Long-Lasting Complex Reaction Behavior in a Closed Ferroin–Bromate–Hydroxybenzenesulfonate System

Abstract

The bromate–phenolsulfonate reaction was found to exhibit spontaneous oscillations in a batch reactor, where the addition of small amounts of ferroin would result in nonoscillatory behavior. As the ferroin concentration was increased, the system produced very rich nonlinear behavior, including three isolated oscillatory regimes that were separated by as long as 48 h nonoscillatory period. The long-lasting nonlinear behavior may be attributed to the slow desulfonation of phenolsulfonate in an acidic solution, forming phenol-like intermediates. However, unlike the bromate–phenol oscillator, oxygen was found to greatly influence the reaction, and various complex oscillations could be observed by tuning the oxygen concentration. Mechanistic studies performed through employing 1H NMR spectroscopy and mass spectrometry to measure intermediate species at different stages of the reaction were able to identify 1,4-benzoquinone, 2-bromo-1,4-benzoquinone, 2,6-dibromo-1,4-benzoquinone, and 2,4,6-tribromophenol as major components during the reaction.

Manipulating the Polymerization of 3,5-Diaminobenzoic Acid with a Bromate Oscillator

“…For uncatalyzed bromate-based chemical oscillators, the addition of a metal catalyst that reacts with BrO 2 • radicals can potentially result in more complex behaviors through the establishment of coupled autocatalytic cycles. , Such a modification may also offer an additional control parameter to the polymerization of 3,5-dABA. When ferroin was added into the bromate–3,5-dABA system, spontaneous oscillations began at around a similar time as in the uncatalyzed system, preceded by the initial excursion.…”

Unusual Chemistry in an Uncatalyzed Bromate–Aniline Oscillator: Ring-Contraction Oxidation of Aniline with Pulsative CO2 Production

“…The UBO substrates are oxidizable organic compounds, such as derivatives of phenol or AN or their precursors, e.g., cyclohexane-1,4-dione. , The BZ system in both standard and modified versions has served for decades as an experimental and theoretical model in the study of nonlinear phenomena such as chemical oscillations, chaos, and traveling waves . In particular, the UBOs and catalyzed BZ reactions with aromatic substrates remain the focus of current research in the field of nonlinear dynamics − as their mechanisms are still generally not known. Such research could open new insights into the oxidation pathways of organic substrates, help to clarify the role of free radicals in such reactions, and explore interactions between the organic and inorganic counterparts of oscillators from both the chemical and nonlinear dynamics points of view.…”