Kinetics of oxidation of nitrite by aqueous chlorine

1973 ◽  
Vol 26 (9) ◽  
pp. 1857 ◽  
Author(s):  
JN Pendlebury ◽  
RH Smith
Keyword(s):  
Nitrous Acid ◽  
Ionization Constant ◽  
Initial Step ◽  
The Other ◽  
Stopped Flow ◽  
Unimolecular Decomposition ◽  
Solution Ph ◽  
Kinetics Of Oxidation ◽  
Aqueous Acid ◽  
Kinetics Of

The kinetics of oxidation of nitrite to nitrate by chlorine in aqueous acid solution (pH 0-1) have been studied using a spectrophotometric stopped flow technique. The rate law is ���������������� -d[Cl2]a/dt =([Cl2][NO2-]/Ka[Cl-]2)(f+g[HNO2]) where [Cl2]a = [Cl2]+[Cl3-] and where Ka is the ionization constant for nitrous acid. At 298.2 K and ionic strength 2.75M, f = 60.8�0.5 mol2 l-2 s-1 and g = (2.35�0.05)x105 mol l-1 s-1: the associated activation energies are 68�3 and 44�2 kJ mol-1 respectively. A mechanism is proposed involving the reversible initial step: �������������������������� NO2-+Cl2 ↔ NO2Cl+Cl- with the NO2Cl undergoing two parallel subsequent reactions, one a unimolecular decomposition and the other an attack by HNO2 upon NO2Cl. ��� Oxidation of nitrite by the three halogens, Cl2, Br2, I2, is discussed.

Kinetics of oxidation of nitrite by hypochlorite ions in aqueous basic solution

1976 ◽  
Vol 54 (21) ◽  
pp. 3401-3406 ◽  
Author(s):  
J. M. Cachaza ◽  
J. Casado ◽  
A. Castro ◽  
M. A. López Quintela
Keyword(s):  
Ionic Strength ◽  
Initial Step ◽  
Activation Energies ◽  
The Other ◽  
Basic Solution ◽  
Unimolecular Decomposition ◽  
Kinetics Of Oxidation ◽  
Rate Law ◽  
Kinetics Of

The kinetics of oxidation of nitrite to nitrate by hypochlorite ions in aqueous basic solution [Formula: see text] have been studied using a dynamic spectrophotometric technique. The rate law is[Formula: see text]At 298.0 K and ionic strength 0.40 M, d = (3.4 ± 0.2) × 10−8 mol l−1 s−1 and e = (2.8 ± 0.2) × 10−6 s−1. The associated activation energies are 56 ± 3 and 61 ± 3 kJ mol−1 respectively. A mechanism is proposed involving the reversible initial step:[Formula: see text]with the NO2Cl undergoing two parallel subsequent reactions, one a unimolecular decomposition and the other an attack by NO2− on NO2Cl.

A Study of Substituent Effect on the Oxidative Strengths of N-Chloroarenesulphonamides: Kinetics of Oxidation of Leucine and Isoleucine in Aqueous Acid Medium

2004 ◽  
Vol 59 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Mahesha Shetty ◽  
B. Thimme Gowda
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ionic Strength ◽  
Acid Medium ◽  
Benzene Ring ◽  
Thermodynamic Data ◽  
Substituent Effect ◽  
Kinetics Of Oxidation ◽  
Aqueous Acid ◽  
Kinetics Of

