A Study of Chromatographic Resolution of Enantiomers: Solvent Characteristics of Supercritical Fluid and Liquefied Gas

本文研究了超临界二氧化碳和液化丙烷作为移动的流动相在色谱拆分光学活性异构体中的分离特性。用手性纤维素衍生物为固定相的硅胶柱拆分了反式二苯乙烯氧化物和1-（9-蒽基）-2，2，2-三氟乙醇两种对映体。实验结果总结如下。(1)二氧化碳，丙烷和己烷的顺序是高分辨率;顺序是平行于在每种溶剂中的扩散。(2)三种溶剂的容量比随醇浓度的增加而减小。在超临界流体的情况下，它也随着压力的增加而减小。这些现象可以用溶质和溶剂分子在活性中心的竞争吸附来解释。(3)分离因子随温度的降低而显著增大，随主流体组合和添加剂的不同而变化不大 ...更多信息 艾德酒精。吸附对映体的相对稳定性主要受吸附相中溶质-聚合物相互作用的控制，其次受吸附相中溶质-溶剂相互作用的控制。(4)随着超临界流体压力的增加，对映体的分离因子略有增加，这与吸附相中醇浓度的降低相对应。(5)在低速区，分子扩散和流体混合占主导地位，聚合物涂层的硅胶的总传质阻力小于裸凝胶;然而，在高速区，聚合物涂层的硅胶显示出比裸更高的阻力。可能有两种合理的解释：1）由于包含聚合物，多孔颗粒中的弯曲因子增加; 2）由于聚合物附着在颗粒外部，颗粒聚结。聚合物包被法的基础研究是提高柱效的必要条件。少

The present work concerns with the separation characteristics of the supercritical carbon dioxide and liquified propane as a mobile phase in chromatographic resolution of potically active isomers. Two enantiomers, trans-stilbene oxide and 1-(9-anthryl)-2,2,2-trifluoroethanol, were resolved by a column with a chiralcellulose derivative coated on a silica gel. The experimental results are summarized as follows.(1) Carbon dioxide, propane and hexane are in the order of high resolution; the order is in parallel to the diffusivity in each solvent.(2) The capacity ratio decreases with increasing the concentration of alcohols for the three solvents. It also decreases with increasing pressure in case of the supercritical fluid. These observations may be explained by the competitive adsorptions of solute and solvent molecules on active sites.(3) The separation factor significantly increases with decreasing temperature, and it changes a little according to the combination of major fluids and add … More ed alcohols. The relative stability of adsorbed enantiomers may be controlled majorly by the solutes-polymer interactions and secondly by the solutes-solvents interactions in the adsorbed phase.(4) The separation factor of enantiomers increases slightly with increasing pressure of the supercritical fluid, which corresponds to the decrease of alcohol concentration in the adsorbed phase.(5) In a low velocity region where molecular diffusion and fluid-mixing are predominant, the overall mass transfer resistance for polymer-coated silica gel is smaller than that for the naked gel; however, in a high velocity region, the polymer-coated silica gel shows higher resistance than the naked. There may be two plausible explanations: 1) increase of the tortuosity factor in the porous particle due to the inclusion of polymers 2) particle coalescence due to the polymers attached on the outside of particles. The fundamental research on polymer coating method will be necessary for improving column efficiency. Less