Nonlinear diffusion in multicomponent liquid solutions

Mutual diffusion in multicomponent liquids is studied. It is taken into consideration that the influence of complex formation on the diffusion process may be substantial. The theory is applied to analyze mass transfer in an acetone-chloroform solution. The molecular complex concentration was obtained from the analysis of Fourier transform infrared spectra of this solution. Taking into account molecular complex formation allows one to explain the experimental dependence of diffusion coefficients on the composition (components concentration). The accuracy of experimental and theoretical data descriptions in the frame of our model is compared to the accuracy for some other approaches.

Figure 1

FTIR absorption spectra of acetone-chloroform solutions between 3750 and 6200 ${\mathrm{cm}}^{-1}$; ${\phi }_1^{\text{tot}}$ is the initial volume fraction of acetone (before mixing).

Figure 2

Calculated volume fractions of mixture components. ${\phi }_1^{\text{tot}}$ is the initial volume fraction of acetone (before mixing).

Figure 3

Concentration dependence of the effective diffusion coefficient for the acetone-chloroform solution: points, experimental data [64]; solid curve, theoretical calculations; ${\phi }_1^{\text{tot}}$, initial volume fraction of acetone (before mixing).