| Reported equilibrium mole fraction solubilities of sinapic acid (3) in {DMSO (1) + water (2)} and {Carbitol
(1) + water (2)} mixtures at several temperatures were analyzed in terms of the Hildebrand solubility
parameter of these aqueous mixtures. Moreover, the preferential solvation parameters of sinapic acid
in these aqueous saturated mixtures at (298.15 and 313.15) K were determined based on the inverse
Kirkwood-Buff integrals (IKBI) as widely described in the literature. Sinapic acid is preferentially solvated
by water in water-rich mixtures, i.e. (0.00 < x1 < 0.21 in {DMSO (1) + water (2)}) and (0.00 < x1 < 0.12 in
{Carbitol (1) + water (2)}) but preferentially solvated by the cosolvents in the other mixtures composi
tion. In the former cases these results could be interpreted as a consequence of hydrophobic hydration
around the non-polar moieties of sinapic acid. Moreover, in the last cases, the observed trends could
be due to the Lewis acidic behavior of sinapic acid in front of DMSO or Carbitol molecules because both
cosolvents exhibit higher Lewis basic character than water, as indicated by the respective solvatochromic
parameters. A single cosolvency model for representing the equilibrium solubility of sinapic acid in bin
ary solvents at various temperatures was also provided based on a combination of Hansen solubility
parameters and Jouyban-Acree model |