Kinetics and mechanism of redox reaction of U(III) ions with trichloroacetic acid

1980 ◽  
Vol 45 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Ľubica Adamčíková ◽  
Ľudovít Treindl
Keyword(s):  
Electron Transfer ◽  
Redox Reaction ◽  
Trichloroacetic Acid ◽  
Outer Sphere ◽  
Elementary Step ◽  
Kinetics And Mechanism ◽  
Kinetic Measurements ◽  
Chloroacetic Acids ◽  
Acetic Acids ◽  
Sphere Mechanism

The kinetics and mechanism of redox reaction of U3+ ions with trichloroacetic acid in the medium of perchloric acid were studied. The form of the dependence of the rate constant on the concentration of H3O+ ions suggests that the U3+ion reacts in the first elementary step with the CCL3.COO- anion under formation of an intermediary radical which reacts rapidly in the second step.The results of kinetic measurements of all three chloro substituted acetic acids are compared. A detailed study of the influence of binary mixtures on kinetic parameters of the studied reaction (especially of water-tert-butanol mixtures) shows that the reduction of chloroacetic acids with U3+ ions proceeds by the outer sphere mechanism of the electron transfer.

Kinetics and mechanism of oxidation of V(II) ions with trichloroacetic acid

1980 ◽  
Vol 45 (12) ◽  
pp. 3287-3292 ◽  
Author(s):  
Ľubica Adamčíková
Keyword(s):  
Exchange Rate ◽  
Redox Reaction ◽  
Trichloroacetic Acid ◽  
Outer Sphere ◽  
Kinetics And Mechanism ◽  
Kinetic Measurements ◽  
Exchange Rate Constant ◽  
Marcus Equation ◽  
Mechanism Of Oxidation ◽  
Sphere Mechanism

The kinetics and mechanism of the redox reaction of V(II) ions with trichloroacetic acid were studied in the medium of 0.04-2.0M-HClO. The results of kinetic measurements were compared with the analogous oxidation of U(III) ions with trichloroacetic acid, and the exchange rate constant for the reaction U3+ + *U4+ → U4+ + *U3+ was calculated. The influence of binary mixtures on the kinetic parameters of the reaction and the application of the Marcus' equation show that the oxidation of V2+ions with trichloroacetic acid proceeds by an outer-sphere mechanism.

scholarly journals Kinetics and mechanism of oxidation of mandelic acid with Bi(V) in phosphoric acid medium

2020 ◽  
Vol 16 (5) ◽  
pp. 50-57
Author(s):  
MUKESH KUMAR JHA ◽  
◽  
AVINASH KUMAR ◽  
Keyword(s):  
Electron Transfer ◽  
Phosphoric Acid ◽  
Acid Medium ◽  
Mandelic Acid ◽  
Reaction Rate ◽  
Outer Sphere ◽  
Kinetics And Mechanism ◽  
Opposite Charge ◽  
Mechanism Of Oxidation ◽  
Sphere Mechanism

The kinetics and mechanism of oxidation of Mandelic acid with Bi(V) has been investigated in phosphoric acid medium. The order with respect to substrate and oxidant each is one. The reaction rate is independent of [H+] ion as well as [Bi(III)]. The reaction rate decreases with increasing ionic strength indicating reactive species of opposite charge. The simple rate law explained all the experimental observations. The mode of electron transfer from the substrate to Bi(V) has been indicated is a bridged outer sphere mechanism.

Kinetics and mechanism of redox reactions of U(III) ions with monochloroacetic and dichloroacetic acids

1979 ◽  
Vol 44 (2) ◽  
pp. 401-405 ◽  
Author(s):  
Ľubica Adamčíková ◽  
Ľudovít Treindl
Keyword(s):  
Redox Reactions ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Outer Sphere ◽  
Alcohol Concentration ◽  
Kinetics And Mechanism ◽  
Solvent Structure ◽  
Influence Of Ph ◽  
Sphere Mechanism

The kinetics and mechanism of the redox reactions of U3+ ions with mono- and dichloroacetic acids were studied. The influence of pH was observed mainly in the second case and led to the determination of the rate constants and activation parameters corresponding to two parallel steps, namely oxidation of U3+ with CHCl2COO- ions and oxidation of U3+ with CHCl2.COOH molecules. The influence of binary mixtures of water with methanol, ethanol, isopropanol, or tert-butenol on the reaction rate was followed. Increasing alcohol concentration influences the rate constant not only through changing dielectric constant and solvation of the reactants but also through a change of the solvent structure which plays a role in reactions with an outer sphere mechanism of the electron transfer.

scholarly journals RuIII(edta) complexes as molecular redox catalysts in chemical and electrochemical reduction of dioxygen and hydrogen peroxide: inner-sphere versus outer-sphere mechanism

RSC Advances ◽  
2021 ◽  
Vol 11 (35) ◽  
pp. 21359-21366
Author(s):  
Debabrata Chatterjee ◽  
Marta Chrzanowska ◽  
Anna Katafias ◽  
Maria Oszajca ◽  
Rudi van Eldik
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transfer ◽  
Electrochemical Reduction ◽  
Molecular Oxygen ◽  
Outer Sphere ◽  
Transfer Processes ◽  
Edta Complexes ◽  
Inner Sphere ◽  
Electron Transfer Processes ◽  
Sphere Mechanism

[RuII(edta)(L)]2–, where edta4– =ethylenediaminetetraacetate; L = pyrazine (pz) and H2O, can reduce molecular oxygen sequentially to hydrogen peroxide and further to water by involving both outer-sphere and inner-sphere electron transfer processes.

