Pd(II)-catalysed and Hg(II)-co-catalysed oxidation of d-glucose and d-fructose by N-bromoacetamide in the presence of perchloric acid: a kinetic and mechanistic study

Singh, Ashok Kumar; Srivastava, Jaya; Rahmani, Shahla; Singh, Vineeta

doi:10.1016/j.carres.2005.11.012

Cited by 24 publications

(27 citation statements)

References 16 publications

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“…It is also reported [37] that when reaction occurs between an ion and a neutral molecule, the transition state becomes less polar than the initial state, because in the transition state the same charge is dispersed over a greater volume. The positive entropy of activation observed in the oxidation of mel and cel by NBA can therefore be [15] and Pd(II) [16]-catalysed oxidations is different from the activated complex, [MeCONH 2 Br(RhCl 4 )S] -, assumed for the Rh(III)-catalysed oxidation of mel and cel. From these distinguishing features, it is clear that the differences in behaviour of the three transition metal catalysts are due to variations in their catalytic functions and coordination chemistry.…”

Section: Discussionmentioning

confidence: 92%

“…Br(RhCl 5 )] -, with a neutral sugar and so less polar than the initial state.The results of the present study of the Rh(III)-catalysed oxidation of mel and cel by NBA can be compared with the results for the Ir(III)-catalysed[15] and Pd(II)-catalysed[16] oxidations of reducing sugars by NBA in acidic medium. The first-order kinetics observed in[NBA] in the present study are different from the other two studies where first-to zero-order kinetics with respect to NBA were observed.…”

mentioning

confidence: 90%

“…NBA has been used as an oxidant for uncatalysed [8][9][10][11][12] and catalysed [13][14][15][16][17][18] reactions involving transition metals including Ru(III), Ir(III) and Pd(II) as homogeneous catalysts. The coordination chemistry of Rh(III) [19] has drawn considerable attention due to its chemical reactivity, anti-tumour activity, electronic structure and catalytic functions of its complexes with potential industrial applications.…”

Section: Introductionmentioning

confidence: 99%

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Kinetics of oxidation of d(+)melibiose and cellobiose by N-bromoacetamide using a rhodium(III) chloride catalyst

Singh

Srivastava

et al. 2010

Transition Met Chem

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The kinetics of oxidation of the sugars D(?)Melibiose (mel) and Cellobiose (cel) by N-bromoacetamide (NBA) in the presence of Rh(III) chloride as homogeneous catalyst in acidic medium at 45°C have been investigated. The reactions are first-order with respect to [NBA], [Rh(III)] and [substrate]. The rate is proportional to [H ? ]. No effects of [Hg(II)], [NHA] or [Cl -] on the rates were observed. Ionic strength and dielectric constant also have little effect. The observed kinetic data, available literature and spectroscopic evidence lead us to conclude that NBAH ? and [RhCl 5 (H 2 O)] 2-are the reactive species of NBA and Rh(III) chloride, respectively. The rate-determining step of the proposed reaction path common for both sugars gives an activated complex by the interaction of a charged complex species and neutral sugar molecule, which in the subsequent steps disproportionates into the reaction products with the regeneration of catalyst. The reactions have been studied at four different temperatures and with the help of first-order rate constant values, various activation parameters have been calculated. The main oxidation products of the reactions were identified as arabinonic acid, formic acid and lyxonic acid in the case of mel and arabinonic acid and formic acid in the case of cel.

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Section: Discussionmentioning

confidence: 92%

mentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

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Kinetics of oxidation of d(+)melibiose and cellobiose by N-bromoacetamide using a rhodium(III) chloride catalyst

Singh

Srivastava

et al. 2010

Transition Met Chem

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“…N-halo compounds have extensively been used as oxidizing agents for the catalyzed and uncatalyzed reactions [4][5][6][7][8][9][10][11][12]. Additionally, N-halo compounds have also been widely used as halogenating reagents of organic compounds [13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Kinetics and mechanism of oxidation of β-Alanine by N-bromophthalimide in the presence of Ru(III) chloride as homogenous catalyst in acidic medium

