scholarly journals Mechanism of Oxidation of L-Histidine by Heptavalent Manganese in Alkaline Medium

2005 ◽  
Vol 2 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Timy P. Jose ◽  
Sharanappa T. Nandibewoor ◽  
Suresh M. Tuwar
Keyword(s):  
Ionic Strength ◽  
Alkaline Medium ◽  
Reaction Medium ◽  
Activation Parameters ◽  
Slow Step ◽  
Thermodynamic Quantities ◽  
Kinetics Of Oxidation ◽  
Reaction Constants ◽  
Kinetics Of ◽  
Equilibrium Step

The kinetics of oxidation of L-histidine by manganese(VII) in aqueous alkaline medium at a constant ionic strength of 0.05 mol dm-3was studied spectrophotometrically. The reaction between permanganate and L-histidine in alkaline medium exhibits 2:1 stoichiometry (KMnO4: L-histidine). The reaction is of first order in [KMnO4], less than unit order in [L-histidine] and [alkali]. Decrease in the dielectric constant of the medium decreases the rate of reaction. Effect of added products and ionic strength of the reaction medium have been investigated. The main products were identified by spot test and I.R. A mechanism involving the free radical has been proposed. In composite equilibrium step L-histidine binds to MnO4-species to form a complex(C). The reaction constants involved in the different steps of mechanism are evaluated. The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities are also determined.

scholarly journals Oxidation of Paracetamol Drug by a New Oxidant Diperiodatoargentate (III) in Aqueous Alkaline Medium

2006 ◽  
Vol 3 (1) ◽  
pp. 13-24 ◽  
Author(s):  
D. C. Hiremath ◽  
C. V. Hiremath ◽  
S. T. Nandibewoor
Keyword(s):  
Ionic Strength ◽  
Alkaline Medium ◽  
Reaction Medium ◽  
Activation Parameters ◽  
Slow Step ◽  
Thermodynamic Quantities ◽  
Kinetics Of Oxidation ◽  
Rate Determining Step ◽  
Reaction Constants ◽  
Kinetics Of

The kinetics of oxidation of anti-pyretic drug, paracetamol by diperiodatoargentate (III) (DPA) in alkaline medium at a constant ionic strength of 0.01 mol dm-3was studied spectrophotometrically. The reaction between DPA and paracetamol in alkaline medium exhibits 1:2 stoichiometry (paracetamol: DPA). The reaction is of first order in [DPA] and has less than unit order in both [PAM] and [alkali]. A decrease in the dielectric constant of the medium increases the rate of the reaction. The effect of added products and ionic strength of the reaction medium have been investigated. The oxidation reaction in alkaline medium has been shown to proceed via a DPA- paracetamol complex, which decomposes slowly in a rate determining step followed by other fast step to give the products. The main products were identified by spot test, IR, NMR and GC-MS. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities are also determined.

scholarly journals Kinetics and Mechanism of Oxidation of L-proline by Trivalent Copper: A free radical intervention and decarboxylation

2004 ◽  
Vol 1 (5) ◽  
pp. 216-227 ◽  
Author(s):  
M. I. Hiremath ◽  
R. S. Shettar ◽  
S. T. Nandibewoor
Keyword(s):  
Ionic Strength ◽  
Alkaline Medium ◽  
Reaction Medium ◽  
Activation Parameters ◽  
Solvent Polarity ◽  
Medium Effect ◽  
Slow Step ◽  
Thermodynamic Quantities ◽  
Reaction Constants ◽  
Kinetics Of

The kinetics of oxidation of L-proline by diperiodatocuprate(III) (DPC) in aqueous alkaline medium at a constant ionic strength of 0.10 mol dm-3was studied spectrophotometrically. The reaction between DPC and L-proline in alkaline medium exhibits 2:1 stoichiometry (DPC: L-Proline). The reaction is of first order in [DPC], less than unit order in [L-proline] and [alkali]. Periodate has no effect on the rate of reaction. The reaction rate increases with increase in ionic strength and decrease in solvent polarity of the medium. Effect of added products and ionic strength of the reaction medium have been investigated. The main products were identified by spot test and I.R spectra. A mechanism involving the DPC as the reactive species of the oxidant and a complex formation with L-proline has been proposed. The reaction constants involved in the different steps of mechanism are calculated. The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities are also calculated.

