Effets de sel sur les mecanismes competitifs de coupure alkyle-oxygene et acyleoxygene lors de l'hydrolyse des esters phenylallyliques en milieu neutre

Salt effects on neutral hydrolysis of α-phenylallyl esters were determined in ethanol-water mixtures. Our results suggest weakening of alkyl-oxygen bond induced by complexation of carbonyl oxygen with the cation and with competition between ester-cation and ester-solvent association. The rate coefficient for hydrolysis of O-alkyl and O-acyl fission depends on water concentration and on cation. When ester-cation association is strong (Ba²⁺ and Li⁺) salt effect is positive; when it is weak, (Na⁺), salt effect is sometimes positive, sometimes negative and changes with the nature of the anion for alkyl-oxygen fission.