Kinetics and mechanism of the cerium(IV)/cerium(III) redox reaction on a platinum electrode

1983 ◽  
Vol 79 (8) ◽  
pp. 1741 ◽  
Author(s):  
Terence H. Randle ◽  
Anselm T. Kuhn
Keyword(s):  
Redox Reaction ◽  
Platinum Electrode ◽  
Kinetics And Mechanism

Kinetics and mechanism of the reduction of CrVI to CrIII by D-ribose and 2-deoxy-D-ribose

1999 ◽  
Vol 77 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Verónica Daier ◽  
Sandra Signorella ◽  
Marcela Rizzotto ◽  
María Inés Frascaroli ◽  
Claudia Palopoli ◽  
...  
Keyword(s):  
Redox Reaction ◽  
Kinetics And Mechanism ◽  
Epr Spectra ◽  
Oxidation Reactions ◽  
Redox Mechanism ◽  
Rate Laws ◽  
Aldonic Acid

The oxidation of D-ribose and 2-deoxy-D-ribose by CrVI yields the aldonic acid and Cr3+ as final products when an excess of sugar over CrVI is used. The redox reaction occurs through CrVI–>CrIII and CrVI–>CrV–>CrIII paths. The complete rate laws for the CrVI oxidation reactions are expressed by -d[CrVI]/dt = kH[H+]2 [ribose][CrVI], where kH = (5.9 ± 0.1) × 10-2 mol-3 dm9 s-1, and -d[CrVI]/dt = (k0 + kH'[H+]2) [2-deoxyribose][CrVI], where k0 = (1.3 ± 0.5) × 10-3 mol-1 dm3 s-1 and kH' = (4.2 ± 0.1) × 10-2 mol-3 dm9 s-1, at 33°C. An intermediate sugar alkoxide radical could be trapped with DMPO and observed by EPR as a multiline signal at g = 2.003. CrV is formed in a rapid step by reaction of the sugar radical with CrVI. CrV reacts with the substrate faster than CrVI does. The EPR spectra show that five- and six-coordinate oxochromate(V) intermediates are formed, and the distribution of these CrV species in the reaction mixture essentially depends on the solution acidity.Key words: ribose, 2-deoxyribose, chromium, redox, mechanism, kinetics.

Kinetics and Mechanism of Redox Reaction between Tetrachloroaurate(III) Ions and Hydrazine

2014 ◽  
Vol 46 (6) ◽  
pp. 328-337 ◽  
Author(s):  
Bartłomiej Streszewski ◽  
Wiktor Jaworski ◽  
Konrad Szaciłowski ◽  
Krzysztof Pacławski
Keyword(s):  
Redox Reaction ◽  
Kinetics And Mechanism

Kinetics of oxidation of α-ketoglutaric acid with Ce(IV) ions in relation to Belousov-Zhabotinskii reaction

1982 ◽  
Vol 47 (11) ◽  
pp. 2831-2837 ◽  
Author(s):  
Ľudovít Treindl ◽  
Vasil Dorovský
Keyword(s):  
Redox Reaction ◽  
Platinum Electrode ◽  
Activation Parameters ◽  
Enol Form ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Redox Catalyst ◽  
Oscillation Reaction ◽  
Belousov Zhabotinskii Reaction ◽  
Kinetics Of

Oxidation of α-ketoglutaric acid with Ce(IV) ions in a solution of sulphuric acid is a reaction of the first order with respect to both Ce(IV) ions and substrate, is acid catalysed, and its rate is proportional to the reciprocal square of the equilibrium HSO4- concentration. From the temperature dependence of the rate constant in 1.5M-H2SO4, the activation parameters were determined as ΔH##f = 57 kJ/mol and ΔS##f = -45 J mol-1 K-1. The redox reaction proper consists apparently of two steps: in the first one, the enol form of α-ketoglutaric acid reacts with Ce(IV) ions with the formation of the corresponding radical; in the second one, the latter is oxidized further with Ce(IV) to give malonic and succinic acids. Conditions are indicated under which α-ketoglutaric acid serves as substrate for the Belousov-Zhabotinskii oscillation reaction in the presence of Ce(IV)-Ce(III) redox catalyst. Oscillations of Ce(IV) and Br2 concentrations, shifted in phase, can be recorded polarographically with a rotating platinum electrode.

Redox reaction of 1,2-dihydroxybenzene with Mn(III) in aqueous perchlorate media. Kinetics and mechanism

1975 ◽  
Vol 12 (1) ◽  
pp. 61-65 ◽  
Author(s):  
E. Mentasti ◽  
E. Pelizzetti ◽  
E. Pramauro ◽  
G. Giraudi
Keyword(s):  
Redox Reaction ◽  
Kinetics And Mechanism
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