Surface tension of binary mixtures of dimethylsulfoxide + methanol, ethanol and, propanol between 293.15 and 308.15 K

Abstract

The main aim of this work is to study the interface of dimethylsulfoxide+n-alkanol mixtures. To achieve this aim, first, the surface tension of (dimethylsulfoxide+methanol, ethanol, and propanol) was measured as a function of mole fraction and temperature. These measurements were conducted in the temperature range of (293.15–308.15) K and atmospheric pressure. Then the surface tensions of binary mixtures were correlated by Shereshefsky model and excellent results were obtained. The average percent deviation in correlation of surface tension of studied mixtures was 0.7%. Based on Shereshefsky model, the standard Gibbs energy of adsorption and the free energy change in the surface region were calculated. The free energy change was used to obtain the excess number of molecular layers in the surface region. Additionally, the extended Langmuir model was applied. The required parameters of the model were adjusted, the standard Gibbs energy of adsorption was calculated, and positive or negative deviations from ideality were determined. Also surface compositions were calculated by using extended Langmuir model. In addition to these two methods, a predictive model based on the equality of the chemical potential of species in the interface and bulk liquid was used to predict surface compositions and surface tension of mixtures. Additionally, by using surface tensions of studied mixtures at different temperaturs, specific surface enthalpy and specific surface entropy were calculated for (dimethylsulfoxide+n-alkanol) mixtures.