Generation of pH-oscillations in closed chemical systems: Method and applications

Abstract

All pH-oscillators reported to date function only under open (flow reactor) conditions. We describe an approach to generating pH-oscillations in a closed system by starting from an open system pH-oscillator, finding semibatch conditions under which it oscillates with an inflow of a single reactant to an otherwise closed reactor containing the remaining components, and replacing this inflow with a layer of silica gel impregnated with the key reactant. We present data showing the successful application of this technique to the BrO 3-Mn2+-SO32-, IO3-Fe(CN) 64-SO32-, and BrO 3-Fe(CN)64-SO32- systems. In all three cases, sulfite ion is the species that is replenished via dissolution from the gel layer. © 2011 American Chemical Society.