Solvent effects on the dissociation of aliphatic carboxylic acids in water-N,N-dimethylformamide mixtures

Abstract

The autoprotolysis constants of several water-N,N-dimethylformamide mixtures were determined. The acid dissociation constants of formic, acetic, propionic, n-butyric, isobutyric, n-valeric, isovaleric, 2-methylbutyric and trimethylacetic acids were evaluated in the same media by potentiometric titration. Empirical equations for the calculation of autoprotolysis constants and acid dissociation constants at 25° C in the mixed solvents are proposed. Approximate solvation numbers were obtained by multiple linear regression analyses of pKa values. © 1990.