Transmission of substituent effects in polar reactions. Part 1.—Field effects in ester hydrolysis

Abstract

Rate coefficients and Arrhenius activation parameters have been determined for the aqueous alkaline hydrolysis of esters X—CH₂COOEt where X— is NC—, CN—, HO— and [graphic omitted]. The finding of similar effects on reactivity when X— is NC— and CN— provides strong support for the view that direct action of electric fields plays a major role in the transmission of substituent effects even across a single intervening methylene group. The changes in the standard enthalpy of activation, relative to the alkaline hydrolysis of ethyl acetate, caused by charged and dipolar substituents, are generally explicable in terms of the temperature dependence to be expected for the dielectric permittivity governing the direct field effects of the substituent polarities.