Measurement and correlation of thermophysical properties in aqueous solutions of some novel bio-based deep eutectic solvents (lactic acid/amino acids) at T = (298.15 to 313.15) K

Publication date: Available online 9 January 2020Source: The Journal of Chemical ThermodynamicsAuthor(s): Masumeh Mokhtarpour, Hemayat ShekaariAbstractThermodynamic properties of novel bio-based deep eutectic solvents (DESs) and their mixture with other solvents would be of great importance in extraction and pharmaceutical sciences. In the present study new class of these neoteric sustainable solvents composed of amino acids and lactic acid were prepared, density and speed of sound data for neat lactic acid/alanine, lactic acid/glycine and lactic acid/histidine and their aqueous mixture were measured over the entire composition range at T = (298.15, 303.15, 308.15 and 313.15) K. Based on these data, some of the thermodynamic properties including the excess molar volumes (VE), apparent molar volume (Vϕ,1), excess isobaric thermal expansion (αp,mE), the excess molar isentropic compressibility (κEs,m) and limiting apparent molar expansibility (ϕE,10) were calculated. For all of the studied systems, these important properties were analysed based on various solute-solvent interactions occurring between the components of the mixtures. Furthermore, it was found that all the investigated DESs act as a structure-maker in water over the whole temperature range using Hepler's constant. The properties were correlated by the Redlich-Kister type equations.Graphical abstract

Source: The Journal of Chemical Thermodynamics - January 11, 2020 Category: Chemistry Source Type: research