Sorption, thermodynamic, and selective properties of camphor-substituted copper(II) tetrapyrazinoporphyrazine as a stationary phase for gas chromatography

Abstract

The surface of a Chromaton N-AW diatomite adsorbent was modified with copper(II) tetra(1',7',7'-trimethylbicyclo[2.2.1]heptano-[2',3'-b]-pyrazino)porphyrazine. Adsorption of vapors of 20 organic compounds on the surface of the modified adsorbent was studied by inverse gas chromatography. Electron-donor isomers of methylpyridine and dimethylpyridine, isomers of weakly polar xylenes and cresols, aliphatic alcohols, and other hydrocarbons capable of showing various types of intermolecular interactions with the complex of camphor-substituted tetrapyrazinoporphyrazine with copper(II) were chosen as adsorbates. Specific retention volumes of adsorbates, heat and adsorption entropy, and Gibbs adsorption energy were calculated. The effects of temperature and chemical nature of the adsorbates on the thermodynamic characteristics of sorption are discussed. Factors of separation of closely-boiling hydrocarbons are calculated. It has been found experimentally that the macroheterocycle-based adsorbent shows high selectivity to closely-boiling compounds of various types, unattainable for the unmodified adsorbent.