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1.
Rajeshwari V. Hosahalli Anita P. Savanur Sharanappa T. Nandibewoor Shivamurti A. Chimatadar 《Transition Metal Chemistry》2010,35(2):237-246
The oxidation of d-panthenol by MnO4
− was studied in the absence and in the presence of ruthenium(III) catalyst in alkaline medium at 298 K and at constant ionic
strength of 0.50 mol dm−3 by spectrophotometry. The stoichiometry in both the cases was [panthenol]: [MnO4
−] = 1:4. The oxidation products were identified by IR and GC–MS. The reaction was first-order with respect to both MnO4
− and ruthenium(III), while the orders with respect to both panthenol and alkali varied from first order to zero order as the
concentrations increased. The effects of added products, ionic strength and dielectric constant were studied. The reaction
constants, activation parameters and thermodynamic quantities were calculated for both the uncatalysed and catalysed reactions. 相似文献
2.
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
3.
Jyothi C. Abbar Shweta J. Malode Sharanappa T. Nandibewoor 《Journal of molecular catalysis. A, Chemical》2009,313(1-2):88-99
The oxidation of dl-ornithine monohydrochloride (OMH) by diperiodatocuprate(III) (DPC) has been investigated both in the absence and presence of ruthenium(III) catalyst in aqueous alkaline medium at a constant ionic strength of 0.20 mol dm−3 spectrophotometrically. The stiochiometry was same in both the cases, i.e., [OMH]/[DPC] = 1:4. In both the catalyzed and uncatalyzed reactions, the order of the reaction with respect to [DPC] was unity while the order with respect to [OMH] was < 1 over the concentration range studied. The rate increased with an increase in [OH−] and decreased with an increase in [IO4−] in both cases. The order with respect to [Ru(III)] was unity. The reaction rates revealed that Ru(III) catalyzed reaction was about eight-fold faster than the uncatalyzed reaction. The oxidation products were identified by spectral analysis. Suitable mechanisms were proposed. The reaction constants involved in the different steps of the reaction mechanisms were calculated for both cases. The catalytic constant (KC) was also calculated for catalyzed reaction at different temperatures. The activation parameters with respect to slow step of the mechanism and also the thermodynamic quantities were determined. Kinetic experiments suggest that [Cu(H2IO6)(H2O)2] is the reactive copper(III) species and [Ru(H2O)5OH]2+ is the reactive Ru(III) species. 相似文献
4.
Shekappa D. Lamani Praveen N. Naik Sharanappa T. Nandibewoor 《Journal of solution chemistry》2010,39(9):1291-1310
The kinetics of the osmium(VIII) (Os(VIII)) catalyzed oxidation of diclofenac sodium (DFS) by diperiodatocuprate(III) (DPC)
in aqueous alkaline medium has been studied spectrophotometrically at a constant ionic strength of 1.0 mol⋅dm−3. The reaction showed first order kinetics in [Os(VIII)] and [DPC] and less than unit order with respect to [DFS] and [alkali].
The rate decreased with increase in [periodate]. The reaction between DFS and DPC in alkaline medium exhibits 1:2 [DFS]:[DPC]
stoichiometry. However, the order in [DFS] and [OH−] changes from first order to zero order as their concentration increases. Changes in the ionic strength and dielectric constant
did not affect the rate of reaction. The oxidation products were identified by LC-ESI-MS, NMR, and IR spectroscopic studies.
A possible mechanism is proposed. The reaction constants involved in the different steps of the mechanism were calculated.
The catalytic constant (K
C) was also calculated for Os(VIII) catalysis at the studied temperatures. From plots of log 10
K
C versus 1/T, values of activation parameters have been evaluated with respect to the catalytic reaction. The activation parameters with
respect to the slow step of the mechanism were computed and discussed, and thermodynamic quantities were also determined.
The active osmium(VIII) and copper(III) periodate species have been identified. 相似文献
5.
S. D. Lamani T. M. Veeresh S. T. Nandibewoor 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(13):2215-2222
The kinetics of oxidation of L-phenylalanine (L-Phe) by diperiodatoargentate(III) (DPA) in alkaline medium at a constant ionic
strength of 0.25 mol/dm−3 has been studied spectrophotometrically. The reaction between DPA and L-phenylalanine in alkaline medium exhibits 1: 1 stoichiometry
(L-phenylalanine: DPA). The reaction shows first order in [DPA] and has less than unit order dependence each in both [L-Phe]
and [Alkali] and retarding effect of [IO4−] under the reaction conditions. The active species of DPA is understood to be as monoperiodatoargentate(III) (MPA). The reaction
is shown to proceed via a MPA-L-Phe complex, which decomposes in a rate-determining step to give intermediates followed by
a fast step to give the products. The products were identified by spot and spectroscopic studies. The reaction constants involved
in the different steps of the mechanisms were calculated. The activation parameters with respect to slow step of the mechanism
were computed and discussed. The thermodynamic quantities were also determined for the reaction. 相似文献
6.
