Multiphase equilibria in systems containing ionic liquids: Experimental investigations of phenomena and molecular modeling

离子液体混合物中近临界气体盐析的相平衡现象在实验和理论两方面都有待探讨。这种特殊现象的特点是，在接近气体汽液平衡临界点的条件下，用气体加压使液体（否则完全混溶的）发生液-液相分裂。song现象有望在化学过程中实现更高的转化率和/或经济地提取反应产物。对离子液体的水体系和非水体系这两种典型体系进行了研究。实验工作将由理论工作补充，旨在通过分子模拟（Gibbs Ensemble Monte Carlo simulation）预测离子液体系统中这种复杂的高压多相平衡。气体组分和第二（低分子）溶剂（如水、己烷）的分子间电势已经可用，但离子液体的分子间电势还需要应用基于量子化学的模型来确定。混合的相互作用必须由混合规则确定。该方法最近在申请人小组中成功地用于预测纯离子液体中气体的溶解度。它为控制离子液体系统相平衡的分子特性提供了强有力的见解，并且该方法也有望实现对song现象的可靠预测。

The phase equilibrium phenomenon salting-out by a nearcritical gas (SONG) in liquid mixtures of ionic liquids is to be explored in both experimental and theoretical work. That particular phenomenon is characterized by a liquid-liquid phase split of (otherwise completely miscible) liquids by pressurization with a gas under conditions which are close to the critical point of vapor-liquid equilibrium of the gas. The SONGphenomenon is expected to enable higher conversion rates in chemical processes and/or an economical extraction of the reaction products. The phenomenon is to be explored for two typical systems, an aqueous system and a nonaqueous system of an ionic liquid. The experimental work is to be supplemented by theoretical work which is aiming to predict such complex high-pressure multiphase equilibria in systems with ionic liquids by molecular simulation (Gibbs Ensemble Monte Carlo Simulations). The intermolecular pair-potentials are already available for the gaseous component and the second (low-molecular) solvent (e.g. water, hexane), but the intermolecular pairpotential of the ionic liquid is to be determined by applying quantum chemistry based models. The mixed interactions have to be determined by mixing rules . That method was recently successfully tested in the applicant s group for predicting the solubility of gases in pure ionic liquids. It provides strong insights into the molecular properties that govern the phase equilibrium in systems with ionic liquids, and the method is also is expected to allow for the reliable prediction of the SONG-phenomenon.