Facilitated proton transfer reactions via water autoprotolysis across oil|water interfaces. Spectroelectrochemical analysis

Abstract

In this paper, we present an integrated experimental-theoretical approach to evaluate the spectroelectrochemical response of the facilitated proton transfer processes via water autoprotolysis at the liquid|liquid (L|L) interface. The aim of these studies is to confirm theoretically and experimentally the pH gradients generated at the L|L interface using coupled electrochemical and spectroscopic techniques. The spectroelectrochemical measurements are performed using a parallel beam configuration, where the light beam passes at grazing incidence over the L|L interface. pH gradients generated by proton transfer assisted by Quinidine via water autoprotolysis are evaluated by the direct measurement of the optical absorption of Thymol Blue, acting as a pH probe. Results obtained are correlated with a numerical model considering all equilibria involved at both phases.