KINETICS OF THE OXIDATION OF URANIUM (IV) BY IRON (III) IN AQUEOUS SOLUTIONS OF PERCHLORIC ACID

1955 ◽  
Vol 33 (12) ◽  
pp. 1780-1791 ◽  
Author(s):  
R. H. Betts
Keyword(s):  
Electron Transfer ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Perchloric Acid ◽  
Rate Constants ◽  
Kcal Mole ◽  
Kinetics Of Oxidation ◽  
Temperature Coefficients ◽  
Kinetics Of ◽  
Rate Controlling Step

The kinetics of oxidation of uranium (IV) by iron (III) in aqueous solutions of perchloric acid have been investigated at four temperatures between 3.1 °C. and 24.8 °C. The reaction was followed by measurement of the amount of ferrous ion formed. For the conditions (H+) = 0.1–1.0 M, ionic strength = 1.02, (FeIII) = 10−4–10−5 M, and (UIV) = 10−4–10−5 M, the observed rate law is d(Fe2+)/dt = −2d(UIV)/dt[Formula: see text]K1 and K2 are the first hydrolysis constants for Fe3+ and U4+, respectively, and K′ and K″ are pseudo rate constants. At 24.8 °C., K′ = 2.98 sec.−1, and K″ = 10.6 mole liter−1 sec−1. The corresponding temperature coefficients are ΔH′ = 22.5 kcal./mole and ΔH″ = 24.2 kcal./mole. The kinetics of the process are consistent with a mechanism which involves, as a rate-controlling step, electron transfer between hydrolyzed ions.

Kinetics and mechanism of the oxidation of several ketones by tris(1,10-phenanthroline)Fe(III) in aqueous acid medium

1977 ◽  
Vol 55 (15) ◽  
pp. 2900-2908 ◽  
Author(s):  
Flora T. T. Ng ◽  
Patrick M. Henry
Keyword(s):  
Electron Transfer ◽  
Aqueous Solutions ◽  
Perchloric Acid ◽  
Rate Constants ◽  
Zero Order ◽  
Enol Form ◽  
Aqueous Acid ◽  
Zero Order Kinetics ◽  
Enol Tautomer ◽  
Kinetics Of

The kinetics of the oxidation of acetone, 2-butanone, 2,4-dimethyl-3-pentanone, 3-methyl-2-butanone, and 3-pentanone by tris(1,10-phenanthroline)Fe(III) (ferriin) were determined in aqueous solutions containing either sulphuric or perchloric acid in the presence or absence of air. The kinetics are consistent only with a mechanism involving oxidation of the enol tautomer by ferriin. The rate constants of enolization calculated from this kinetic analysis agree well with the literature values. Relative reactivity of the four enols from symmetrical ketones were found to be in the order: 2,4-dimethyl-3-pentanone > 3-pentanone > cyclohexanone > acetone. The rate of oxidation of the enol form of 2,4-dimethyl-3-pentanone is approximately 1000 fold larger than that of the enol form of acetone, indicating that electron-donating methyl substituents enhance the rate of electron transfer from the enol tautomer to ferriin.Kinetics of the oxidation carried out in air were generally the same as in its absence; the rates of oxidation were found to be slower by a factor of 2 in most cases. This suggests that the initially formed enol radical reacts with O2 rather than a second ferriin to give the oxidized product. At high [ferriin] in air, pseudo zero-order kinetics were observed initially as in its absence. However, above about 50% reduction of ferriin, the reaction appears to involve auto-catalysis and was not studied further.

Kinetics of oxidation of reduced cytochrome c by aquacopper(II) and chlorocopper(II) complexes in the presence of oxygen

1981 ◽  
Vol 34 (1) ◽  
pp. 99 ◽  
Author(s):  
JK Yandell
Keyword(s):  
Reaction Mechanism ◽  
Ionic Strength ◽  
Cytochrome C ◽  
Rate Constants ◽  
Kinetics Of Oxidation ◽  
Ferrocytochrome C ◽  
Kinetics Of

The rate constants for the oxidation of reduced cytochrome c by aquacopper(II) ion, aquachloro- copper(II) ion and aquadichlorocopper(II) were found to be 5.7�0.3 1. mol-1 s-1, 2.3×102 1. mol-1 s-1 and 5.6xl031. mol-1 s-1 respectively at 25�C, ionic strength 0.1 and pH 4.0. At low ratios of aquacopper(II) ion to ferrocytochrome c, when oxygen is required to completely oxidize the cytochrome, the reaction mechanism was found to be complex. No evidence for the involvement of copper bound to the cytochrome was found.