Kinetics of Ir (III)-catalyzed Oxidation of D-glucose by Potassium Iodate in Aqueous Alkaline Medium
Surya Prakash Singh Ashok Kumar Singh Ajaya Kumar Singh 《Journal of carbohydrate chemistry》2013,32(5):278-292
The kinetics of Ir (III) chloride-catalyzed oxidation of D-glucose by iodate in aqueous alkaline medium was investigated at 45°C. The reaction follows first-order kinetics with respect to potassium iodate in its low concentration range but tends to zero order at its higher concentration. Zero-order kinetics with respect to [D-glucose] was observed. In the lower concentration range of Ir (III) chloride, the reaction follows first kinetics, while the order shifts from first to zero at its higher concentration range. The reaction follows first-order kinetics with respect to [OH?] at its low concentration but tends towards zero order at higher concentration. Variation in [Cl?] and ionic strength of the medium did not bring about any significant change in the rate of reaction. The first-order rate constant increased with a decrease in the dielectric constant of the medium. The values of rate constants observed at four different temperatures were utilized to calculate the activation parameters. Sodium salt of formic acid and arabinonic acid have been identified as the main oxidation products of the reaction. A plausible mechanism from the results of kinetic studies, reaction stoichiometry, and product analysis has been proposed. 相似文献
7.
Veeresh Seregar T. M. Veeresh Sharanappa T. Nandibewoor 《Transition Metal Chemistry》2009,34(6):647-654
The kinetics of Ru(III)-catalyzed oxidation of l-alanine (Ala) by diperiodatoargentate(III) (DPA) in alkaline medium at 25 °C and a constant ionic strength of 0.90 mol dm−3 was studied spectrophotometrically. The products are acetaldehyde, Ag(I), ammonia and bicarbonate. The [Ala] to [DPA] stoichiometry
is 1:1. The reaction is first order in both [Ru(III)] and [DPA] and has less than unit order in both [Ala] and [alkali]. Addition
of periodate has a retarding effect on the reaction. The effects of added products, ionic strength and dielectric constant
of the reaction medium have been investigated. The reaction proceeds via a Ru(III)–Ala complex, which further reacts with
one molecule of monoperiodatoargentate(III) in the rate-determining step. The reaction constants were calculated at different
temperatures and the activation parameters have been evaluated. 相似文献
8.
Rajeshwari V. Hosahalli Anita P. Savanur Sharanappa T. Nandibewoor Shivamurti A. Chimatadar 《国际化学动力学杂志》2010,42(7):440-452
The oxidation of D ‐mannitol by cerium(IV) has been studied spectrophotometrically in aqueous sulfuric acid medium at 25°C at constant ionic strength of 1.60 mol dm?3. A microamount of ruthenium(III) (10?6 mol dm?3) is sufficient to enhance the slow reaction between D ‐mannitol and cerium(IV). The oxidation products were identified by spot test, IR and GC‐MS spectra. The stoichiometry is 1:4, i.e., [D ‐mannitol]: [Ce(IV)] = 1:4. The reaction is first order in both cerium(IV) and ruthenium(III) concentrations. The order with respect to D ‐mannitol concentration varies from first order to zero order as the D ‐mannitol concentration increases. Increase in the sulfuric acid concentration decreases the reaction rate. The added sulfate and bisulfate decreases the rate of reaction. The active species of oxidant and catalyst are Ce(SO4)2 and [Ru(H2O)6]3+, respectively. A possible mechanism is proposed. The activation parameters are determined with respect to a slow step and reaction constants involved have been determined. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 440–452, 2010 相似文献
9.
Kinetics and Mechanistic Approach to the Oxidative Behavior of Biological Anticancer Platinum(IV) Complex toward ‐Asparagine in Acid Medium and the Effect of Copper(II) Catalyst
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AHMED FAWZY 《国际化学动力学杂志》2015,47(1):1-12
The catalytic effect of copper(II) ions toward the oxidation of ‐asparagine (Asn) by an anticancer platinum(IV) complex in the form of hexachloroplatinate(IV) (HCP) has been investigated in aqueous acid medium at the constant ionic strength and temperature. The progress of both uncatalyzed and copper(II)‐catalyzed oxidation reactions has been monitored spectrophotometrically. The stoichiometry in both cases is [Asn]/[HCP] = 1:1. The kinetics of both redox reactions is first order with respect to [oxidant] and less than the unit order in [acid]. The order with respect to [Asn]T decreases from unity in the uncatalyzed path to less than unity in the catalyzed one. The catalyzed path is first order in [CuII]T. Increasing ionic strength and dielectric constant decreases the oxidation rates. The final oxidation products of ‐asparagine are identified as the corresponding aldehyde (α‐formyl acetamide), ammonium ion, and carbon dioxide. Tentative mechanisms of both reactions have been suggested. The appropriate rate laws are deduced. The activation parameters of the uncatalyzed reaction have been evaluated and discussed. 相似文献
10.
