Simple and accurate correlations for diffusion coefficients of solutes in liquids and supercritical fluids over wide ranges of temperature and density

Abstract

The binary diffusion coefficients at infinite dilution, D-12, are fundamental properties in chemical engineering simulation and design. In this work, very simple and accurate expressions involving two parameters are proposed/analyzed for their estimation. They depend only on temperature and/or solvent density and/or solvent viscosity. Their correlation and prediction abilities are tested with the largest database ever compiled, composed of 539 binary systems and 8219 data points, where polar/non-polar, symmetrical/asymmetrical, small/large, and light/heavy molecules are included without exception. It is shown that only two experimental D-12 values are sufficient to get good parameters for the subsequent estimation of reliable diffusivities far away from the conditions of the experimental data utilized to fit them. Globally, Eqs. (2)-(4) and (9) are recommended for D-12 calculation, due to the excellent results achieved for both correlation (average errors between 2.78% and 3.05%) and prediction (average errors between 4.21% and 4.44%). A comparison with models from the literature is also accomplished. (C) 2013 Elsevier B.V. All rights reserved.