Abstract
High-Performance liquid chromatography (HPLC) of anisole and benzaldehyde on macroporous silica (Silochrom C80) with a hydroxylated surface and a surface covered with polyoxyethylene (POE) monolayer have been studied. On the basis of data obtained from liquid adsorption chromatography the adsorption isotherms of aromatic compounds from solutions were calculated. It has been found that adsorption isotherms obtained by HPLC and static adsorption methods coincide for anisole adsorbed either on hydroxylated or modified surfaces. In the case of benzaldehyde adsorption on hydroxylated silica surface the adsorption values obtained by the chromatographic method are smaller than those obtained by static adsorption method due to specific features of adsorption kinetics. Henry's constants, KΓ distribution factors, f, and adsorption solution activity coefficient, γa,i, for anisole and benzaldehyde adsorbed on hydroxylated and POE modified silica have been calculated. The values of KΓ and f obtained by both the static adsorption and HPLC methods have been compared. The enthalpies and entropies of adsorption of aromatic compounds have been compared with the polarity parameters.
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