The objectives of this project are: (1) Identify the sources of error in existing group-contribution models for the thermodynamic properties used in chemical process design; (2) develop, using interaction-site potentials, rigorous group-interaction models for predicting the excess properties of aqueous solutions of hydrocarbons and organics when experimental data are unavailable; (3) employ N, p, T Monte Carlo and molecular dynamics simulations to determine the fundamental limitations on the predictive capability of group-interaction and group-contribution models; (4) use simulations and molecular perturbation theory to study the effect of the choice of interaction-sites on predictions for excess properties and to develop a table of group-interaction parameters from experimental mixture data; (5) suggest how simplified engineering equations for activity coefficients can be modified to account for the influence of intramolecular structure on both the combinatorial and residual contributions; (6) develop a practical design tool by combining the rigorous molecular theory with the engineering correlative approach, in particular, use the new group-interaction models to predict significant physical properties, such as infinite dilution activity coefficients, at the temperatures of interest; and (7) use simple activity coefficient models to predict the composition dependence.
