Kinetic Modeling of the KMnO4/H2C2O4/H2SO4 Reaction: Origin of the bistability in a CSTR

Pimienta, Véronique; Lavabre, D.; Lévy, G.; Micheau, J. C.

doi:10.1021/j100039a025

Cited by 16 publications

(44 citation statements)

References 2 publications

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“…20 This autocatalytic role usually takes place when colloidal MnO 2 is one of the reaction products, as happens in the permanganate oxidation of the amino acid L-threonine in neutral phosphatebuffered solutions, 21 but it can also occur when the colloid is formed as an intermediate, as in the permanganate oxidation of formic acid in perchloric media. 22 Moreover, for the permanganate oxidation of oxalic acid in sulfuric solutions, arguably the most important and most studied of the permanganate reactions, 23 although its mechanism has proven so far to be rather elusive, 24,25 it has been recently reported that its autocatalysis cannot be explained if the Mn(II)-oxalate complex formed as reaction product is considered the only autocatalyst, and that an essential reaction pathway to explain its kinetic behavior takes place on the surface of the MnO 2 colloidal particles formed as a long-lived intermediate, hence providing a positive feedback loop for the reaction. 26 It thus seems a plausible hypothesis that soluble forms of colloidal MnO 2 might play the role of a heterogeneous autocatalyst in many permanganate reactions, not only when formed as a reaction product (in neutral solutions) but also when formed as a long-lived intermediate (in acidic solutions).…”

Section: Introductionmentioning

confidence: 99%

Autocatalytic Reaction Pathway on Manganese Dioxide Colloidal Particles in the Permanganate Oxidation of Glycine

Perez‐Benito

2009

J. Phys. Chem. C

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The progress of the reaction of permanganate ion with the amino acid glycine in near-neutral aqueous solutions was monitored with a UV-vis spectrophotometer at two different wavelengths in order to observe the decay of the oxidant (MnO 4 -, at 526 nm) and the formation of one of the reaction products (colloidal MnO 2 , at 418 nm). The use of a phosphate buffer resulted in the stabilization of MnO 2 as a soluble colloid during the kinetic runs. The experimental data are consistent with the hypothesis that of the two conjugated buffer ions H 2 PO 4 -/HPO 4 2-the acidic one (H 2 PO 4 -) is the predominant species responsible for that stabilization, suggesting that the formation of hydrogen bonds between the MnO 2 oxygen atoms and the hydrogen atoms from phosphate ions might be involved in the process. An increase of the phosphate concentration resulted in a notable decrease of both the molar absorption coefficient and the size of the MnO 2 colloidal particles. The reaction showed an autocatalytic behavior, but the kinetic plots deviated from the differential rate law usually employed for the study of autocatalytic reactions. The experimental data suggest that these deviations might be caused by the competitive adsorption of both phosphate ions and glycine on the surface of the MnO 2 colloidal particles, with the adsorption of the two species being too slow for the quasi-equilibrium approximation to hold, and resulting in an inhibition of the autocatalytic reaction pathway by phosphate ions.

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Section: Introductionmentioning

confidence: 99%

Autocatalytic Reaction Pathway on Manganese Dioxide Colloidal Particles in the Permanganate Oxidation of Glycine

Perez‐Benito

2009

J. Phys. Chem. C

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“…The aim of this phase was that all elementary reaction steps which can occur in a decomposition must be included at least in one generated decomposition. Some of these decompositions satisfied (6) with a positive integer n greater than 1, although the greatest common divisor of the components of the appropriate vector y was in all cases 1. The total number of possible decompositions is unknown and is with several magnitude higher than 294.…”

Section: Computation Of Reaction Mechanismsmentioning

confidence: 99%

“…Of the 673 elementary steps we have found 314, not taking part in any of the decompositions, and they cannot even take part in any decomposition. If we prescribe the presence of any of them in a decomposition then (6) will have no solution.…”

Section: Computation Of Reaction Mechanismsmentioning

confidence: 99%

“…It is a well-known reaction which has been studied since 1866, 2 and was recently investigated by several groups. [3][4][5][6][7][8] The basis of our decomposition method has been outlined in ref. 9; an alternative method can be found in ref.…”

Section: Introductionmentioning

confidence: 99%

“…The authors of ref. 6 have defined a mechanism consisting of eight reversible and six irreversible steps, of which three are not elementary in the sense defined above. The reaction mechanism includes the following 18 species: Here the square bracket [] refers to encounter pairs or triplets, 11 if they contains more than one species.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Decomposition of the permanganate/oxalic acid overall reaction to elementary steps based on integer programming theory

Kovács

Vízvári

Riedel

et al. 2004

Phys. Chem. Chem. Phys.

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Kinetics of permanganate–sulfuric acid redox reaction with cetyltrimethylammonium bromide

Zaheer,

Bawazir,

Bahaidarah

et al. 2024

Int J of Chemical Kinetics

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The permanganate–H2SO4 redox reaction, useful in oxidative treatments under aqueous conditions, was studied spectrophotometrically in the absence and presence of cetyltrimethylammonium bromide (CTAB). The decolorization reactions were influenced by the [MnO4−], [H2SO4], and temperature. Permanganate reduction follows first‐, and complex–order kinetics with permanganate, and H2SO4 concentrations, respectively. The reduction of permanganate (Mn(VII)) proceeds through a complex formation between MnO4− and H2SO4. The characteristic absorption peaks for MnO42− (λmax = 439 and 606 nm), MnO43− (λmax = 667 nm), and MnO2 (λmax = 400–418 nm) were not appeared during the redox reaction. The KMnO4 degradation efficiency remains unaffected with sodium pyrophosphate and sodium fluoride. The results of this study demonstrated the formation of Mn(II) as the stable product in acidic reaction media. The degradation efficiency increases drastically from 15 to 100% with 2.0 × 10−4 to 16.0 × 10−4 mol/L CTAB concentration under sub‐, and post‐micellar reaction conditions, respectively. The thermodynamic parameters (activation energy = 98.8 and 43.2 kJ/mol), activation of enthalpy (96.3, and 39.0 kJ/mol), activation of entropy (16.2 and −149.5 J/K/mol), free energy of activation (93.1 and 83.5 kJ/mol) were calculated without and with CTAB, respectively. Hence, CTAB can be exploited for its multifunctional applications, and specifically for the catalytic role in the permanganate‐assisted redox reactions in future.

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Kinetic Modeling of the KMnO4/H2C2O4/H2SO4 Reaction: Origin of the bistability in a CSTR

Cited by 16 publications

References 2 publications

Autocatalytic Reaction Pathway on Manganese Dioxide Colloidal Particles in the Permanganate Oxidation of Glycine

Autocatalytic Reaction Pathway on Manganese Dioxide Colloidal Particles in the Permanganate Oxidation of Glycine

Decomposition of the permanganate/oxalic acid overall reaction to elementary steps based on integer programming theory

Kinetics of permanganate–sulfuric acid redox reaction with cetyltrimethylammonium bromide

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