[Study on enantioselectivity of celluloses derived by phenylcarbamate at 2,3- or 2,3,6-positions]

Cellulose-2, 3, 6-trisphenylcarbamate, cellulose-2, 3-bisphenylcarbamate, cellulose2,3,6-tris(3,5-dimethylphenylcarbamate) and cellulose-2,3-bis(3,5-dimethylphenylcarbamate) were synthesized and respectively coated on silica gel as chiral stationary phases for high performance liquid chromatography (HPLC). Nine pairs of enantiomers, which are ( +/- )-phenyl-1, 2-ethanediol, ( +/- )-2-phenyl-1 -propanol, DL-alpha-methylbenzylamine, DL-mandelic acid, ( +/- ) -1-(1-naphthyl) ethanol, ( +/- ) -propranolol, ( +/- ) -3-benzyloxy-1, 2-propanediol, DL-tyrosine and ( +/- ) -di-O, O-p-toluyl-D-tartaric acid, were separated using hexane-isopropanol as mobile phase on the columns packed with the chiral stationary phases. For comparative reasons, the ratio of hexane/isopropanol in the eluent was kept at 9: 1 (v/v) in all experiments, and the chromatographic separations were performed at 30 degrees C with a flow rate of 0. 5 mL/min. All the test solutes were detected at 254 nm. The results showed that enantioseparation of cellulose-2,37bisphenylcarbamate was better than cellulose-2,3,6-trisphenylcarbamate for the test enantiomers, and cellulose-2,3-bis (3 ,5-dimethylphenylcarbamate) had low retention factors and short analysis times for most enantiomers and good separation factors for some racemates compared to cellulose-2,3,6-tris(3,5-dimethylphenylcarbamate).