Singh¹,

Jain²,

Negi³

et al. 2009

Transition Met Chem

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The kinetics of Ru(III) chloride-catalyzed oxidation of b-Alanine (NH 3 ? CH 2 CH 2 COOH, b-Ala) by Nbromophthalimide (NBP) in aqueous perchloric acid medium was studied at 35°C. The rate law followed a first-order and zero-order dependence with respect to [NBP] and [b-Ala], respectively. The reaction followed first-order kinetics with respect to [Ru(III)] chloride at a range of low concentrations while the order changed from first-to zero-order at high concentration of [Ru(III)] chloride; demonstrating the catalytic effect for the oxidation of b-Ala by NBP. The rate decreased with increase in acidity. Chloride ions positively influenced the rate of the reaction. Neither phthalimide (NHP) nor Hg(II) influenced the reaction rate. Ionic strength (I) and dielectric constant (D) of the medium had no significant effect on the rate. Activation parameters of the reactions were determined by studying the reaction at different temperatures (30-50°C). The colorimetric, FTIR, and GC-MS techniques were used to identify methyl cyanide (CH 3 CN) and CO 2 as products of the reaction. In the reaction, approximately 2.3 moles of NBP oxidized one mole of b-Ala. A reaction scheme of the oxidation of b-Ala by NBP in the presence of Ru(III) chloride was found to be in consistent with the rate law and the reaction stoichiometry.

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“…N-halo compounds have been extensively used as an oxidizing agent for catalyzed and uncatalyzed reactions [4][5][6][7][8]. Additionally, N-halo compounds have also been widely used as halogenating reagents for organic compounds [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Oxidation of d-glucose by N-bromophthalimide in the presence of chlorocomplex of iridium(III): a kinetic and mechanistic study

Singh¹,

Sachdev

Shrivastava³

et al. 2011

Res Chem Intermed

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The kinetics of Iridium (III) catalyzed oxidation of D-glucose [D-glu] has been studied by N-bromophthalimide [NBP] in the acidic medium (pH 1.3) at 303 K. The reaction followed first-order kinetics with respect to [NBP] from 0.5 9 10 -4 to 4.0 9 10 -4 mol dm -3 . The results indicate the first-order kinetics in [iridium(III)] chloride at lower concentrations from 0.75 9 10 -6 to 5.8 9 10 -6 mol dm -3 tends towards a zero order at its higher concentrations (up to 13.36 9 10 -6 mol dm -3 ). Zero-order kinetics with respect to [D-glu] from 2.0 9 10 -3 to 20.0 9 10 -3 mol dm -3 was observed throughout its variation. A positive effect on the oxidation rate was observed for [Cl -] from 0.2 9 10 -5 to 2.4 9 10 -5 mol dm -3 and the rate of reaction decreased with increase in dielectric constant (decreasing acetic acid from 35 to 15%) of the medium. A negative effect was observed on the reaction rate for [H ? ] from 1.5 9 10 -2 to 12.0 9 10 -2 mol dm -3 . Addition of reduced product of oxidant, i.e., phthalimide from 1.0 9 10 -4 to 8.0 9 10 -4 mol dm -3 did not show a significant effect on the oxidation velocity. Rate of reaction increased with increase in ionic strength from 0.2 9 10 -1 to 4.0 9 10 -1 mol dm -3 of the medium, i.e., increase in [KNO 3 ]; the rate of reaction was increased. From the linear Arrhenius plot of log k 1 versus 1/T, the activation energy (Ea = 50.91 kJ mol -1 ) was calculated. With the help of the energy of activation, parameters such as enthalpy of activation (DH # = 48.39 kJ mol -1 ), entropy of activation (DS # = -321.63 JK mol -1 ), Gibbs free energy of activation (DG # = 145.84 kJ mol -1 ) and frequency factor (Log A = -3.97) were also calculated. A suitable mechanism in conformity with kinetic observations was proposed to explain reaction stoichiometry and product analysis.

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Pd(II)-catalysed and Hg(II)-co-catalysed oxidation of d-glucose and d-fructose by N-bromoacetamide in the presence of perchloric acid: a kinetic and mechanistic study

Cited by 24 publications

References 16 publications

Kinetics of oxidation of d(+)melibiose and cellobiose by N-bromoacetamide using a rhodium(III) chloride catalyst

Kinetics of oxidation of d(+)melibiose and cellobiose by N-bromoacetamide using a rhodium(III) chloride catalyst

Kinetics and mechanism of oxidation of β-Alanine by N-bromophthalimide in the presence of Ru(III) chloride as homogenous catalyst in acidic medium

Oxidation of d-glucose by N-bromophthalimide in the presence of chlorocomplex of iridium(III): a kinetic and mechanistic study

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