The mutual diffusion coefficient of the methanol-n-hexane mixture around the coexistence line

A comparison between experimental and calculated mutual diffusion coefficients is presented for the methanol-n-hexane mixture, around the coexistence line. For the experimental data, we used previous reported values, as well as our own measurements performed with the Taylor dispersion technique between 288 and 313 K, for several concentrations. For theory, we used the mean-field kinetic variational theory, i.e., the exact van der Waals theory. We reproduced the experimental values, in a semiquantitative way. The mean-field theory uses attractive interaction parameters which can be estimated when the binary system is classified according to the Scott and van Konynenburg scheme used for classifying binary phase diagrams. As a by-product, our method can give a mean-field theory spinodal curve prediction.