scholarly journals Kinetics and Mechanism of Oxidation oft-Butylbenzylamine by Diperiodatoargentate(III) in Aqueous Alkali

2012 ◽  
Vol 9 (1) ◽  
pp. 203-210 ◽  
Author(s):  
Mahantesh A. Angadi ◽  
Suresh M. Tuwar

t-Butylbenzylamine (t-BA) is used as a free base in the synthesis of salbutamol drug. Its mechanism of oxidation was proposed from kinetic studies. The kinetics of oxidation oft-butylbenzylamine by diperiodatoargentate(III) (DPA) was studied spectrophotometrically by monitoring decrease in absorbance of DPA. The reaction was found to be first order each in [DPA] and [t-BA]. The effect of alkali concentration in a wide range on rate of reaction was studied. The rate of reaction was found to be increased with increase in [OH–] in the lower range of [OH–], decreasing effect in the middle range and at higher range again increasing effect on rate of reaction was observed. The added periodate retarded the rate of reaction. The polymerization test revealed that oxidation was occurred with the intervention free radical. A suitable mechanism was proposed for a middle range of [OH–]. The active species of silver(III) periodate for all the three different stages of [OH–] are assayed. Rate law was derived and verified. The oxidative product oft-BA was characterized by LC-ESI-MS spectra.

2011 ◽  
Vol 8 (4) ◽  
pp. 1472-1477
Author(s):  
N. M. I. Alhaji ◽  
S. Sofiya Lawrence Mary

The kinetics of oxidation of glutamic acid (Glu) withN-bromophthalimide (NBP) was studied in perchloric acid medium at 30°C by potentiometric method. The reaction is first order each in NBP and glutamic acid and is negative fractional order in [H+]. Addition of KBr or the reaction product, phthalimide had no effect on the rate. Similarly variation of ionic strength of the medium did not affect the rate of the reaction. Also the rate increased with decrease in dielectric constant of the reaction medium. The thermodynamic parameters were computed from Arrhenius and Eyring plots. A suitable mechanism consistent with the kinetic results has been proposed.


1985 ◽  
Vol 63 (12) ◽  
pp. 3317-3321 ◽  
Author(s):  
M. M. Girgis ◽  
S. A. El-Shatoury ◽  
Z. H. Khalil

The initial oxidation stages of lactic acid by acid permanganate were investigated. The rate of the induction period was slow and then gradually increased. The kinetics of oxidation were second order, first order with respect to both lactic acid and Mn(VII). The reaction was acid catalyzed. Addition of Mn(II) ions largely increased the rate of the initial stages and decreased the rate of the following stages. The oxidation rate was decreased by the addition of F− or [Formula: see text] ions. The Arrhenius equation was valid for the reaction between 16.5 and 34 °C. Activation parameters were evaluated and a mechanism consistent with the results obtained was proposed.


2009 ◽  
Vol 6 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Annapurna Nowduri ◽  
Kalyan Kumar Adari ◽  
Nageswara Rao Gollapalli ◽  
Vani Parvataneni

Kinetics of oxidation ofL-cystine by hexacyanoferrate(III) was studied in alkaline medium at 30 °C. The reaction was followed spectrophotometrically at λmax = 420 nm. The reaction was found to be first order dependence each on [HCF(III)] and [cystine]. It was found that the rate of the reaction increases with increase in [OH-]. The oxidation product of the reaction was found to be cysteic acid. A plausible mechanism has been proposed to account for the experimental results.


2011 ◽  
Vol 8 (1) ◽  
pp. 159-166 ◽  
Author(s):  
N. M. I. Alhaj ◽  
A. M. Uduman Mohideen ◽  
S. Sofia Lawrence Mary

The kinetics of oxidation of (phenylthio)acetic acid (PTAA) withN-chlorosaccharin (NCSA) have been studied potentiometrically in 80:20 (v/v) acetonitrile-water medium at 298 K. The reaction is first-order each with respect to PTAA and NCSA and shows a negative dependence on [H+]. NCSA itself is shown to be the active oxidizing species. Effects of ionic strength variation, added saccharin, added acrylonitrile, added NaCl and solvent composition variation have been studied. Effect of substituents on the reaction rate has been analysed by employing various (p-sustituted phenylthio)acetic acids. The electron-releasing substituent in the phenyl ring of PTAA accelerates the reaction rate while the electron-withdrawing substituent retards the rate. The excellently linear Hammett plot yields a large negative ρ value, supporting the involvement a chlorosulphonium ion intermediate in the rate-determining step.


