Étude cinétique de la N-chloration de l'acide cyanurique en phase aqueuse

1990 ◽  
Vol 68 (2) ◽  
pp. 307-313 ◽  
Author(s):  
Denise Matte ◽  
Bernard Solastiouk ◽  
André Merlin ◽  
Xavier Deglise
Keyword(s):  
Aqueous Medium ◽  
Rate Constants ◽  
Cyanuric Acid ◽  
Stopped Flow ◽  
Experimental Values ◽  
Kinetics Of Reaction ◽  
Limiting Case ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Phase Aqueuse

A complete kinetic study of the N-chlorination, in basic aqueous medium, of cyanuric acid by the stopflow spectrophotometric method is presented. Our experimental results can be interpreted by two pairs of kinetically indistinguishable mechanisms.[Formula: see text]or[Formula: see text]and[Formula: see text]or[Formula: see text]The rate constants and their corresponding activation energies were determined in the limiting case where one of the elementary steps in each pair is involved alone in the kinetics of reaction.[Formula: see text]The rate constants for hydrolysis of the monochlorinated cyanuric acid derivatives were derived from our experimental values. Keywords: kinetics, N-chlorination, 1,3,5-triazine-2,4,6-trione, aqueous medium, stopped flow.

Étude cinétique de la N-chloration de la succinimide en phase aqueuse

1992 ◽  
Vol 70 (1) ◽  
pp. 89-99 ◽  
Author(s):  
Denise Matte ◽  
Bernard Solastiouk ◽  
André Merlin ◽  
Xavier Deglise
Keyword(s):  
Aqueous Medium ◽  
Rate Constants ◽  
Low Ph ◽  
Chloride Ions ◽  
Nucleophilic Attack ◽  
Stopped Flow ◽  
Molecular Chlorine ◽  
Kinetics Of ◽  
Limiting Values ◽  
Phase Aqueuse

A kinetic study of the N-chlorination, in aqueous medium, of succinimide (SH) at low pH (<5) and at high pH (>9) is presented. We have derived the rate constants and activation energies of the processes involved. A stopped-flow spectrophotometric technique was used to study the kinetics. Without chloride ions, our experimental results can be interpreted by two kinetically indistinguishable mechanisms:[Formula: see text]The limiting values of the rate constants for the case in which only one process is involved in the kinetics of chlorination were evaluated: [Formula: see text]; [Formula: see text].In acid medium, in the presence of chloride ions, we observe a nucleophilic attack of the S− ion on molecular chlorine Cl2. This process is added to the two former processes. Keywords: kinetics, N-chlorination, succinimide, aqueous medium, stopped flow.

Kinetics of hydrolysis of peroxodisulphate ions in acidic medium to peroxomonosulphuric acid

1981 ◽  
Vol 46 (5) ◽  
pp. 1229-1236 ◽  
Author(s):  
Jan Balej ◽  
Milada Thumová
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Acidic Medium ◽  
Measured Data ◽  
Molar Ratios ◽  
Starting Solution ◽  
Kinetics Of Hydrolysis ◽  
Rate Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

The rate of hydrolysis of S2O82- ions in acidic medium to peroxomonosulphuric acid was measured at 20 and 30 °C. The composition of the starting solution corresponded to the anolyte flowing out from an electrolyser for production of this acid or its ammonium salt at various degrees of conversion and starting molar ratios of sulphuric acid to ammonium sulphate. The measured data served to calculate the rate constants at both temperatures on the basis of the earlier proposed mechanism of the hydrolysis, and their dependence on the ionic strength was studied.

scholarly journals Metal Enolates – Enamines – Enol Ethers: How Do Enolate Equivalents Differ in Nucleophilic Reactivity?

Synthesis ◽  
2019 ◽  
Vol 51 (05) ◽  
pp. 1157-1170 ◽  
Author(s):  
Artem Leonov ◽  
Daria Timofeeva ◽  
Armin Ofial ◽  
Herbert Mayr
Keyword(s):  
Rate Constants ◽  
Correlation Equation ◽  
Stopped Flow ◽  
Quinone Methides ◽  
Enol Ethers ◽  
Reactivity Descriptors ◽  
Silyl Enol Ethers ◽  
Nucleophilic Reactivity ◽  
Kinetics Of ◽  
Least Squares Minimization

The kinetics of the reactions of trimethylsilyl enol ethers and enamines (derived from deoxybenzoin, indane-1-one, and α-tetralone) with reference electrophiles (p-quinone methides, benzhydrylium and indolylbenzylium ions) were measured by conventional and stopped-flow photometry in acetonitrile at 20 °C. The resulting second-order rate constants were subjected to a least-squares minimization based on the correlation equation lg k = s N(N + E) for determining the reactivity descriptors N and s N of the silyl enol ethers and enamines. The relative reactivities of structurally analogous silyl enol ethers, enamines, and enolate anions towards carbon-centered electrophiles are determined as 1, 107, and 1014, respectively. A survey of synthetic applications of enolate ions and their synthetic equivalents shows that their behavior can be properly described by their nucleophilicity parameters, which therefore can be used for designing novel synthetic transformations.

