Reduction of potassium chromate by d-fructose, d-galactose, d-mannose, d-glucose, and l-sorbose

Rao, Chebrolu P.; Kaiwar, Sharada P.

doi:10.1016/0008-6215(93)80002-v

Cited by 36 publications

(14 citation statements)

References 23 publications

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“…The hydrolysis of the Cr III -aldobionic acid complex in 0.2 M HClO 4 precludes its separation, and consequently, its structural characterization. At pH > 2, where these kind of complexes are stable enough toward hydrolysis to be characterized (44,45), the redox reaction between Cr VI and the disaccharide is extremely slow at the temperature used in this work and does not reach completion, even after 1 year. The reaction of chromate with saccharides is completed in shorter periods only when the reaction is allowed to proceed under reflux (44,45).…”

Section: Spectrophotometric Measurementsmentioning

confidence: 92%

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Kinetics and mechanism of the oxidation of disaccharides by Cr^VI

Roldán¹,

González²,

Santoro³

et al. 2002

Can. J. Chem.

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; à 33°C, les réactivités relatives des disaccharides vis-à-vis du Cr(VI) sont les suivantes: Mel > Lac > Cel > Mal. En milieu acide, il se forme du Cr(V) comme intermédiaire qui réagit avec le substrat plus rapidement que le Cr(VI). Les spectres de RPE montrent qu'il se forme des intermédiaires penta-et hexacoordinés d'oxo-Cr(V) dans lesquels le disaccharide agit comme ligand bidentate. Les espèces pentacoordinées oxo-Cr(V) sont présentes à toutes les [H + ] alors qu'on n'observe les espèces hexacoordinées qu'à des pH < 2 et que dans ces conditions elles se décomposent rapidement en produits d'oxydoréduction. À des pH allant de 3 à 7 où on n'observe pas de formation des espèces hexacoordinées d'oxo-Cr(V), les complexes de Cr(V) sont suffisamment stables pour être observés en solution pour des périodes allant de plusieurs jours à plusieurs mois.

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Section: Spectrophotometric Measurementsmentioning

confidence: 92%

“…(29,31,43,44). The hydrolysis of the Cr III -aldobionic acid complex in 0.2 M HClO 4 precludes its separation, and consequently, its structural characterization.…”

Section: Spectrophotometric Measurementsmentioning

confidence: 99%

Kinetics and mechanism of the oxidation of disaccharides by Cr^VI

Roldán¹,

González²,

Santoro³

et al. 2002

Can. J. Chem.

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“…Only in the case of hexoses, the chromate reduction reactions were carried out at different pH values, i.e., 0.35, 0.7, 1.10, 1.65, 2.54, 4.5 (by adjusting with appropriate amounts of HC1) and 7.5 (obtained on mixing hexoses and chromate) at 5mM chromate concentration [13,14]. Based on the results of these studies, an appropriate pH that suited these reactions was chosen as 0.35 and therefore all the chromate reduction reactions reported in this paper were studied at this pH value.…”

Section: Methodsmentioning

confidence: 99%

“…Such absorption spectral pattern is common for all the molecules reported in this paper. ''Reductive coefficients' characteristic of reducing ability of these molecules towards Cr(VI) have been derived based on the spectral changes as explained earlier [13,14]. Such studies are carried out with all the reported reductants in the experimental section and found a behaviour that is parallel in all the cases.…”

Section: A) Absorption Spectramentioning

confidence: 99%

Chromium toxicity: spectral and electrochemical studies of Cr(vi) reduction by biomimicking molecules

Rao

Kaiwar

Raghavan

1998

International Journal of Environmental Studies

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The reductive abilities of a variety of biomimicking molecules, including OH-containing ones such as, saccharides and their derivatives, nucleotides and their components and mixed group ligands have been determined in vitro using absorption spectra and electrochemical characterisations and were explained based on the nature of the reductants. While the reductive coefficients of these molecules showed a linear correlation with respect to oxidation potential of the ligand (E a P ) and/or reduction potential (E c p ) of the final Cr(III)-products, in any given set, such as hexoses, pentoses, polyols, glycols, saccharide derivatives, nucleotides and their components and mixed group ligands, the plot of all the reductants reported in this paper exhibited interesting correlations with respect to these electrochemical parameters. These correlations are expected to be important in the identification of species in routine analysis carried out with pollutants. As reduction of Cr(VI) to Cr(III) by saccharides and their derivatives progresses via soluble and reactive intermediates of Cr(V) having long t 1/2 periods, this may be implicated in the transport of toxic chromium salts from soil to plants and their ultimate entry into the biosphere causing ecological hazards. Based on the results obtained on chromate reduction studies, a working model has been proposed for the toxicity of Cr(VI).

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“…The good linear plot of ln(Abs) (at 350 nm) versus time indicates that Cr(V) reacts faster than Cr(VI) [61,71,73]. In many cases, the overall reactivity has been reported [92][93][94] without any discrimination of the individual contribution of Cr(VI) and Cr(V). When Cr(VI) and Cr(V) react at comparable rates, the consecutive reaction is [66,69,91] (Scheme 8) The rate constants k 5 and k 6 for the said consecutive reaction can be evaluated from the measurement of absorbance at 350 nm by using the molar absorptivity of Cr(VI) and Cr(V) [66,69,91].…”

Section: The Common Pathways Leading To Reduction Of Chromium(vi) To mentioning

confidence: 99%

Micellar effect on the kinetics and mechanism of chromium(VI) oxidation of organic substrates

Das

2004

Coordination Chemistry Reviews

119

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Reduction of potassium chromate by d-fructose, d-galactose, d-mannose, d-glucose, and l-sorbose

Cited by 36 publications

References 23 publications

Kinetics and mechanism of the oxidation of disaccharides by Cr^VI

Kinetics and mechanism of the oxidation of disaccharides by Cr^VI

Chromium toxicity: spectral and electrochemical studies of Cr(vi) reduction by biomimicking molecules

Micellar effect on the kinetics and mechanism of chromium(VI) oxidation of organic substrates

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Reduction of potassium chromate by d-fructose, d-galactose, d-mannose, d-glucose, and l-sorbose

Cited by 36 publications

References 23 publications

Kinetics and mechanism of the oxidation of disaccharides by CrVI

Kinetics and mechanism of the oxidation of disaccharides by CrVI

Chromium toxicity: spectral and electrochemical studies of Cr(vi) reduction by biomimicking molecules

Micellar effect on the kinetics and mechanism of chromium(VI) oxidation of organic substrates

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Product

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Kinetics and mechanism of the oxidation of disaccharides by Cr^VI

Kinetics and mechanism of the oxidation of disaccharides by Cr^VI