On the cooperativity of association and reference energy scales in thermodynamic perturbation theory

TL;DR

This paper introduces a new method to couple hydrogen bond and reference energy scales in thermodynamic models, improving predictions of water-hydrocarbon solubilities by accounting for their interdependence.

Contribution

It proposes a novel approach to link the reference energy scale with hydrogen bonding degree, enhancing the accuracy of thermodynamic predictions for hydrogen bonding fluids.

Findings

Improved prediction of water-hydrocarbon mutual solubilities.

Demonstrates the dependence of energy scales on hydrogen bonding.

Provides a coupled energy scale model for better thermodynamic descriptions.

Abstract

Equations of state for hydrogen bonding fluids are typically described by two energy scales. A short range highly directional hydrogen bond energy scale, as well as a reference energy scale which accounts for dispersion and orientationally averaged multi-pole attractions. These energy scales are always treated independently. In recent years, extensive first principles quantum mechanics calculations on small water clusters have shown that both hydrogen bond and reference energy scales depend on the number of incident hydrogen bonds of the water molecule. In this work we propose a new methodology to couple the reference energy scale to the degree of hydrogen bonding in the fluid. We demonstrate the utility of the new approach by showing that it gives improved predictions of water-hydrocarbon mutual solubilities.