Transport properties of nonelectrolyte liquid mixtures—I. Viscosity coefficients for n-alkane mixtures at saturation pressure from 283 to 378 K

Abstract

Viscosity coefficient measurements at saturation pressure are reported for n-hexane + n-hexadecane, n-hexane + n-octane + n-hexadecane, and n-hexane + n-octane + n-dodecane + n-hexadecane at temperatures from 283 to 378 K. The results show that the Congruence Principle applies to the molar excess Gibbs free energy of activation for flow, δ* G E, at temperatures other than 298 K. However, curves of δ* G E versus index number of the mixture are temperature dependent, and this must be taken into account for accurate prediction of mixture viscosity coefficients by this approach. The purely empirical equation of Grunberg and Nissan; 1 $$\ln \eta = x_1 \ln \eta _1 + x_2 \ln \eta _2 + x_1 x_2 G$$ which has the advantage of not involving molar volumes, satisfactorily reproduces the experimental results for the binary mixture, but G is definitely composition dependent.