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1.
D. S. Munavalli R. K. Patil S. A. Chimatadar S. T. Nandibewoor 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(13):2210-2214
The kinetics of ruthenium(III) catalyzed oxidation of sulfanilic acid by diperiodatocuprate(III) (DPC) in alkaline medium
at a constant ionic strength of (0.50 mol dm−3) has been studied spectrophoto-metrically. The reaction between sulfanilic acid and DPC in alkaline medium exhibits 1: 4
stoichiometry (sulfanilic acid: DPC). The reaction is first order with respect to [DPC] and [RuIII] and has less than unit order both in [sulfanilic acid] and [alkali]. The active species of catalyst and oxidant have been
identified. Intervention of free radicals was observed in the reaction. The main products were identified by spot test and
IR. Probable mechanism is proposed and discussed. The reaction constants involved in the different steps of the mechanism
are calculated. The activation parameters with respect to the slow step of the mechanism are computed and discussed. Thermodynamic
quantities are also determined. 相似文献
2.
R. K. Patil S. T. Nandibewoor S. A. Chimatadar 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(3):369-374
The kinetics of ruthenium(III) catalyzed oxidation of atenolol by diperiodatocuprate(III) in aqueous alkaline medium at a
constant ionic strength of I = 0.10 M has been studied spectrophotometrically at 27°C. The reaction between diperiodatocuprate(III) and atenolol in alkaline
medium in presence of ruthenium(III) exhibits 2: 1 stoichiometry (atenolol: diperiodatocuprate(III)). The main products were
identified by spot test, IR, NMR, and LC-MS. The reaction is of first order in DPC concentrations and has less than unit order
in both ATN and alkali concentrations. The order in ruthenium(III) was unity. Intervention of free radicals was observed in
the reaction. Increase in periodate concentration decreases the rate. The oxidation reaction in alkaline medium has been shown
to proceed via a ruthenium(III)-atenolol complex, which reacts with monoperiodatocuprate(III) in a rate determining step followed
by other fast steps to give the products. Probable mechanism is proposed and discussed. The activation parameters with respect
to the slow step of the mechanism and thermodynamic quantities were determined and discussed. 相似文献
3.
Deepak S. Munavalli Praveen N. Naik Shivamurti A. Chimatadar Sharanappa T. Nandibewoor 《Reaction Kinetics and Catalysis Letters》2008,94(2):359-366
The effect of La2O3, K2O and Li2O on the properties and catalytic performance of silica-supported nickel catalysts for the hydrogenation of m-dinitrobenzene was investigated. The catalysts promoted with La2O3, Li2O and K2O showed better catalytic performance than the catalyst without promotion, especially the ones co-promoted with La2O3 and K2O or Li2O. 相似文献
4.
The kinetics of oxidation of vanillin (VAN) by diperiodatocuprate(III) (DPC) in alkaline medium at a constant ionic strength of 0.50 mol dm?3 was studied spectrophotometrically. The reaction between DPC and vanillin in alkaline medium exhibits 1:2 stoichiometry (vanillin: DPC). The reaction is of first order in [DPC] and has less than unit order in both [VAN] and [alkali]. Intervention of free radicals was observed in the reaction. Increase in periodate concentration decreases the rate. The oxidation reaction in alkaline medium has been shown to proceed via a monoperiodatocuprate(III)–vanillin complex, which decomposes slowly in a rate‐determining step followed by other fast steps to give the products. The main products were identified by spot test, IR, and MS studies. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to slow step of the mechanism are computed and discussed, and thermodynamic quantities are also determined. © 2007 Wiley Periodicals, Inc. 39: 236–244, 2007 相似文献
5.
The kinetics of oxidation of atenolol (ATN) by diperiodatocuprate(III) (DPC) in aqueous alkaline medium at a constant ionic strength of 0.10 mol dm−3 was studied spectrophotometrically. The reaction between DPC and ATN in alkaline medium exhibits 1:2 stoichiometry (ATN:DPC). The reaction is of first order in [DPC] and has less than unit order in both [ATN] and [alkali]. However, the order in [ATN] and [alkali] changes from first order to zero order as their concentration increase. Intervention of free radicals was observed in the reaction. Increase in periodate concentration decreases the rate. The oxidation reaction in alkaline medium has been shown to proceed via a monoperiodatocuprate(III)–ATN complex, which decomposes slowly in a rate-determining step followed by other fast steps to give the products. The main oxidative products were identified by spot test, IR, NMR and LC–ESI-MS studies. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to slow step of the mechanism are computed and discussed, and thermodynamic quantities are also determined. 相似文献
6.
