Chromatographic resolution

Cellulose triphenylcarbamate and eighteen mono- or disubstituted derivatives were adsorbed on silica gel and their chiral recognition abilities as stationary phases for high-performance liquid chromatography were investigated. The inductive effect of the substituents greatly influenced the optical resolution ability when they were at the 3- or 4-position. 2-Substituted derivatives showed a low degree of resolution. Among nine 4-substituted phenylcarbamates, the 4-methyl, 4-ethyl, 4-chloro, or 4- trifluoromethyl derivative showed the most efficient chiral recognition for racemic compounds. Dimethylphenyl- and dichlorophenylcarbamates substituted at the 3,4- or 3,5-positions showed better chiral recognition for most enantiomers than the monosubstituted derivatives. Most stationary phases possessed high durability and many racemic compounds were resolved on these phenylcarbamates.