scholarly journals Study on Catalyzed Tungstophosphoric Acid oxidation of p-Chloro Benzhydrol and p-Methyl Benzhydrol by N-Bromoisonicotinamide in Aqueous Acetic Acid Medium

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
S. Shree Devi ◽  
B. Muthukumaran ◽  
P. Krishnamoorthy

Kinetics and mechanism of oxidation of substituted 5-oxoacids by sodium perborate in aqueous acetic acid medium have been studied. The reaction exhibits first order both in [perborate] and [5-oxoacid] and second order in [H+]. Variation in ionic strength has no effect on the reaction rate, while the reaction rates are enhanced on lowering the dielectric constant of the reaction medium. Electron releasing substituents in the aromatic ring accelerate the reaction rate and electron withdrawing substituents retard the reaction. The order of reactivity among the studied 5-oxoacids is p-methoxy ≫ p-methyl > p-phenyl > –H > p-chloro > p-bromo > m-nitro. The oxidation is faster than H2O2 oxidation. The formation of H2BO3+ is the reactive species of perborate in the acid medium. Activation parameters have been evaluated using Arrhenius and Eyring’s plots. A mechanism consistent with the observed kinetic data has been proposed and discussed. Based on the mechanism a suitable rate law is derived.


2012 ◽  
Vol 14 (4) ◽  
pp. 35-41 ◽  
Author(s):  
Raja Manickam ◽  
Karunakaran Kulandaivelu

Abstract The catalytic properties of the first generation catalyst meso-tetraphenylporphyriniron(III) chloride and magnesium monoperoxyphthalate (MMPP) as oxidant have been studied in the oxidation of aniline and its substituents in acetic acid medium. The thermodynamic parameters for the oxidation have been determined and discussed. It confirms the Exner relationship (only at the low range of temperatures) and also some of the activation parameters to the isokinetic relationships. The magnesium monoperoxyphthalate oxidation with 18 ortho- meta- and para-substituted anilines fulfills with isokinetic relationship but not to any of the linear free energy relationships. The reaction mechanism and the rate law were proposed.


2004 ◽  
Vol 1 (2) ◽  
pp. 127-131 ◽  
Author(s):  
N. A. Mohamed Farook ◽  
R. Prabaharan ◽  
S. Rahini ◽  
R. Senthil Kumar ◽  
G. Rajamahendran ◽  
...  

The kinetics of oxidation of some amino acids namely, glycine, alanine, aspartic acid, arginine, and histidine, (AA) byN-chlorosaccharin (NCSA) in aqueous acetic acid medium in the presence of perchloric acid have been investigated. The observed rate of oxidation is first order in [AA], [NCSA] and of inverse fractional order in [H+]. The main product of the oxidation is the corresponding aldehyde. The ionic strength on the reaction rate has no significant effect. The effect of changing the dielectric constant of the medium on the rate indicates the reaction to be of dipole-dipole type. Hypochlorous acid has been postulated as the reactive oxidizing species. The reaction constants involved in the mechanism are derived. The activation parameters are computed with respect to slow step of the mechanism.


Author(s):  
S. Parimala Vaijayanthi ◽  
N. Mathiyalagan

The kinetics of oxidation of amino acids namely, alanine, glycine, leucine, phenyl alanine and valine by N-chloropyrazinamide (NCPZA) in aqueous acetic acid medium in the presence of hydrochloric acid have been investigated. The observed rate of oxidation is first order in [NCPZA], [H+] and [Clˉ]. The order with respect to [amino acid] is zero. The rate of oxidation increases with increase in the percentage of acetic acid. The reaction rate increases slightly with increase in ionic strength, while retards with addition of pyrazinamide. Arrhenius and thermodynamic activation parameters have been evaluated from Arrhenius plot by studying the reaction at different temperatures. A most probable reaction mechanism has been proposed and an appropriate rate law is deduced toaccount for the observed kinetic data.


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