Metal-ion oxidations in solution. Part XXI. Kinetics and mechanism of the reaction of ascorbic acid, hydroquinone, and catechol with 12-tungstocobaltoate(III)

Amjad, Zahid; Brodovitch, Jean‐Claude; McAuley, Alexander

doi:10.1139/v77-502

Cited by 47 publications

(20 citation statements)

References 11 publications

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“…The heteropolytungstates, 12-tungstocobaltate(III), and 12-tungstocobaltate(I1) (hereafter designated as Co"'W and Co"W respectively), have been prepared as their potassium salts, characterized and standardized by reported methods [5,61. Recrystallized lithium perchlorate, sodium perchlorate, sodium nitrate, sodium sulphate, and potassium nitrate (all of reagent grade) have been used for cation variation studies.…”

Section: Methodsmentioning

confidence: 99%

Kinetics and mechanism of the alkali metal ions promoted electron transfer between 12‐tungstocobaltate(III) and citric acid

Saha

Ghosh

Banerjee

1988

Int J of Chemical Kinetics

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The kinetics of the interactions of the Keggin type heteropolyanion [CoWI2O4~l5-, with all the molecular and anionic forms of citric acid have been investigated spectrophotometrically in the pH range 0.60-5.45 a t 60°C. With the exception of the molecular form of the acid (H3L), all the other species (H&, HL2-, and L3-) undergo oxidation through an alkali metal ion catalyzed path in addition to the uncatalyzed one. The catalytic power increases with increasing size of the alkali metal ion. The contributions of each path have been evaluated from the kinetic data with the help of the measured dissociation constant values of citric acid. A plausible mechanism involving the formation of a bridged outer-sphere complex of the reacting species with the alkali cation, has been suggested. The observed limiting dependence of koL on [citratel at high concentrations owing to a n equilibrium between the reactants preceeding the electron transfer step supports the proposed mechanism. The pH-rate profile gives an excellent fit with the evaluated kinetic parameters.

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Section: Methodsmentioning

confidence: 99%

Kinetics and mechanism of the alkali metal ions promoted electron transfer between 12‐tungstocobaltate(III) and citric acid

Saha

Ghosh

Banerjee

1988

Int J of Chemical Kinetics

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“…1). The rate constants, k2, evaluated from data on the temperature dependence of K, at I = 1 .OM (20,21) are presented in Table 1. corresponding to the overall reaction where H2Q is the benzene diol and Q the corresponding quinone.…”

Section: ( I ) Reaction Of [ N I ( G -~N E N~)~j " With Ascorbic Acidmentioning

confidence: 99%

Kinetics and mechanism of the oxidation of benzenediols and ascorbic acid by bis(1,4,7-triazacyciononane)nickel(III) in aqueous perchlorate media

McAuley¹,

Spencer²,

West³

1985

Can. J. Chem.

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A. MCAULEY, LEE SPENCER, and P. R. WEST. Can. J . Chem. 63, 1198Chem. 63, (1985. The reactions of the outer-sphere electron transfer reagent, Ni(9-aneN&", (Dis(l,4,7-triazacyclononane)nickel(III) ion) with ascorbic acid, hydroquinone, catechol, and resorcinol have been investigated. The absence of any proton related equilibria with the oxidant provides a means of ascribing the observed inverse hydrogen ion dependences to reactions of the dissociated ascorbate or quinolate ions, (HA-). The data are consistent with the rate-determining one-electron transfer reactions: k, ~i ( 9 -a~~~~)~~' + HA-4 Ni(9-ane N-c)2" + HA followed by rapid oxidation of the radical ions formed. In the reaction with ascorbic acid, kl -0 and k 2 ( T = 25°C) = 5.2

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“…It is used as a reducing agent with one or two electron reductants in chemical and biological systems [1][2][3][4][5][6][7]. Rate of reduction by ascorbic acid depends on nature of oxidant and pH of the medium.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and Mechanism of Oxidation of L-Ascorbic Acid by Pt(IV)(aq) in Aqueous Hydrochloric Acid Medium

Senapati

Das

Patnaik

2012

Advances in Physical Chemistry

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Reduction of [PtCl 6 ] 2− by L-ascorbic acid (H 2 ASc) in 0.1 M aqueous acid medium has been investigated spectrophotometrically under pseudo-first order condition at [PtCl 6 The redox reaction follows the rate law:, where k is the second-order rate constant and [H 2 ASc] is the total concentration of ascorbic acid. Electron transfer from [H 2 ASc] to Pt(IV) center leading to the release of two halide ions and formation of the reaction products, square planner Pt(II) halide complex, and dehydrated ascorbic acid is suggested. This redox reaction follows an outersphere mechanism as Pt(IV) complex is substituted inert. Activation parameters were calculated corresponding to rate of electron transfer reaction k. Activation parameters favor the electron transfer reaction.

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Metal-ion oxidations in solution. Part XXI. Kinetics and mechanism of the reaction of ascorbic acid, hydroquinone, and catechol with 12-tungstocobaltoate(III)

Cited by 47 publications

References 11 publications

Kinetics and mechanism of the alkali metal ions promoted electron transfer between 12‐tungstocobaltate(III) and citric acid

Kinetics and mechanism of the alkali metal ions promoted electron transfer between 12‐tungstocobaltate(III) and citric acid

Kinetics and mechanism of the oxidation of benzenediols and ascorbic acid by bis(1,4,7-triazacyciononane)nickel(III) in aqueous perchlorate media

Kinetics and Mechanism of Oxidation of L-Ascorbic Acid by Pt(IV)(aq) in Aqueous Hydrochloric Acid Medium

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