Nucleophilic catalysis of hydrolyses of phosphate and carboxylate esters by metallomicelles - Facts and misconceptions

Metallomicelles of Zn(II) and Cu(II) provide impressive accelerations of hydrolyses of triarylphosphates and p-nitrophenyl acetate, which are often ascribed to some special feature due to incorporation in an association colloid. if the rate data are analyzed in terms of local reactant concentrations in the micellar pseudo-phase, the second-order rat constants are very similar to those of reactions of monomeric complexes in water, i.e. the rate increases are due largely to concentration of reactants in the small volume at the micelle-water interface. Therefore the special micellar effects which are postulated to provide impressive accelerations of reactions are chimera which disappear a;hen transfer equilibria between the aqueous and micellar pseudo-phases are taken into account, (C) 1998 Elsevier Science B.V. All rights reserved.