The Mechanism of the Reaction of Chlorate with Chloride Ion in Sulfuric Acid Solution

Abstract

The mechanism of the reaction between chlorate and chloride ion in sulfuric acid solution was studied.
By considering material balances and effects of coexistent ions in these systems, it was found that the species: concerned were chlorate ion, chloride ion, hydrogen ion, perchlorate ion, chlorine dioxide, chlorine and water, and that these reactions were represented by the following three equations.
ClO^2- + Cl- + 2 H⁺=ClO^2- + 1/2 Cl2 + H₂0 (1)
ClO^2- + 5 Cl- + 6 H⁺=3 Cl2 + 3 H₂0 (2)
3 ClO^2- + 2 11+=2 ClO^2- + ClO^2-- + H₂0 (3)
Based on the assumption of the reaction mechanism proposed in the previous reports by other authors, the elementaly reaction equations could be derived as shown below,
ki ClO^2- + Cl- + 2 H⁺ HOCl HClO^2- (a)
k2 HClO^2- + ClO^2- + H⁺ (b)
2 ClO^2- + H₂O b HOCl + ClO^2- ClO^2-- + HCl c HClO^2- Cl- H⁺ 2 HOCl d HOCl H⁺ -7-4-0 Cl2 + H₂O e
Experimental results, favored the appropriateness of these derived equations. The rate constant ratio kelk4 and k3/k3 (at 30°C) are 2.75 X 1O^2-, and 7.5 respectively.