Use of smectic liguid crystals for the gas-liquid chromatographic separation of positional isomers

Abstract The smectogenic compounds terephthal-bis- n -butylaniline and 4-(4- n -hexyloxybenzylideneamino)azobenzene were prepared and used as stationary phases for the gas-liquid chromatographic separation of positional isomers of dibromobenzenes, chloroacetophenones, chloronaphthalenes and methybiphenyls. These solute isomers cannot be sharply separated in the smectic B state whereas a complete separation was achieved in both the smectic A and C phases. It is suggested that the unique selectivity of the smectic A and C states relative to the smectic B state can be explained by the difference in the molecular packing in the layer between the smectic B and the smectic A or C state.