Probing molecular interactions in the system {water+2-(diethylamino) ethanol} using solvatochromic dyes and excess partial molar enthalpies, at 298.15 K

The polarity of the binary {water + 2-(diethylamino)ethanol (DEEA)} mixtures was investigated, across the whole composition range using solvatochromic dyes, expressed in terms of the Kamlet-Abboud-Taft (pi*, alpha, beta) and E-T(N) Reichardt parameters, at 298.15 K. The preferential solvation model of Bosch and co-workers was applied to each solvatochromic dye. Direct excess partial molar enthalpies, H-i(E), for the same system, at the same temperature and atmospheric pressure, were obtained at both ends of the composition range using a semi-adiabatic isoperibol solution calorimeter and an expeditious method pioneered by Yoshikata Koga. Infinite dilution values of this same thermodynamic property were calculated for the DEEA in water and for the water in DEEA and compared with the literature values for the systems {water + 2-(dimethylamino) ethanol (DMAE)} and {water + 2-(ethylamino)ethanol (EEA)}, to infer the effect of branching and chain length on this property. Values for the interaction enthalpy between pairs of molecules of the same species, H-ii(E), were also estimated, in the same composition ranges studied, revealing endothermic processes, at both ends. A successful multiparametric correlation between excess partial molar enthalpy of DEEA and the solvent polarity parameters, pi*, alpha and beta allowed to quantitatively discriminate the relative relevance of the different types of the DEEA-solvent interactions. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

The polarity of binary mixtures of water and 2-(diethylamino)ethanol (DEEA) was investigated using solvatochromic dyes, and the preferential solvation model and multiparametric correlation analysis were applied to study the DEEA-solvent interactions.