Selectivity of 2-(1-Pyrenyl)ethylsilylated Silica Gel in the Isomer Separation of Cyclohexane Derivatives

Abstract
Separations of trans and cis isomers of disubstituted cyclohexanes are studied by using 2-(1-pyrenyl)ethylsilylated silica gel and octadecylsilylated silica gel in aqueous methanol mobile phases. The C18 phase gives better separations for 1,4-disubstituted compounds based on the differences in the hydrophobicities of the solutes, while the stationary phase containing pyrenyl groups gives better separations for 1,2-disubstituted cyclohexanes based on the recognition of the structural planarity and the orientation of the polar substituents. The complementary use of the two stationary phases seems to be useful in isomer separations by reversed-phase liquid chromatography.