Comment on “Mechanistic Investigations on the Belousov−Zhabotinsky Reaction with Oxalic Acid Substrate. 2. Measuring and Modeling the Oxalic Acid−Bromine Chain Reaction and Simulating the Complete Oscillatory System”

Abstract

The aim of the present paper is to study radical reactions important in the mechanism of the Belousov−Zhabotinsky (BZ) reaction with its simplest organic substrate, oxalic acid, and to model the oscillatory system applying the newly determined rate constants. We considered five radical species in this BZ system: carboxyl radical, bromine atom, dibromine radical ion, and bromine monoxide and dioxide radicals. To study separately reactions of only three radicals, •CO2H, •Br, and •Br2-, semibatch experiments were performed. The semibatch reactor contained oxalic acid, elemental bromine, and bromide ions in a solution of 1 M H2SO4 at 20 °C, and a continuous inflow of Ce4+ generated carboxyl radicals. The carboxyl radicals initiate a chain reaction: first they react with elemental bromine and produce bromine atoms (CR1); then the bromine atoms react with oxalic acid, producing carboxyl radicals again (CR2). Consumption of elemental bromine in the chain reaction was followed with a bright Pt electrode. By mea...