Rahamatalla M. Mulla Gurubasavaraj C. Hiremath Sharanappa T. Nandibewoor 《Monatshefte für Chemie / Chemical Monthly》2004,135(12):1489-1502
Summary. The kinetics of ruthenium(III) catalysed oxidation of sulfanilic acid (p-aminobenzenesulfonic acid) by hexacyanoferrate(III) in alkaline medium at a constant ionic strength of 2.5mol·dm–3 has been studied spectrophotometrically using a rapid kinetic accessory. The reaction exhibits 2:8 stoichiometry (SNA:HCF(III)). The reaction showed first order kinetics in [hexacyanoferrate(III)] and [ruthenium(III)] and apparent less than unit order in both sulfanilic acid and alkali concentrations. The reaction rate increases with increasing ionic strength but the relative permittivity (T) of the medium has a negligible effect on the rate of the reaction. Initial addition of reaction products did not affect the rate significantly. A mechanism involving the formation of a complex between sulfanilic acid and hydroxylated species of ruthenium(III) has been proposed. The active species of HCF(III) and ruthenium(III) are understood as [Fe(CN)63–] and [Ru(H2O)5OH]2+, respectively. The main products were identified by IR, NMR, and mass spectral studies. The reaction constants involved in the different steps of mechanism are calculated. The activation parameters with respect to the slow step of the mechanism are computed and discussed and thermodynamic quantities are also calculated. 相似文献
11.
12.
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
13.
Rahamatalla M. Mulla Gurubasavaraj C. Hiremath Sharanappa T. Nandibewoor 《Journal of Chemical Sciences》2005,117(1):33-42
Kinetics of ruthenium (III) catalyzed oxidation of atenolol by permanganate in alkaline medium at constant ionic strength
of 0.30 mol dm3 has been studied spectrophotometrically using a rapid kinetic accessory. Reaction between permanganate and atenolol in alkaline
medium exhibits 1 : 8 stoichiometry (atenolol : KMnO4). The reaction shows first-order dependence on [permanganate] and [ruthenium (III)] and apparently less than unit order on
both atenolol and alkali concentrations. Reaction rate decreases with increase in ionic strength and increases with decreasing
dielectric constant of the medium. Initial addition of reaction products does not affect the rate significantly. A mechanism
involving the formation of a complex between catalyst and substrate has been proposed. The active species of ruthenium (III)
is understood as [Ru(H2O)5OH]2+. The reaction constants involved in the different steps of mechanism are calculated. Activation parameters with respect to
the slow step of the mechanism are computed and discussed and thermodynamic quantities are also calculated. 相似文献
14.
The kinetics of RuIII catalyzed reduction of hexacyanoferrate(III) [Fe(CN)6]3–, by atenolol in alkaline medium at constant ionic strength (0.80 mol dm–3) has been studied spectrophotometrically, using a rapid kinetic accessory. The reaction between atenolol and [Fe(CN)6]3– in alkaline medium exhibits 1:2 stoichiometry [atenolol:Fe(CN)6
3–]. The reaction showed first order kinetics in [Fe(CN)6]3– concentration and apparent less than unit order dependence, each in atenolol and alkali concentrations. Effect of added products, ionic strength and dielectric constant of the reaction medium have been investigated. A retarding effect was observed by one of the products i.e., hexacyanoferrate(II). The main products were identified by i.r., n.m.r., fluorimetric and mass spectral studies. A mechanism involving the formation of a complex between the atenolol and the hydroxylated species of ruthenium(III) has been proposed. The active species of oxidant and catalyst were [Fe(CN)6]3–and [Ru (H2O)5OH]2+, respectively. The reaction constants involved in the mechanism were evaluated. The activation parameters were computed with respect to the slow step of the mechanism, and discussed. 相似文献
15.
M. I. Hiremath S. T. Nandibewoor 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(7):1029-1033
The kinetics of ruthenium(III) catalyzed oxidation of L-proline by diperiodatocuprate(III) (DPC) in alkaline medium at constant
ionic strength (0.10 mol dm−3) has been studied spectrophotometrically using a rapid kinetic accessory. The reaction showed first order kinetics in [DPC]
and [RuIII] and apparently less than unit order dependence each in L-proline and alkali concentrations. A mechanism involving the formation
of a complex between the L-proline and the hydroxylated species of ruthenium (III) has been proposed. The active species of
oxidant and catalyst were [Cu(OH)2 (H3IO6)2 (H2IO6)2]4− and [Ru (H2O)5OH]2+ respectively. The reaction constants involved in the mechanism were evaluated. The activation parameters were computed with
respect to the slow step of the mechanism and discussed.
