Oxygen transfer reactions. 3. The oxidation of sulfides by sodium perruthenate

1995 ◽  
Vol 73 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Donald G. Lee ◽  
Huifa Gai
Keyword(s):  
Reaction Mechanism ◽  
Transition Metal ◽  
Transition State ◽  
Oxygen Transfer ◽  
Coordination Shell ◽  
Transfer Reactions ◽  
Hydroxide Ion ◽  
First Order ◽  
Order Dependence ◽  
Substituent Constants

The transfer of oxygen from transition metal oxidants to sulfur (MO4− + R2S → MO3− + R2SO) has been studied using the oxidation of alkylthio or arylthioacetic acids (RSCH2CO2H) by perruthenate as models. These reactions exhibit a first-order dependence on the concentrations of both the oxidant and the reductant, and are directly proportional to the basicity of the medium. The Hammet ρ value is negative (ρ = −0.66), a better correlation being obtained when σ, rather than σ+, substituent constants are used. The entropies of activation for the reactions are large and negative, indicating that the transition state is highly structured. A reaction mechanism involving an activating expansion of the ruthenium coordination shell through incorporation of a hydroxide ion is proposed. Oxygen transfer is then initiated by reaction of a nonbonding pair of sulfur electrons with either a vacant ruthenium d-orbital or a Ru=O π*-orbital. Keywords: perruthenate, sulfides, oxygen transfer, oxidation.

Kinetics and Mechanism of Reaction of 2,4-Dinitrobenzaldehyde with Hydroxide Ion

1994 ◽  
Vol 59 (10) ◽  
pp. 2262-2268 ◽  
Author(s):  
Vladimír Macháček ◽  
Jana Manová ◽  
Miloš Sedlák ◽  
Vojeslav Štěrba
Keyword(s):  
Reaction Mechanism ◽  
Equilibrium Constant ◽  
Reaction Order ◽  
Kinetics And Mechanism ◽  
Hydroxide Ion ◽  
First Order ◽  
Mechanism Of Reaction

The reaction of 2,4-dinitrobenzaldehyde with hydroxide ion in water is first order in the substrate. The reaction order in hydroxide ion varies from one to two at lower and higher OH- concentrations, respectively. The reaction mechanism has been suggested, the pKa value of reaction product 2-nitro-4-nitrosophenol and the equilibrium constant of formation of the Meisenheimer adduct from 2-nitro-4-nitrosophenoxide and hydroxide ion have been determined.

scholarly journals Nonenzymatic NADH-Dependent Reduction of Keggin-Type 12-Tungstocobaltate(III) in Aqueous Medium

2011 ◽  
Vol 8 (3) ◽  
pp. 1152-1157
Author(s):  
Prabla Kumari ◽  
Alaka Das ◽  
Dillip Kumar Baral ◽  
A. K. Pattanaik ◽  
P. Mohanty
Keyword(s):  
Electron Transfer ◽  
Transition State ◽  
Aqueous Medium ◽  
Transfer Reaction ◽  
Activation Parameters ◽  
Electron Transfer Reaction ◽  
Transfer Reactions ◽  
Electron Transfer Reactions ◽  
First Order ◽  
Kinetics Of

The kinetics of the electron transfer reaction of NADH with 12-tungstocobaltate(III) has been studied over the range 5.07 ≤ 104[NADH] ≤ 15.22 mol dm-3, 7.0 ≤ pH ≤ 8.0 and 20 ≤ t ≤ 35oC in aqueous medium. The electron transfer reaction showed first-order dependence each in [NADH]Tand [12-tungstocobaltate(III)]T. The products of the reaction were found to be NAD+and 12-tungstocobaltate(II). The activation parameters ΔH#(kJ mol-1) and ΔS#(JK-1mol-1) of the electron transfer reactions were found to be 64.4±1.8 and -48.86±6.0. Negative value of ΔS#is an indicative of an ordered transition state for the electron transfer reaction.

scholarly journals Mechanisms and consequences of oxygen transfer reactions

2000 ◽  
Vol 72 (12) ◽  
pp. 2259-2264 ◽  
Author(s):  
Peter Beak ◽  
David R. Anderson ◽  
Stephen G. Jarboe ◽  
Mitchell L. Kurtzweil ◽  
Keith W. Woods
Keyword(s):  
Double Bond ◽  
Transition State ◽  
Molecular Oxygen ◽  
Oxygen Transfer ◽  
Large Angle ◽  
Transfer Reactions ◽  
Oblique Angle ◽  
Leaving Groups ◽  
Transition State Structures

