Estimation of the boiling point and prediction of the VLE in methyl benzoate + N-octane binary liquid systems via viscosity-temperature dependence at atmospheric pressure

Abstract

Prediction and estimation of physicochemical properties of binary mixtures are of high importance for understanding the structure and molecular interactions. Excess and deviation properties exhibiting non-linear behaviour in methyl benzoate + n-Octane binary liquid mixtures at (303.15, 308.15, and 313.15) K for density and viscosity experimental values were presented in our earlier work. Here these experimental and calculated values were utilized to explore the applicability of the predictive Haj-Kacem equation and the recently proposed Messaâdi equation as well as their corresponding relative and derivative functions. Their correlation ability at different temperatures, with different parameters are also discussed in the case of limited experimental data. These relative functions are important to reduce the effect of temperature and, consequently, to unveil the effects of different natures of interactions. Despite the quasi-equality between the enthalpy for viscous flow activation ΔH*, and the viscosity Arrhenius energy of activation Ea, it limits excess partial molar energy of activation Ea1 and Ea2 for methyl benzoate and n-Octane, respectively, are investigated, along with their individual contributions independently. Molar activation energies at infinite dilution were deduced from different methods, activation parameters and partial molar Gibbs energy of activation for viscous flow against compositions were investigated. The results of these observations have been interpreted in terms of the structural effects of the solvents. In this context, a correlating equation is proposed in the present work and to estimate the normal boiling temperature of pure constituents and the nature of the isobaric vapour-liquid diagram in the binary liquid mixture. The obtained equations present a satisfactory result and are expected to be useful for future studies.