The magnitude of the electrostatic effect of substituents on reaction velocity depends on the solvent in which the reaction is carried out. In order to investigate the influence of solvent, the first and second saponification constants of diethyl malonate and diethyl adipate have been measured, both in water and in 80hyphen;percent alcohol, in solutions of varying ionic strength. The saponification constants have been extrapolated to infinite dilution. The ratio of the first to the second velocity constant at infinite dilution in any one solvent is a measure of the effect of a charged substituent on the rate of saponification. The results obtained in water are compared with those for 80hyphen;percent alcohol, and it has been shown that they are in good qualitative agreement and in fair quantitative agreement with the predictions of the Kirkwoodhyphen;Westheimer theory.
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