Thermodynamics properties of binary mixtures of aqueous solutions of glycols at several temperatures and atmospheric pressure

Abstract

© 2018 Elsevier LtdDensities (ρ), speeds of sound (u) and viscosities (η) for binary mixtures of {water + ethanol, or + ethylene glycol (EG), or + diethylene glycol (DEG), or + triethylene glycol (TEG), or + polyethylene glycol (PEG) 200, or + polyethylene glycol (PEG) 300, or + polyethylene glycol (PEG) 400, or + polyethylene glycol (PEG) 600, or + glycerol} have been determined as a function of composition at T = (293.15, 298.15, 303.15 and 308.15 K) and atmospheric pressure. From these results, excess molar volume (VmE), deviation in isentropic compressibility (ΔκS), deviation in viscosity (Δη), and excess Gibbs energy of activation for viscous flow (ΔG∗E) were calculated and fitted by the Myers-Scott equation, as a function of mole fraction. Values of VmE and ΔκS were negative over the entire composition range for all mixtures studied. The values of Δη were negative for the systems containing ethylene glycol and glycerol and positive for the systems containing ethanol, PEG 400 and PEG 600. For other systems, the deviation of viscosity presented an S-shape, with negative values at high water concentration. For all mixtures studied, the values of ΔG∗E were positive over the entire composition range. The results obtained were discussed in terms of structural effects and intermolecular interactions between like and unlike molecules.