7.
The kinetics of oxidation of the anti-ulcer drug, ranitidine hydrochloride (RNH) by diperiodatocuprate(III) (DPC) in alkaline
medium was studied spectrophotometrically. The reaction exhibits 1:2 stoichiometry (ranitidine:DPC). The reaction is of first
order in [DPC] and has less than unit order in [RNH] and negative fractional order in [alkali]. The involvement of free radicals
was observed in the reaction. The oxidation has been found to proceed via a DPC-ranitidine complex, which decomposes slowly
in a rate-determining step followed by other fast steps to give the products, which were identified as ranitidine sulfoxide
by spot test and spectroscopic studies.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
8.
The kinetics of oxidation of L-cystine (L-CYS) by diperiodatocuprate (III) (DPC) in aqueous alkaline medium at a constant
ionic strength of 0.20 mol/1 was studied spectrophotometrically at 298 K. The reaction between DPC and L-cystine in alkaline
medium exhibits 1: 4 stoichiometry (L-cystine: DPC = 1: 4). The reaction is of first order in [DPC] and has less than unit
order in [L-CYS] and [alkali], negative fractional order in [periodate] and intervention of free radicals was observed in
the reaction. The oxidation reaction in alkaline medium has been shown to proceed via a monoperiodatocuprate(III)-L-ystine
complex, which decomposes slowly in a rate determining step followed by other fast steps to give the products. The main products
were identified by spot test, IR and GC-MS. The reaction constants involved in the different steps of the mechanism are calculated.
The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities
were also determined. 相似文献
9.
The kinetics of oxidation of isoniazid (INH) by diperiodatocuprate(III) (DPC) in aqueous alkaline medium at a constant ionic
strength of 0.05 mol dm−3 has been studied spectrophotometrically. The reaction showed first order kinetics both in [DPC] and [INH] and negative less
than unit order, both in alkali and periodate concentrations under the experimental conditions. Intervention of free radicals
was observed in the reaction. Products of the reaction, isonicotinic acid and copper(II) have no effect on the rate of reaction.
Ionic strength and dielectric constant did not affect the rate of reaction. Based on the observed orders and experimental
evidences, a mechanism involving the monoperiodatocuprate(III) (MPC) as the reactive oxidant species has been proposed. The
main products were identified by I.R, N.M.R. and GC-MS spectral studies. The reaction constants involved in the mechanism
were evaluated. Investigations at different temperatures allowed the determination of the activation parameters with respect
to the slow step of proposed mechanism. The mechanism proposed and the derived rate laws are consistent with the observed
kinetics. 相似文献
10.
The kinetics of oxidation of a non-steroidal analgesic drug, aspirin (ASP) by diperiodatocuprate(III)(DPC) in the presence and absence of osmium(VIII) have been investigated at 298 K in alkaline medium at a constant ionic strength of 0.10 mol dm−3 spectrophotometrically. The reaction showed a first-order in [DPC] and less than unit order in [ASP] and [alkali] for both the osmium(VIII) catalysed and uncatalysed reactions. The order with respect to Os(VIII) concentration was unity. The effects of added products, ionic strength, periodate and dielectric constant have been studied. The stoichiometry of the reaction was found to be 1:4 (ASP:DPC) for both the cases. The main oxidation product of aspirin was identified by spot test, IR, NMR and GC–MS. The reaction constants involved in the different steps of the mechanisms were calculated for both reactions. Activation parameters with respect to slow step of the mechanisms were computed and discussed for both the cases. The thermodynamic quantities were also determined for both reactions. The catalytic constant (KC) was also calculated for catalysed reaction at different temperatures and the corresponding activation parameters were determined. 相似文献
11.
12.
Timmanagoudar Prakash L. Hiremath Gouri A. Nandibewoor Sharanappa T. 《Transition Metal Chemistry》1997,22(2):193-196
Permanganate oxidation of CrIII in aqueous medium (pH>;12) at25°C has been studied by the stopped-flow technique, combined with a rapid scan spectrophotometry, and obeys the rate equation:¶ where K is the formation constant of the MnVII-CrIII adduct and k is the rate constant for its decomposition. The rate is independent of [OH–]. The active oxidant and reductant species are understood to be [MnO4]– and [Cr(OH)4]–, respectively. 相似文献
13.
