Adsorption phenomena on a mercury electrode in aqueous cryptand[2.2.2] solutions by the background of tetraalkylammonium salts

Abstract

The electrochemical behavior of cryptand[2.2.2] (Cry) is studied on a mercury electrode in aqueous solutions of tetraalkylammonium tetrafluoroborates (Me4N+, Et4N+, and Bu4N+). Cryptand [2.2.2] is shown to exhibit high surface activity in Me4 NBF4 nd Et4NBF4 solutions. Based on the model of two parallel capacitors supplemented by the Frumkin adsorption isotherm, the adsorption parameters of Cry by the background of Me4BNF4 were calculated using the regression analysis methods. The calculated dependences of the differential capacitance on the potential adequately agree with experimental curves. The adsorption characteristics of Cry in the studied solutions are compared with those in MgSO4 solutions. By the background of Bu4NBF4, Cry molecules and Bu4N+ cations exhibit very close surface activity and form a mixed adsorption layer.