离子液体萃取分离结构相似化合物研究进展

结构相似化合物的高效分离是化学工业最具挑战的难题之一，传统分离方法存在选择性低、溶剂消耗大、能耗高等不足。基于离子液体较强的氢键、π-π作用能力及良好的成相能力，离子液体液-液萃取过程能够有效识别结构相似化合物物化性质的微小差异，提高分离选择性，同时还可获得较高的分配系数和萃取容量，并抑制乳化的发生。本文在简要介绍离子液体偶极性/可极化性、氢键酸碱性和液-液相平衡规律的基础上，系统综述了离子液体液-液萃取技术在不同类型结构相似化合物选择性分离方面的研究进展，探讨了研究中存在的问题和未来发展方向。与亲水性化合物的分离相比，离子液体液-液萃取技术在疏水性结构相似化合物及表面活性结构相似化合物的分离中更具优势。离子液体-分子溶剂复合萃取剂的研究则为解决离子液体黏度大、成本高等问题提供了可行途径。

Research progress on the extractive separation of structurally-related compounds by ionic liquids

The separation of structurally-related compounds is one of the most challenging problems in chemical industry, and conventional separation methods usually suffer from low selectivity, large solvent consumption, and high energy cost. Based on the strong hydrogen-bonding/π-π interaction ability and good phase-forming ability of ionic liquids, ionic liquid-based liquid-liquid extraction can efficiently recognize the small differences in the physicochemical properties of structurally-related compounds, improve the separation selectivity, obtain high distribution coefficients and large extraction capacity, and resist emulsification. This review described the dipolarity/polarizability, hydrogen-bond acidity/basicity and liquid-liquid phase equilibrium of ionic liquids, introduced the research progress in the selective separation of various structurally-related compounds by ionic liquid-based liquid-liquid extraction, and discussed the existing problems and future work in research. Compared with hydrophilic compounds, ionic liquid-based liquid-liquid extraction is more suitable for separating hydrophobic or surface-active structurally-related compounds. The studies on ionic liquid-molecular solvent composite extractant offer a feasible way to address the problems of ionic liquids such as large viscosity and high cost.