Separation of cis/ trans isomers of 1,4-disubstituted cyclohexanes and of Z/ E-monounsaturated fatty acid methyl esters by gas—liquid chromatography on novel liquid crystal phases

Abstract

Three liquid cyrstals, rans- p-[5-(4- n-heptylcyclohexyl)-2-pyrimidinyl]benzonitrile (RO-CP-7870), p-[5-( n-butylphenyl)-2-pyrimidinyl]benzonitrile (RO-CP-7334) and 4′- n-pentyl-4-cyanoterphenyl (RO-CB-5515), have been applied as stationary phases for gas—liquid chromatography (GLC). These compounds have been utilized to solve several difficult separation problems, for example separation of the cis/ trans isomers of 1,4-disubstituted cyclohexanes, the Z/ E-isomers of monounsaturated fatty acid methyl esters and the xylene isomers. The described nematic phases can be applied as GLC phases in the range between 60°C and ca. 180°C.