Kinetics and mechanism of chloride based chlorine dioxide generation process from acidic sodium chlorate.

The reaction between sodium chlorate and sodium chloride in presence of aqueous sulfuric acid is studied in a well stirred reactor at various temperatures and molar concentrations of chlorate, chloride and acid. The reaction rate is evaluated by analyzing the consumption of chlorate or chloride iodometrically or argentometrically. The rate law is established. Reaction has been found first and second order with respect to chlorate and chloride concentration, respectively. Reaction order is found about 13-14 with respect to molar concentration of sulfuric acid but it reduced to 2.4 when acidity function, h_, is substituted in place of molar concentration. The temperature dependence of the reaction is also investigated and pre-exponential Arrhenius parameter as well as activation energy are determined. It has been observed that ClO(2)/Cl(2) ratio is markedly affected by chlorate to chloride ratio. Reaction mechanism compatible with the reaction kinetics is proposed.