Oxidation of hydrazine by halogeno-complexes of iridium(IV) in acidic perchlorate solutions

Morris, D.F.C.; Ritter, T.J.

doi:10.1039/dt9800000216

Cited by 17 publications

(18 citation statements)

References 3 publications

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“…The progress of the reaction was followed by measuring the decrease in absorbance of [IrCl 6 ] 2at its absorption maximum, 489 nm, where all other reagents of the reaction mixture do not absorb significantly at this wavelength, as a function of time. The applicability of beer`s law for [IrCl 6 ] 2at 489 nm has been verified giving  = 4050 ± 20 dm 3 mol -1 cm -1 in good agreement with the values reported elsewhere [16][17][18][19][20][21]. The absorbance measurements were made in a thermostated cell compartment at the desired temperature within ± 0.05˚C on a Shimadzu UV-2101/3101 PC automatic scanning double beam spectrophotometer fitted with a wavelength program controller using cells of pathlength 1.0 cm.…”

Section: Kinetic Measurementssupporting

confidence: 88%

Orientation on Electron-Transfer Nature for Oxidation of Some Water-Soluble Carbohydrates: Kinetics and Mechanism of Hexacholroiridate (IV) Oxidation of Methyl Cellulose in Aqueous Perchlorate Solutions

Hassan¹

2019

TJSR

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The kinetics and mechanism of oxidation of methyl cellulose (MC) polysaccharide by hexacholroiridate (IV) in aqueous perchlorate solutions at a constant ionic strength of 0.1 mole dm -3 has been investigated, spectrophotometrically. The experimental results showed first-order dependence in [IrCl 6 ] 2and fractional first-order kinetics with respect to the MC concentration. The reaction rate was found to increase with decreasing the [H + ]. A kinetic evidence for formation of 1:1 intermediate complex was revealed. The reaction kinetics seems to be of considerable complexity where one chloride ion from hexacholoiridate (IV) oxidant may act as a bridging ligand between the oxidant and the substrate within the formed intermediate complex. However the added chloride ions and oxidation products were found to have negligible effects on the reaction rate, the added acrylonitrile indicated the intervention of freeradical mechanism during the oxidation process. The kinetic parameters have been evaluated and a tentative reaction mechanism consistent with the kinetic results is discussed.

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Section: Kinetic Measurementssupporting

confidence: 88%

Orientation on Electron-Transfer Nature for Oxidation of Some Water-Soluble Carbohydrates: Kinetics and Mechanism of Hexacholroiridate (IV) Oxidation of Methyl Cellulose in Aqueous Perchlorate Solutions

Hassan¹

2019

TJSR

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“…The retarding effect of C1-ion could therefore be attributed to either of the equilibria shown in eqs. [8] and [9] where NH,OH+Cl-is an ion-pair. These two equilibria offer scope for proposing two different mechanisms, each leading to a rate law that is consistent with the empirical rate law in eq.…”

Section: Discussionmentioning

confidence: 99%

“…[6]. The mechanism based on equilibrium [8] will be discussed in detail whereas the mechanism based on equilibrium [9], in which [Kl,(OH,)Iwould react with NH30H' as in reaction [13], is less likely, in view of the fact that the spectra of freshly prepared s o htions and those aged for 24 h are the same, indicating that '~a b l e s of supplementary data (Tables S1-S4) fast [16] 2NH20He+ -N2 + 2HZ0 + 2H' where K,,, is the equilibrium constant for the dissociation of the NH,OH+Cl-ion pair, KO, (= kI/k-,) is the equilibrium constant for the formation of the outer-sphere complex [I~CI,NH,OH]'-, k,, is the rate constant for the electron transfer within the outer-sphere complex, and k, is the rate constant for the dissociation of the product after the electron transfer. Reaction [16], with an excess of Ir(IV), is replaced by the reactions [16a] and [16b], leading to the formation of N20, and thus explaining the high stoichiometric ratio with excess of Ir(1V).…”

Section: Discussionmentioning

confidence: 99%

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Kinetics and mechanism of oxidation of hydroxylamine by hexachloroiridate(IV) ion in buffer solutions

Rekha¹,

Prakash²,

Mehrotra³

1993

Can. J. Chem.

