Selective gas-liquid chromatographic separation of aromatic compounds with tetrahalophthalate esters

Abstract

Tetrahalophthalate esters were found to be selective liquid substrates for separating aromatic hydrocarbons by gas chromatography. The tetrachlorophthalates are unusually specific in separating meta- and para-isomers, including the xylenes; this makes possible the gas chromatographic analysis of mixtures of these isomers. “Charge transfer” interaction between the volatile aromatic compounds (donors) and the tetrahalophthalates (acceptors) is apparently responsible for selectivity. Variations in the elution order of alkylaromatics may be interpreted qualitatively in terms of structure or molecular composition. Gas chromatography, in turn, provides a measure of the complexing or degree of interaction of aromatic compounds with the tetrahalophthalate esters as well as information on salient stereochemical features that effect interaction.