Volumetric Thermodynamic Properties of Aqueous Binary Mixtures of Some Alkanols at Different Temperatures
Farid I. El-Dossoki *
Department of Chemistry, Faculty of Science, Port Said University, Port Said, Egypt
*Author to whom correspondence should be addressed.
Abstract
The densities of aqueous binary mixtures of some alkanols (1-butanol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol and 1,2,4-butanetriol including those of the pure liquids, over a wide composition range of alkanols at temperatures of 293.15, 298.15, 303.15, 308.15 and 313.15 K and atmospheric pressure were measured. From the experimental data, the excess molar volume,, of the binary mixtures, partial molar volumes, , and , at infinite dilution, and the corresponding excess partial molar volumes of the component solvents, and , at infinite dilution were calculated. The variation of these parameters with composition and temperature of the mixtures are discussed in terms of molecular interactions in these mixtures. The partial molar expansivities of the individual solvents, and at infinite dilution and the corresponding excess partial molar expansivities, and, at infinite dilution were also calculated. The excess partial molar volumes values were found to be negative for all the mixtures at each temperature studied. The results show that the addition of OH groups causes sensible changes in volumetric properties and its contribution presents a clear dependence on the position of OH groups. The values of the excess partial molar expansibility at infinite dilution are positive for all binary systems studied, indicating that there is an expansion in volume of the mixture with increasing temperature.
Keywords: Alkanol, density, molar volume, molar expansivity