Some numerical analyses on the solubility of vanillin in carbitol + water solvent mixtures [Alguns an?lises numé ricas da solubilidade de vanilina em misturas de solventes carbitol + ?gua] [Algunos an?lisis numé ricos sobre la solubilidad de la vainillina en mezclas cosolventes Carbitol + agua]

Abstract

In this communication some reported solubility values of vanillin (component 3) in 2-(2-ethoxyethoxy)ethanol (Carbitol, 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 ?x1,3 value in the mixture x1 = 0.05, i.e. -4.29 x 10-2) but preferentially solvated by the cosolvent in mixtures with compositions 0.12 < x1 < 1.00 (with a maximum ?x1,3 value equal to 3.61 x 10-2 in the mixture x1 = 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. © 2015, Universidad Nacional de Colombia. All rights reserved.