Solvent Effect on the Dissociation Constants of Aliphatic Carboxylic Acids

Abstract

Dissociation constants of 10 aliphatic carboxylic acids, of general formula R-COOH, were measured by potentiometric titration in acetonitrile, propylene carbonate, acetone, N,N- dimethylformamide and dimethyl sulfoxide. The p* reaction constants of the Taft equation were found to depend on the solvent polarity, whereas the influence of the Lewis basicity and acidity is negligible. The p* values determined earlier in water, methanol and nitromethane also fulfil this rule.