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.

The calculation of the viscosity of 51 multicomponent (48 ternary and 3 quaternary) nonelectrolyte liquid systems has been performed by means of a model based on Eyring's theory of viscous flow and the UNIQUAC equation. More than 1000 viscosity data points, under 0.1 MPa and in the temperature range of 283.15-323.15 K, have been calculated. The model is based on purecomponent viscosities, pure-component molar volumes, and pure-component size and shape parameters, as well as two interaction parameters per binary system. The model binary interaction parameters were determined previously by correlation of experimental literature data on the viscosity of binary systems. A rather good agreement between experimental and calculated viscosities of ternary and quaternary liquid mixtures has been achieved. The overall mean relative standard deviation of the calculation is 2.95%. The results show that the model is adequate for estimating liquid mixture viscosities for different types of mixtures containing polar and nonpolar components.

This article presents experimental viscosity and density data for binary systems containing ethanol and one of the following 1-alkanols as the second component: butan-1-ol, pentan-1-ol, heptan-1-ol, octan-1-ol, nonan-1-ol, and decan-1-ol. These properties were measured at 0.1 MPa and at five different temperatures, ranging from 283.15 K to 313.15 K. The viscosity data have also been correlated by a model which combines Eyring's theory of viscous flow with a thermodynamic framework (Ind. Eng. Chem. Res. 2000, 39, 849). The model binary interaction parameters, for each of the binary systems, are also reported. The agreement between calculated and experimental data was rather good. The overall mean relative standard deviations did not exceed 0.01. The experimental viscosity deviations, obtained by the difference between the viscosity of the mixture and the mole fraction average of the pure component viscosities, were adjusted by means of Redlich−Kister polynomials. For all the systems studied negative values of viscosity deviations were obtained, for all temperatures, and over the whole mole fraction range.

In this paper we present a new model for correlating the dynamic viscosity of Newtonian liquids at high pressures. The proposed model is based on Eyring's absolute rate theory for liquid viscosity and considers the activation energy for viscous flow as being a thermodynamic free energy. The viscosity of the system is described by a combination of a reference term, given by the Chapman-Enskog theory, and a deviation contribution. A virial-type expansion in pressure and a term comprising an expression for the residual Helmholtz free energy of the system account for the deviation from the nonattracting rigid sphere model viscosity behavior. Three cubic equations of state, Peng-Robinson, Soave-Redlich-Kwong, and Peng-Robinson-Stryjek-Vera, have been tested for evaluating the residual Helmholtz free energy. The model requires only two adjustable parameters for each pure liquid, at each temperature. The parameters have been determined by fitting literature viscosity data of 49 different pure liquid compounds from pressures of 0.1-250 MPa within the reduced temperature interval of 0.4-0.7. The performance of the model has been found to be insensitive to the choice of the equation of state, except at pressures above 100 MPa for which only the Soave-Redlich-Kwong equation of state has been able to describe the volumetric behavior of the liquids. The studied liquids are n-alkanes, substituted alkanes, n-alkenes, cyclic alkanes, aromatics, alcohols, esters, 1-butylamine, argon, nitrogen, oxygen, ammonia, and water. The calculated values are in good agreement with the experimental ones. The value of the overall average absolute deviation, for the 4380 data points correlated with the present model, is 1.22%.

In this paper, we present the experimental values of the density and dynamic viscosity, obtained at 101 kPa, for binary systems containing 1-octanol, 1-nonanol, 1-decanol, and 1-undecanol over the entire range of mole fractions and at the following temperatures:  (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K. The experimental viscosity data have been correlated by means of a model previously developed in our group. The binary interaction parameters of this model are also presented. The agreement between experimental and calculated values is quite good. The overall mean relative standard deviations are 0.2 % for the system 1-octanol + 1-nonanol, 0.5 % for the system 1-octanol + 1-decanol, 0.7 % for the system 1-octanol + 1-undecanol, 0.2 % for the system 1-nonanol+1-decanol, 0.6 % for the system 1-nonanol + 1- undecanol, and 0.2 % for the system 1-decanol + 1-undecanol.