409 - Adsorption of p-aminobenzenesulfonamide and its N1-phenyl and N1-pyridyl derivatives at the electrode-solution interface

The adsorption of some sulfa-drugs, p-NH2ØSO2NH2,p-NH2ØSO2NHO,p-NH2ØSO2NHPy, was studied by a differential capacitance method at pH = 12 at the dropping mercury electrode. The area occupied by each molecules of the N1-derivative compounds adsorbed at the mercury{curly logical or}electrolyte solution interface is {reversed tilde equals} 80 Å2 which corresponds closely to the area expected for a molecule adsorbed flat on the electrode surface with its p-NH2ØO moiety. The ΔGoods (θ → 0) values obtained at different potentials suggest that the adsorption process is less favoured when the potential decreases; however, the N1-pyridine derivative is always less adsorbed than the other sulfanilamides. © 1981.