Kinetics and mechanism of hydrogen peroxide decomposition by hydroxonitrilotri (methylenephosphonato) Mn (II)

Anis, Samy S.; Mansour, Mohamed A.; Khalil, L. H.

doi:10.1051/jcp/1991880643

Cited by 2 publications

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“…Mn II complexes with NTMP and other phosphonate chelating agents are known to catalyze hydrogen peroxide disproportionation, with rates of catalysis increasing with increasing pH. 50,51 We have conducted experiments at pH 3.8 and 7.0 and have found that at the low pH, no decomposition of H 2 O 2 in the presence of Mn II NTMP takes place while at pH 7.0, a rapid decomposition of H 2 O 2 is indeed observed. This reaction can explain the observed plateau in H 2 O 2 concentration during oxidation of Mn II -NTMP at pH 7 (Figure 5).…”

Section: Oxidation Of Ntmp By Mnooh In the Absence Of Molecular Oxygenmentioning

confidence: 99%

Homogeneous and Heterogeneous Oxidation of Nitrilotrismethylenephosphonic Acid (NTMP) in the Presence of Manganese(II, III) and Molecular Oxygen

Nowack

Stone

2002

J. Phys. Chem. B

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In the absence of oxygen, NTMP (nitrilotrismethylenephosphonic acid) is oxidized by aqueous suspensions of the Mn III -containing mineral manganite (MnOOH), yielding iminodimethylenephosphonic acid (IDMP) as the sole phosphonate-containing product, along with orthophosphate and two equivalents of Mn II . Hence, both C-P and C-N bond cleavage take place. The reaction proceeds via formation of a Mn III -NTMP surface complex and oxidation of NTMP by Mn III via a carbon-centered methylene radical. Mn II strongly inhibits the reaction, presumably by competition for available surface sites. Homogeneous NTMP oxidation in Mn IIand O 2 -containing solutions yields IDMP, formate, phosphate, and hydrogen peroxide. Interception of the methylene radical by O 2 leads to N-formyl-IDMP and a second not-identified product. The dual presence of MnOOH and O 2 yields autocatalytic NTMP oxidation, owing to the generation of dissolved Mn II . Although the ultimate oxidants in the Mn II -NTMP-O 2 and MnOOH-NTMP systems are different (O 2 versus Mn III ), both oxidation reactions begin with C-N bond cleavage. This finding supports the hypothesis that Mn III is generated in the Mn II -NTMP-O 2 system.

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Section: Oxidation Of Ntmp By Mnooh In the Absence Of Molecular Oxygenmentioning

confidence: 99%

Homogeneous and Heterogeneous Oxidation of Nitrilotrismethylenephosphonic Acid (NTMP) in the Presence of Manganese(II, III) and Molecular Oxygen

Nowack

Stone

2002

J. Phys. Chem. B

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“…Chromium reacts either by catalaselike systems [7] or by peroxidase-like systems [8]. For the catalytic decomposition of hydrogen peroxide with iron [9][10][11], vanadium [12,13], cobalt [14], manganese [15,16] and cerium [17], there is general agreement that decomposition proceeds through an intermediate involving hydrogen peroxide in the inner-sphere of the metal.…”

Section: Introductionmentioning

confidence: 99%

Kinetic studies on the reaction of N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetate chromium(III) with hydrogen peroxide

Anis

Mansour

Sabry

2009

Transition Met Chem

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The rate of reaction of Cr(III)L (L=N-(2-hydroxyethyl)ethylenediamine-N,N 0 ,N 0 -triacetate) with hydrogen peroxide was studied in aqueous media and was found to yield Cr(VI) over the temperature range of 25-41°C. The reaction was followed spectrophotometrically at 396 nm under pseudo-first order conditions with hydrogen peroxide in a large excess. The reaction follows first-order kinetics in Cr(III). The dependence of the rate constant on hydrogen peroxide concentration is attributed to the formation of an intermediate between the monohydroxy chromium(III) complex and hydrogen peroxide which decomposes in the rate determining step. At high hydrogen peroxide concentration, the order is changed from first to zero order.The values of the intramolecular electron transfer rate constant, the formation constant of the intermediate complex and the activation parameters were calculated.

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Kinetics and mechanism of hydrogen peroxide decomposition by hydroxonitrilotri (methylenephosphonato) Mn (II)

Cited by 2 publications

References 0 publications

Homogeneous and Heterogeneous Oxidation of Nitrilotrismethylenephosphonic Acid (NTMP) in the Presence of Manganese(II, III) and Molecular Oxygen

Homogeneous and Heterogeneous Oxidation of Nitrilotrismethylenephosphonic Acid (NTMP) in the Presence of Manganese(II, III) and Molecular Oxygen

Kinetic studies on the reaction of N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetate chromium(III) with hydrogen peroxide

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