An hydration scale for ketones in polar aprotic solvents

Abstract

An hydration scale (W0) for aqueous sulfolane and dimethyl sulfoxide (DMSO) has been developed that represents the effect of the solvent on the equilibrium hydration of a series of trifluoroacetophenones; [Formula: see text]. The equilibrium constants are correlated with the substituent parameter σ+; ρ+ = −1.62 for dehydration. The function W0, defined as [Formula: see text] is zero for pure water and rises to a value of 2.72 in 99 mole% sulfolane. W0 in aqueous DMSO is negative from 0 to 85 mole% DMSO, meaning that these systems hydrate the ketones to a greater extent than does pure water.