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1.
Abdulazizkhan L. Harihar Mohammadsaleem R. Kembhavi Sharanappa T. Nandibewoor 《Monatshefte für Chemie / Chemical Monthly》2000,31(4):739-748
The kinetics of the oxidation of L-valine, (L-Val) by permanganate in aqueous alkaline medium at a constant ionic strength of 0.50 molċdm−3 was studied spectrophotometrically. The reaction is of first order in [permanganate ion] and of fractional order in both [L-Val] and [alkali]. Addition of products has no significant effect on the reaction rate. However, increasing ionic strength and decreasing dielectric constant of the medium increase the rate. The oxidation process in alkaline medium has been shown to proceed via two paths, one involving the interaction of L-valine with permanganate ion in a slow step to yield the products, and the other path the interaction of alkali with permanganate ion to give manganate. Some reaction constants involved in the mechanism were determined; calculated and observed rate constants agree excellently. The activation parameters were computed with respect to the slow step of the mechanism. 相似文献
2.
Abdulazizkhan L. Harihar Mohammadsaleem R. Kembhavi Sharanappa T. Nandibewoor 《Monatshefte für Chemie / Chemical Monthly》2000,131(7):739-748
Summary. The kinetics of the oxidation of L-valine, (L-Val) by permanganate in aqueous alkaline medium at a constant ionic strength of 0.50 molċdm−3 was studied spectrophotometrically. The reaction is of first order in [permanganate ion] and of fractional order in both
[L-Val] and [alkali]. Addition of products has no significant effect on the reaction rate. However, increasing ionic strength
and decreasing dielectric constant of the medium increase the rate. The oxidation process in alkaline medium has been shown
to proceed via two paths, one involving the interaction of L-valine with permanganate ion in a slow step to yield the products, and the other path the interaction of alkali with permanganate
ion to give manganate. Some reaction constants involved in the mechanism were determined; calculated and observed rate constants
agree excellently. The activation parameters were computed with respect to the slow step of the mechanism.
Received December 30, 1999. Accepted (revised) March 6, 2000 相似文献
3.
Shweta J. Malode Nagaraj P. Shetti Sharanappa T. Nandibewoor 《Journal of solution chemistry》2010,39(3):417-430
The oxidation of ketorolac (KET) by diperiodatocuprate(III) (DPC) in aqueous alkaline medium at a constant ionic strength
of 0.10 mol⋅dm−3 was studied spectrophotometrically at 298 K. The reaction is of first order in [DPC] and has less than unit order in both
[KET] and [alkali], and negative fractional order in [periodate]. The oxidation reaction in alkaline medium has been shown
to proceed via a DPC-ketorolac 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 spectral studies. The reaction constants involved
in the different steps of the mechanism were calculated at different temperatures, which yielded thermodynamic quantities
for different steps of the reaction scheme. The activation parameters with respect to the slow step of the mechanism were
computed and discussed; thermodynamic quantities were also determined. 相似文献
4.
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
5.
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
6.
Sanjeevagowda T. Patil Mahantesh A. Angadi Abdulazizkhan L. Harihar 《Journal of solution chemistry》2008,37(12):1795-1808
The kinetics of the oxidation of L-asparagine, (L-asp) by diperiodatonickelate(IV), (DPN) in aqueous alkaline medium at a
constant ionic strength of 0.5 mol⋅dm−3, was studied spectrophotometrically. The reaction is first order in [DPN] and of fractional order in both [L-asp] and [alkali].
Addition of the products has no significant effect on the reaction rate. However, increasing the ionic strength or decreasing
the dielectric constant of the medium increases the reaction rate. The oxidation process in alkaline medium is shown to proceed
via two paths, one involving the interaction of L-asparagine with diperiodatonickelate(IV) ion in a slow step to yield the
products, and the other path involving the interaction of alkali with the diperiodatonickelate(IV) ion to give nickel(II).
Some reaction constants involved in the mechanism were determined, and calculated and observed rate constants are in excellent
agreement. The activation parameters were computed for the slow step of the mechanism. 相似文献
7.
Shweta J. Malode Jyothi C. Abbar Sharanappa T. Nandibewoor 《Monatshefte für Chemie / Chemical Monthly》2011,34(6):469-479
Abstract
The kinetics of the oxidation of ruthenium(III)-catalyzed oxidation of pentoxifylline (PTX) by diperiodatocuprate(III) (DPC) in aqueous alkaline medium at a constant ionic strength of 0.30 mol dm−3 was studied spectrophotometrically. The reaction between PTX and DPC in alkaline medium in the presence of Ru(III) exhibits 1:2 stoichiometry (PTX:DPC). The reaction was of first order in DPC, less than the unit order in [PTX] and [OH−] and negative fractional order in [IO4 −]. The order in [Ru(III)] was unity. Intervention of free radicals was observed in the reaction. The main products were identified by TLC and spectral studies including LC-MS. The oxidation reaction in alkaline medium has been shown to proceed via a Ru(III)-PTX complex, which reacts with monoperiodatocuprate(III) to decompose in a rate determining step followed by a fast step to give the products. 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 quantities were also determined. The active species of catalyst and oxidant have been identified. 相似文献8.
