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Complex‐precipitation using functionalized chiral ionic liquids with L ‐proline anion and chromatographic analysis for enantioseparation of racemic amino acids
Author(s) -
Zang Huimin,
Yao Shun,
Luo Yingjie,
Tang Dan,
Song Hang
Publication year - 2018
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.23011
Subject(s) - chemistry , enantiomer , ionic liquid , solubility , enantioselective synthesis , chiral resolution , phenylalanine , chiral derivatizing agent , organic chemistry , solvent , thermogravimetric analysis , amino acid , catalysis , chiral column chromatography , biochemistry
As one kind of functionalized green medium, chiral ionic liquids (CILs) have been widely applied in fields of asymmetric catalysis, enantioseparation, and so on. In this study, four kinds of amino acid–based CILs were synthesized by using trimethylamine, N‐methylpyrrolidine, N‐methylimidazole, and tropine as cationic nucleus, respectively. Then their specific optical rotation and solubility in common solvents were determined for further resolution application. The effect of different cations in these CILs was explored on the separation of racemic phenylalanine in complex‐precipitation way. Moreover, various factors were systematically investigated for their effects on resolution efficiency, including the type of additive copper salts, the molar ratio of Cu (II) to CIL, pH value, the amount of racemic phenylalanine, and temperature. Under the appropriate conditions, L‐phenylalanine mainly existed in solid phase and could be separated from its enantiomers in liquid phase. Furthermore, the mechanism of resolution was studied by thermogravimetric analysis, infrared spectrum, and molecular simulation. The resolution system has characteristics of no organic solvent, fast separation speed, simple resolution process, and easy scale‐up.