scholarly journals Oxidative Cleavage of β-Lactam Ring of Cephalosporins with Chloramine-T in Alkaline Medium: A Kinetic, Mechanistic, and Reactivity Study

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Anu Sukhdev ◽  
A. S. Manjunatha ◽  
Puttaswamy Puttaswamy
Keyword(s):  
Alkaline Medium ◽  
Activation Parameters ◽  
Oxidation Products ◽  
Oxidation Reactions ◽  
Mass Spectral ◽  
Dielectric Effect ◽  
Lactam Ring ◽  
Chloramine T ◽  
Reactivity Study ◽  
Reaction Constants

Cephalosporins are β-lactam antibiotics, and the important drugs of this group are cephalexin, cefadroxil and cephradine. In the present research, the kinetics and mechanism of oxidation of cephalexin (CEX), cefadroxil (CFL), and cephradine (CPD) with chloramine-T (CAT) in alkaline medium were investigated at 301 K. All the three oxidation reactions follow identical kinetics with a first-order dependence each on [CAT]o and [substrate]o. The reaction is catalyzed by hydroxide ions, and the order is found to be fractional. The dielectric effect is negative. Proton inventory studies in H2O-D2O mixtures with CEX as a probe have been made. Activation parameters and reaction constants have been evaluated. Oxidation products were identified by mass spectral analysis. An isokinetic relation was observed with β = 378 K, indicating that enthalpy factors control the rate. The rate increases in the following order: CPD > CFL > CEX. The proposed mechanism and the derived rate law are consistent with the observed kinetics.

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.

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 of Micellar Effect of Non-Ionic Surfactant on Oxidative Degradation of Ciprofloxacin

2019 ◽  
Vol 32 (2) ◽  
pp. 359-368
Author(s):  
Ajaya Kumar Singh ◽  
Alpa Shrivastava ◽  
Dilip R. Shrivastava ◽  
Rajmani Patel ◽  
Neerja Sachdev
Keyword(s):  
Degradation Kinetics ◽  
Oxidative Degradation ◽  
Activation Parameters ◽  
Solvent Polarity ◽  
Degradation Process ◽  
Oxidation Products ◽  
Ionic Surfactant ◽  
Reaction Conditions ◽  
Chloramine T ◽  
Kinetics Of

Oxidative degradation kinetics of leading fluoroquinolone family drug ciprofloxacin (CIP) by chloramine-T (CAT) in TX-100 micelle media was studied spectrophotometrically at 275 nm and 298 K. In pseudo-first-order conditions the rate constant (kobs) decreased regularly with increasing [TX-100]. To understand the self-organizing activities of TX-100, CMC values in varying reaction conditions had been evaluated. The role of non-ionic surfactant in the oxidative degradation process of ciprofloxacin by chlorinating agent chloramine-T is explained in terms of mathematical model explained by Menger-Portnoy. The reaction showed first to zero order dependence on [CAT] and fractional order on [CIP]. Increasing [H+] decreased the rate of reaction. The effect of ionic strength and solvent polarity of the medium in reaction conditions were studied. The effects of added salts [HSO4Na], [KCl], [KNO3] and [K2SO4] had also been studied. The stoichiometry of the reaction determined was 1:2 and the oxidation products were identified by LC-EI-MS. The analysis of degradation product of ciprofloxacin evidently reveals that the piperazine moiety is active site for oxidation in the reaction. Activation parameters were studied to propose appropriate mechanism for the reaction.

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 Kinetic, Mechanistic, and Thermodynamic Studies for Oxidation of L-Alanine by Alkaline Sodium Periodate in Presence of Os(VIII) in its Nano Concentration Range as Homogenous Catalyst

2018 ◽  
Vol 13 (2) ◽  
pp. 355 ◽  
Author(s):  
Madhu Gupta ◽  
Amrita Srivastava ◽  
Sheila Srivastava
Keyword(s):  
Sodium Periodate ◽  
Activation Parameters ◽  
Spectroscopic Studies ◽  
Oxidation Products ◽  
Slow Step ◽  
Thermodynamic Quantities ◽  
Thermodynamic Studies ◽  
Negative Effect ◽  
Reaction Constants ◽  
Homogenous Catalyst

