Volumetric properties of (PEG 400 + water) and (PEG 400 + ethanol) mixtures at several temperatures and correlation with the Jouyban-Acree model / Propiedades volumétricas de mezclas binarias (PEG 400 + agua) y (PEG 400 + etanol) a diferentes temperaturas y correlación con el modelo Jouyban-Acree

Molar volumes and excess molar volumes were investigated from density values for (PEG 400 + water) and (PEG 400 + ethanol) binary mixtures at temperatures from 283.15 K to 313.15 K. Both systems exhibit negative excess volumes probably due to increased interactions like hydrogen bonding and/or large differences in molar volumes of components. Volume thermal expansion coefficients were also calculated for binary mixtures and pure solvents. The Jouyban-Acree model was used for density and molar volume correlations of the studied mixtures at different temperatures. The mean relative deviations between experimental and calculated density data were 0.1 and 0.5 %, for aqueous and ethanolic mixtures, respectively; whereas, in molar volume data the values were 18.0 and 6.9 %, for aqueous and ethanolic mixtures, respectively. The trained versions of the model for PEG 400 binary solvents could be used to predict the density values of other PEGs with reasonable prediction error employing the density of mono-solvents.

En este artículo se calcularon los volúmenes molares y molares de exceso a partir de valores de densidad para los sistemas PEG 400 + agua y PEG 400 + etanol, en todo el intervalo de composición, a temperaturas entre 283,15 y 313,15 K. Los sistemas estudiados presentan volúmenes de exceso negativos probablemente debido a las fuertes interacciones por unión de hidrógeno entre las moléculas de los dos compuestos y a la gran diferencia en los volúmenes molares de los dos componentes puros. También se calcularon los coeficientes de expansión térmica-volumétrica en los solventes puros y las respectivas mezclas. Asimismo, se usó el modelo Jouyban- Acree para correlacionar la densidad y el volumen molar de las mezclas a las distintas temperaturas. Las desviaciones medias relativas en densidad fueron 0,1% y 0,5% para las mezclas acuosas y etanólicas, respectivamente, mientras que las desviaciones obtenidas para volumen molar fueron 18% y 6,9% para las mezclas acuosas y etanólicas, respectivamente. Los modelos obtenidos para las mezclas binarias con PEG 400 pueden usarse para predecir los valores con otros PEG, con un adecuado margen de error, utilizando las densidades de los solventes puros.

Termodinámica de disolución de triclosán y triclocarbán en algunos solventes orgánicos volátiles / Solution thermodynamics of triclosan and triclocarban in some volatile organic solvents

Thermodynamic functions of Gibbs energy, enthalpy, and entropy for the solution processes of the antimicrobial drugs Triclosan (TS) and Triclocarban (TCC) in five volatile organic solvents were calculated from solubility values at temperatures from 293.15 to 313.15 K. TS and Triclocarban solubility was determined in acetone, acetonitrile (AcCN), ethyl acetate (AcOEt), methanol (MetOH), and cyclohexane (CH). The excess of Gibbs energy and the activity coefficients of the solutes were also calculated. The TS solubilities were greater than those of TCC in all the solvents studied. At 298.15 K the solubility diminished for TS in the order, acetone > AcOEt > AcCN > MetOH > CH, while it diminished for TCC in the order, acetone > AcOEt > MetOH > AcCN > CH. On the other hand, thermodynamic quantities relative to the transfer process of these drugs from CH to all other organic solvents, as well as from water to organic solvents for TS were also calculated in order to estimate the hydrogen-bonding contributions.