PHASE-TRANSFER MODEL FOR THE DYNAMICS OF MICELLAR AUTOCATALYSIS

The biphasic alkaline hydrolysis of ethyl caprylate (EC) exhibits high ly nonlinear kinetics that has been attributed in the literature to '' micellar autocatalysis'' (Bachmann, P. A. et al. Nature 1992, 357, 57) . New experimental results enable us to establish a macroscopic kineti c model quantitatively accounting for the dynamics of this reaction. A ccording to the model, EC is carried from the organic to the aqueous p hase by a transient micelle-EC complex (MEC). Curve fitting of the exp erimental kinetic data by inverse treatment shows that the formation o f MEC is more favorable than that of the pure caprylate micelles (M) a nd occurs at a critical concentration that is smaller than the cmc ass ociated with the formation of M. We demonstrate, in contrast to previo us claims, that classical micellar catalysis is not involved in the ov erall reaction process, but the observed nonlinear kinetics is a conse quence of the dynamics of the MEG-mediated phase-transfer reaction.