Some numerical analyses on the solubility of vanillin in Carbitol (R)

Abstract

In this communication some reported solubility values of vanillin (component 3) in 2-(2-ethoxyethoxy) ethanol (Carbitol (R), component 1) + water (component 2) mixtures at five temperatures from 298.15 to 318.15 K were correlated with the Jouyban-Acree model combined with van't Hoff or Apelblat equations, obtaining models in second degree regarding the mixtures compositions. Mean percentage deviations were near to 6.0%. On the other hand, by means of the inverse Kirkwood-Buff integrals it was demonstrated that vanillin is preferentially solvated by water in waterrich mixtures (with a minimum delta x(1,3) value in the mixture x(1) = 0.05, i.e. -4.29 x 10(-2)) but preferentially solvated by the cosolvent in mixtures with compositions 0.12 < x(1) < 1.00 (with a maximum delta x(1,3) value equal to 3.61 x 10(-2) in the mixture x(1) = 0.25). It is conjectural that hydrophobic hydration plays a relevant role in the first case, whereas, in the second case, vanillin would be acting as Lewis acid with Carbitol (R).