Thermodynamics Research Center / ThermoML | Thermochimica Acta

ABSTRACT

Ionic liquids analogues known as Deep Eutectic Solvents (DESs) are increasingly realized in many chem-ical and industrial applications. The physical and chemical characteristics of these fluids are affectedconsiderably by their moisture content. This study focuses on the evaluation and prediction of the den-sity of choline chloride-based DES aqueous mixtures. The study involved six well known DESs with watermole fraction ranging between 0 and 1 within the temperature range (298.15 353.15 K). Since, the den-sity of pure DESs is more than that of water, the resulting aqueous mixtures density trends were similar.The Jouyban-Acree mixture density correlation was adopted for each DES mixture separately with verygood prediction accuracy. In addition, an alternative modified model was suggested. This model is capa-ble of predicting all DES mixtures density data based on their corresponding critical properties. Negativeexcess molar volume suggests formation of stronger H-bond and a more extensive H-bond networkwithin the mixture. This is enhanced by the packing effect created by difference between the molecularstructures of the DES and water. The aqueous DES solutions density model presented in this work mayassist in evaluating the effect of moisture content on this important physical property. This will furtherhelp in adopting proper chemical equipment design considerations and relevant process modeling andsimulation calculations.