Solubility of trans-resveratrol in {ethanol (1) + water (2)} mixtures revisited: Correlation, dissolution thermodynamics and preferential solvation

Abstract

ABSTRACT Reported equilibrium mole fraction solubility values of trans-resveratrol in some aqueous-ethanolic mixtures in the temperature interval from (273.2 to 323.2) K were correlated by means of some cosolvency models, like multi-linear models of Jouyban-Acree and Jouyban-Acree-van’t Hoff and non-linear models of the modified Wilson and Buchowski-Ksiazczak. Apparent thermodynamic functions of the dissolution processes were computed using the van’t Hoff and Gibbs equations. Gibbs energy and enthalpy were positive in all cases, while negative and positive entropies were observed. The plot of enthalpy vs. Gibbs energy of dissolution was non-linear with negative slopes in the region of 0.00 ≤ x 1 ≤ 0.60 but positive slope in the region of 0.60 ≤ x 1 ≤ 0.90. Further, by means of the inverse Kirkwood-Buff integrals is observed that trans-resveratrol is preferentially solvated by water in water-rich mixtures but preferentially solvated by ethanol in the composition interval of 0.24 < x 1 < 1.00.