Chemical oscillations in the 4-aminophenol–bromate photoreaction

Harati, Mohammad; Amiralaei, Sheida; Green, James; Wang, Jichang

doi:10.1016/j.cplett.2007.03.099

Cited by 17 publications

(9 citation statements)

References 26 publications

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Tang

Wang

2020

J. Phys. Chem. C

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Manifestation of the properties of 3,5-diaminobenzoic acid polymer film was explored by polymerizing 3,5-diaminobenzoic acid in the presence of bromate. Depending on the initial concentration of bromate, the 3,5diaminobenzoic acid solution was observed to transit from steady to oscillatory evolution in a batch reactor. The thus-fabricated film on Au electrodes exhibited different activities toward the electrochemical oxidation of pyrocatechol. The film synthesized at nonoscillatory conditions has a primary oxidation peak of pyrocatechol at about 0.20 V (vs Hg/Hg 2 SO 4 electrode), as opposed to 0.0 V with the film that was prepared under oscillatory conditions. A phase diagram in the bromate−sulfuric acid phase was constructed to demonstrate the influence of each parameter on the emergence of oscillatory behavior in the 3,5-diaminobenzoic acid system. Experiments showed that an increase in the concentrations of sulfuric acid and bromate greatly increased the frequency and reduced the induction period of these transient oscillations. Unlike the systems that used ortho-and para-disubstituted organic substrates, this 1,3,5-trisubstituted compound did not evolve through the dihydroxy intermediate (pyrocatechol/hydroquinone) as no peak for resorcinol (110 m/z) was found in any of the mass spectrometry results.

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Section: Introductionmentioning

confidence: 99%

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

Tang

Wang

2020

J. Phys. Chem. C

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“…Arguably, bromate-based reaction systems are the most extensively investigated and best understood chemical oscillators, − which involve the oxidation and bromination of an organic substrate by acidic bromate. In the past two decades, a host of aromatic compounds have been found to be capable of reacting with acidic bromate to exhibit spontaneous oscillations even in the absence of metal catalysts − and have seen increasing use due to the lack of the formation of gas molecules, which is a desired property when the system is employed to explore pattern formation in reaction–diffusion media. , The reaction of phenol with acidic bromate, for example, has been found to give rich nonlinear behavior, , and derivatives of phenol such as 4-aminophenol have also been found to result in oscillatory behavior when reacting in acidic bromate solution, although some cases require the presence of external illumination. − The continuous supply of organic substrate through desulfonation of PSA makes the proposed chemical system similar to a semiopen bromate–aromatic compounds oscillator. , Such a dynamic property provides opportunities of significantly prolonging the oscillatory window and discovering new phenomena.…”

Section: Introductionmentioning

confidence: 99%

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

2018

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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.

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“…To enrich the family of chemical oscillators exhibiting sequential oscillations, the uncatalyzed bromate oscillator using 2‐aminophenol (2‐AP) as the aromatic substrate has been systematically investigated here. The Wang research group have previously studied the reaction kinetics and wave patterns of bromate–4‐aminophenol (4‐AP) oscillators . Studying a system using an ortho substituted substrate may help gain new insights into such a system since the structures 4‐AP and 2‐AP only vary by the location of the functional groups; therefore, only the reaction rate of steps involving 4‐AP are altered, allowing for further mechanistic understanding of the occurrence of complex behavior.…”

Section: Introductionmentioning

confidence: 99%

Complex Nonlinear Behavior in the Bromate–2‐Aminophenol Reaction

Tang

Bell

Green

et al. 2016

Int J of Chemical Kinetics

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The bromate–2‐aminophenol reaction in a batch reactor was investigated in this research, in which both simple and sequential oscillations were observed. The occurrence of sequential oscillations were found to be very sensitive to changes of the initial concentrations, where decreasing the concentration of sulfuric acid or sodium bromate or increasing the 2‐aminophenol concentration caused the two oscillation windows to coalesce. Lowering the reaction temperature from 30 to 5°C also caused the two oscillation windows to merge into one. A phase diagram in the bromate–sulfuric acid concentration plane demonstrates that sequential oscillations only occur within a narrow band of conditions. Mechanistic studies of the system through employing 1H NMR and mass spectrometry suggest that a dibrominated ortho‐benzoquinone is a major product. The oxidation of 2‐aminophenol, on the other hand, can lead to the formation of pyrocatechol, which may be the substrate responsible for the second set of oscillations.

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Chemical oscillations in the 4-aminophenol–bromate photoreaction

Cited by 17 publications

References 26 publications

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

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

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

Complex Nonlinear Behavior in the Bromate–2‐Aminophenol Reaction

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