Prediction of the heat of mixing for binary fluids using molecular dynamics simulation

Isothermal-isobaric ensemble (NPT) molecular dynamics (MD) simulation was applied to calculate the heats of mixing for binary fluids based on an all-atom force field. The calculation protocol was tested on mixtures of 1-propanol/n-heptane, n-butylamine/n-heptane and n-butylamine/water at various temperatures and compositions. Based on a simple error analysis and comparisons of calculated and experimental data, we propose that a necessary but not sufficient condition in the predictions of the heats of mixing is to have a force field highly accurate in evaluating energetic properties for pure substances. More work is required in order to find out the sufficient conditions. (c) 2005 Elsevier B.V. All rights reserved.