The reactivity of p-nitrophenyl esters with surfactants in nonaqueous solvents. II. The effects of added water in benzene solutions of dodecylammonium propionate, and the reaction in toluene and cyclohexane

Abstract

The rate of decomposition of p-nitrophenyl acetate, pnpa, in benzene containing up to 0.11 mol dm^-3 of solubilized water in the presence of dodecylammonium propionate, dap, has been measured at 298 K. Although the micellar rate constant is decreased due to hydration of the head- groups, the bimolecular rate constant due to general acid-general base catalysis from the head-group components of dap is unchanged. There is no evidence to suggest that the substrate undergoes hydrolysis. Changing the solvent to either toluene or cyclohexane increases the micellar rate constant and changes the second term in the rate equation to one which includes the square of the surfactant concentration.