Lu Ruichen, He Quan, Feng Cai, Peng Yangfeng
School of Chemical Engineering, East China University of Science and Technology, Shanghai, China.
Department of Engineering, Faculty of Agriculture, Dalhousie University, Truro, Nova Scotia, Canada.
Chirality. 2017 Nov;29(11):708-715. doi: 10.1002/chir.22738. Epub 2017 Aug 23.
A liquid-liquid extraction resolution of 4-chloro-mandelic acid (4-ClMA) was studied by using 2-chloro-N-carbobenzyloxy-L-amino acid (2-Cl-Z-AA) as a chiral extractant. Important factors affecting the extraction efficiency were investigated, including the type of chiral extractant, pH value of aqueous phase, initial concentration of chiral extractant in organic phase, initial concentration of 4-ClMA in aqueous phase, and resolution temperature. It was observed that the concentration of (R)-4-ClMA was much higher than that of (S)-4-ClMA in organic phase due to a higher stability of the complex formed between (R)-4-ClMA and 2-Cl-Z-AA. A separation factor (α) of 3.05 was obtained at 0.02 mol/L 2-Cl-Z-Valine dissolved in dichloromethane, pH of 2.0, concentration of 4-ClMA of 0.11 mmol/Land T of 296.7K.
以2-氯-N-苄氧羰基-L-氨基酸（2-Cl-Z-AA）为手性萃取剂，研究了4-氯扁桃酸（4-ClMA）的液-液萃取拆分。考察了影响萃取效率的重要因素，包括手性萃取剂的种类、水相pH值、有机相中手性萃取剂的初始浓度、水相中4-ClMA的初始浓度以及拆分温度。结果表明，由于（R）-4-ClMA与2-Cl-Z-AA形成的配合物稳定性较高，有机相中（R）-4-ClMA的浓度远高于（S）-4-ClMA。在溶解于二氯甲烷的0.02 mol/L 2-Cl-Z-缬氨酸、pH为2.0、4-ClMA浓度为0.11 mmol/L以及温度为296.7K的条件下，分离因子（α）为3.05。
