Sanz, Luis Felipe, González, Juan Antonio, Hevia, Fernando, Lozano-Martín, Daniel, García de la Fuente, Isaías, and Cobos, José Carlos
[Display omitted] • Experimental viscosities for C 6 H 5 I + n -C n at (288.15–308.15) K are reported. • Correlation equations and Bloomfield-Dewan's model have been applied. • The systems studied theoretically are of the type aromatic compound, or C 6 H 12 + n -C n. • A close relationship exists between U V m E (n) and Δ η (n). • The free volume theory describes well η of the solutions. • DISQUAC is used to calculate the residual Gibbs energy in Bloomfield-Dewan's model. Kinematic viscosities were measured for iodobenzene + n -alkane mixtures at (288.15–308.15) K and atmospheric pressure. The corresponding dynamic viscosities (η) were also determined using density data previously obtained in our laboratory. This set of data was employed to calculate Δ η (deviations in absolute viscosity) and quantities of viscous flow. In addition, the correlation equations: McAllister, Grunberg-Nissan, Fang-He, and the Bloomfield-Dewan's model were applied to the systems: iodobenzene, or 1-chloronaphthalene, or 1,2,4-trichlorobenzene, or methyl benzoate or benzene or cyclohexane + n -alkane. It is remarkable that, within the Bloomfield-Dewan's model, residual Gibbs energies were calculated using DISQUAC with interaction parameters available in the literature. From the dependence of U V m E (isochoric molar excess internal energy) and Δ η with n (the number of C atoms of the n -alkane), it is shown that the loss of fluidization of mixtures containing iodobenzene, 1,2,4-trichlorobenzene, or 1-chloronaphthalene when n increases can be ascribed to a decrease, upon mixing, of the number of broken interactions between like molecules. The breaking of correlations of molecular orientations characteristic of longer n -alkanes may explain the decreased negative Δ η values of benzene mixtures with n = 14,16. The replacement, in this type of systems, of benzene by cyclohexane, leads to increased positive Δ η values, probably due to the different shape of cyclohexane. On the other hand, binary mixtures formed by an aromatic polar compound mentioned above and a short n -alkane show large structural effects and large negative Δ η values. From the application of the models, it seems that dispersive interactions are dominant and that size effects are not relevant on η values. The free volume model provides good results for most of the systems considered, since deviations are less than 6% for 20 mixtures from the 29 solutions under study, and only 4 systems show deviations higher than 10%, with a maximum deviation of 15%. Results improve when, within the Bloomfield-Dewan's theory, the contribution to η of the absolute reaction rate model is also considered. [ABSTRACT FROM AUTHOR]