Sorption and selective chromatographic properties of isomer-selective composite sorbent based on a eutectic mixture of nematic liquid crystals and perbenzoylated beta-cyclodextrin

摘要

Mesomorphic, sorption, and selective properties of a three-component sorbent based on a mixture of nematic (N) liquid crystals of 4-methoxy-4'-ethoxyazoxybenzene (MEAB) and 4,4'-diethoxyazoxybenzene (azoxyphenetol, AOP) of an eutectic composition and heptakis-(2,3,6-tri-O-benzoyl)-beta-cyclodextrin (Bz-beta-CD) are studied. For 30 organic compounds of different classes with linear and cyclic molecular structures, including optical isomers of limonene, pinene, camphene, and butanediol-2,3, thermodynamic functions are determined for their gas-phase sorption using a three-component MEAB-AOP-Bz-beta- CD sorbent (62: 28: 10 wt %). It is found that the investigated sorbent possesses high structural selectivity (alpha(p/m) = 1.128-1.059, 100-130A degrees C, N) and moderate enantioselectivity (1.07-1.02) within a broad temperature range (95-170A degrees C) including both mesomorphic and isotropic phases of the sorbent. It is shown that the enantioselectivity of the sorbent is apparent under conditions of both increasing retention when a chiral Bz-beta-CD additive is introduced into the MEAB-AOP system (limonenes, pinenes, camphenes) and decreasing retention (butanediols-2,3).