The bromide/bromous acid reaction. Switch-controlling step of the Belousov-Zhabotinskii oscillating system

Ariese, Freek; Nagy, Z.

doi:10.1021/j100399a005

Cited by 10 publications

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“… Disproportion is much faster under these more acidic conditions, and no kinetic effect of Br - was noted by Faria et al, presumably because of the greater speed of reaction 12 as compared to that of reactions −3 followed by 10. Ariese and Nagy suggested that the well-known 4,5 rapid bimolecular reaction between Br(III) and Br - in a strongly acid medium (reaction 2) passes through H 2 BrO 2 + rather than BrO 2 - or HBrO 2 and thus is expected to be unimportant at this moderate acidity. Faria et al detected no effects attributable to reaction 8.…”

Section: Kinetics Of Hbro2 Disproportionationmentioning

confidence: 99%

Activation Energy for the Disproportionation of HBrO₂and Estimated Heats of Formation of HBrO₂and BrO₂

Field

2006

J. Phys. Chem. A

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The kinetics of the reaction HBrO(2) + HBrO(2) --> HOBr + BrO(3)(-) + H(+) is investigated in aqueous HClO(4) (0.04-0.9 M) and H(2)SO(4) (0.3-0.9 M) media and at temperatures in the range 15-38 degrees C. The reaction is found to be cleanly second order in [HBrO(2)], with the experimental rate constant having the form k(exp) = k + k'[H(+)]. The half-life of the reaction is on the order of a few tenths of a second in the range 0.01 M < [HBrO(2)](0) < 0.02 M. The detailed mechanism of this reaction is discussed. The activation parameters for kare found to be E(double dagger) = 19.0 +/- 0.9 kJ/mol and DeltaS(double dagger) = -132 +/- 3 J/(K mol) in HClO(4), and E(double dagger) = 23.0 +/- 0.5 kJ/mol and DeltaS(double dagger) = -119 +/- 1 J/(K mol) in H(2)SO(4). The activation parameters for k' are found to be E(double dagger) = 25.8 +/- 0.5 kJ/mol and DeltaS(double dagger) = -106 +/- 1 J/(K mol) in HClO(4), and E(double dagger) = 18 +/- 3 kJ/mol and DeltaS(double dagger) = -130 +/- 11 J/(K mol) in H(2)SO(4). The values Delta(f)H(29)(8)(0)[BrO(2)(aq)] = 157 kJ/mol and Delta(f)H(29)(8)(0)[HBrO(2)(aq)] = -33 kJ/mol are estimated using a trend analysis (bond strengths) based on the assumption Delta(f)H(29)(8)(0)[HBrO(2)(aq)] lies between Delta(f)H(29)(8)(0)[HOBr(aq)] and Delta(f)H(29)(8)(0)[HBrO(3)(aq)] as Delta(f)H(29)(8)(0)[HClO(2)(aq)] lies between Delta(f)H(29)(8)(0)[HOCl(aq)] and Delta(f)H(29)(8)(0)[HClO(3)(aq)]. The estimated value of Delta(f)H(29)(8)(0)[BrO(2)(aq)] agrees well with calculated gas-phase values, but the estimated value of Delta(f)H(29)(8)(0)[HBrO(2)(aq)], as well as the tabulated value of Delta(f)H(29)(8)(0)[HClO(2)(aq)], is in substantial disagreement with calculated gas-phase values. Values of Delta(r)H(0) are estimated for various reactions involving BrO(2) or HBrO(2).

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Section: Kinetics Of Hbro2 Disproportionationmentioning

confidence: 99%

Activation Energy for the Disproportionation of HBrO₂and Estimated Heats of Formation of HBrO₂and BrO₂

Field

2006

J. Phys. Chem. A

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“…The NFT mechanism can explain the bistability found in the Ce 3+ −BrO 3 - system and the bistability and oscillations found in a stirred flow reactor (CSTR) for the minimal bromate oscillator, Ce 3+ −BrO 3 - −Br - and Mn 2+ −BrO 3 - −Br - . − The NFT set of reactions is the inorganic core of the mechanism proposed by Field, Körös, and Noyes (FKN) to explain the Belousov−Zhabotinsky (BZ) reaction. The NFT mechanism has been discussed, revised, and updated as a consequence of simulations and experimental results obtained from kinetics studies on specific reactions and from experimental work with oscillating systems related to the minimal bromate oscillator and to the BZ system. − …”

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confidence: 99%

Comment on “Oscillations in the Bromomalonic Acid/Bromate System Catalyzed by [Ru(bipy)₃]²⁺”

and

Faria

1997

J. Phys. Chem. A

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New strategies for studies on the kinetics and energetics of the Belousov‐Zhabotinskii reaction

Koch

Nagy-Ungvárai

1987

Ber Bunsenges Phys Chem

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Catalysis / Chemical Kinetics / Computer Experiments / Oscillatory Chemical Reactions / Thermal AnalysisThe oscillatory Belousov-Zhabotinskii reaction and its subsystems were studied by z 1700 DTA and UV experiments performed at linearly increased temperature. The starting concentrations of bromate, bromide, catalyst, and malonic acid were varied in order to obtain "concentration codes" of such series. These represent the dependence of any parameters in discrete ranges of the starting concentrations of the different components. Particularly adequate for a model check are the mechanistic codes (= MCC's), which concern the shape index and reaction type index: If these mechanistic coordinates remain constant in such a concentration interval, other data, e.g. activation energies, can be attributed to a rate-determining process. -The results led to a nine-step model which is based on the FKN mechanism and is capable of roughly reproducing the influence of the initial concentrations and heating rate on 11 parameters characteristic of the envelope and of the oscillations of the experimental signals. The MCC's of the experimental and theoretical series are similar, revealing 4-5 rate-determining steps in the different concentration ranges. -The activation energies agree with values from the literature, cited for three steps; these and further resulting activation energies are consistent with our studies with subsystems.

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The bromide/bromous acid reaction. Switch-controlling step of the Belousov-Zhabotinskii oscillating system

Cited by 10 publications

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Activation Energy for the Disproportionation of HBrO₂and Estimated Heats of Formation of HBrO₂and BrO₂

Activation Energy for the Disproportionation of HBrO₂and Estimated Heats of Formation of HBrO₂and BrO₂

Comment on “Oscillations in the Bromomalonic Acid/Bromate System Catalyzed by [Ru(bipy)₃]²⁺”

New strategies for studies on the kinetics and energetics of the Belousov‐Zhabotinskii reaction

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The bromide/bromous acid reaction. Switch-controlling step of the Belousov-Zhabotinskii oscillating system

Cited by 10 publications

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Activation Energy for the Disproportionation of HBrO2and Estimated Heats of Formation of HBrO2and BrO2

Activation Energy for the Disproportionation of HBrO2and Estimated Heats of Formation of HBrO2and BrO2

Comment on “Oscillations in the Bromomalonic Acid/Bromate System Catalyzed by [Ru(bipy)3]2+”

New strategies for studies on the kinetics and energetics of the Belousov‐Zhabotinskii reaction

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Product

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Activation Energy for the Disproportionation of HBrO₂and Estimated Heats of Formation of HBrO₂and BrO₂

Activation Energy for the Disproportionation of HBrO₂and Estimated Heats of Formation of HBrO₂and BrO₂

Comment on “Oscillations in the Bromomalonic Acid/Bromate System Catalyzed by [Ru(bipy)₃]²⁺”