Kulkarni Prashant S, Branco Luís C, Crespo João G, Afonso Carlos A M
REQUIMTE, Departamento de Química, FCT-UNL, 2829-516 Caparica, Portugal.
Chemistry. 2007;13(30):8470-7. doi: 10.1002/chem.200700160.
A novel study on organic solute absorption from the vapor phase is reported. The organic solutes chosen for the absorption studies include 1,4-benzodioxane, biphenyl, xanthene, and menthol. A series of imidazolium, ammonium, and guanidinium-based ionic liquids (ILs) containing several types of anions were used as absorbents. Absorption of water vapor was also studied along with the organic solutes. Absorption studies of each organic solute were performed by using a specially devised glass apparatus at 50 degrees C. It was observed that the rate of absorption increases with time and is faster in the case of 1,4-benzodioxane (24 h). The absorption process for each organic solute with different classes of ionic liquids was studied and the results were compared with each other. Absorption values of more than 25,000 ppm were observed in some ionic liquids. Distribution ratios of organic solutes in an ionic liquid and in the vapor phase were measured and the selectivity was evaluated by using the distribution ratio values. A remarkable selectivity was observed for some ionic liquids towards a specific organic solute. Importantly, it was observed that the selectivity remained constant, even though a mixture of solute was used for the absorption study. Desorption of organic vapors from ionic liquids was successfully carried out by applying a vacuum. Further, it was observed that the same ionic liquid can be repeatedly reused several times for absorption. These studies reveal that, in future, a task-specific ionic liquid can be prepared and used for specific solute capture from the vapor phase.
报道了一项关于从气相中吸收有机溶质的新研究。用于吸收研究的有机溶质包括1,4 - 二氧六环、联苯、呫吨和薄荷醇。一系列含有几种阴离子的咪唑鎓、铵和胍基离子液体（ILs）被用作吸收剂。还研究了水蒸气与有机溶质一起的吸收情况。每种有机溶质的吸收研究是在50摄氏度下使用专门设计的玻璃仪器进行的。观察到吸收速率随时间增加，在1,4 - 二氧六环的情况下（24小时）更快。研究了不同类别的离子液体对每种有机溶质的吸收过程，并将结果相互比较。在一些离子液体中观察到吸收值超过25,000 ppm。测量了有机溶质在离子液体和气相中的分配比，并使用分配比值评估了选择性。观察到一些离子液体对特定有机溶质具有显著的选择性。重要的是，观察到即使在吸收研究中使用溶质混合物，选择性也保持恒定。通过施加真空成功地实现了离子液体中有机蒸汽的解吸。此外，观察到相同的离子液体可以重复使用几次进行吸收。这些研究表明，未来可以制备特定任务的离子液体并用于从气相中捕获特定溶质。
