Thermodynamics of proton dissociations from imidazolium ion, 6-uracilcarboxylic acid, and protonated hypoxanthine in aqueous solution

Equilibrium constants have been determined potentiometrically for proton dissociations from imidazolium ion, 6-uracilcarboxylic acid (pK 1 and pK 2 ), and protonated hypoxanthine (Pk 1 , pK 2 , and pK 3 ) in aqueous solution at 25 °C and used for calculation of ΔG° values for the corresponding reactions. Enthalpies of these same proton dissociations have been measured calorimetrically and combined with the ΔG° values to yield ΔS° values for these reactions.