Molecular thermodynamics of organic mixtures--fluid phase equilibria, functional group contributions, and quantum chemistry applications

The goal of this work was to develop a fundamental understanding of molecular thermodynamics of organic mixtures, which is crucial to chemical process research and development. Accurate binary and ternary phase equilibrium experiments were performed for the macroscopic characterization of organic functional groups, to provide data for the development of new chemical separation processes, and to understand the phase behavior of multicomponent complex mixtures. Problems with current group contribution activity coefficient models are discussed critically and in detail. Applications of the group contribution concept to chemical process research are demonstrated. Novel separation processes for organic compounds from aqueous solutions are developed based on the strategies developed in this work.;The first application of quantum chemistry to thermodynamic group contribution models is presented. Here, principles for determining unique organic functional groups are proposed based on quantum mechanical ab initio calculations. From these principles and the quantum mechanics calculation, significant improvement in the UNIFAC group contribution model is obtained using the newly defined functional groups. Quantum mechanical supermolecule calculations were also used to better understand microscopic molecular interactions, especially in hydrogen-bonding systems.