Rate of reaction of chlorine dioxide and hydrogen peroxide

Because of environmental concerns about molecular chlorine, chlorine dioxide is replacing chlorine in some important industrial applications. This situation has increased the interest in chlorine dioxide and has stimulated research related to its production. One process for manufacturing chlorine dioxide involves reducing sodium chlorate with hydrogen peroxide. In this process, there is a side-reaction in which some chlorine dioxide is consumed by reaction with hydrogen peroxide. Initial rates of this side-reaction were measured in a laboratory batch reactor. The side-reaction rate was compared with the rate that chlorine dioxide is produced under a typical set of industrial conditions: 80 degrees C, 2 M sulfuric acid, 3.4 M sodium chlorate and 3.2 M sodium sulfate. To make this comparison, an empirical kinetic model of the side-reaction was developed from the experimental data. The reaction approximately follows first-order kinetics for chlorine dioxide and for hydrogen peroxide; the activation energy is 12.4 kcal mol(-1). At the cited industrial conditions, the reaction model predicts that chlorine dioxide is consumed by the side-reaction at about 0.80/0-1.5% of the rate at which it is produced.