Four different dicyanamide-based ionic liquids (ILs), [C_nmpy][DCA] (n = 4, 6, 8, and 10), were synthesized, characterized, and used to separate ethylbenzene from n-octane. Equilibrium data for the corresponding ternary systems were measured at 313.15 K under atmospheric pressure. A higher selectivity is observed for lower aromatic concentrations in the feed (20% max); this is a key factor in selecting a suitable IL. The distribution ratio and selectivity obtained in this work are comparable to those of commercial solvents. The nonrandom two-liquid model (NRTL) was successfully used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. Moreover, the antimicrobial activities of the ILs were evaluated by examining their 50% effective concentrations (EC₅₀) using the standard microbroth dilution test against four human bacterial pathogens. 1-Butyl 3-methylpyridinium dicyanamide [C₄mpy][DCA] was found as the most suitable IL among those investigated because of its low toxicity with EC₅₀ values between 41.35 and 58.08 mmol·L^–1 and its performance in liquid–liquid extraction for the ethylbenzene/n-octane mixture.

中文翻译：

---

双氰胺基离子液体的合成，表征和抗微生物研究及其在液-液萃取中的应用

合成，表征并表征了四种不同的基于双氰胺的离子液体（ILs）[C _n mpy] [DCA]（n = 4、6、8和10），并将其与n中的乙苯分离-辛烷。在大气压力下，在313.15 K下测量了相应的三元系统的平衡数据。对于进料中较低的芳烃浓度，观察到较高的选择性（最大值为20％）；这是选择合适的IL的关键因素。在这项工作中获得的分配比和选择性与市售溶剂相当。非随机两液模型（NRTL）已成功用于关联实验联系线并计算三元系统的相组成。此外，ILs的抗微生物活性是通过使用标准微泡稀释测试针对四种人类细菌病原体检查其50％有效浓度（EC ₅₀）来评估的。1-丁基3-甲基吡啶二氰胺[C ₄mpy] [DCA]被认为是最合适的IL，因为它的低毒性（EC ₅₀值在41.35至58.08mmol·L ^–1之间）以及在液-液萃取乙苯/正辛烷混合物中的性能。