SYSTEMATIC DESIGN CHEMICAL OSCILLATORS - KINETICS AND MECHANISM OF THE REACTION BETWEEN CHLORITE ION AND HYPOCHLOROUS ACID

The reaction between ClO2•- and HOCl has been studied by spectrophotometrically monitoring the production of ClO2 at pH 5-6. In excess ClO2-, the reaction is first order in ClO2-, HOCl, and H+, and the stoichiometry is given by HOCl + 2ClO2- + H+ → 2ClO2 + Cl- + H2O. In excess HOCl and at higher pH's, ClO3- is produced, and the order of the reaction is between 1 and 2 for HOCl and between 0 and 1 for H+. By combining computer simulation and least-squares analysis, we obtain a mechanism in which the reaction 2HOCl + ClO2- → ClO3- + Cl2 + H2O (k = (2.1 ± 0.1) × 10-3 M-2 s-1) plays a key role in explaining the behavior at high [HOCl]/[ClO2-]. © 1990 American Chemical Society.