Sorption and Selective Properties of the "Supramolecular Liquid Crystal – Acetyltosilized β-Cyclodextrin" Binary Sorbent in Gas Chromatography Conditions

Abstract
The mesomorphic and sorption properties of a binary system containing a supramolecular smectic-nematic liquid crystal 4-(3-hydroxypropyloxy)-4'-formylazobenzene (HPOFAB) and 10 wt.%-additive of heptakis-(2,3-di-O-acetyl-6-O-tosyl)-β-cyclodextrin (Ac-Ts-β-CD) were investigated. It was established that the introduction of chiral macrocyclic compound Ac-Ts-β-CD does not change the type of mesophase (SA, N) in HPOFAB, but leads to distortion of the texture due to pronounced «LC – macrocycle» solvation. The thermodynamic sorption characteristics from the gas phase of 25 non-mesogenic sorbates (hydrocarbons and alcohols with acyclic and cyclic structure) were studied by reversed gas-liquid chromatography. It was established that, due to solvation, the binding of molecules of sorbates to a macrocycle is due to inclusive complexation, which is more pronounced for hydrocarbons. The binary system studied has a high selectivity to para- and meta-xylenes (α_п/м = 1,18, T = 110 °С) and a moderate enantioselectivity with respect to isomers of camphene and butanediol-2,3.

Keywords: supramolecular liquid crystal, bifunctional derivative of β-cyclodextrin, binary sorbent, gas-liquid chromatography, sorption thermodynamics, structural selectivity, enantioselectivity, "host-guest" complexes