KINETICS OF THE AMINOLYSIS AND HYDROLYSIS OF PARA-NITROPHENYL CARBOXYLATES IN THE PRESENCE OF DODECYLAMMONIUM PROPIONATE AND AEROSOL-OT AGGREGATES IN BENZENE

Kinetics of the reaction of p-nitrophenyl carboxylates with alkylamines (RNH2; R = butyl, octyl, dodecyl and hexadecyl) and with N-alkylimidazoles (RImz; R = methyl, butyl, octyl, dodecyl and hexadecyl) were studied spectrophotometrically in the presence of dodecylammonium propionate (DAP) and bis(2-ethylhexyl) sodium sulfosuccinate (Aerosol-OT or AOT) reversed micelles in benzene. In the pure solvent, aminolysis of p-nitrophenyl acetate (NPA) is a function of the amine chain length. In the presence of 0.2 M DAP the reaction is ca. 39 to 50 times faster than that in the absence of the surfactant, due to bifunctional catalysis by the latter. Rates of diazole-catalyzed ester aminolysis (DAP concentration = 0.2 M) decrease with increasing alkyl chain length of both the diazole and/or the ester. Addition of water decreases the observed rates due to hydration of the DAP head groups. In the presence of AOT, the rates of Melmz-catalyzed ester hydrolysis decrease with increasing chain length of the ester alkyl group and increase as a function of added water. This reflects the importance of the substrates distribution between the bulk solvent and the micellar water “pool”. © 1979, American Chemical Society. All rights reserved.