A kinetic study of the degradation and interconversion of glucose and fructose in alkaline solution has been carried out. The change in sugar concentration has been followed by electrometric titration of lactic and saccharinie acids, which are the main products of the degradation in the range of alkali concentration used. A kinetic analysis of the results indicates that all the reactions which occur are of first order with respect to the sugar concentration. In a general discussion of parts I and II of this series, it is shown that the observed dependence of the rates of the degradation and interconversion reactions of glucose upon the sugar and alkali concentration can be explained in terms of the ionic intermediates postulated for the autoxidation reaction. These intermediates are therefore probably concerned in the rate-determining steps of the reactions in the range of alkali concentration used. The absolute velocity constants of most of the reactions have been calculated on this basis. The structure of the intermediates and the mechanism of the reactions are discussed.


2016 ◽  
Vol 230 (8) ◽  
Author(s):  
Muthusamy Rukmangathan ◽  
Vetrivel Santhoshkumar ◽  
Balasubramanian Ramkumar

AbstractThe kinetics of oxidation of a few aliphatic primary alcohols with 1-chlorobenzimidazole (CBI) was studied in aqueous acetic acid medium. The reactions were found to be first order each with respect to the concentrations of CBI and alcohol. The added HClO


2005 ◽  
Vol 70 (4) ◽  
pp. 585-592 ◽  
Author(s):  
J.H. Shan ◽  
S.Y. Huo ◽  
S.G. Shen ◽  
H.W. Sun

The kinetics of oxidation of 1,2-propanediol and 1,2,3-propanetriol by dihydroxyditelluratoargentate(III) (DDA) were studied spectrophotometrically between 298.2 K and 313.2 K in alkaline medium. The reaction rate showed first order dependence on DDA and 1 < nap < 2 order on the reductant. It was found that the pseudo-first order rate constant kobs increased with increasing concentration of OH-1 and decreasing concentration of TeO42-. There is a negative salt effect and no free radicals were detected. In view of this, the dihydroxymonotelluratoargentate(III) species is assumed to be the active species. A plausible mechanism involving a two-electron transfer is proposed and the rate equations derived from the mechanism can explain all the experimental results. The activation parameters, as well as the rate constants of the rate-determining step were calculated.


2009 ◽  
Vol 6 (3) ◽  
pp. 920-927 ◽  
Author(s):  
G. Vanangamudi ◽  
S. Srinivasan

The kinetics of oxidation of cinnamic acids by pyridinium bromochromate (PBC) in the presence of oxalic acid has been studied in acetic acid-water (60:40%) medium. The reaction shows unit order dependence each with respect to oxidant as well as oxalic acid [OX], the order with respect to [H+] and [CA] are fractional. The reaction is acid catalyzed and a low dielectric constant favours the reaction. Increase the ionic strength has no effect on the reaction rate. In the case of substituted cinnamic acids the order with respect to substrate vary depending upon the nature of the substituent present in the ring. In general, the electron withdrawing substituents retard the rate while the electron releasing substituents enhance the rate of reaction. From the kinetic data obtained the activation parameters have been computed and a suitable mechanism has been proposed.


2003 ◽  
Vol 2003 (4) ◽  
pp. 182-183 ◽  
Author(s):  
Gamal Abdel-Whab Ahmed ◽  
Khalid Suliman Khairou ◽  
Refat Moustafa Hassan

The kinetics of oxidation of chitosan as polysaccharide by permanganate in aqueous perchlorate media at a constant ionic strength was found to have second-order overall kinetics and to be first-order in the concentration of both reactants, the results obtained showed that the reaction is acid catalysed.


2011 ◽  
Vol 8 (3) ◽  
pp. 1371-1377
Author(s):  
Shan Jinhuan ◽  
Yang Yafeng

The kinetics of oxidation of isobutylamine and 1,4-butanediamine by home-made potassium ferrate(VI) at different conditions has been studied spectrophotometrically in the temperature range of 288.2 -303.2 K. The results show first order dependence on potassium ferrate(VI) and on each reductant. The observed rate constant (kobs) decreases with the increase of [OH-], the reaction was negative fraction order with respect to [OH-]. A plausible mechanism was proposed and the rate equations derived from the mechanism can explain all the experimental results. The rate constants of the rate-determining step and the thermodynamic activation parameters were calculated.


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