VISCOSITY OF SOME TERNARY LIQUID NONELECTROLYTE MIXTURES

Viscosities, densities, excess Gibbs free energies of activation of flow, and excess volumes are reported for mixtures of 11 ternary nonelectrolyte systems at 25°C. from among the components:n-hexadecane, n-tetradecane, n-hexane, 2-bromobutane, carbon tetrachloride, benzene, and 4-methylcyclohexanone. Experimental viscosities are compared with values obtained by fitting the data by the approaches of Kalidas and Ladd ha and an extension of that of Katti and Chaudhri, both based on theEyring viscosity equation. The first approach produces a standard error of 0.3 to 1.3%; the second, 0.3 to 0.5%. Both tend toward better representation of the data than that obtained by fitting viscosity directly with a power series in mole fraction. For one system, hexadecane-tetradecane-hexane, the principle of congruence is applied to predicting the viscosity, with a standard error of 1.3%, less than one tenth that of several equations commonly used in predicting viscosities of mixtures. The excess Gibbs free energy of activation of flow and the excess volumes arecompared with values previously reported for the binary subsystems. Both excess properties are fitted by power series equations in mole fraction. The former is represented to a standard error of from 2 to 7 cal. per mole, and the latter to 0.01 to 0.06 ml. per mole. Correlation between the predicted algebraic signs of the excess volume and the excess Gibbs free energy of activation of flow is poor in terms of a presumed dominance of free volume effects in governing viscosity. © 1969, American Chemical Society. All rights reserved.