Separation of mixtures of chiral volatile anestethics via modified porous glasses

分离作为麻醉性气体使用的外消旋的氟烷混合物是很有意义的，因为单独的对映体的具体作用还不是很清楚。由于相应的纯对映体的可获得性有限，相应的研究仍然受到阻碍。在本项目的第一阶段，合成了不同孔径和粒度的玻璃微珠。有可能将合适的基于环糊精的选择剂固定在这些珠子的表面，并首次成功地进行对映体分离。在目前正在进行的供资期间，载体的合成得到了进一步的改进。通过赝形变换改变了玻璃微珠的孔结构，合成了表面已经功能化的玻璃微珠。该合成方法重现性好，可为色谱研究提供更多的样品。与第一阶段使用的方法相比，对映体选择性选择子的固定可以进一步改进，从而获得更好的分离结果。利用红外显微成像对手性分子的颗粒内质量传输进行了更详细的表征。通过对色谱柱超载实验结果的分析，确定了吸附容量和分离因子。建立了一个简化的数学模型，能够描述和优化填充了制备好的颗粒的色谱柱，并将其应用于估计较大直径色谱柱的分离效率。应该使用更大的柱尺寸和改进的实验装置。离开分离柱的对映体应随后在解吸和冷凝它们之前在吸附器中被捕获。此外，还计划测试所开发的模型在较大参数范围内预测较大塔中发生的分离过程的适用性。模型的预期扩展将通过纳入现有的运输参数来实现。此外，计划在第三阶段用更大直径的新粒子和核壳粒子进行定向小规模实验。这些新的支撑物对于以后更大规模的分离具有潜在的优势。

The separation of racemic mixture of fluranes applied as anaesthetic gases is of large interest, since the specific effects of the individual enantiomers is not sufficiently known. Corresponding investigations are still hampered due to the limited availability of the corresponding pure enantiomers.In the first period of this project glass beads of various pore and particle sizes were synthesized. It was possible to immobilize suitable cyclodextrin-based selectors on the surface of these beads and to perform first successful enantioseparations.In the currently ongoing funding period the synthesis of the supports has been improved further. Glass beads in which the pore structure was altered by pseudomorphic transformation were synthesized exhibiting already functionalized surfaces. The synthesis was reproducible and larger amounts of samples could be provided for chromatographic investigations. In comparison to the pathway used in the first period, the fixation of the enantioselective selector could be further improved allowing for better separation results. A more detailed characterization regarding the intraparticle mass transport of chiral molecules was performed exploiting IR micro-imaging. Adsorption capacities and separation factors were determined analyzing results of chromatographic column overloading experiments. A simplified mathematical model, which is capable to describe and optimize the chromatographic columns filled with the prepared particles, was developed and applied to estimate the productivity of the separation for columns with larger diameters.The production of pure enantiomers is in the focus of the third funding period. Larger column dimensions and an improved experimental set-up should be used. The enantiomers leaving the separation column should be subsequently captured in an adsorber before desorbing and condensing them. It is further planned to test the applicability of the model developed with respect to predict the separation process occurring in larger columns over a wider parameter range. An anticipated extension of the model will be realized by incorporating available transport parameters. In addition, it is planned in the third period to perform orienting small scale experiments with new particles of larger diameter and with core-shell-particles. These new supports are potentially advantageous for later separations in an even larger scale.