Thermodynamic study on pKa values of some imines and their acids conjugate derived from different aromatic carbonyl compounds


Abstract The project was concerned with synthesis of mono acidic or diacidic Schiff bases having oxime or phenol groups or a combination of them respectively . Other syn and anti oximes were derived from 2-acetyl pyridine , and others included and synthesized by a standard methods . Potentiometric titration was found previously , an accurate , simple and fast method for determination of pKa for acids or pKa for acid conjugates of Schiff bases using NaOH and HCl titrant respectively . This method was applied successfully in this investigation for the determination of ionization constants of imines in a range of temperature (293-313)K . This encourage the workers in this study to deal with thermodynamic parameters such as ∆Gْ , ∆Hْ and ∆Sْ for the ionization reactions of imines at 10% ethanol solvent as interpreted and discussed .