The present study reports on the experimental measurement of the dissociation constants and the determination of related thermodynamic properties for five amines of importance in the area of CO2 capture. Measurements were performed for 2-(butylamino)ethanol, m-xylylenediamine, 3-picolylamine, isopentylamine, and 4-(aminoethyl)-piperidine. The experiments were done at an average pressure of 95.0 kPa and in a temperature range varying from 288.15 to 323.15 K. pK(a) measurements were performed using the potentiometric titration method. Based on the experimental data obtained, thermodynamic properties such as the standard state enthalpy, entropy, and free energies were regressed using the van't Hoff equation. Gaussian was used to determine in the case of diamines which amino group in the molecule would react first in the titration when the structure was unsymmetrical. In addition, the Perrin-Dempsey-Serjeant prediction model and its updated version were used to predict the first pK(a) values.