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The oxidation of hydroxylammonium ion by [IrCl6]2− ion in acetic acid – acetate buffer solutions, studied by stopped flow, has the stoichiometric ratio Δ[IrCl6]2−/Δ[NH2OH] = 1. The oxidation involves the species [IrCl6]2− and NH3OH+ although spectral analysis of the spent reaction mixture indicates [IrCl5(OH2)]2− to be the main product (almost to the extent of 80%). This anomaly arises because of the aquation of the reduced product [IrCl6]3−. The rate is retarded both by H+ and Cl− ions and the plots of [Formula: see text] against respective concentrations are linear. The proposed mechanism is given by reactions [i]–[v].[Formula: see text]The values of the rate constants at 25 °C are as follows: k1 = 147 dm3 mol−1 s−1 and 102ketKia = 2.8 s−1. The related activation parameters are [Formula: see text], and,[Formula: see text], and [Formula: see text] and [Formula: see text], respectively. The value of Kipd is 2.91 ± 0.03 mol dm−3 and that of Kipa (= 1/Kipd) is 0.344 ± 0.004 dm3 mol−1; both values are almost independent of temperature.

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“…This suggestion is supported by the observed protons released in the stoichiometric equations. 1−3 Because hexachloroiridate(IV) is known to be extremely inert, 31 then, the CS substrate is only responsible for releasing such protons.…”

Section: Discussionmentioning

confidence: 99%

Oxidation of Some Sustainable Sulfated Natural Polymers: Kinetics and Mechanism of Oxidation of Water-Soluble Chondroitin-4-Sulfate Polysaccharide by Hexachloroiridate(IV) in Aqueous Solutions

Hassan

Ibrahim

2019

ACS Omega

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The kinetics and mechanism of hexachloroiridate(IV) oxidation of chondroitin-4-sulfate as a sustainable coordination biopolymer macromolecule (CS) in aqueous acidic solutions at a constant ionic strength of 0.1 mol dm –3 has been investigated spectrophotometrically. Pseudo first-order plots gave sigmoidal curves of S-shape nature, indicating that the kinetics is complex. Two distinct stages have been observed. The first stage was relatively fast corresponding to the autoacceleration period, followed by a slow stage which became linear at a longer time period called the induction period. First-order dependence with respect to the [OX] and fractional first order in [CS] was observed for both stages. Kinetic evidence for formation of the 1:1 intermediate complex within the two stages has been revealed. The influence of [H + ] on the rate constants indicated that the oxidation was of acid inhibition nature. The kinetic parameters have been evaluated, and a suitable reaction mechanism is suggested and discussed in terms of the nature of the electron-transfer process.

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Oxidation of hydrazine by halogeno-complexes of iridium(IV) in acidic perchlorate solutions

Cited by 17 publications

References 3 publications

Orientation on Electron-Transfer Nature for Oxidation of Some Water-Soluble Carbohydrates: Kinetics and Mechanism of Hexacholroiridate (IV) Oxidation of Methyl Cellulose in Aqueous Perchlorate Solutions

Orientation on Electron-Transfer Nature for Oxidation of Some Water-Soluble Carbohydrates: Kinetics and Mechanism of Hexacholroiridate (IV) Oxidation of Methyl Cellulose in Aqueous Perchlorate Solutions

Kinetics and mechanism of oxidation of hydroxylamine by hexachloroiridate(IV) ion in buffer solutions

Oxidation of Some Sustainable Sulfated Natural Polymers: Kinetics and Mechanism of Oxidation of Water-Soluble Chondroitin-4-Sulfate Polysaccharide by Hexachloroiridate(IV) in Aqueous Solutions

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