A new way to prepare cellulose-type chiral stationary phases （CSPs） has been established in the present work.Cellulose microspheres with a volume-average diameter of 11.5 m were prepared by an emulsion-solidification method.Three new CSPs were obtained by crosslinking the cellulose microspheres with terephthaloyl chloride （TPC）,and then modifying the crosslinked microspheres with 4-methylbenzoyl chloride,3,5-dimethylbenzoyl chloride and 3,5-dichlorobenzoyl chloride,respectively.The microspheres and the CSPs were characterized by FT-IR,element analysis and scanning electronic microscopy （SEM）.The chiral recognition ability of the CSPs was evaluated with high-performance liquid chromatography （HPLC）.The chromatographic results demonstrate that the CSP prepared from 3,5-dichlorobenzoyl chloride possesses better chiral recognition ability compared with two other CSPs.
JIN FenfenZHANG JuanCHEN WeiFAN QingchunBAI Zhengwu
A new method to prepare polysaccharide-coating type chiral stationary phases （CSPs） was developed in this work. As a typical example, naked silica gel was coated by cellulose, which was then derivatized with 3,5-dimethylbenzoyl chloride to afford cellulose tris（3,5-dimethylbenzoate）-silica gel （CTDBS） complex. The silanols on CTDBS were end-capped with 3- aminopropyltriethoxysilane to obtain CSP 1. The amino groups on CSP 1 were further end-capped with 3,5-dimethylbenzoyl chloride to give CSP 2. The silanols on CTDBS were end-capped with methyltrimethoxysilane to yield CSP 3. CSPs 1-3 were characterized by FTIR, solid-state 13C-NMR and elemental analysis. The enantioseparation abilities of CSPs 1-3 were evaluated with structurally various chiral analytes. The enantioseparation results demonstrated that the end-capping moieties on CSPs 1 and 2 significantly affected enantioseparation. In addition, the effect of the structures of chiral analytes and end- capping moieties on the retention factors and the resolutions was discussed.
Two chiral selectors were synthesized from tartaric acid. The selectors were simultaneously immobilized on 3-aminopropyl silica gel to obtain a new biselector chiral stationary phase （CSP） in order to determine the influence of selector structure of biselector CSPs on the chiral recognition capability. For comparison, the single-selector CSP was also prepared. The biselector CSP shows an improved overall chiral recognition capability in comparison with the single-selector CSP. During the enantioseparation, temporary diastereoisomers are likely formed by complexation between a chiral analyte and the two selectors on the biselector CSP. The functional groups in the two selectors are complementary in electronic effect and/or in steric hindrance for the chiral recognition.
