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

近临界气体(SONG)在离子液体液体混合物中的相平衡现象需要从实验和理论两方面进行探索。这种特殊现象的特征是，在接近气体汽液平衡临界点的条件下，通过与气体加压，液体发生液-液相分离(否则完全互溶)。SONG现象有望在化学过程中实现更高的转化率和/或反应产物的经济提取。这一现象将被用来研究两个典型的体系，一个是水体系，另一个是离子液体的非水体系。作为实验工作的补充，理论工作旨在通过分子模拟(Gibbs系综蒙特卡罗模拟)来预测离子液体体系中的这种复杂的高压多相平衡。气态组分和第二(低分子)溶剂(如水、正己烷)的分子间对势已经可用，但离子液体的分子间对势将通过应用基于量子化学的模型来确定。混合相互作用必须由混合规则来确定。该方法最近在申请者S小组中成功测试，用于预测气体在纯离子液体中的溶解度。它提供了对控制离子液体体系中相平衡的分子性质的强烈见解，该方法也有望允许可靠地预测歌曲现象。

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.