The geometry about oxygen in the transition-state structures for oxygen transfers from a nitrone to phosphorous, from a percarboxylic acid to a carbon­carbon double bond, and from an N-sulfonyl oxaziridine to a carbon­carbon double bond have been evaluated by the endocyclic restriction test. The former can proceed at an oblique angle, while the latter two require a large angle between the entering and leaving groups on oxygen. This information is used to determine the mechanism of the aldehyde-dependent oxygen transfer from molecular oxygen to a carbon­carbon double bond.

scholarly journals Non enzymatic NADH-dependent reduction of Cis-[Co(en)2(H2O)2]3+ in aqueous medium

2018 ◽  
Vol 6 (2) ◽  
pp. 163
Author(s):  
Bharati Behera ◽  
Jashoda Behera
Keyword(s):  
Electron Transfer ◽  
Aqueous Medium ◽  
Transfer Reaction ◽  
Activation Parameters ◽  
Electron Transfer Reaction ◽  
Transfer Reactions ◽  
Electron Transfer Reactions ◽  
First Order ◽  
Order Dependence ◽  
Kinetics Of

The kinetics of the electron transfer reaction of NADH with Cis-[Co(en)2(H2O)2]3+ has been studied over the range 1.0 ≤ 102 [NADH] ≤ 3.0 mol dm-3, 7.0 ≤ pH ≤ 8.0 and 200C ≤ t ≤ 350C in aqueous medium. The rate of electron transfer reaction was found to be first-order dependence each in [NADH]T and Cis-[Co(en)2(H2O)2]3+T. The products of the reaction were found to be NAD+ and Co(II). The corresponding activation parameters of the electron transfer reactions were found to be as ΔH#=27.55 kJ mol-1 and  ΔS#= -189.35 JK-1mol-1. 

Oxidation of Hydrazine by Alkaline Ferricyanide in Water-methanol Mixtures

1970 ◽  
Vol 25 (2) ◽  
pp. 188-190 ◽  
Author(s):  
V. K. Jindal ◽  
M. C. Agrawal ◽  
S. P. Mushran
Keyword(s):  
Ion Concentration ◽  
Hydroxide Ion ◽  
First Order ◽  
Order Dependence ◽  
Buffer Solutions ◽  
Entropy Of Activation ◽  
Alkaline Ferricyanide ◽  
Specific Ion Effect ◽  
Kinetics Of

Kinetics of the oxidation of hydrazine by ferricyanide was investigated in water-methanol mixtures using several buffer solutions. The reaction showed first order dependence in both hydrazine and ferricyanide. The order with respect to hydroxide ion concentration was zero. Increase in concentration of methanol had a retarding influence on the rate while the addition of neutral salts showed a specific ion effect. The energy and entropy of activation were calculated as 12.3 kcals. mole-1 and -20.8 cals. deg-1 mole-1 respectively. A suitable mechanism has been proposed which suggests the primary rate determining reaction between N2H4 and Fe (CN)63⊖. Nitrogen was found to be the product of the reaction.

scholarly journals Ruthenium (VI) Catalysed Oxidation of Diols by Alkaline Hexacyanoferrate(III) ion – a Kinetic Study

2001 ◽  
Vol 2001 (5) ◽  
pp. 182-184 ◽  
Author(s):  
Kunj Behari ◽  
Roli Srivastava ◽  
Veena
Keyword(s):  
Reaction Mechanism ◽  
Ionic Strength ◽  
Kinetic Study ◽  
Zero Order ◽  
Reduced Form ◽  
Aqueous Alkaline Medium ◽  
First Order ◽  
Order Dependence ◽  
Catalysed Oxidation ◽  
Kinetics Of

The kinetics of Ru(VI) catalysed oxidation of 1,5 pentane diol; 1,6-hexane-diol, 1-pentanol and 1-hexanol by hexacyanoferrate (III) ion in an aqueous alkaline medium at constant ionic strength shows zero order dependence on hexacyanoferrate (III) and first order dependence on Ru(VI) and substrate. The result suggest that a complex is formed between Ru(VI) and diol, which slowly decomposes to give a reduced form of ruthenium, which is reoxidised to Ru(VI) in a fast step be alkaline hexacyanoferrate(III). A plausible reaction mechanism is proposed.

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