Solubility and preferential solvation of benzocaine in {methanol (1) + water (2)} mixtures at 298.15 K |
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| Authors: | Zaira J. Cárdenas Daniel M. Jiménez Ovidio A. Almanza Abolghasem Jouyban William E. Acree |
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| Affiliation: | 1. Grupo de Investigaciones Farmacéutico-Fisicoquímicas, Departamento de Farmacia, Facultad de Ciencias, Universidad Nacional de Colombia –Sede Bogotá, Bogotá D.C., Colombia;2. Grupo de Física Aplicada, Departamento de Física, Facultad de Ciencias, Universidad Nacional de Colombia – Sede Bogotá, Bogotá D.C., Colombia;3. Pharmaceutical Analysis Research Center and Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran;4. Kimia Idea Pardaz Azarbayjan (KIPA) Science Based Company, Tabriz University of Medical Sciences, Tabriz, Iran;5. Department of Chemistry, University of North Texas, Denton, TX, USA |
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| Abstract: | The equilibrium solubility of benzocaine (BZC) in several {methanol (1) + water (2)} mixtures at 298.15 K was determined. Solubility values are expressed in mole fraction and molarity and were calculated with the Jouyban–Acree model. Preferential solvation parameters of BZC by methanol (δx1,3) were derived from their thermodynamic solution properties using the inverse Kirkwood–Buff integrals method. δx1,3 values are negative in water-rich mixtures (0.00 < x1 < 0.32) but positive in the other mixtures (0.32 < x1 < 1.00). To explain the preferential solvation by water in the former case, it is conjecturable that the hydrophobic hydration around non-polar groups of BZC plays a relevant role in the solvation. Moreover, the higher solvation by methanol in mixtures of similar cosolvent compositions and methanol-rich mixtures could be explained in terms of the higher basic behaviour of methanol regarding water. |
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| Keywords: | Benzocaine solubility Jouyban–Acree model inverse Kirkwood–Buff integrals preferential solvation |
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