COSMO-RS and LSER models of solution thermodynamics: Towards a COSMO-LSER equation of state model of fluids

Abstract

The present work examines the formulation of a statistical thermodynamic framework for the direct interconnection of the quantum-mechanics based COSMO-RS (Conductor Screening Model for Realistic Solvation) model with Abraham’s LSER (Linear Solvation Energy Relationship) model and LSER molecular descriptors. The focus is on the hydrogen-bonding (HB) contribution to solvation enthalpy. An extensive comparison is made between COSMO-RS predictions of the HB contribution to solvation enthalpy of a variety of solute – solvent systems and the corresponding LSER predictions. A rather good agreement is observed in most of the studied systems. The cases of large discrepancies are also compared with corresponding equation-of-state calculations. The perspectives for a combination of COSMO-RS, LSER and equation-of-state approaches, which would lead to the development of a COSMO-LSER equation-of-state framework are critically discussed.

Keywords: Generalized lattice-fluid, Hydrogen-bonding, Quantum-chemical calculations, Solvation enthalpy, Statistical thermodynamics