The text was submitted by the authors in English. 相似文献
16.
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
17.
Deepak S. Munavalli Shivamurti A. Chimatadar Sharanappa T. Nandibewoor 《Transition Metal Chemistry》2008,33(5):535-542
The kinetics of oxidation of l-lysine by diperiodatoargentate(III) (DPA) in aqueous alkaline medium at a constant ionic strength of 0.50 mol dm−3 was studied spectrophotometrically. The oxidation products are aldehyde, 5-aminopentanal and Ag(I). The main products were
identified by spot test, IR and GC-MS. The stoichiometry is [l-lysine]:[DPA] = 1:1. The reaction is first order with respect to diperiodatoargentate(III) concentrations, whereas the order
with respect to l-lysine and alkali concentrations changes from first order to zero order as the l-lysine and alkali concentrations are increased. The effects of added products, periodate, ionic strength, and dielectric
constant of the reaction medium were investigated. Based on the experimental results, a mechanism involving complex formation
between DPA species and l-lysine is proposed. The reaction constants involved in the mechanism were evaluated. The activation parameters with respect
to the slow step of the mechanism were determined and discussed. 相似文献
18.
《国际化学动力学杂志》2017,49(3):143-156
The catalytic effect of silver(I) and copper(II) ions on the oxidation of histidine by cerium(IV) in aqueous sulfuric acid solutions was studied spectrophotometrically at a constant ionic strength of 3.0 mol dm−3 and at 25°C. In both uncatalyzed and metal ions‐catalyzed paths, the reactions exhibited first‐order kinetics with respect to [Ce(IV)] and [catalyst], and fractional first‐order dependences with respect to [His] and [H+]. The oxidation rates increased as the ionic strength and dielectric constant of the reactions media increased. The catalytic efficiency of Ag(I) was higher than that of Cu(II). Plausible mechanistic schemes for both uncatalyzed and catalyzed reactions were proposed, and the rate laws associated with the suggested mechanisms were derived. In both cases, the final oxidation products of histidine were identified as 2‐imidazole acetaldehyde, ammonium ion, and carbon dioxide. The activation parameters associated with the second‐order rate constants were evaluated. 相似文献
19.
The kinetics of the oxidation of sulfanilic acid (SAA) by sodium N-chloro-p-toluenesulfonamide (CAT) in the presence and absence of ruthenium(III) chloride have been investigated at 303 K in perchloric
acid medium. The reaction shows a first-order dependence on [CAT]o and a non-linear dependence on both [SAA]o and [HClO4] for both the ruthenium(III)-catalyzed and uncatalyzed reactions. The order with respect to [RuIII] is unity. The effects of added p-toluenesulfonamide, halide, ionic strength, and dielectric constant have been studied. Activation parameters have been evaluated.
The rate of the reaction increases in the D2O medium. The stoichiometry of the reaction was found to be 1:1 and the oxidation product of SAA was identified as N-hydroxyaminobenzene-4-sulfonic acid. The ruthenium(III)-catalyzed reactions are about four-fold faster than the uncatalyzed
reactions. The protonated conjugate acid (CH3C6H4SO2NH2Cl+) is postulated as the reactive oxidizing species in both the cases. 相似文献
20.
Ahmed Fawzy 《Transition Metal Chemistry》2014,39(5):567-576
The kinetics of oxidation of l-histidine (His) by platinum(IV) in the absence and presence of copper(II) catalyst was studied using spectrophotometry in alkaline medium at a constant ionic strength of 0.1 mol dm?3 and at 25 °C. In both cases, the reactions exhibit a 1:1 stoichiometry ([His]:[PtIV]). The rate of the uncatalyzed reaction is dependent on the first power of each of the concentrations of oxidant, substrate and alkali. The catalyzed path shows a first-order dependence on both [PtIV] and [CuII], but the order with respect to both [His] and [OH?] is less than unity. The rate constants increase with increasing ionic strength and dielectric constant of the medium. The catalyzed reaction has been shown to proceed via formation of a copper(II)_histidine intermediate complex, which reacts with the oxidant by an inner-sphere mechanism leading to decomposition of the complex in the rate-determining step. Platinum(IV) is reduced to platinum(II) by the substrate in a one-step two-electron transfer process. This is followed by other fast steps, giving rise to the oxidation products which were identified as 2-imidazole acetaldehyde, ammonia and carbon dioxide. A tentative reaction mechanism is suggested, and the associated rate laws are deduced. The activation parameters with respect to the slow step of the mechanism are reported and discussed. 相似文献