scholarly journals The Kinetics of Peroxynitrite on Insulin Nitration Damage

2020 ◽  
Author(s):  
Congxiao Zhang ◽  
Fusheng Sun ◽  
Congjiang Zhang ◽  
Yunjing Luo
Keyword(s):  
Activation Energy ◽  
Biological Activity ◽  
Glucose Metabolism ◽  
Rate Constants ◽  
The Body ◽  
Stopped Flow ◽  
Tyrosine Nitration ◽  
Protein Nitration ◽  
Physiological Conditions ◽  
Kinetics Of

Abstract Background: Insulin is one of the most important versatile hormones that is central to regulating the energy and glucose metabolism in the body. There has been accumulating evidence supporting that diabetes was associated with peroxynitrite and protein nitration, and insulin nitration induced by peroxynitrite affected its biological activity. Methods: In this paper, the kinetics of insulin nitration by peroxynitrite in physiological conditions was studied by the stopped flow technique. Results: We determined the values of the reactive rate constants of peroxynitrite decomposition and peroxynitrite-induced tyrosine nitration in the presence of insulin. The activation energy of peroxynitrite decomposition and 3-nitrotyrosine yield in the presence of insulin is 48.8 kJ·mol−1 and 42.7 kJ·mol−1 respectively. Conclusions: It is inferred that the glutamate residue of insulin accelerated peroxynitrite decomposition and tyrosine nitration by reducing the activation energy of reactions. The results could be beneficial for exploring the molecular mechanism of diabetes and offering a new target for diabetes therapies.

Studies on the kinetics of reaction and hydrolysis of fluorescamine

1974 ◽  
Vol 163 (1) ◽  
pp. 400-403 ◽  
Author(s):  
Stanley Stein ◽  
Peter Böhlen ◽  
Sidney Udenfriend
Keyword(s):  
Kinetics Of Reaction ◽  
Kinetics Of ◽  
Hydrolysis Of

KINETICS OF THE AQUEOUS ALKALINE HOMOGENOUS HYDROLYSIS OF HIGH EXPLOSIVE 1, 3,5,7-TETRAAZA- 1, 3,5,7-TETRANITROCYCLOOCTANE (HMX)

1994 ◽  
Vol 30 (3) ◽  
pp. 53-61 ◽  
Author(s):  
Harro M. Heilmann ◽  
Michael K. Stenstrom ◽  
Rolf P. X. Hesselmann ◽  
Udo Wiesmann
Keyword(s):  
Temperature Dependence ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Elevated Temperatures ◽  
Second Order ◽  
Order Rate ◽  
Subsequent Calculation ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Order Rate Equation

In order to get basic data for the design of a novel treatment scheme for high explosives we investigated the kinetics for the aqueous alkaline hydrolysis of 1,3,5,7-tetraaza-1,3,5,7-tetranitrocyclooctane (HMX) and the temperature dependence of the rate constants. We used an HPLC procedure for the analysis of HMX. All experimental data could be fit accurately to a pseudo first-order rate equation and subsequent calculation of second-order rate constants was also precise. Temperature dependence could be modeled with the Arrhenius equation. An increase of 10°C led to an average increase in the second-order rate constants by the 3.16 fold. The activation energy of the second-order reaction was determined to be 111.9 ±0.76 kJ·moJ‒1. We found the alkaline hydrolysis to be rapid (less than 2.5% of the initial HMX-concentration left after 100 minutes) at base concentrations of 23 mmol oH‒/L and elevated temperatures between 60 and 80°C.

scholarly journals Effect of Cationic/Anionic Mixed Micelles on Reaction Kinetics of Alkaline Hydrolysis of Crystal Violet

2019 ◽  
Vol 31 (3) ◽  
pp. 651-655
Author(s):  
Qidist Yilma ◽  
Dunkana Negussa ◽  
Y. Dominic Ravichandran
Keyword(s):  
Crystal Violet ◽  
Alkaline Hydrolysis ◽  
Mixed Micelles ◽  
Sodium Dodecyl ◽  
Binding Constants ◽  
Regression Parameters ◽  
Experimental Values ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Good Agreement

Kinetics of alkaline hydrolysis of crystal violet, a triphenylmethane dye in the micellar environment of cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfonate (SDS) and binary mixtures of these surfactants was studied. The regression parameters, together with rate constants and binding constants were obtained by analyzing the rate surfactant profiles using cooperativity model. It was observed that the reaction was catalyzed by both surfactants. The catalytic factor increased by 10 times in SDS and 38 times in CTAB indicating that binding of crystal violet to the micellar surface is stronger in pure CTAB than SDS but the strength drastically reduced in the mixtures of the surfactants. Reduction of binding constant became more important as the mole fraction of CTAB was improved in the mixture. The kinetic data were investigated using Piszkiewicz model and Raghavan-Srinivasan model. The data obtained from the models were in good agreement with the experimental values.

Stopped-flow cryoenzymological investigation of the pre-steady-state kinetics of hydrolysis of Leu-Gly-NHNH-Dns by leucine aminopeptidase

Biochemistry ◽  
1988 ◽  
Vol 27 (14) ◽  
pp. 5068-5074 ◽  
Author(s):  
Wann Yin Lin ◽  
Spencer H. Lin ◽  
Roger J. Morris ◽  
Harold E. Van Wart
Keyword(s):  
Steady State ◽  
Leucine Aminopeptidase ◽  
Stopped Flow ◽  
Kinetics Of Hydrolysis ◽  
Steady State Kinetics ◽  
Kinetics Of ◽  
Hydrolysis Of
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