The use of capillary microreactors for enantioselective liquid–liquid extraction (ELLE) was successfully demonstrated using a model system consisting of a buffered aqueous amino acid derivative (3,5-dinitrobenzoyl-(R,S)-leucine) solution (phosphate buffer, pH 6.58) and a chiral cinchona alkaloid (CA) host in an organic solvent. It was shown that 1-octanol is a suitable replacement for the commonly used chlorinated solvents like 1,2-dichloroethane. Experiments were conducted in a capillary microreactor set-up (0.8 mm internal diameter) operated in the slug flow regime at 294 K (residence times between 12 and 900 s, 1:1 flow ratio of the aqueous to organic phases, 1 mM of host and 1 mM of amino acid derivative). The enantiomeric excess (ee) was shown to be a function of the solvent and residence time and varied between 37% and 49% in 1,2-DCE and 28 and 46% in 1-octanol in the organic phase. The ee values in the organic phase at shorter residence times were higher than the independently determined equilibrium ee values (41% in 1,2-DCE and 31% in 1-octanol at a host concentration of 1 mM). This is an unprecedented observation with large implications for ELLE, as it implies that operation in the kinetic regime may lead to improved enantioseparation performance.

中文翻译：

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使用1-辛醇作为可持续溶剂的毛细管微反应器中连续对映选择性液-液萃取的概念验证

使用由缓冲的氨基酸衍生物（3,5-二硝基苯甲酰基-（R，S）-亮氨酸）水溶液（磷酸盐缓冲液，pH）组成的模型系统成功证明了使用毛细管微反应器进行对映选择性液-液萃取（ELLE）6.58）和在有机溶剂中的手性金鸡纳生物碱（CA）主体。结果表明，1-辛醇是常用的氯化溶剂（如1,2-二氯乙烷）的合适替代品。实验是在294K（停留时间为12到900 s，停留时间为1 ：水相和有机相的流量比为1，主机为1 mM，氨基酸衍生物为1 mM。对映体过量（ee）被证明是溶剂和停留时间的函数，在有机相中，在1,2-DCE中为37％至49％，在1-辛醇中为28％至46％。在较短停留时间下，有机相中的ee值高于独立确定的平衡ee值（在1 mM的宿主浓度下，1,2-DCE中的ee值为41％，1-辛醇中的ee值为31％）。这是史无前例的观察结果，对ELLE具有重大意义，因为这表明在动力学条件下操作可能会导致对映体分离性能的提高。