Excess Gibbs Free Energy Model for Calculating the Viscosity of Binary Liquid Mixtures

Abstract

In this article we present a model for correlating dynamic and kinematic viscosities of liquid mixtures, which is based on Eyring's absolute rate theory for liquid viscosity and the UNIQUAC equation. The proposed model involves the concept of ideal viscosity and uses the UNIQUAC equation to represent the deviation from ideal behavior. The expression adopted to describe the ideal term viscosity has been chosen after a thorough investigation of the performance of different equations previously proposed in the literature. The correlation results have shown a strong dependence on the expression used to account for the ideal viscosity contribution. Besides size and shape parameters, for each pure component, the model requires only two adjustable parameters per binary system. The binary interaction parameters have been determined by fitting literature viscosity data. More than 350 binary systems, 4619 viscosity data points at 0.1 MPa, have been correlated using this model. The binary systems investigated are representative of different types of intermolecular interactions (e.g., nonpolar/nonpolar, nonpolar/polar, and polar/polar). The calculated values are in good agreement with the experimental ones. The overall average mean relative standard deviation of the correlations is 1.20%, which is comparable with those of other correlation models available in the literature.

How ideal are binary mixtures of room-temperature ionic liquids?

“…The viscosity of an ideal mixture is not uniquely defined and various empirical models can be found in the literature [39,40]. Within the accuracy of the present data (Fig.…”

Citric acid-based deep eutectic solvents: Physical properties and their use as cosolvents in sulphuric acid-catalysed ethanolysis of oleic acid

“…Arrhenius equations for conductivity with calculated pre-exponential factors and activation energies for DESs Thermodynamic functions of activation of two citric acid-based deep eutectic solvents In order to understand the viscous flow better, Eyring's transition state theory was used for calculating the thermodynamic functions of activation from the dynamic viscosity. For liquid mixtures, the expression (21) for the dynamic viscosity can be written as [41,42] (21) where: h represents the Planck's constant; NA represents Avogadro's number; V represents the molar volume of the eutectic mixture (the ratio of the average molar mass and density of the eutectic mixture); ΔG* represents the molar Gibbs energy of activation for the viscous flow process. Combining the previous equation with equation (22) Table 9 contains obtained values of thermodynamic functions of activation at 303.15 K, together with the coefficients of correlation for the fits to equation (23).…”

Separating Rare-Earth Elements with Ionic Liquids

“…It is important to consider the variation of G ij by solvent mole fraction because it expresses the extent of the nonideality of the system [67] by quantifying the rise in interchange energy due to the increase in the lattice activation energy of solvent 2 due to the juxtaposition of solvent 1 molecules [68]. Moreover, with additional formula manipulation, x 1 x 2 G ij can be related to the molar Gibbs free energy of activation of the flow process by the Eyring absolute rate theory [69]. A plot of the relationship between the G ij of each PY 15 TFSI-solvent mixture and its respective solvent mole fraction can be found in Fig.…”