Physical properties of alkanolamine-choline chloride deep eutectic solvents

The utilization of deep eutectic solvents (DESs) for industrial processes requires an understanding of their fundamental physical properties. In this study, we report experimental measurements of the density, viscosity, conductivity, and pH of three different DESs, (Choline chloride + monoethanolamine, ChCl-MEA), (Choline chloride + diethanolamine, ChCl-DEA) and (Choline chloride + methyldiethanolamine, ChCl-MDEA). The experimental data was obtained at different temperatures and for three different choline chloride: Amine molar ratios. Experimental results showed that amine-based DESs are more thermally stable as compared to the corresponding pure amines. The density, viscosity, and conductivity increased with decreasing molar ratio of the amine in the DESs. However, there was no clear trend in the pH with molar ratio. The prepared amine based DESs have many important potential applications, with CO₂ capture being one of the main target of these type of DESs. Preliminary results for our group, not presented in this work, showed that amine based DESs have higher CO₂ absorption capacity as compared to conventional aqueous amine solvents.