The kinetics of the thermal decomposition of the peroxodisulphate ion in aqueous solutions of various cationic surface‐active agents

A study has been undertaken of the kinetics of the thermal decomposition of potassium peroxodisulphate in aqueous solutions of n‐butyltrimethyl‐, n‐butyltriethyl‐, and n‐octyltriethylammonium chlorides. It has been found that the rate of disappearance of the peroxodisulphate ion is markedly increased in the presence of the cationic surfactants. Experiments with allyl acetate (a free‐radical scavenger) show that there is no direct reaction between peroxodisulfate and surfactant, and that the increased rate of disappearance of the peroxide is due to a free‐radical induced decomposition. The rate law has been elucidated, rate coefficients and activation parameters computed, and free‐radical mechanistic sequence discussed.