Adsorption Isotherms of Enantiomer on Hippuric Acid Crystals Obtained under Viedma Ripening Conditions Using a Temperature Gradient

The work is devoted to the study of the capacity for chiral recognition during the adsorption process of hippuric acid crystals obtained by the temperature gradient method under Viedma ripening conditions. This method is distinguished by the fact that the primary violation of chiral equilibrium between the nuclei formed during crystallization is not caused by the mechanical action of the stirrer but by crystallization at low temperatures. Limonenes and α-pinenes were used as test enantiomers. Adsorption isotherms were obtained using inverse gas chromatography, and their analysis made it possible to establish the chiral recognition ability of the surface. It was shown that both the enantioselectivity and adsorption capability of the synthesized hippuric acid crystals were significantly higher than those of crystals obtained under classical Viedma ripening conditions. High surface heterogeneity is probably the reason for this phenomenon.