Kinetics of the reaction of p-nitrophenyl acetate with amines in the presence of dodecylammonium propionate and aerosol-OT aggregates in benzene

Abstract

Aminolysis of p-nitrophenyl acetate (NPA) by dodecylamine (DA) is 53 times faster in the presence of dodecyclammonium propionate (DAP) aggregates than in pure.benzene. Reaction with imidazole (Imz) and N-methylimidazole (Melmz) in the presence of DAP displays much more micellar catalysis. Thus addition of 0.2M-DAP to 0.08M-Imz in benzene reduced the reaction half-life from 25 h to 3 min. Addition of water decreases the reaction rates. This decrease is mainly due to DAP head-group hydration with subsequent loss of catalytic activity. Reaction between NPA and the amines, is faster in presence of DAP than Aerosol-OT(AOT). Addition of water to the amine–AOT system increases the rates. The results are discussed in terms of bifunctional catalysis by DAP and the effects of the surfactants on the reactivities of substrates solubilized in their micellar cores.