Mechanistic Study of the Oxidation of Isonicotinate ion by Diperiodatocuprate(III) in Aqueous Alkaline Medium

2005 ◽  
Vol 2005 (3) ◽  
pp. 197-201 ◽  
Author(s):  
G.C Hiremath ◽  
R.M Mulla ◽  
S.T Nandibewoor
Keyword(s):  
Ionic Strength ◽  
Alkaline Medium ◽  
Activation Parameters ◽  
Mechanistic Study ◽  
Slow Step ◽  
Thermodynamic Quantities ◽  
Aqueous Alkaline Medium ◽  
Kinetics Of Oxidation ◽  
Reaction Constants ◽  
Kinetics Of

The kinetics of oxidation of isonicotinate ion by diperiodatocuprate(III) (DPC) in aqueous alkaline medium at a constant ionic strength of 0.60 mol dm−3 was studied spectrophotometrically. A mechanism involving the formation of an intermediate complex between the diperiodatocuprate(III) as the oxidant species and isonicotinate ion is proposed. The reaction constants involved in the different steps of mechanism have been calculated. The activation parameters with respect to the slow step of the mechanism have been computed and discussed and thermodynamic quantities were also determined.

scholarly journals Mechanistic aspects of oxidation on L-tyrosine by diperiodatocuprate(III) complex in alkali media: a kinetic model

2009 ◽  
Vol 7 (4) ◽  
pp. 929-937 ◽  
Author(s):  
Nagaraj Shetti ◽  
Rajesh Hegde ◽  
Sharanappa. Nandibewoor
Keyword(s):  
Alkaline Medium ◽  
Activation Parameters ◽  
Spectral Studies ◽  
Slow Step ◽  
Isokinetic Temperature ◽  
Thermodynamic Quantities ◽  
Radical Intermediate ◽  
Different Temperatures ◽  
Reactive Oxidant ◽  
Reaction Constants

AbstractOxidation of an amino acid, L-tyrosine (L-Tyr) by diperiodatocuprate(III) (DPC) in alkaline medium at a constant ionic strength of 0.1 mol dm−3 was studied spectrophotometrically at different temperatures (288.1–313.1 K). The reaction between DPC and L-Tyr in alkaline medium exhibits 1:4 stoichiometry (L-Tyr:DPC). Intervention of free radicals was observed in the reaction. Based on the observed orders and experimental evidence, a mechanism involving monoperiodatocuprate(III) (MPC) as the reactive oxidant species has been proposed. A suitable mechanism is proposed through the formation of a complex and free radical intermediate. The products were identified by spot test and characterized by spectral studies. The reaction constants involved in the different steps of the mechanism were calculated. The activation parameters with respect to slow step of the mechanism were computed and are discussed. The thermodynamic quantities were determined for different equilibrium steps. Isokinetic temperature was also calculated and found to be 252.3 K.

scholarly journals Kinetics and Mechanistic Study of Permanganate Oxidation of Fluorenone Hydrazone in Alkaline Medium

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ahmed Fawzy ◽  
Saleh A. Ahmed ◽  
Ismail I. Althagafi ◽  
Moataz H. Morad ◽  
Khalid S. Khairou
Keyword(s):  
Ionic Strength ◽  
Alkaline Medium ◽  
Equilibrium Constants ◽  
Activation Parameters ◽  
Active Species ◽  
Mechanistic Study ◽  
Thermodynamic Quantities ◽  
Rate Limiting Step ◽  
Expression Rate ◽  
Reaction Constants

The oxidation kinetics of fluorenone hydrazone (FH) using potassium permanganate in alkaline medium were measured at a constant ionic strength of 0.1 mol dm−3 and at 25°C using UV/VIS spectrophotometer. A first-order kinetics has been monitored in the reaction of FH with respect to [permanganate]. Less-than-unit order dependence of the reaction on [FH] and [OH−] was revealed. No pronounced effect on the reaction rate by increasing ionic strength was recorded. Intervention of free radicals was observed in the reaction. The reaction mechanism describing the kinetic results was illustrated which involves formation of 1 : 1 intermediate complex between fluorenone hydrazones and the active species of permanganate. 9H-Fluorenone as the corresponding ketone was found to be the final oxidation product of fluorenone hydrazone as confirmed by GC/MS analysis and FT-IR spectroscopy. The expression rate law for the oxidation reaction was deduced. The reaction constants and mechanism have been evaluated. The activation parameters associated with the rate-limiting step of the reaction, along with the thermodynamic quantities of the equilibrium constants, have been calculated and discussed.

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.

