On N-acetylcysteine. Part II. Oxidation of N-acetylcysteine by hydrogen peroxide: kinetic study of the overall process

1994 ◽  
Vol 72 (10) ◽  
pp. 2102-2107 ◽  
Author(s):  
Zohreh Abedinzadeh ◽  
Jlil Arroub ◽  
Monique Gardès-Albert
Keyword(s):  
Hydrogen Peroxide ◽  
Kinetic Study ◽  
Oxidation Kinetics ◽  
Reaction Mechanisms ◽  
Kinetic Data ◽  
Concentration Ratio ◽  
Low Concentration ◽  
Neutral Ph ◽  
Kinetics Of ◽  
Concentration Ratios

The oxidation kinetics of N-acetylcysteine (RSH) by hydrogen peroxide has been studied at neutral pH at different concentration ratios from 0.2 to 20 (4 × 10−4 mol L−1 ≤ [RSH]0 ≤ 2 × 10−2 mol L−1, 10−4 mol L−1 ≤ [H2O2]0 ≤ 10−2 mol L−1). In all the cases studied, N-acetylcystine (RSSR) is the only oxidized product formed. Our kinetic data have focused on the importance of the concentration ratio to reach the stoichiometric oxidation of N-acetylcysteine by hydrogen peroxide. Indeed non-stoichiometric oxidation of RSH occurs at relatively low concentration ratios (R < 2.5) whereas stoichiometric oxidation is observed when R > 2.5. Moreover, it has been shown that in the first minutes of the reaction there is the formation of a complex between RSH and H2O2, the stoichiometry of the complex being RSH concentration-dependent for a given R (R > 2.5). Reaction mechanisms have been quantitatively established and the k values of each step determined.

Kinetics of the oxidation of diphenyl sulfide with hydrogen peroxide catalyzed by sodium metavanadate

1982 ◽  
Vol 60 (7) ◽  
pp. 848-852 ◽  
Author(s):  
Yoshiro Ogata ◽  
Kazushige Tanaka
Keyword(s):  
Hydrogen Peroxide ◽  
Rate Constant ◽  
Reaction Rate ◽  
Catalytic Amount ◽  
Probable Mechanism ◽  
Initial Concentration ◽  
Sodium Metavanadate ◽  
Low Concentration ◽  
Diphenyl Sulfide ◽  
Kinetics Of

The oxidation of diphenyl sulfide (Ph2S) by hydrogen peroxide in the presence of a catalytic amount of sodium metavanadate (NaVO3) has been studied kinetically by means of iodometry of hydrogen peroxide. The reaction rate is expressed as: v = k[NaVO3]st[Ph2S]2, when the concentration of catalyst is very low and [Ph2S]0/[H2O2]0 > 2, where []st and []0 mean stoichiometric and initial concentration, respectively. The effective oxidant may consist of polymeric as well as monomeric peroxyvanadate in view of the effect of concentration of catalyst on the rate. The main oxidizing species at low concentration of catalyst seems to be diperoxyvanadate VO5−. The rate constant k2 in v = k2[Ph2S]2 tends to decrease with initial concentration of H2O2, which is present in excess of the catalyst. A probable mechanism for the oxidation is discussed.

Oxidation kinetics of two pesticides in natural waters by ozonation and ozone combined with hydrogen peroxide

2011 ◽  
Vol 45 (8) ◽  
pp. 2517-2526 ◽  
Author(s):  
Pamela Chelme-Ayala ◽  
Mohamed Gamal El-Din ◽  
Daniel W. Smith ◽  
Craig D. Adams
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidation Kinetics ◽  
Natural Waters ◽  
Kinetics Of

Thermal oxidation reaction process and oxidation kinetics of abietic acid

RSC Advances ◽  
2015 ◽  
Vol 5 (22) ◽  
pp. 17123-17130 ◽  
Author(s):  
Fan Ren ◽  
Yan-Fei Zheng ◽  
Xiong-Min Liu ◽  
Qiong-Qiong Yang ◽  
Qiang Zhang ◽  
...  
Keyword(s):  
Kinetic Study ◽  
Thermal Oxidation ◽  
Oxidation Kinetics ◽  
Oxidation Reaction ◽  
Abietic Acid ◽  
Reaction Process ◽  
Basic Data ◽  
Kinetics Of

