The selective separation of strongly hydrophilic structurally related compounds in aqueous solutions is a long-standing challenge due to a trade-off between separation selectivity and capacity. This work shows a new method to separate strongly hydrophilic structurally related compounds through hydrophobic ionic solution-based liquid-liquid extraction, with L-ascorbic acid 2-glucoside (AA-2G) and L-ascorbic acid as model compounds. Extraordinary distribution coefficient, superb molecular selectivity, large extraction capacity and good recyclability without using strong acids and salts were all achieved, with a small consumption of phosphonium bromide ionic liquid and aprotic molecular diluent. The essence of this method is the successful combination of both strong hydrogen-bond basicity and good hydrophobicity along with significant preferential solvation phenomena of the constructed ionic solutions. Even if at a high feed concentration of 100 mg/mL, the purity of AA-2G could be greatly elevated from 50% to 96.2% with an ultrahigh yield of almost 100% after five-stage countercurrent extraction. © 2017 American Institute of Chemical Engineers AIChE J, 2017

中文翻译：

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通过疏水离子溶液高效分离强亲水结构相关化合物

由于在分离选择性和容量之间的权衡，在水溶液中选择性分离强亲水的结构相关化合物是一个长期的挑战。这项工作显示了一种新方法，该方法可通过基于疏水性离子溶液的液-液萃取，以L-抗坏血酸2-葡糖苷（AA-2G）和L-抗坏血酸为模型化合物，分离与亲水性强的结构相关的化合物。无需使用强酸和盐就可实现非凡的分配系数，极好的分子选择性，大的提取能力和良好的可回收性，而溴化phospho离子液体和非质子分子稀释剂的消耗量却很小。该方法的本质是强结合氢键的碱性和良好的疏水性以及所构建离子溶液的显着优先溶剂化现象的成功结合。即使在100 mg / mL的高进料浓度下，五阶段逆流萃取后，AA-2G的纯度也可以从50％大大提高到96.2％，超高收率接近100％。©2017美国化学工程师学会AIChE的Ĵ，2017年