THERMODYNAMIC AND SELECTIVE PROPERTIES OF DIATOMITE ADSORBENT MODIFIED BY THE MIXTURE OF 4-(2-HYDROXYETHOXY)-4'-FORMYLAZOBENZENE AND IRON ?-OXODIMER OF 2,8,12,18-TETRAMETHYL-3,7,13,17-TETRA-N-AMYLPORPHIN UNDER CONDITIONS OF INVERTED GAS CHROMATOGRAPHY

摘要

The sorption of vapors from a gas phase of a number of compounds on the surface of wide-pore adsorbent Chromaton N-AW modified with the mixture of mesogenic 4-(2-hydroxyethoxy)-4'-formylazobenzene and iron mu-oxodimer of 2,8,12,18-tetramethyl-3,7,13,17-tetra-n-amylporphin has been studied. Electron-donating isomers of methylpyridines and dimethylpyridines, isomers of weakly polar xylenes, and a number of enantiomers were selected as sorbates. The specific retained volumes of these sorbates were calculated and the enthalpy and entropy contributions to sorption process were estimated. The analytical properties of the resulting stationary phase have been studied. The effect of temperature and chemical nature of the sorbates on the sorption thermodynamic characteristics is discussed. The separation factors of both structural and optical isomers as well as low-boiling hydrocarbons of various structures have been calculated. The influence of both components of the mixture on the sorption process is considered. One should note the formation of supramolecular ensembles with specific interactions and the possible complex formation with iron mu-oxodimer of 2,8,12,18-tetramethyl-3,7,13,17-tetra-n- amylporphin. It has been experimentally established that the sorbent based on the studied mixture exhibits high selectivity with respect to low-boiling compounds of various nature, which is unattainable for an unmodified adsorbent. It can be concluded that the application of the studied modifier in gas chromatography makes it possible to develop new stationary phases based on similar mixtures. The use of macrocycles of various structures and natures is promising from the point of view of both structural and chiral gas chromatography.