Outer-sphere electron transfer reactions of aqua(5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1-acetato) nickel(II) and (III).

2003 ◽  
Vol 81 (2) ◽  
pp. 186-192 ◽  
Author(s):  
Robert I Haines ◽  
Dean R Hutchings
Keyword(s):  
Electron Transfer ◽  
Exchange Rate ◽  
Outer Sphere ◽  
Second Order ◽  
Marcus Theory ◽  
Pendant Arm ◽  
Key Words Nickel ◽  
Kinetics Of ◽  
Kinetics Of Reduction ◽  
Sphere Mechanism

The outer-sphere oxidation of the nickel(II) complex of the deprotonated pendant-arm macrocycle, 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1-acetate, [NiL1(OH2)]+ by bis-(1,4,7-triazacyclononane)nickel(III), [Ni(tacn)2]3+ has been studied in aqueous perchlorate media. The reaction displays reversible second-order behaviour and the kinetic study reveals the forward and reverse rate constants for the reaction: [Formula: see text] The kinetics show the forward reaction to be acid dependent, a feature that is attributed to protonation of the acetato group of the nickel(II) complex. Using Marcus theory, the self-exchange rate for the [NiL1(OH2)]+/2+ couple has been calculated. The nickel(II/III) electron transfer is a reversible one electron process with E° = 1.04 V (vs. S.H.E.). The formation of the authentic nickel(III) product has been confirmed by esr spectroscopy. The kinetics of reduction of the [NiL1(OH2)]2+ species by Fe2+(aq) exhibits a second-order rate law, the reaction being independent of acid. Using the calculated self-exchange rate for the nickel complex, its reaction with Fe2+(aq) has been examined in terms of an inner- versus outer-sphere mechanism. Key words: nickel(III), pendant-arm macrocycles, hexaaquairon(II), outer sphere, kinetics, Marcus theory.

scholarly journals Kinetics and Mechanism of Redox Reaction of Neutral Red with Nitrite Ion in Aqueous Acidic Medium

2016 ◽  
Vol 67 ◽  
pp. 50-57
Author(s):  
Ismaila Ibrahim ◽  
Sulaiman Ola Idris ◽  
Ameh David Onu
Keyword(s):  
Redox Reaction ◽  
Outer Sphere ◽  
Neutral Red ◽  
Nitrite Ion ◽  
First Order ◽  
Hydrochloric Acid Medium ◽  
Plausible Mechanism ◽  
Kinetics Of ◽  
Sphere Mechanism ◽  
Aqueous Acidic Medium

The kinetics of redox reaction of neutral red, NR+, with nitrite ion, NO2-, was studied in aqueous hydrochloric acid medium under pseudo-first order conditions at 25 ± 1°C, [H+] = 2.0 × 10-3mol dm-3, I = 0.1 mol dm-3(NaCl) and λmax= 525 nm. The reaction was first order with respect to [NR+], [NO2-] and [H+]. The reaction displayed a negative Bronsted-Debye salt effect. There was no evidence of the formation of an intermediate complex of significant stability and free radicals are probably not present in the reaction. The observations above, coupled with the result of Michaelis-Menten plot suggests an outer sphere mechanism for the reaction. The reaction obeys the rate law: -d [NR+]/dt = (a + b [H+])[NR+][NO2-]. A plausible mechanism has been proposed for the reaction.

scholarly journals Kinetics and mechanism of the reduction of n-(2-hydroxyethyl)ethylenediaminetriacetatoiron(III) complex by thioglycol in bicarbonate buffer medium

2018 ◽  
Vol 6 (1) ◽  
pp. 102 ◽  
Author(s):  
I U. Nkole ◽  
C R. Osunkwo ◽  
A D. Onu ◽  
O D. Onu
Keyword(s):  
Salt Effect ◽  
Reaction Medium ◽  
Outer Sphere ◽  
Reaction Rates ◽  
Kinetics And Mechanism ◽  
Bicarbonate Buffer ◽  
First Order ◽  
Buffer Medium ◽  
Activated Complex ◽  
Sphere Mechanism

The kinetics and mechanism of reduction of N-(2-hydroxyethyl) ethylenediaminetriacetatoiron (III) complex (hereafter [Fe(III)HEDTAOH2]) by thioglycol (hereafter RSH) has been studied spectrophotometrically in a bicarbonate buffer medium. The study was carried out under pseudo-first order conditions of an excess of thioglycol concentration at 28 ± 1℃, I = 0.44 mol dm-3 (KNO3) and λmax = 490 nm. The reaction is first order in [Fe(III)HEDTAOH2] and half order in [RSH] and a stoichiometric mole ratio of [Fe(III)HEDTAOH2]: RSH is 2:1. Reaction rates increased with increase in ionic strength (I) and dielectric constant (D) of the reaction medium of the reaction. The reaction displayed positive primary salt effect, which suggests the composition of activated complex are likely charged reactants ions. Test for possibility of an intermediate complex formation shows negative as Michaelis-Menten plot was linear with very negligible intercept. Based on the findings, outer-sphere mechanism is proposed for the reaction. The experimental rate law obtained is; - = k2 [Fe(III)HEDTAOH2][RSH]½   

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