Aftab Aslam Parwaz Khan Ayaz Mohd Shaista Bano Ahmad Husain K. S. Siddiqi 《Transition Metal Chemistry》2010,35(1):117-123
The kinetics and mechanism of oxidation of levofloxacin (LF) by manganese(VII) in alkaline medium at constant ionic strength
was studied spectrophotometrically. The reaction exhibits 2:1 Mn:LF stoichiometry and is first order in permanganate but fractional
order in both LF and alkali. Decrease in the dielectric constant of the medium results in a decrease in the rate of reaction.
The effects of added products and ionic strength have also been investigated. The main products identified were hydroxylated
LF and Mn(VI). A mechanism involving free radicals is proposed. In a composite equilibrium step, levofloxacin binds to MnO4
− to form a complex that subsequently decomposes to the products. Investigations of the reaction at different temperatures
allowed the determination of the activation parameters with respect to the slow step of the proposed mechanism. 相似文献
9.
Pandurang D. Pol Ramdurg T. Mahesh Sharanappa T. Nandibewoor 《Reaction Kinetics and Catalysis Letters》2004,81(1):113-119
The kinetics of chromium(III) catalyzed oxidation of 1,10-phenanthroline by permanganate in alkaline medium at a constant ionic strength has been studied spectrophotometrically. The reaction between permanganate and 1,10-phenanthroline in alkaline medium exhibits 4:1 stoichiometry (KMnO4:1,10-phenanthroline). The reaction shows first order dependence on [permanganate] and [chromium(III)] and less than unit order dependence in 1,10-phenanthroline, zero order in alkali concentrations. The results suggest the formation of a complex between the 1,10-phenanthroline and the chromium(III) which reacts further with one mole of permanganate species in the rate-determining step, resulting in the formation of a free radical, which again reacts with three moles of permangante species in a subsequent fast step to yield the products. The reaction constants involved in the mechanism were evaluated. The activation parameters were computed with respect to the slow step of the mechanism.This revised version was published online in December 2005 with corrections to the Cover Date. 相似文献
10.
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
11.
Veeresh C. Seregar Ragunatharaddi R. Hosamani Sharanappa T. Nandibewoor 《Transition Metal Chemistry》2010,35(1):55-63
The kinetics of oxidation of l-cystine by diperiodatoargentate(III) (DPA) in alkaline medium at a constant ionic strength of 0.10 mol dm−3 was studied spectrophotometrically. The reaction exhibits a 1:2 stoichiometry (l-cys:DPA) and is first order in [DPA]. The order in both [l-cystine] and [alkali] changes from first to zero order as their concentrations increase. Added periodate retards the rate
of reaction. The effects of added products have been investigated. The active species of silver(III) is identified as monoperiodatoargentate(III)
(MPA). The oxidation is thought to proceed via an MPA–l-cystine complex, which decomposes in a rate-determining step to give a free radical followed by a fast step to give the products.
The products were identified by spot test, IR and GC–MS. The reaction constants involved in different steps of the mechanism
were evaluated. The activation parameters with respect to the slow step of the mechanism were computed and discussed. 相似文献
12.
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
13.
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
14.
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
15.
Kulkarni Raviraj M. Bilehal Dinesh C. Nandibewoor Sharanappa T. 《Transition Metal Chemistry》2003,28(2):199-208
The kinetics of CrIII-catalysed oxidation of L-valine by permanganate in alkaline medium at a constant ionic strength has been studied spectrophotometrically. The reaction between permanganate and L-valine in alkaline medium exhibits 2:1 stoichiometry (KMnO4:l-valine). The reaction shows first order dependence on [permanganate] and [chromium(III)], and less than unit order dependence each in [L-valine] and alkali concentrations under the experimental conditions. However the order in [L-valine] and [alkali] changes from first order to zero order as the concentrations change from lower to higher respectively. The results suggest the formation of a complex between L-valine and the hydroxylated species of CrIII. The complex reacts further with 1 mol of alkaline permanganate species in a rate-determining step, resulting in the formation of a free radical, which again reacts with 1 mol of alkaline permanganate species in a subsequent fast step to yield the products. The reaction constants involved in the mechanism were evaluated. The activation parameters with respect to the slow step of the mechanism were obtained and discussed. The title reaction has been utilised to analyse chromium(III) in the 26.0 ng cm–3–1.0 g cm–3 range. 相似文献
16.
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
17.
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
18.
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
19.
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
20.
Nirmala N. Halligudi Saleem M. Desai Surekha K. Mavalangi Sharanappa T. Nandibewoor 《Monatshefte für Chemie / Chemical Monthly》2000,131(4):321-332
Summary. The kinetics of the oxidation of rac-serine by permanganate in aqueous alkaline medium was studied spectrophotometrically. The reaction showed first order kinetics
in permanganate ion concentration and an order less than unity in rac-serine and alkali concentration. Increasing ionic strength and decreasing dielectric constant of the medium increase the
rate. The oxidation reaction proceeds via an alkali-permanganate species which forms a complex with rac-serine. The latter decomposes slowly, followed by a fast reaction between a free radical of rac-serine and another molecule of permanganate to give the products. There is a good agreement between the observed and the
calculated rate constants under different experimental conditions. Investigations at different temperatures allowed the determination
of the activation parameters with respect to the slow step of the proposed mechanism.
Received October 15, 1999. Accepted (revised) December 15, 1999 相似文献