The oscillatory Briggs-Rauscher reaction. 3. A skeleton mechanism for oscillations

Noyes, Richard M.; Furrow, Stanley D.

doi:10.1021/ja00365a011

Cited by 118 publications

(109 citation statements)

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“…radicals in its oscillatory behavior. With this new mechanism, now referred to as the FCA model, Furrow et al [7] obtained not only better agreement between experimental results and simulations for malonic acid and its derivatives with respect to a previous mechanism [8], but the FCA model is able to simulate oscillations in BR systems with substrates that are iodinated in a different way than malonyl derivatives, such as crotonic and acrylic acids ( (2E)-but-2-enoic and prop-2-enoic acids, resp. ), anisole (PhOMe), and 4-nitrophenol [7].…”

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confidence: 77%

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An Experimental and Mechanistic Investigation of the Complexities Arising During Inhibition of the BriggsRauscher Reaction by Antioxidants

Cervellati

Höner

Furrow

et al. 2004

Helvetica Chimica Acta

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A method to determine the relative antioxidant capacity of radical scavengers based on the inhibition of the oscillations of the BriggsÀRauscher (BR) oscillating reaction was previously reported. A semiquantitative mechanistic interpretation of the inhibitory effects required two steps to obtain simulated inhibition times in very good agreement with the experimental ones. The first step is inhibitory, involving H-atom transfer from antioxidant to the HOO . radical; the second step is a first-order degradation of the antioxidant to unspecified products. Since the degradation may be due to oxidation and/or iodination of the antioxidant, we studied the kinetics of the subsystems IO À 3 (H ) antioxidant and I 2 (H ) antioxidant. We used 2,5-and 2,6-dihydroxybenzoic acids, caffeic acid ( 3-(3,4-dihydroxyphenyl)prop-2-enoic acid), ferulic acid ( 3-(4-hydroxy-3-methoxyphenyl)prop-2-enoic acid), pyrocatechol ( benzene-1,2-diol), and hydroquinone ( benzene-1,4-diol) as antioxidants. Spectra in the wavelength range 500 ± 250 nm were repeated at given time intervals to follow the peaks of the iodine and oxidation products, which were mainly quinones. For the iodination of the above diphenols ( benzenediol derivatives) the substitution and/or addition reactions with I 2 or HOI were found to be relatively slow compared to oxidation by IO À 3 . Approximate rate constants for oxidation were obtained on the basis of a reasonable kinetic model by using a suitable numerical integration program. Although these complexities can arise also in the completely inhibited BR oscillator, we believe that the inhibitory effects are due to the HOO . scavenging action by diphenols or by quinones since HOO . radicals are also potential reducing agents. We propose two steps that could maintain a small reservoir of diphenol, while both quinone and diphenol deplete HOO . radicals. In short, the complexities do not affect the method for monitoring the relative activity of antioxidants based on the BR oscillating reaction. The effects of temperature on the inverse of the oscillatory time in the BR-uninhibited system, on the inverse of inhibition times, and on the time length of the resumed oscillations for four antioxidants were also investigated. Apparent average activation energies were obtained.

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confidence: 77%

“…The simulations are based on the FCA model [7], reproduced in Table 1 with addition of the steps IN and DEG. References for the rate constants are given in [7], except for k C3 , k C3R , and k C4 [8]. The species on the left, not in parentheses, are those included in the rate laws.…”

Section: Inmentioning

confidence: 99%

An Experimental and Mechanistic Investigation of the Complexities Arising During Inhibition of the BriggsRauscher Reaction by Antioxidants

Cervellati

Höner

Furrow

et al. 2004

Helvetica Chimica Acta

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“…Noyes and Furrow [15], and Kepper and Epstein [17] proposed some skeleton processes that account for oscillation catalyzed by Mn 2þ . Based on the NÀF model and the experimental observations, we suggest a tentative mechanism for the oscillator.…”

Section: 4mentioning

confidence: 99%

A Novel BriggsRauscher Oscillation with a Macrocyclic Nickel(II) Complex as Catalyst and Pentane‐2,4‐dione as the Substrate

Zhao

Lü

et al. 2011

Helvetica Chimica Acta

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A new BriggsÀRauscher oscillating reaction with a tetraazamacrocyclic nickel(II) complex [NiL](ClO 4 ) 2 as catalyst and pentane-2,4-dione (pe) as the substrate is reported. The ligand L is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The experimental results indicate that iodine ion may be an important intermediate, and free radicals can be involved in the reaction. A tentative mechanism based on NoyesÀFurrow model (NF model) is proposed. Moreover, other factors, such as the variation of concentration of the components and temperature on the oscillator, are discussed.

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“…Noyes and S.D. Furrow [8], is able to reproduce some of the basic features of the oscillations in the system. At the same time, P. De Kepper and I.R.…”

Section: Interpretation Of the Inhibitory Effects The Briggs -Rauschementioning

confidence: 99%

“…Since our purpose is to propose an interpretation of the bromide ions' inhibitory effects in batch conditions, it seems appropriate to refer to the NF skeleton mechanism that we sketch here briefly. For the sake of clarity we have subdivided the 11 pseudo-elementary processes into four groups as follows, maintaining the original reactions notation [8]:…”

Section: Interpretation Of the Inhibitory Effects The Briggs -Rauschementioning

confidence: 99%

Inhibition of chemical oscillations by bromide ion in the Briggs-Rauscher reaction

Cervellati

Mongiorgi

1998

Int. J. Chem. Kinet.

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The oscillatory Briggs-Rauscher reaction. 3. A skeleton mechanism for oscillations

Cited by 118 publications

References 1 publication

An Experimental and Mechanistic Investigation of the Complexities Arising During Inhibition of the BriggsRauscher Reaction by Antioxidants

An Experimental and Mechanistic Investigation of the Complexities Arising During Inhibition of the BriggsRauscher Reaction by Antioxidants

A Novel BriggsRauscher Oscillation with a Macrocyclic Nickel(II) Complex as Catalyst and Pentane‐2,4‐dione as the Substrate

Inhibition of chemical oscillations by bromide ion in the Briggs-Rauscher reaction

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