Studies on equilibrium of anthranilic acid in aqueous solutions and in two-phase systems: Aromatic solvent-water

The acid-base equilibria of anthranilic acid have been characterized in terms of macro- and microdissociation constants (dissociation constants Ka1, Ka2 and tautomeric constant Kz). On the basis of spectrophotometric investigations the values of the distribution ratio D of anthranilic acid in the two-phase systems: aromatic solvent (benzene, ethylbenzene, toluene, chlorobenzene, bromobenzene)-aqueous solution were obtained. Employing the results of potentiometric titration in the two-phase systems: aromatic solvent-aqueous solution the distribution constant KD and dimerization constant Kdim values were calculated. The influence of organic solvent polarity and pH of the aqueous phase on the contents of the particular forms of the acid in the two-phase systems were analyzed.