Solubility of sinapic acid in some (ethylene glycol + water) mixtures: Measurement, computational modeling, thermodynamics, and preferential solvation

At 298.15–318.15 K and 0.1 MPa, the solubility of a naturally-derived chemical sinapic acid (SA) (3) in various {ethylene glycol (EG) (1) + water (2)} mixtures has been recorded. The solubility values of SA were correlated computationally using five different models. In {EG (1) + water (2)} mixtures, the equilibrium solubility of SA was shown to rise with increasing temperature and EG mass fraction. The maximum of solubility of SA in mole fraction was obtained in pure EG (9.40 × 10⁻³ at 318.15 K) and the least solubility was obtained in pure water (6.20 × 10⁻⁵ at 298.15 K). The mean percent deviations (MPD) were recorded as 1.81%, 4.96%, 18.13%, 1.1% and 1.4% for Apelblat, van't Hoff, Yalkowsky-Roseman, Jouyban-Acree and Jouyban-Acree-van't Hoff models, respectively, suggesting good correlations. Thermodynamic research revealed that SA dissolution was endothermic and entropy-driven in all {EG (1) + water (2)} solutions tested. In all {EG (1) + water (2)} mixtures, enthalpy–entropy compensation data suggested that the enthalpy-driven process was the main mechanism for SA solvation. SA is preferentially hydrated in water-rich mixtures, but preferentially solvated by EG in mixtures of 0.24 < x₁ < 1.00, according to the inverse Kirkwood-Buff integrals approach.