A modified UNIFAC (Dortmund) model. 3. Revision and extension

The group contribution method Modified UNIFAC (Dortmund) is a well-known mo del for the reliable prediction of phase equilibria (VLE, LLE, SLE of eutec tic systems, azeotropic data and gamma(infinity)) and excess properties (h( E)). Compared to the original UNIFAC method, Modified UNIFAC (Dortmund) pro vides a much better description of the temperature dependence of the activi ty coefficients, and a more reliable presentation of the real behavior of p hase equilibria in the dilute region; in addition, it also leads to better results for asymmetric mixtures (i.e., those involving molecules of very di fferent size). Nevertheless, the parameters published previously sometimes give poor results, especially at high (>140 degrees C) and low (<0 degrees C) temperatures. To overcome these weaknesses, solid-liquid equilibria (SLE ) of eutectic systems and enthalpies of mixing (h(E)) at high temperatures have been included additionally in the database used for fitting the requir ed group interaction parameters in order to ensure reliable results at low and high temperatures. This paper contains details of 78 new or revised pai rs of group interaction parameters for Mod. UNIFAC (Do) covering a large te mperature range.