Abstract

DELGADO, Daniel Ricardo; PENA, María Ángeles  and  MARTINEZ, Fleming. Solvatación preferencial de algunas sulfonamidas en mezclas cosolventes 1,4-dioxano + agua a 298,15 K según el método de las integrales inversas de Kirkwood-Buff. Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2014, vol.38, n.146, pp.104-114. ISSN 0370-3908.

The preferential solvation parameters, that is, the difference between the local and bulk mole fractions of the solvents in solutions of some structurally related sulfonamides in 1,4-dioxane + water binary mixtures are derived from their thermodynamic properties by means of the inverse Kirkwood-Buff integrals method. From solvent effect studies, it was found that all the sulfonamides considered were very sensitive to solvation effects, so the preferential solvation parameter, dx_D,S, was negative in water-rich and 1,4-dioxane-rich mixtures but positive in intermediate co-solvent compositions. It may be possible that in water-rich mixtures the hydrophobic hydration around the non-polar groups plays a relevant role in the solvation. The greater solvation by 1,4-dioxane in mixtures of similar co-solvent compositions could be due mainly to polarity effects. Finally, the preference of these drugs for water in 1,4-dioxane-rich mixtures could be explained in terms of the acidic behavior of water interacting with the hydrogen-acceptor groups in the sulfonamides.

Keywords : Sulfonamides; solubility; inverse Kirkwood-Buff integrals; preferential solvation.

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