Proton transfer between organic acids and bases at the acoustic bubble-aqueous solution interface

Abstract

The multibubble sonoluminescence (MBSL) emission intensity from aqueous solutions containing simple aliphatic organic acids (RCOOH) and bases (RNH 2) and mixtures of the two types of solutes has been examined as a function of pH. In solutions containing either an organic acid or base, under pH conditions where the solutes are predominately in their ionized form (i.e., RCOO- and RNH3+), the MBSL intensity is identical with that obtained in pure water. Alternatively, under pH conditions where the solutes are in their un-ionized form the MBSL intensity is suppressed. However, in solute mixtures of RCOO- and RNH3+ in the pH range of 7 to 9, the MBSL intensity was significantly suppressed relativ..