水温 (TW) 2 87K条件下 ,二级反应速率常数k值为 0 11L·(mol·s) -1,反应活化能为 73 11kJ·mol-1,表明ClO2 氧化苯胺的反应在一般水处理条件下即可发生 .酸性和碱性条件下反应速率常数k值均较中性条件下大 ;亚氯酸根ClO-2 对反应速率的影响不大 .GC MS检测到对氨基酚和偶氮苯 2种主要反应中间产物 ,文中对ClO2 氧化苯胺的反应机理进行了初步探讨 .

Reaction kinetics of aniline oxidation with chlorine dioxide in water were investigated systematically by detecting concentrations of aniline with HPLC at regular intervals. Results showed that the reaction was first-order with respect to both chlorine dioxide and aniline, and the entire reaction was of second-order. Under condition of pH6.86 and water temperature(T W)287K, the second-order reaction rate constant k was 0.11 L·(mol·s) -1. Reaction activation energy was 73.11 kJ·mol -1, revealing that the reaction could take place under usual water treatment conditions. The reaction rate constants in acidic and alkali media were greater than that in neutral medium. Effect of chlorite ion on the reaction rate was insignificant. P-aminophenol and azobenzene were detected by GC-MS as intermediates. Oxidation pathways were proposed and discussed elementarily.