Cheng Yan, Yu Shuai, Xue Fumin
Qilu University of Technology (Shandong Academy of Sciences), Shandong Analysis and Test Center, 19 Keyuan Road, Jinan, Shandong Province 250014, P. R. China.
ACS Omega. 2020 Apr 9;5(15):8962-8971. doi: 10.1021/acsomega.0c00724. eCollection 2020 Apr 21.
Although the field of natural product extraction with ionic liquids (ILs) is already a crowded one, the guiding rules regarding the selection of suitable ILs for extraction are still lacking. In this study, the extraction capacity of 32 ILs was investigated using as a testing material, namely, 11 [BMIM]-based, 9 [CMIM]-based, 8 [C MIM][Br] and 8 [C MIM][BF] ILs ( = 2, 4, 6, 8, 10, 12, 14, 16) were studied. Three series of concentrations (0.02, 0.50, 2.00 M) were investigated, and the results demonstrated that the extraction capacity increased with the rising IL concentrations except for 1-butyl-3-methyl-imidazolium tosylate ([BMIM][Tos]). Generally, all the 0.50 and 2.00 M ILs led to the best extraction results. At low concentrations, the IL extraction capacity is strongly dependent on the anions and cations. However, the relationship between extraction capacity and anions or cations gradually becomes weak as increasing IL concentrations. Finally, the solution of ILs was prepared in aqueous or 60% methanol depending on the solubility. The pH can vary from strong acid to weak alkaline. Extraction capacity of 32 ILs varying in concentrations has a good negative correlation with the pH, except for five [BMIM]-ILs.
尽管离子液体（ILs）用于天然产物提取的领域已经竞争激烈，但仍缺乏关于选择合适离子液体进行提取的指导规则。在本研究中，以[具体测试材料名称]作为测试材料，研究了32种离子液体的萃取能力，即研究了11种基于[BMIM]的、9种基于[CMIM]的、8种[C MIM][Br]和8种[C MIM][BF]离子液体（ = 2, 4, 6, 8, 10, 12, 14, 16）。研究了三个系列的浓度（0.02、0.50、2.00 M），结果表明，除了对甲苯磺酸1-丁基-3-甲基咪唑鎓盐（[BMIM][Tos]）外，萃取能力随离子液体浓度的升高而增加。一般来说，所有0.50 M和2.00 M的离子液体都能得到最佳萃取结果。在低浓度下，离子液体的萃取能力强烈依赖于阴离子和阳离子。然而，随着离子液体浓度的增加，萃取能力与阴离子或阳离子之间的关系逐渐变弱。最后，根据溶解度在水或60%甲醇中制备离子液体溶液。pH值可以从强酸变化到弱碱性。除了五种基于[BMIM]的离子液体外，32种不同浓度的离子液体的萃取能力与pH值具有良好的负相关关系。
