Measurement and calculation of multicomponent diffusion coefficients in liquids

In the literature, several prediction models for binary diffusion coefficients are found. For multicomponent systems however, only a few models exist. Due to lack of ternary diffusion data, these models have not been verified for real systems until now. To overcome this limitation, multicomponent diffusivities were measured within the whole concentration space of the ternary system acetone-1 -butanol-1-propanol. Fick diffusivities were transformed to less concentration-dependent Maxwell-Stefan diffusivities, using the Wilson model for calculating the thermodynamic correction factor. Three suggested prediction models and one newly developed were tested by a comparison of predicted values to experimental data. The new prediction method shows the best results. All tested prediction models show larger deviations with increasing distance to the binary edge of the concentration triangle. (c) 2006 Elsevier B.V. All rights reserved.