Exploring solvent–solvent interactions in deep eutectic systems: choline chloride/propanoic acid with aliphatic diols: a Jouyban–Acree model analysis

A comprehensive study was conducted to evaluate the thermodynamic behaviour of binary mixtures comprising a deep eutectic solvent (DES), formed by choline chloride and propanoic acid in a 1:2 molar ratio, with three diols: 1,3-propanediol, 1,4-butanediol and 1,5-pentanediol. Density, speed of sound and viscosity measurements were carried out over the temperature range of 303.15–313.15 K. To elucidate the non-ideal mixing behaviour of these systems, excess molar volume (VE), excess partial molar volumes, deviation in isentropic compressibility(ksE), viscosity deviation (Δη) and logarithmic excess viscosity (lnηᴱ) were calculated from the experimental data. To correlate the experimental data, the Jouyban–Acree model was successfully applied to density, speed of sound and viscosity, yielding satisfactory agreement between experimental and calculated values. These findings contribute to a deeper understanding of molecular interactions in DES–diol systems and support their potential in green chemistry applications