Kinetic and Mechanistic Aspects of Osmium(VIII) Catalyzed Oxidation of DL-ornithine by Copper(III) Periodate Complex in Aqueous Alkaline Medium

2010 ◽  
Vol 224 (06) ◽  
pp. 865-882 ◽  
Author(s):  
Jyothi C. Abbar ◽  
Shweta J. Malode ◽  
Sharanappa T. Nandibewoor
Keyword(s):  
Alkaline Medium ◽  
Activation Parameters ◽  
Reaction Rates ◽  
Oxidation Products ◽  
Slow Step ◽  
Thermodynamic Quantities ◽  
Aqueous Alkaline Medium ◽  
Uncatalyzed Reaction ◽  
Different Temperatures ◽  
Reaction Constants

AbstractThe oxidation of DL-ornithine monohydrochloride (OMH) by diperiodatocuprate(III) (DPC) has been investigated in the presence of osmium(VIII) catalyst in aqueous alkaline medium at a constant ionic strength of 0.20 mol dm−3 spectrophotometrically. The reaction exhibits 1:4 stoichiometry i.e., [OMH]: [DPC]. The order of the reaction with respect to [DPC] was unity while the order with respect to [OMH] was less than unity over the concentration range studied. The rate increased with an increase in [OH –] and decreased with an increase in [IO4−]. The order with respect to [Os(VIII)] was unity. The reaction rates revealed that Os(VIII) catalyzed reaction was about nine-fold faster than the uncatalyzed reaction. The oxidation products were identified by spectral analysis. Suitable mechanism has been proposed. The reaction constants involved in the different steps of the reaction mechanism were calculated. The catalytic constant (KC) was also calculated at different temperatures. The activation parameters with respect to slow step of the mechanism and also the thermodynamic quantities were determined. Kinetic experiments suggest that [OsO4(OH)2]2− is the reactive Os(VIII) species and [Cu(H2IO6)(H2O)2] is the reactive copper(III) species.

Kinetics and Mechanism of Oxidation of L-Proline by Heptavalent Manganese: A Free Radical Intervention and Decarboxylation

2005 ◽  
Vol 2005 (1) ◽  
pp. 13-17 ◽  
Author(s):  
R.T. Mahesh ◽  
M.B. Bellakki ◽  
S.T. Nandibewoor
Keyword(s):  
Reaction Rate ◽  
Activation Parameters ◽  
Solvent Polarity ◽  
Reaction Scheme ◽  
Slow Step ◽  
Reaction Products ◽  
Experimental Conditions ◽  
Kinetics Of Oxidation ◽  
Reaction Constants ◽  
Kinetics Of

The kinetics of oxidation of L-proline by permanganate in alkaline medium was studied spectrophotometrically. The reaction is first order with respect to[MnO4-] and is an apparent less than unit order, each in [L-proline] and [alkali] under the experimental conditions. The reaction rate increases with increase in ionic strength and decrease in solvent polarity of the medium. Addition of reaction products has no effect on the reaction rate. A mechanism involving the formation of a complex between the oxidant and substrate has been proposed. The reaction constants involved in the mechanism were evaluated. There is a good agreement between the observed and calculated rate constants under varying experimental conditions. The activation parameters with respect to the slow step of the proposed reaction scheme were evaluated and discussed.

scholarly journals Mechanistic Study on the Oxidation of 4-Hydroxycoumarin by Diperiodatonickelate(IV) in Aqueous Alkaline Medium

2009 ◽  
Vol 6 (3) ◽  
pp. 601-610 ◽  
Author(s):  
Ramesh S. Shettar ◽  
Nagaraj P. Shetti ◽  
Sharanappa T. Nandibewoor
Keyword(s):  
Alkaline Medium ◽  
Activation Parameters ◽  
Spot Test ◽  
Mechanistic Study ◽  
Slow Step ◽  
Thermodynamic Quantities ◽  
Aqueous Alkaline Medium ◽  
First Order ◽  
Rate Determining Step ◽  
Reaction Constants

The oxidation of 4-hydroxycoumarin (HDC) by diperiodato- nickelate(IV) (DPN) in aqueous alkaline medium at a constant ionic strength of 1.0 mol dm-3was studied spectrophotometrically at 298 K. The reaction between DPN and 4-hydroxycoumarin in alkaline medium exhibits 1:3 stoichiometry (HDC: DPN). The reaction is of first order in [DPN] and has less than unit order in [HDC] and fractional order in [alkali]. The oxidation reaction in alkaline medium has been shown to proceed via a DPN- 4-hydroxycoumarin complex, which decomposes slowly in a rate-determining step followed by other fast steps to give the products. The main products were identified by spot test, IR,1HNMR studies. The reaction constants involved in the different steps of the mechanism were calculated. The activation parameters with respect to slow step of the mechanism were computed and discussed and thermodynamic quantities were also determined.

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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