碱性介质中二过碘酸合铜(III)配离子氧化四氢糠醇的动力学及机理 总被引:7,自引:0,他引:7
本文采用分光光度法研究了二过碘酸合铜(III)配离子在碱性介质中氧化四氢糠醇的动力学及机理. 结果表明反应对[Cu(III)]是一级, 对四氢糠醇是1.3级. 反应速率随体系中[OH^-]的增大而增大, 随过碘酸浓度的增大而减小, 反应体系加入硝酸钾盐时,速率增大, 有正盐效应. 在氮气保护下, 体系能够诱发丙烯酰胺聚合. 提出了一种含有自由基过程的反应机理, 据此导出了一个能够解释本文全部实验事实的速率方程. 求得了速率控制步骤的速率常数, 并给出了相应的活化参数. 相似文献
14.
T. S. Kiran D. C. Hiremath S. T. Nandibewoor 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2007,81(12):2070-2077
The kinetics of oxidation of L-lysine by diperiodatocuprate (III) (DPC) in alkaline medium at a constant ionic strength of
0.15 mol/dm3 was studied spectrophotometrically. The reaction between DPC and L-lysine in an alkaline medium had a 1: 2 stoichiometry
(L-lysine: DPC). The reaction was first order in [DPC] and less than first order in [L-lysine] and [alkali]. The addition
of periodate had no effect on the rate of the reaction. The intervention of free radicals was observed in the reaction. The
oxidation reaction in alkaline medium was shown to proceed via a DPC-L-lysine complex. The main products were identified by
spot test and spectral studies. The reaction constants involved in different steps of the mechanism were calculated. The activation
parameters with respect to the slow step of the mechanism were computed and discussed, and thermodynamic values were also
determined.
The article is published in the original. 相似文献
15.
Shivamurti A. Chimatadar Manjalee S. Salunke Sharanappa T. Nandibewoor 《Transition Metal Chemistry》2004,29(7):743-750
The kinetics of oxidation of AsIIIby Fe(CN)6
3– has been studied spectrophotometrically in 60% AcOH–H2O containing 4.0moldm–3HCl. The oxidation is made possible by the difference in redox potentials. The reaction is first order each in [Fe(CN)6
3–] and [AsIII]. Amongst the initially added products, Fe(CN)6
4– retards the reaction and AsVdoes not. Increasing the acid concentration at constant chloride concentration accelerates the reaction. At constant acidity increasing chloride concentration increases the reaction rate, which reaches a maximum and then decreases. H2Fe(CN)6
–, is the active species of Fe(CN)6
3–, while AsCl5
2– in an ascending portion and AsCl2
+ in a descending portion are considered to be the active species of AsIII. A suitable reaction mechanism is proposed and the reaction constants of the different steps involved have been evaluated. 相似文献
16.
Praveen K. Tandon Alka Mehrotra Manish Srivastava Santosh B. Singh 《Transition Metal Chemistry》2007,32(4):541-547
Oxidation of iodide ions by K3Fe(CN)6, catalyzed by hydrogen ions obtained from hydrochloric acid was found to be further catalyzed by iridium(III) chloride. Rate,
when the reaction is catalyzed only by the hydrogen ions, was separated from the rate when iridium(III) and H+ions both, catalyze the reaction. Reactions studied separately in the presence as well as in the absence of IrCl3 under similar conditions were found to follow second order kinetics with respect to [I−]. While the rate showed direct proportionality with respect to [K3Fe(CN)6] and [IrCl3]. At low concentrations the reaction shows direct proportionality with respect to [H+] which tends to become proportional to the square of hydrogen ions at higher concentrations. Strong retarding affect of externally
added hexacyanoferrate(II) ions was observed in the beginning but further addition affects the rate to a little extent. Changes
in [Cl−] and also ionic strength of the medium have no effect on the rate. With the help of the intercept of catalyst graph, the
extent of the reaction, which takes place without adding iridium(III), was calculated and was found to be in accordance with
the values obtained from the separately studied reactions in which only H+ ions catalyze the reaction. It is proposed that iridium forms a complex, which slowly disproportionates into the rate-determining
step. Thermodynamic parameters at four different temperatures were calculated. 相似文献
17.
