Kinetics and mechanism of aniline oxidation with chlorine dioxide in water

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.