Using Molecular Orbital Calculations To Describe the Phase Behavior of Cross-associating Mixtures

Abstract

In previous studies, we have used molecular orbital calculations to determine the thermodynamic changes of dimerization for a number of pure and cross-associated species. We have shown that by using these results in a physical equation of state, the statistical associating fluid theory (SAFT), we are able to accurately model the phase behavior of pure self-associating compounds and binary mixtures of a self-associating compound and a nonassociating compound with a reduction in the number of adjustable parameters. In this study, we consider the phase behavior of binary mixtures in which cross-associated species may occur. To determine the equation of state parameters describing cross association, we introduce a mixing rule based on the results of our molecular orbital calculations. We show that using information derived from our quantum-mechanical calculations results in correlations of mixture vapor−liquid equilibrium data with fewer adjustable parameters and no loss of accuracy, indeed frequently with improved accuracy, compared to the original SAFT model.

Measurement and PC-SAFT modeling of solid-liquid equilibrium of deep eutectic solvents of quaternary ammonium chlorides and carboxylic acids

“…Simple combining rules for the cross-association interactions between the two components, proposed by Wolbach and Sandler [36], were further applied when dealing with mixtures.…”

Influence of humidity on the phase behavior of API/polymer formulations

“…Simple combining rules were used to describe the cross-association interactions between two different associating components without including an additional parameter [28].…”

Modeling thermodynamic properties of aqueous single‐solute and multi‐solute sugar solutions with PC‐SAFT

“…The combining rules proposed by Wolbach and Sandler 24 were used in this work to describe the association between a sugar and water…”