The adsorption of ethylene glycols and their cyclic compounds at the mercury-aqueous solution interface

Abstract

Differential double layer capacities were measured at the interface between mercury and aqueous solutions containing ethylene glycols and their cyclic compounds, and free energies of adsorption were calculated in order to study the structure of adsorbed layers of these compounds. Free energies for cyclic compounds were higher than those of others, more than half of the free energies of cyclic compounds were in parallel and others in inclined ring. The calculation of adsorbed amounts showed that cyclic compounds were in parallel, and others in inclined, orientation on the mercury surface. It was concluded that the adsorption of cyclic compounds was governed by the interaction between intra-molecular π-electrons and electrons of mercury surface. Free energies of adsorption per -CH2 and -OH were calculated to be -400 to-600 cal/mole, respectively.