NEW EQUATIONS FOR TRACER DIFFUSION-COEFFICIENTS OF SOLUTES IN SUPERCRITICAL AND LIQUID SOLVENTS BASED ON THE LENNARD-JONES FLUID MODEL

In this paper, on the basis of our recent works on self-diffusion coef ficients of Lennard-Jones and real fluids, prediction and correlation models are proposed for the representation of tracer diffusivities of solutes in liquids and supercritical fluids. It has been found that wi th the parameters obtained from self-diffusion data (the Lennard-Jones energy and diameter) it is possible to predict the tracer coefficient s with acceptable accuracy by means of simple combining rules. Moreove r, two correlation models involving only one binary parameter (for ene rgy and diameter corrections, respectively) are proposed. Both models exhibit accuracies well inside the experimental uncertainties and give results comparable to the two-parameter Dymond-modified Hildbrand-Bat schinski equation.