Chromatographic chiral resolution : XIV. Cellulose tribenzoate derivatives as chiral stationary phases for high-performance liquid chromatography

Cellulose tribenzoate and its ten derivatives substituted on phenyl groups were adsorbed on silica gel and their chiral recognition abilities as stationary phases for high-performance liquid chromatography were investigated, using a hexane-2-propanol mixture as eluent. Alkyl, halogen, trifluoromethyl, and methoxy groups were selected as substituents. Inductive effect of the substituents seemed to affect greatly the optical resolution ability. 2-Substituted derivatives showed a low degree of resolution. Among 4-substituted tribenzoates, the derivatives having electron-donating substituents showed better chiral recognition ability than those having electron-with-drawing substituents. However, the most electron-donating methoxy group was not a suitable substituent because of the high polarity of the substituent itself. 3-Methyl-, 4-methyl-, and 3,4-dimethylbenzoates showed better chiral recognition for several enantiomers than the other benzoates. Most stationary phases possessed high durability and many racemic compounds were resolved on these methyl-substituted benzoates.