A kinetic study on the oxidation of abietic acid, providing new basic data.

scholarly journals THERMAL DISAPPEARANCE KINETICS OF RADICALS FORMED DURING RADIOLYSIS IN POLYCRYSTALLINE SOLID STATE OF SODIDM WOLFRAMATE DIHYDRATE

2010 ◽  
Vol 18 (18) ◽  
pp. 49-64
Author(s):  
Mihail Contineanu ◽  
Adina-Elena Stanciu ◽  
Iulia Contineanu ◽  
Ana Neacsu
Keyword(s):  
Solid State ◽  
Gamma Irradiation ◽  
Kinetic Study ◽  
Thermal Annealing ◽  
Kinetic Data ◽  
Room Temperature ◽  
Paramagnetic Centers ◽  
Polycrystalline Solid ◽  
Kinetics Of ◽  
Disappearance Kinetics

A kinetic study of the WO4- radical, formed by gamma irradiation of polycrystalline Na2 WO4.2H2O UCB at room temperature has been performed using the EPR technique. A suitable mechanism for the formation of paramagnetic centers by irradiation and thermal annealing is proposed. The mechanism agrees well with the experimental kinetic data.

THE KINETICS OF THE DECOMPOSITION AND SYNTHESIS OF SOME DITHIOCARBAMATES

1962 ◽  
Vol 40 (2) ◽  
pp. 246-255 ◽  
Author(s):  
D. M. Miller ◽  
R. A. Latimer
Keyword(s):  
Kinetic Study ◽  
Rate Constants ◽  
Reaction Mechanisms ◽  
Dissociation Constants ◽  
Activation Energies ◽  
Spectral Evidence ◽  
Kinetics Of

Rate constants, activation energies, and dissociation constants were determined in a kinetic study of the synthesis and decomposition of a number of N-substituted dithiocarbamates. These data combined with certain spectral evidence are evaluated and reaction mechanisms suggested.

Kinetics of Formation of Peroxyformic Acid

1996 ◽  
Vol 61 (10) ◽  
pp. 1457-1463 ◽  
Author(s):  
Vladimír Mošovský ◽  
Zuzana Cvengrošová ◽  
Alexander Kaszonyi ◽  
Milan Králik ◽  
Milan Hronec
Keyword(s):  
Hydrogen Peroxide ◽  
Kinetic Model ◽  
Formic Acid ◽  
Oxidation Kinetics ◽  
Oxidation Process ◽  
Aqueous Hydrogen Peroxide ◽  
Kinetics Of Formation ◽  
Peroxyformic Acid ◽  
Kinetics Of

Oxidation kinetics of formic acid with aqueous hydrogen peroxide (30-70%) has been studied at 45 °C with 0-0.1 M H2SO4 as a catalyst. A kinetic model has been suggested which satisfactorily describes the oxidation process of formic acid to peroxyformic acid.

A Kinetic Study of the Reaction of Horseradish Peroxidase with Hydrogen Peroxide

1975 ◽  
Vol 53 (5) ◽  
pp. 495-501 ◽  
Author(s):  
D. Dolman ◽  
G. A. Newell ◽  
M. D. Thurlow ◽  
H. B. Dunford
Keyword(s):  
Hydrogen Peroxide ◽  
Horseradish Peroxidase ◽  
Kinetic Study ◽  
Enzyme Analysis ◽  
Cyanide Binding ◽  
Rate Of Reaction ◽  
Form Compound ◽  
Ph Range ◽  
Kinetics Of ◽  
Ionizable Groups

A kinetic study has been carried out over the pH range of 2.63–9.37 for the reaction of horseradish peroxidase with hydrogen peroxide to form compound 1 of the enzyme. Analysis of the results, indicates that there are two kinetic influencing, ionizable groups on the enzyme with pKa values of 3.2 and 3.9. Protonation of these groups results in a decrease in the rate of reaction of the enzyme with H2O2.A previous study of the kinetics of cyanide binding to horseradish peroxidase (Ellis, W. D. &Dunford, H. B.: Biochemistry 7, 2054–2062 (1968)) has been extended down to pH 2.55, and analysis of these results also indicates the presence of two kinetically important ionizable groups on the enzyme with pKa values of 2.9 and 3.9.

Sign in / Sign up

Export Citation Format

Share Document