title: Immobilized chiral tropine ionic liquid on silica gel as adsorbent for separation of metal ions and racemic amino acids.
abstract: Tropine-type chiral ionic liquid with proline anion was immobilized on silica gel by chemical modification method for the first time, which was proved by elemental, infrared spectrum and thermogravimetric analysis. Secondly, the performance of this kind of ionic liquid-modified silica gel was investigated in the adsorption of some metal ions, which included Cu(2+), Fe(3+), Mn(2+) and Ni(2+). Then the effects of time, initial concentration and temperature on adsorption for Cu(2+) ions were studied in detail, which was followed by the further research of adsorption kinetics and thermodynamics. The adsorption could be better described by pseudo-second-order kinetics model and that the process was spontaneous, exothermic and entropy decreasing. In the mode of 'reuse after adsorption', the ionic liquid-modified silica gel with saturated adsorption of Cu(2+) was finally used in resolution of racemic amino acids for the first time. The static experiment showed that adsorption rate of two enantiomers was obviously different. Inspired by this, the complex was packed in chromatographic column for the separation of racemic amino acids and d-enantiomers were firstly eluted by water or ethanol. Steric hindrance was found as one of key influencing factors for its effect on the stability of the complex.
authors.affiliation: School of Chemical Engineering, Sichuan University, Chengdu 610065, China.
authors.forename: Guofei
authors.initials: G
authors.lastname: Qian
authors.affiliation: School of Chemical Engineering, Sichuan University, Chengdu 610065, China.
authors.forename: Hang
authors.initials: H
authors.lastname: Song
authors.affiliation: School of Chemical Engineering, Sichuan University, Chengdu 610065, China. Electronic address: Cusack@scu.edu.cn.
authors.forename: Shun
authors.initials: S
authors.lastname: Yao
mesh_terms: D000327:Adsorption; D000596:Amino Acids / Q000737:chemistry*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D052578:Ionic Liquids / Q000737:chemistry*; D007477:Ions / Q000737:chemistry*; D007700:Kinetics; D008670:Metals / Q000737:chemistry*; D058428:Silica Gel / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D014326:Tropanes / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000596:Amino Acids; D052578:Ionic Liquids; D007477:Ions; D008670:Metals; D014326:Tropanes; D014867:Water; D058428:Silica Gel; C005864:tropine
keywords: Adsorption; Amino acids; Immobilized chiral ionic liquids; Metal ions; Resolution; Tropine