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.

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.

Oxidation of 1- and 2-acetylnaphthalenes by iodate - a kinetic study

1990 ◽  
Vol 55 (6) ◽  
pp. 1535-1540 ◽  
Author(s):  
Prerepa Manikyamba
Keyword(s):  
Solvent Effect ◽  
Enol Form ◽  
Aqueous Methanol ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Carbonium Ion ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting ◽  
Kinetics Of

Kinetics of oxidation of 1- and 2-acetylnaphthalenes by iodate in the presence of sulphuric acid in aqueous methanol has been studied. The reaction is first order with respect to both [iodate] and [acetylnaphthalene]. Solvent effect indicates a cation-dipole type of interaction in the rate limiting step. A mechanism is proposed with a slow attack of IO2+ on enol form of acetylnaphthalene forming an intermediate carbonium ion, which ultimately gives corresponding ω-hydroxyacetylnaphthalene. The higher reactivity of 2-acetyl isomer is attributed to the greater stability of the corresponding carbonium ion than that of 1-acetyl isomer.

scholarly journals Kinetics and Mechanism of Oxidation of Diethanolamine and Triethanolamine by Potassium Ferrate

2011 ◽  
Vol 8 (2) ◽  
pp. 903-909 ◽  
Author(s):  
Shan Jinhuan ◽  
Zhang Jiying
Keyword(s):  
Activation Parameters ◽  
Rate Equations ◽  
Potassium Ferrate ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Order Dependence ◽  
Rate Determining Step ◽  
Thermodynamic Activation Parameters ◽  
Plausible Mechanism ◽  
Kinetics Of

The kinetics of oxidation of diethanolamine and triethanolamine by potassium ferrate(VI)in alkaline liquids at a constant ionic strength has been studied spectrophotometrically in the temperature range of 278.2K-293.2K. The reaction shows first order dependence on potassium ferrate(VI), first order dependence on each reductant, The observed rate constant (kobs) decreases with the increase in [OH-], the reaction is negative fraction order with respect to [OH-]. A plausible mechanism is proposed and the rate equations derived from the mechanism can explain all the experimental results. The rate constants of the rate-determining step and the thermodynamic activation parameters are calculated.

scholarly journals Oxidation of Some Aliphatic Alcohols by Pyridinium Chlorochromate -Kinetics and Mechanism

2009 ◽  
Vol 6 (1) ◽  
pp. 237-246 ◽  
Author(s):  
Sapana Jain ◽  
B. L. Hiran ◽  
C. V. Bhatt
Keyword(s):  
Dielectric Constant ◽  
Carbonyl Compounds ◽  
Activation Parameters ◽  
Dipole Interaction ◽  
Hydrogen Ion ◽  
Pyridinium Chlorochromate ◽  
Secondary Alcohols ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

Kinetics of oxidation of some aliphatic primary and secondary alcoholsviz.,ethanol, propan-1-ol, propan-2-ol, butan-1-ol, butan-2-ol and 2-methyl butanol by pyridinium chlorochromate (PCC) have been studied in water- perchloric acid medium. The reaction shows first order dependence with respect to pyridinium chlorochromate [PCC] and hydrogen ion [H+]. The rate of oxidation decreases with increase in dielectric constant of solvent suggests ion-dipole interaction. Activation parameters have been evaluated. Products are carbonyl compounds and free radical absence was proved. A tentative mechanism has been proposed.

Kinetics and mechanism of oxidation of lactic acid by KMnO4 in H2SO4 medium

1985 ◽  
Vol 63 (12) ◽  
pp. 3317-3321 ◽  
Author(s):  
M. M. Girgis ◽  
S. A. El-Shatoury ◽  
Z. H. Khalil
Keyword(s):  
Lactic Acid ◽  
Oxidation Rate ◽  
Arrhenius Equation ◽  
Activation Parameters ◽  
Initial Oxidation ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Acid Catalyzed ◽  
Mechanism Of Oxidation ◽  
Kinetics Of

The initial oxidation stages of lactic acid by acid permanganate were investigated. The rate of the induction period was slow and then gradually increased. The kinetics of oxidation were second order, first order with respect to both lactic acid and Mn(VII). The reaction was acid catalyzed. Addition of Mn(II) ions largely increased the rate of the initial stages and decreased the rate of the following stages. The oxidation rate was decreased by the addition of F− or [Formula: see text] ions. The Arrhenius equation was valid for the reaction between 16.5 and 34 °C. Activation parameters were evaluated and a mechanism consistent with the results obtained was proposed.

scholarly journals Kinetics of Oxidation of Cychlohexanol by N-Chloronicotinamide in Aqueous Acetic Acid Medium

2004 ◽  
Vol 3 (1) ◽  
pp. 1-6
Author(s):  
R. Sridharan ◽  
N. Mathiyalagan
Keyword(s):  
Acetic Acid ◽  
Acid Medium ◽  
Activation Parameters ◽  
Acid Mixture ◽  
Aqueous Acetic Acid ◽  
Acetic Acid Medium ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Retarding Effect ◽  
Kinetics Of

