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978-3-8439-2486-3, Reihe Thermodynamik
Phase Equilibria and Solvent Effects in Liquid-Phase Reactions (Band 16)
153 Seiten, Dissertation Technische Universität Dortmund (2015), Softcover, A5
Homogeneous liquid-phase reactions enable manifold reaction pathways to valuable products based on e.g. renewable feedstock. A crucial factor for the industrial feasibility of such reactions is the catalyst recycling. It is usually carried out by liquid-liquid extraction processes. The phase equilibrium as underlying thermodynamic phenomenon is a complex function of the involved reactants, products, and solvents and influences the reaction itself.
Thus, one aspect of this thesis focuses on the examination of the influence of reactants and products on the phase equilibria of such liquid-phase reactions to model their effect on the efficiency of catalyst recycling by the corresponding liquid-liquid equilibrium. As model reaction, the homogeneously catalyzed hydroamination of the terpene β-myrcene with morpholine in various process approaches was examined. The investigation performed within this work comprises both experimental examination and thermodynamic modeling. As thermodynamic model the Perturbed Chain – Statistical Associating Fluid Theory (PC-SAFT) was applied. It was found that the reacting molecules affect the liquid-liquid equilibria as solubilizers, which is unattractive for an application in catalyst recycling. Thus, the overall reactant concentration is limited with respect to catalyst recycling. As the modeling enables accurate predictions of multi-component systems with respect to the temperature and the applied solvent system, a valuable tool for optimization is provided.
Solvent effects on homogeneous, liquid-phase reactions were investigated as another aspect of this thesis. As model reactions, esterifications of carboxylic acids with ethanol were chosen. PC-SAFT modeling allows for a prediction of pure solvent effects in excellent agreement with experimental data. Thereby, model parameter estimation was solely based on phase equilibrium data. For the first time, such solvent effect investigations were extended to solvent mixtures. Predictions with PC-SAFT were found in almost quantitative agreement with the experimental observations. Thus, a holistic reaction description by thermodynamic modeling is developed. This approach considers the physics of the reactants/products and solvents and is thus a valuable tool for modeling equilibrium-limited reactions.