Dielectric constants of aqueous diisopropanolamine, diethanolamine, N-methyldiethanolamine, triethanolamine, and 2-amino-2-methyl-1-propanol solutions

Dielectric constants of aqueous diisopropanolamine, diethanolamine, N-methyldiethanolamine, triethanolamine, and 2-amino-2-methyl-1-propanol solutions for temperatures of (303.15 to 328.15) K were measured using a dielectric analyzer. The dielectric constants of the corresponding pure alkanolamines were also measured for the same temperature range. The measured dielectric constants of diethanolamine and propylene glycol were found to be in good agreement with literature values. The relation between the dielectric constant of alkanolamines and the concentration of the hydroxyl groups per unit volume was discussed. The Kirkwood relation was also applied to represent the temperature dependence of dielectric constants of alkanolamines, and the apparent dipole moments were obtained from the measured data. The dielectric constants of aqueous alkanolamine solutions were correlated satisfactorily by using a Redlich-Kister type equation, and the positions of the relative minimum in the plot of Delta epsilon versus x(1) for aqueous alkanolamine solutions were presented. The compositions of the potential complexes formed from alkanolamines and water molecules were discussed.