Effects of copper(II) mixed micelles on autooxidation of 3,5-di-tert-butylcatechol and hydrolysis of p-nitrophenyl diphenyl phosphate

The rates of autooxidation of 3,5-di-tert-butylcatechol and hydrolysis of p-nitrophenyl diphenyl phosphate in various mixed micelles formed from copper(II) surfactants and sodium dodecyl sulphate, cetyltrimethylammonium bromide and octaethylene glycol monododecyl ether were measured under the condition which obeys the first-order kinetic law. When compared to the pure copper(II) surfactant alone, the autooxidation rate of 3,5-di-tert-butylcatechol was found to be significantly increased in mixed micellar medium where octaethylene glycol monododecyl ether is the co-surfactant. The other two co-surfactants have relatively smaller effects on the rates as compared to the neutral co-surfactant. In the hydrolysis of p-nitrophenyl diphenyl phosphate, other than a small increase in rate on addition of small amount of co-surfactant in some cases, the overall effect of the co-surfactant is to decrease the rate. Various reasons are presented to account for the observed rate effects.