Abstract To study the variation of oxidative strengths of N-chloro-arenesulphonamides with substitution in the benzene ring, six mono- and five di-substituted N-chloro-arenesulphonamides are employed as oxidants for studying the kinetics of oxidation of two neutral amino acids, L-leucine and Lisoleucine in aqueous acid medium. The N-chloro-arenesulphonamides studied are of the constitution: ArSO2NaNCl·H2O (where Ar = C6H5, 4-CH3C6H4, 4-C2H5C6H4, 4-FC6H4, 4-ClC6H4, 4-BrC6H4, 2,3-(CH3)2C6H3, 2,4-(CH3)2C6H3, 2-CH3-4-ClC6H3, 2,4-Cl2C6H3, and 3,4-Cl2C6H3). The reactions show second order kinetics in [oxidant], fractional order in [amino acid] and inverse dependence on [H+]. Addition of the reduced product of the oxidants or variation in ionic strength of the medium has no significant effect on the rates of oxidations. A two-pathway mechanism is considered to explain the experimental results. Effective oxidizing species of the oxidants is Cl+ in different forms. Therefore the oxidising strengths of N-chloro-arenesulphonamides depend on the ease with which Cl+ is released from them. The study reveals that the introduction of substituent in the benzene ring of the oxidant affects both the kinetic and thermodynamic data for the oxidations The electron releasing groups such as CH3 generally inhibit the rates, while electron-withdrawing groups such as Cl enhance this ability, as the electron withdrawing groups ease the release of Cl+ from the reagents and hence increase the oxidising strengths. The on Ea and logA and validity of the Hammett and isokinetic relationships for the oxidations are also analysed.

Kinetics of oxidation of thiocyanate by aqueous iodine

1973 ◽  
Vol 26 (9) ◽  
pp. 1863 ◽  
Author(s):  
GT Briot ◽  
RH Smith
Keyword(s):  
Rate Constants ◽  
Activation Energies ◽  
Stopped Flow ◽  
Kinetics Of Oxidation ◽  
Rate Law ◽  
General Base ◽  
Present Rate ◽  
Rapid Equilibrium ◽  
Ph Range ◽  
Kinetics Of

The kinetics of oxidation of thiocyanate to sulphate by aqueous iodine in the pH range 9.2-12.5 have been studied using a spectrophotometric stopped flow technique. The reaction is general base-catalysed, having the rate law ��������������������� -d[I2]a/dt = ([SCN-][I3-]/[I-]2)Σ kB[B] where [I2]a is the total analytical concentration of iodine, [B] is the concentration of base, and where the summation is taken over all bases present. Rate constants, kB, and activation energies have been measured for the bases, OH-, PO43- and CO32-. ��� A mechanism involving the initial steps ����������������� I2+SCN- ↔ ISCN+I- �����������������(rapid equilibrium) ������������� ISCN+H2O+B → HOSCN+I- + HB+ �����������(rate determining) followed by rapid reactions of HOSCN with itself or with iodine is proposed.

Kinetics of oxidation and dissolution of uranium dioxide in aqueous acid solutions

2012 ◽  
Vol 83 ◽  
pp. 471-477 ◽  
Author(s):  
Coralie Gaulard-Balandret ◽  
Nathalie Larabi-Gruet ◽  
Frédéric Miserque ◽  
Jean Radwan ◽  
Cécile Ferry ◽  
...  
Keyword(s):  
Uranium Dioxide ◽  
Acid Solutions ◽  
Kinetics Of Oxidation ◽  
Aqueous Acid ◽  
Kinetics Of

scholarly journals A mechanistic investigation of the oxidation of N,α-diphenylnitrones by dichloramine-T in aqueous acetonitrile medium - a non-linear Hammett plot

2009 ◽  
Vol 74 (5) ◽  
pp. 493-502
Author(s):  
S. Manivarman ◽  
G. Rajarajan ◽  
G. Manikandan ◽  
M. Sekar ◽  
J. Jayabharathi ◽  
...  
Keyword(s):  
Reaction Rate ◽  
The Other ◽  
Hammett Constant ◽  
Kinetics Of Oxidation ◽  
Aqueous Acetonitrile ◽  
First Order ◽  
Mechanistic Investigation ◽  
Non Linear ◽  
Kinetics Of ◽  
Acetonitrile Medium

The kinetics of oxidation of a number of meta- and para-substituted N,?-diphenylnitrones (nitrone) by dichloramine-T (DCT) was investigated in the presence of alkali in aqueous acetonitrile medium. The order with respect to DCT was one and to OH- an inverse fractional order. The reaction was first order with respect to nitrone. Both electron releasing and withdrawing substituents suppress the reaction rate. The observed rate constant for the substituents were plotted against the Hammett constant, ?, and a non-linear concave downward curve was obtained. The electron withdrawing substituents fall on one side of the curve, having a negative ? value and the electron releasing substituents fall on the other side, with a positive ? value. A mechanism is proposed and the derived rate law is in conformity with the observed results.

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