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Enantioselective resolution of 4‐chloromandelic acid by liquid–liquid extraction using 2‐chloro‐N‐carbobenzyloxy‐L‐amino acid
Author(s) -
Lu Ruichen,
He Quan,
Feng Cai,
Peng Yangfeng
Publication year - 2017
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.22738
Subject(s) - chemistry , dichloromethane , extraction (chemistry) , resolution (logic) , aqueous solution , aqueous two phase system , chromatography , mandelic acid , enantioselective synthesis , phase (matter) , liquid–liquid extraction , liquid phase , amino acid , organic chemistry , catalysis , solvent , artificial intelligence , computer science , biochemistry , physics , thermodynamics
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.