On estimating self-diffusivities by the extended corresponding states principle

• The extended corresponding states principle is used to predict self-diffusivities.
• Corrections by the modified Enskog theory are examined.
• Correlation with a new parameter reduces the errors of the model.
• Hydrogen-bonding substances present some peculiarities.

The ability of the extended corresponding states principle (ECSP) to predict the self-diffusion coefficients of several types of fluids has been studied. Two versions of the model were compared with the traditional two-parameter corresponding states principle (where the equilibrium shape factors are set to unity): one using the equilibrium shape factors and another one that additionally introduces a correction based on the modified Enskog theory (MET). Ethane was chosen as a reference fluid and the experimental database comprises 3163 points from 37 substances (polar, non-polar and hydrogen-bonding ones). Results show that a third complementary parameter, generated from diffusion data, is necessary to accurately correlate this transport property.