Ultraviolet-Visible Kinetic Study of the Uncatalyzed Bromate Oscillator with Phenol by Multivariate Curve Resolution

Abstract

A kinetic study of the uncatalyzed bromate oscillator (UBO) using phenol was carried out by chemometric analysis of the UV/Vis data. The reaction was studied with different starting concentrations of the reagents (sulfuric acid and potassium bromate) and by changing phenol for 2-bromophenol and 4-bromophenol. The number of chemical absorbing species involved in the UV/Vis data was established by singular value decomposition and by the residual fit parameter. Multivariate curve resolution with alternating least squares generated valuable information about the different chemical species along the process (spectral and concentration profiles). These results show the presence of four principal components: two intermediates and two products. The products can be assigned as o-quinone and 4,4 -diphenoquinone, and the principal components associated with the intermediates represent the linear combination of all the intermediates in the reaction mixture. These data were used to generate a model of the UBO-phenol oscillator that reproduces qualitatively the experimental results. C

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

“…Existing investigations have illustrated that bromination of the organic substrates and their subsequent oxidation play a crucial role in the development of various oscillatory phenomena in bromate oscillators. The majority of uncatalyzed bromate oscillators use ortho- and para-disubstituted aromatic complexes as their organic substrates, − in which the presence of functional groups on the benzene ring may hinder the bromination processes. In complement to these earlier studies that have been largely focused on mono- or disubstituted aromatic substrates, this 1,3,5-trisubstituted aromatic is expected to offer new opportunities of seeing different dynamics in the reaction with acidic bromate.…”

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.…”