Experimental Studies on Complex Oscillations in a Mn2+-Catalyzed Acidic Bromate–Glucose Reaction

Abstract

Abstract Under batch-reactor conditions, the BrO3−–glucose–Mn2+–H2SO4 system exhibits several types of oscillations, depending on the concentrations of the reactants. In certain cases, dual-frequency oscillations are observed owing to a sequential appearance of different types of oscillations. Since glucose is not subject to bromination, these oscillations may be considered as being typically radical-controlled, and can be distinguished from bromide-controlled oscillations by adding acetone, which also results in dual-frequency oscillations due to the presence of both radical-controlled and bromide-controlled oscillations. Further experimental results demonstrate that the different types of oscillations observed in the absence of acetone can be possibly attributed to the Mn2+-catalyzed reactions between bromate and glucose, or various intermediates produced from the oxidative degradation of glucose. The effects of the [BrO3−]/[glucose] ratio and [H2SO4] on the oscillatory behaviors are discussed on the basis of their effects on either the depth of oxidative degradation of glucose or the oxidizing ability of bromate.