Mobility of aliphatic amino-alcohols molecules in aqueous solutions investigated by broadband dielectric spectroscopy

Abstract

The mobilities of two aliphatic amino-alcohols in their aqueous solutions were studied by broadband dielectric spectroscopy in the frequency range 100 MHz–60 GHz over the entire concentration range of their liquid state at 7 temperatures. Dielectric spectra of aqueous solutions of vicinal amino alcohols - monoethanolamine (MEA) and 3-amino-1-propanol (3AP) were obtained. The main dielectric parameters of the solutions, such as the dielectric force, the characteristic dielectric relaxation time, and the dielectric loss peak broadening parameter α, are determined. It is shown that the temperature dependences of the relaxation time obey the Arrhenius equation, and the activation energies of the process of orientational mobility of molecules and particles in aqueous solutions of amino-alcohols are calculated. A comparison was made with the activation energies of the translational motion of molecules, which we determined earlier by the NMR method [1]. It is concluded that different types of mobilities of molecules and particles in aqueous solutions of amino alcohols have an activation character and are interconnected, which is explained by the presence of a spatial network of hydrogen bonds in water, amino alcohols and their aqueous solutions.