Kinetics of oxidation of cis-bis(ethylenediamine)isothiocyanatonitrocobalt(III) ion with peroxodisulphate

1979 ◽  
Vol 44 (12) ◽  
pp. 3588-3594 ◽  
Author(s):  
Vladislav Holba ◽  
Olga Volárová
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Oxidation Kinetics ◽  
Reaction Rate ◽  
Salt Effect ◽  
Activation Parameters ◽  
Reaction Products ◽  
Kinetics Of Oxidation ◽  
Thermodynamic Activation Parameters ◽  
Kinetics Of

The oxidation kinetics of cis-bis(ethylenediamine)isothiocyanonitrocobalt(III) ion with peroxodisulphate was investigated in the medium of 0.01 M-HClO4 in dependence on the ionic strength and temperature and the reaction products were identified. Extrapolated values of thermodynamic activation parameters were determined from the temperature dependence of the rate constants extrapolated to zero ionic strength. The distance of the closest approach was estimated for the reacting ions by evaluating the primary salt effect. To elucidate the mechanism, the influence of the cyclic polyether 18-crown-6 on the reaction rate was followed.

Kinetics of oxidation of hypophosphitopentamminechromium(III) ion with periodate

1981 ◽  
Vol 46 (10) ◽  
pp. 2503-2508 ◽  
Author(s):  
Olga Volárová ◽  
Vladislav Holba
Keyword(s):  
Ionic Strength ◽  
Oxygen Atom ◽  
Perchloric Acid ◽  
Redox Reaction ◽  
Reaction Rate ◽  
Kinetics Of Oxidation ◽  
Kinetics Of

The kinetics of oxidation of hypophosphitopentamminechromium(III) ion with periodate was investigated as a function of the temperature, ionic strength, and concentration of perchloric acid. The reaction rate decreased with increasing ionic strength and concentration of perchloric acid. The redox reaction proper involving transfer of an oxygen atom is preceded by dissociation of hydrogen from the coordinated hypophosphite. The reactivity of the latter is compared with that of the free hypophosphite.

THE KINETICS OF THE FORMATION OF THE MONO–FLUORO COMPLEX OF IRON (III) IN AQUEOUS SOLUTION

1960 ◽  
Vol 38 (4) ◽  
pp. 567-575 ◽  
Author(s):  
D. Pouli ◽  
W. MacF. Smith
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Temperature Interval ◽  
Kcal Mole ◽  
Entropy Of Activation ◽  
Fluoro Complex ◽  
Kinetics Of

The kinetics of the reactions involved in the formation of the mono–fluoro complex of iron (III) in aqueous solutions have been examined spectrophotometrically at ionic strength 0.5 and over the temperature interval 0.1 to 12.1 °C. The results are interpretable on the assumption that the following two reactions contribute significantly to the rate Fe+++ + F− = FeF++ and Fe+++ + HF = FeF++ + H+, the former having a heat of activation of 22.8 ± 2.5 kcal mole−1 and an entropy of activation of 35 ± 9 cal deg−1 mole−1, the latter having a heat of activation of 8.7 ± 0.7 kcal mole−1 and an entropy of activation of −24.5 ± 3 cal deg−1 mole−1.

