Temperature Effect on the Acid-Base Properties of β-Alanine in Aqueous Solution

The acid-base properties of beta-alanine (beta-Ala) in aqueous solution were studied by the pH-metric method in the temperature range 278.2-318.2 K and at I = 0.1 M KCl. The ionization constants (pK(i)) of beta-Ala at different temperatures were calculated. The ionization constants were found to change depending on the temperature: an increase in the temperature leads to a decrease in pK(i) for both carboxyl and amine groups, which indicates that the degree of ionization of beta-alanine increased and its acidic properties were enhanced. The thermodynamic characteristics (Delta H-0, Delta S-0, and Delta G) of the corresponding ionization processes were determined by the temperature coefficient method.