DISQUAC structure-dependent interaction parameters for mixtures containing sec-alkanols and benzene, toluene, or n-alkanones

Abstract

Mixtures containing sec-alkanols and benzene, toluene, or n-alkanones are characterized in terms of DISQUAC by means of structure-dependent interaction parameters. The quasichemical (QUAC) interchange coefficients are independent of the size alcohol for a given organic solvent; while the dispersive (DIS) ones change with the size of the alcohol. This behaviour has been found for other many alcoholic solutions. DISQUAC represents well the thermodynamic properties of these mixtures: vapor-liquid equilibria, VLE, molar excess Gibbs energies, GE, and molar excess enthalpies, HE. So, the mean deviations between experimental and calculated results are about 2% for pressure, and 8% for HE. A short comparison between DISQUAC results and those given by the Dortmund version of UNIFAC, the UNIQUAC association theory and other similar model is also presented. In the case of the Dortmund version of UNIFAC, poorer predictions are obtained for HE, as this property is more sensitive to molecular structure. Association theories provide better results because are used as correlation equations.Key words: thermodynamics, 2-alkanols, group contributions, interactions.