Kinetics of oxidation o Cyclohexanol by N-Chloronicotinamide(NCN) in 50% V/V aqueous acetic acid mixture has been investigated in the presence of HCIO4 and NaCl. The observed rate of oxidation is first-order with respect to oxidation (NCN) and fractional-order with respect to cyclohexanol. A decrease in dielectric constant of the medium increases the rate. Addition of nicotinamide (NA), the reduction product of NCN, has a retarding effect an the rate of oxidation. Arrhenius and activation parameters are calculated. Kinetics of bromination1 and oxidation2,3 of saturated organic compounds by N-bromosuccinimide(NBS) have been received considerable attention. Kinetics and mechanism of oxidation of amino acids by NCN has been reported in aqueous acetic acid medium, we report herein the result of similar studies on the oxidation of cyclohexanol with NCN in aqueous acetic acid medium.

scholarly journals Kinetics of Oxidation of 3-Benzoylpropionic Acid byN-Chlorobenzamide in Aqueous Acetic Acid Medium

2011 ◽  
Vol 8 (2) ◽  
pp. 561-564 ◽  
Author(s):  
N. A. Mohamed Farook ◽  
G. A. Seyed Dameem
Keyword(s):  
Acetic Acid ◽  
Acid Medium ◽  
Reaction Medium ◽  
Activation Parameters ◽  
Slow Step ◽  
Aqueous Acetic Acid ◽  
Acetic Acid Medium ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of 3-benzoylpropionic acid(KA)byN-chlorobenzamide(NCB)in aqueous acetic acid medium in the presence of perchloric acid have been investigated. The observed rate of oxidation is first order dependence each in[KA],[NCB]and [H+]. The main product of the oxidation is the corresponding carboxylic acid. The rate decreases with the addition of benzamide, one of the products of the reaction. Variation in ionic strength of the reaction medium has no significant effect on the rate of oxidation. But the rate of the reaction is enhanced by lowering the dielectric constant of the reaction medium. Hypochlorous acidium ion (H2O+Cl), has been postulated as the reactive oxidizing species. A mechanism consistent with observed results have been proposed and the related rate law deduced. The activation parameters have been computed with respect to slow step of the mechanism.

scholarly journals Kinetics and Mechanism of Oxidation of Isoleucine byN-Bromophthalimide in Aqueous Perchloric Acid Medium

2011 ◽  
Vol 8 (4) ◽  
pp. 1728-1733 ◽  
Author(s):  
N. M. I. Alhaji ◽  
S. Sofiya Lawrence Mary
Keyword(s):  
Acid Medium ◽  
Perchloric Acid ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Halide Ions ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Hypobromous Acid ◽  
Different Temperatures ◽  
Kinetics Of

The kinetics of oxidation of isoleucine withN-bromophthalimide has been studied in perchloric acid medium potentiometrically. The reaction is of first order each in [NBP] and [amino acid] and negative fractional order in [H+]. The rate is decreased by the addition of phthalimide. A decrease in the dielectric constant of the medium increases the rate. Addition of halide ions or acrylonitrile has no effect on the kinetics. Similarly, variation of ionic strength of the medium does not affect the reaction rate. The reaction rate has been determined at different temperatures and activation parameters have been calculated. A suitable mechanism involving hypobromous acid as reactive species has been proposed.

Kinetics of oxidation of 2,4-pentanedione with Ce(IV) ions in relation to Belousov-Zhabotinskii reaction

1981 ◽  
Vol 46 (8) ◽  
pp. 1734-1739 ◽  
Author(s):  
Ľudovít Treindl ◽  
Peter Kaplán
Keyword(s):  
Induction Period ◽  
Sulphuric Acid ◽  
Reaction Step ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Inner Sphere ◽  
Belousov Zhabotinskii Reaction ◽  
Kinetics Of

Oxidation of 2,4-pentanedione with Ce(IV) ions in a solution of sulphuric acid is an inner-sphere reaction which proceeds via an intermediary complex. The reaction is of the first order with respect to both reactants, it is catalysed with H3O+ ions, and its rate diminishes with increasing concentrations of HSO4- and Ce(III) ions. According to the proposed mechanism, the rate-determining reaction step is an intramolecular redox step of the intermediary complex. The modified Belousov-Zhabotinskii reaction with 2,4-pentanedione as substrate is interesting in that oscillations with an increasing amplitude are formed after an induction period even in the absence of stirring.

Oscillations of the enol form of 2,4-pentanedione during Belousov-Zhabotinskii reaction

1983 ◽  
Vol 48 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Ivan Tkáč ◽  
Ľudovít Treindl
Keyword(s):  
Phase Shift ◽  
Intermediate Product ◽  
Time Course ◽  
Enol Form ◽  
Intermediate Complex ◽  
Redox Catalyst ◽  
Oscillation Reaction ◽  
Belousov Zhabotinskii Reaction

In the Belousov-Zhabotinskii oscillation reaction with 2,4-pentanedione and Mn2+ /Mn3+ redox catalyst, also the enol form of the substrate has an oscillating concentration. The decrease of the concentration of the enol form is due to its reaction with bromine and Mn3+ ions; its increase corresponds to the reestablishment of the keto-enol equilibrium, when the concentrations of bromine and Mn3+ ions are low. An oscillating time-course was observed also with the concentration of the intermediate product of the reaction, of 2,4-pentanedione with Mn3+ ions, probably an intermediate complex [Mn(III)-enol], which oscilated with a phase shift against Mn3+ ions.

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