Rate and Product studies of solvolyses of benzyl fluoroformate

Abstract

The specific rates of solvolysis of benzyl fluoroformate have been measured in several hydroxylic solvents at 25.0 degrees C. For methanolysis, the solvent deuterium isotope effect and activation parameters were determined and activation parameters were also determined for solvolyses in ethanol and 80% ethanol. For several of the binary hydroxylic solvents, measurement of product ratios allowed selectivity values to be determined. An extended Grunwald - Winstein treatment of the data led to sensitivities to changes in solvent nucleophilicity and ionizing power. Comparison with previously determined specific rates for solvolysis of the chloroformate gave fluorine/chlorine rate ratios greater than unity. All of the determinations made were consistent with an addition - elimination ( association dissociation) mechanism, with addition rate-determining.