Diffusion Coefficients of Organic Compounds at Infinite Dilution in Mixtures Involving Associating Compounds. Experimental Determination and Modeling by Group Contribution Methods

Diffusion coefficients of aromatic compounds at infinite dilution in binary mixtures have been measured at 298.15 K with respect to composition using the Taylor dispersion technique. The binary mixtures considered in this work were from alcohols (methanol, ethanol) and acetone with hexane, heptane, cyclohexane, carbon tetrachloride, and chloroform; the aromatic compounds were benzene, benzaldehyde, acetophenone, and phenol. The purpose of this work was to study the influence of the polarity of the binary mixtures on diffusion coefficients. The data were correlated by the Leffler−Cullinan equation, using the measured values of diffusion coefficients in pure solvents and estimating the viscosity of the binary mixtures with group contribution methods. Special attention was paid to the capability of models to take into account the polarity of the mixtures; for this purpose, in addition to the Grunberg−Nissan model, the UNIFAC-VISCO group contribution method was also considered.