H. S. Singh V. P. Singh B. S. Arya G. R. Varma 《Monatshefte für Chemie / Chemical Monthly》1981,112(11):1253-1260
Kinetics of oxidation of xylitol and galactitol by hexacyanoferrate(III) ion in aqueous alkaline medium is reported. The reaction rate is of first order with respect to hexacyanoferrate(III) in each substrate. The reaction is first order at lower concentrations of xylitol and galactitol and tends towards zero order as the concentration increases. Similarly first order kinetics was obtained with respect to hydroxide ion at lower concentrations and tends to lower order at higher concentration in the oxidation of xylitol; in the oxidation of galactitol the reaction is first order with respect to hydroxide ion even up to manyfold variation. The course of reaction has been considered to proceed through the formation of an activated complex between [K Fe(CN)6]2– and substrate anion which decomposes slowly into radical and [K Fe(CN)6]3–. A probable reaction mechanism is proposed.
Kinetik und Mechanismus der Oxidation von Xylit und Galaktit mit Hexacyanoferrat(III) in wäßriger, alkalischer Lösung
Zusammenfassung Das Geschwindigkeitsgesetz der Titelreaktion ist in beiden Fällen erster Ordnung bezüglich Hexacyanoferrat(III). Die Oxidation ist erster Ordnung bei niedrigen Konzentrationen von Xylit und Galaktit und geht bei Erhöhung der Konzentration gegen null. In gleicher Weise wurde eine Kinetik erster Ordnung bezüglich Hydroxyl bei niedrigen Konzentrationen und eine erniedrigte Ordnung bei höheren Konzentrationen für die Oxidation von Xylit beobachtet; bei Galaktit bleibt die Oxidation auch bei höheren Hydroxyl-Konzentrationen erster Ordnung. Es wird angenommen, daß die Reaktion über einen aktivierten Komplex zwischen [KFe(CN)6]2– und dem Substrat-Anion verläuft; dieser Komplex zerfällt in [KFe(CN)6]3– und ein Substrat-Radikal. Ein möglicher Reaktionsmechanismus wird vorgeschlagen.相似文献
18.
M. D. Meti K. S. Byadagi S. T. Nandibewoor S. A. Chimatadar 《Monatshefte für Chemie / Chemical Monthly》2014,145(10):1561-1573
19.
《印度化学会志》2021,98(8):100104
The kinetics approach of oxidation of torsemide (TOR) by hexacyanoferrate (III) [HCF (III)] has been identified spectrophotometrically at 420 nm in the alkaline medium in the presence and absence of catalyst ruthenium (III) at 25 °C, by keeping ionic strength (1 × 10−2 mol dm−3) constant. The reaction exhibits at the stoichiometry ratio 1:2 of TOR and HCF (III), for uncatalysed and catalysed reactions. In the absence and presence of the catalyst, the order of the reactions obtained for TOR and HCF (III) was unity. However, the rate of the reactions enhanced by the increase in the concentration of catalyst, as well as the rate increases with an increase in alkaline concentration. The activation parameters for the reaction at the slow step were identified, and the effect of temperature on the rate of the reaction was analysed. A suitable mechanism has been demonstrated by considering the obtained results. The derived rate laws are reliable with analysed experimental kinetics. 相似文献
20.
Balesh A. Deganatti Nagaraj P. Shetti Sharanappa T. Nandibewoor 《Transition Metal Chemistry》2009,34(2):143-152
The oxidation of l-valine (l-val) by diperiodatocuprate(III) (DPC) in aqueous alkaline medium at a constant ionic strength of 3.0 × 10−3 mol dm−3 was studied spectrophotometrically at 298 K and follows the rate law;
where K
4, K
5 and K
6 are the equilibrium constants for the different steps involved in the mechanism, k is the rate constant for the slow step of the reaction. The appearance of [l-val] term in both numerator and denominator explains the observed less than unit order in [l-val]. Similarly the appearances of [H3IO6
2−] and [OH−] in the denominator obey the experimental negative less than unit order in [H3IO6
2−] and [OH−], respectively. The oxidation reaction in alkaline medium proceeds via a DPC-l-valine complex, which decomposes slowly in a rate determining step followed by other fast steps to give the products. The
main products were identified by spot test and spectroscopic studies. 相似文献