Abstract Aqueous biphasic systems containing water-miscible ionic liquids (ILs) and inorganic salt are considered as an effective media for liquid-liquid extraction of bioactive materials. One of the important advantages of ILs is the possibility for a modification of their chemical structure and, as a result, their properties, i.e. their multifunctionality. Among the modified ILs, the amino acid ILs (AAILs) attract much attention due to their low toxicity and biodegradability. In the present work, new experimental data on phase behavior (binodal curves and tie lines) were obtained at 298.15 K for the systems containing 1-alkyl-3-methylmidazolium AAILs, [Cnmim]Х, with different hydrocarbon chain length (n = 4, 8), and with the amino acid anions: X = [Leu] (L-Leucine), [Val] (L-Valine), [Lys] (L-Lysine), and inorganic salts (K3PO4, K2CO3). AAILs under investigation were synthesized and characterized by means of thermogravimetric analysis, 1H- and 13C-NMR spectra. The ability of the studied systems to phase separation, the lengths and the slopes of the tie lines were discussed in terms of AAIL's structure. Systems containing [C8mim][Lys] show stronger tendency for phase separation. The slopes of the tie lines increase with the length of alkyl chain of IL's cation. For the aqueous systems [Сnmim]X + inorganic salt, the slopes of the tie lines increase in the sequence: [Lys]

中文翻译：

---

含有具有不同阴离子（L-亮氨酸、L-缬氨酸、L-赖氨酸）和无机盐（磷酸三钾、碳酸钾）的 1-烷基-3-甲基咪唑鎓氨基酸离子液体的水性双相系统的液-液平衡

摘要 含有可与水混溶的离子液体 (ILs) 和无机盐的水性双相体系被认为是生物活性材料液液萃取的有效介质。ILs 的重要优点之一是可以对其化学结构进行修饰，因此可以对其性质进行修饰，即它们的多功能性。在修饰的ILs中，氨基酸ILs（AAILs）因其低毒性和生物降解性而备受关注。在目前的工作中，对于含有 1-烷基-3-甲基咪唑鎓 AAILs，[Cnmim]Х，具有不同烃链长度 (n = 4) 的系统，在 298.15 K 下获得了关于相行为（双节点曲线和连接线）的新实验数据, 8) 和氨基酸阴离子：X = [Leu] (L-亮氨酸), [Val] (L-缬氨酸), [Lys] (L-赖氨酸), 和无机盐 (K3PO4, K2CO3)。研究中的 AAIL 是通过热重分析、1H-和 13C-NMR 光谱合成和表征的。根据AAIL的结构讨论了所研究系统的相分离能力、连接线的长度和斜率。含有 [C8mim][Lys] 的系统显示出更强的相分离趋势。连接线的斜率随着 IL 阳离子的烷基链长度而增加。对于水性体系 [Сnmim]X + 无机盐，连接线的斜率按以下顺序增加：[Lys] 含有 [C8mim][Lys] 的系统显示出更强的相分离趋势。连接线的斜率随着 IL 阳离子的烷基链长度而增加。对于水性体系 [Сnmim]X + 无机盐，连接线的斜率按以下顺序增加：[Lys] 含有 [C8mim][Lys] 的系统显示出更强的相分离趋势。连接线的斜率随着 IL 阳离子的烷基链长度而增加。对于水性体系 [Сnmim]X + 无机盐，连接线的斜率按以下顺序增加：[Lys]