Transition from internal to external oxidation in indium–silver alloys

1968 ◽  
Vol 46 (8) ◽  
pp. 1187-1196 ◽  
Author(s):  
L. D. Pethe ◽  
H. B. Mathur ◽  
A. B. Biswas
Keyword(s):  
Cross Sections ◽  
Absolute Temperature ◽  
Kcal Mole ◽  
Kinetics Of Oxidation ◽  
External Oxidation ◽  
Parabolic Oxidation ◽  
Parabolic Oxidation Rate ◽  
Straight Lines ◽  
Kinetics Of ◽  
Rate Controlling Step

The kinetics of oxidation of In–Ag alloys of 5,10, and 15 at. % indium have been studied on a vacuum microbalance. The 15 at. % indium alloy oxidizes externally and the 5 at. % alloy internally. A plot of logarithm of the parabolic oxidation rate, kp, versus reciprocal of the absolute temperature for 10 at. % indium alloy gives two intersecting straight lines corresponding to the energies of activation of 23 and 39.6 kcal/mole for the oxidation below and above 600 °C respectively. These are comparable to the energies of activation of 23 kcal/mole for the internal oxidation of 5 at. % indium alloy and 40 kcal/mole for the external oxidation of 15 at. % indium alloy. The rate–controlling step in the external oxidation of 15 at. % indium alloy is the diffusion of indium through the alloy. Photomicrographs of the cross sections of the oxidized foils of these alloys confirm the conclusions derived from the kinetic data.

Effects of salts on the kinetics of oxidation of alkenes by thallic salts in aqueous solutions

1981 ◽  
Vol 46 (3) ◽  
pp. 693-700 ◽  
Author(s):  
Milan Strašák ◽  
Jaroslav Majer
Keyword(s):  
Aqueous Solutions ◽  
Phase Transfer ◽  
Heterogeneous Reaction ◽  
Qualitative Model ◽  
Kinetic Effect ◽  
Tetraalkylammonium Salts ◽  
Reaction Conditions ◽  
Kinetics Of Oxidation ◽  
Kinetics Of ◽  
Heterogeneous Reaction Conditions

The kinetics of oxidation of alkenes by thallic sulphate in aqueous solutions, involving the two reaction steps-the hydroxythallation and the dethallation - was studied, and the effect of salts on the kinetics was examined; this made it possible to specify more precisely the reaction mechanism and to suggest a qualitative model of the reaction coordinate. It was found that in homogeneous as well as in heterogeneous reaction conditions, the reaction can be accelerated appreciably by adding tetraalkylammonium salts. These salts not only operate as catalysts of the phase transfer, but also exert a significant kinetic effect, which can be explained with a simplification in terms of a stabilization of the transition state of the reaction.

Kinetics of hydrolysis of peroxodisulphate ions in acidic medium to peroxomonosulphuric acid

1981 ◽  
Vol 46 (5) ◽  
pp. 1229-1236 ◽  
Author(s):  
Jan Balej ◽  
Milada Thumová
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Acidic Medium ◽  
Measured Data ◽  
Molar Ratios ◽  
Starting Solution ◽  
Kinetics Of Hydrolysis ◽  
Rate Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

The rate of hydrolysis of S2O82- ions in acidic medium to peroxomonosulphuric acid was measured at 20 and 30 °C. The composition of the starting solution corresponded to the anolyte flowing out from an electrolyser for production of this acid or its ammonium salt at various degrees of conversion and starting molar ratios of sulphuric acid to ammonium sulphate. The measured data served to calculate the rate constants at both temperatures on the basis of the earlier proposed mechanism of the hydrolysis, and their dependence on the ionic strength was studied.

Kinetics and Mechanism of Hexachloroiridate(IV) Oxidation of Arsenic(III) in Acidic Perchlorate Solutions

1992 ◽  
Vol 57 (7) ◽  
pp. 1451-1458 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Ionic Strength ◽  
Fractional Order ◽  
Activation Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
Intermediate Complex ◽  
Constant Ionic Strength ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of arsenic(III) by hexachloroiridate(IV) at lower acid concentrations and at constant ionic strength of 1.0 mol dm-3 have been investigated spectrophotometrically. A first-order reaction in [IrCl62-] and fractional order with respect to arsenic(III) have been observed. A kinetic evidence for the formation of an intermediate complex between the hydrolyzed arsenic(III) species and the oxidant was presented. The results showed that decreasing the [H+] is accompanied by an appreciable acceleration of the rate of oxidation. The activation parameters have been evaluated and a mechanism consistent with the kinetic results was suggested.

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