The kinetics and mechanism of homogenously Os(VIII) catalysed oxidation of L-alanine (L-ala) by alkaline sodium periodate in temperature range 30 to 45°C have been studied. The involvement of free radicals was observed in the reactions. The oxidation products were acetaldehyde and IO3-, identified by spot test and spectroscopic studies. The stoichiometry between [L-ala]: IO4- is 1:2. The reaction show negligible effect of mercuric acetate and ionic strength of medium. The experimental results show first order in oxidant [NaIO4] and negative effect of [OH-]. The order in [Os(VIII)] as well as L-alanine was unity. A mechanism involving the formation of complex between L-alanine and Os(VIII) was proposed. The reaction constants concerned in the different steps of mechanism were calculated at different temperature. The activation parameters for the slow step of mechanism were computed and discussed. The thermodynamic quantities were also calculated for the reaction. Copyright © 2018 BCREC Group. All rights reservedReceived: 11st October 2017; Revised: 11st February 2018; Accepted: 18th February 2018; Available online: 11st June 2018; Published regularly: 1st August 2018How to Cite: Gupta, M., Srivastava, A., Srivastava, S. (2018). Kinetic, Mechanistic, and Thermodynamic Studies for Oxidation of L-Alanine by Alkaline Sodium Periodate in Presence of Os(VIII) in its Nano Concentration Range as Homogenous Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (2): 355-364 (doi:10.9767/bcrec.13.2.1583.355-364) 

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.

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 Sodium Periodate as a Selective Oxidant for Diclofenac Sodium in Alkaline Medium: A Quantum Chemical Approach

2020 ◽  
Vol 15 (2) ◽  
pp. 545-560
Author(s):  
Madhu Gupta ◽  
Amrita Srivastava ◽  
Sheila Srivastava
Keyword(s):  
Alkaline Medium ◽  
Quantum Chemical ◽  
Density Functional ◽  
Sodium Periodate ◽  
Diclofenac Sodium ◽  
Waste Water Treatment ◽  
Activation Parameters ◽  
Active Species ◽  
Oxidation Products ◽  
Spectral Studies

Diclofenac sodium is a well known anti-inflammatory drug. It has also been proclaimed to exhibit adverse effects on aquatic animals through sewage and waste water treatment plants. Kinetic and mechanistic studies of the novel oxidation of diclofenac sodium (DFS) by sodium periodate were discussed with an emphasis on structure and reactivity by using kinetic and computational approach. The proposed work had been studied in alkaline medium at 303 K and at a constant ionic strength of 0.60 mol.dm−3. Formation of [2-(2,6-dicloro-phynylamino)-phenyl]-methanol as the oxidation product of DFS is confirmed with the help of structure elucidation. The active species of catalyst, oxidant and oxidation products were recognized by UV and IR spectral studies. Proton inventory studies in H2O−D2O mixtures had been shown the involvement of a single exchangeable proton of OH− ion in the transition state. All quantum chemical calculations were executed at level of density functional theory (DFT) with B3LYP function using 6-31G (d,p) basis atomic set for the validation of structure, reaction and mechanism. Molecular orbital energies, nonlinear optical properties, bond length, bond angles, reactivity, electrophilic and nucleophilic regions were delineated. Influence of various reactants on rate of chemical reaction were also ascertained and elucidated spectro-photometrically. Activation parameters have been assessed using Arrhenius-Eyring plots. A suitable mechanism consistent with observed kinetic results had been implicated and rate law deduced. Copyright © 2020 BCREC Group. All rights reserved 

Kinetic and Mechanistic Study of Oxidative Degradation of Paracetamol by Diperiodatonickelate (IV) in Aqueous Alkaline Medium

2002 ◽  
Vol 2002 (4) ◽  
pp. 147-148 ◽  
Author(s):  
R.M. Kulkarni ◽  
D.C. Bilehal ◽  
S.T. Nandibewoor
Keyword(s):  
Alkaline Medium ◽  
Oxidative Degradation ◽  
Activation Parameters ◽  
Reactive Species ◽  
Mechanistic Study ◽  
Slow Step ◽  
Aqueous Alkaline Medium ◽  
Reaction Constants

A mechanism involving the monoperiodatonickelate (IV) (MPN) as the reactive species of the oxidant has been proposed. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to the slow step of the mechanism are computed and discussed.

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