Micellar Effects on the Reactions of Chromium(VI) Oxidation of Lactic Acid and Malic Acid in the Presence and Absence of Picolinic Acid in Aqueous Acid Media

Saha, Bidyut; Islam, Monirul; Das, Asim K.

doi:10.1515/irm.2006.6.2.141

Cited by 4 publications

(3 citation statements)

References 15 publications

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“…Kinetic studies of oxidation of different types of organic substrate by halochromate have also been investigated by different workers [4,5] to explore the effect of the substituent on the redox activity of Cr(VI). In this regard, micellar effect as a powerful probe [6] has been utilised by different workers to explore the redox activity of chromium(VI) [6][7][8][9]. Among the different types of chelating agents [10][11][12][13][14][15] to catalyse the Cr(VI) oxidation of different types of organic substrates, 2,2´-bpyridyl (bpy) is quite important [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Kinetics and Mechanism of Oxidation of D-Galactose by Chromium(VI) in Presence of 2,2’-Bipyridine Catalyst in Aqueous Micellar Media

Bayen¹,

K.²

2009

TOCATJ

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In aqueous H 2 SO 4 media, the chromic acid oxidation of D-galactose in the presence and absence of 2,2´bipyridine (bpy) has been carried out under the conditions, [D-galactose] T >> [Cr(VI)] T at different temperatures. The monomeric species of Cr (VI) has been found to be kinetically active in the absence of bpy whereas in the bpy-catalysed path, the Cr(VI)-bpy complex has been suggested as the active oxidant. In the bpy-catalysed path, Cr(VI)-bpy complex receives a nucleophilic attack by the substrate to form a ternary complex, which subsequently experiences a redox decomposition (through 2e transfer) at the rate-determining step leading to the product lactone and Cr(IV)-bpy complex. Then the Cr(IV)-bpy complex participates in faster steps in further oxidation of D-galactose and ultimately it is converted into Cr(III)-bpy complex. In the uncatalysed path, Cr(VI)-substrate ester experiences acid catalysed redox decomposition (2e-transfer) at the rate determining step. The uncatalysed path shows second order dependence on [H + ] while the bpycatalysed path shows a first order dependence on [H + ]. Both the uncatalysed path and bpy-catalysed path show the first order dependence on both [D-galactose] T and [Cr(VI)] T. The bpy-catalysed path is first order in [bpy] T. These observations remain unaltered in the presence of externally added surfactants. Effect of the surfactants like N-cetylpyridinium chloride (CPC, a cationic surfactant) and sodium dodecyl sulfate (SDS, an anionic surfactant), on both the uncatalysed and bpycatalysed paths has been studied. CPC inhibits both the uncatalysed and bpy-catalysed path, while SDS accelerates the reactions. In the catalysed path, cationic Cr(VI)-bpy complex is the reactive species which is attracted by the anionic micellar head groups of SDS but repelled by the cationic micellar head groups of CPC. The neutral substrate is accumulated in the Stern layer of both types of micelles. Thus the observed micellar effects have been explained by considering the hydrophobic and electrostatic interactions between the reactants and surfactants in terms of the proposed mechanism.

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Section: Introductionmentioning

confidence: 99%

Kinetics and Mechanism of Oxidation of D-Galactose by Chromium(VI) in Presence of 2,2’-Bipyridine Catalyst in Aqueous Micellar Media

Bayen¹,

K.²

2009

TOCATJ

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“…Previous works on chromic acid directed oxidation of many organic compounds suggests that, the oxidation rate was further in uenced by utilising some N-bases such as 1,10-Phenanthroline, 2,2'-Bipyridine, 2-Picolinic acid, etc. [31][32][33][34][35][36] which was materialized as Cr(III)-N-base complexes at the end of oxidation. These heteroaromatic N-bases compounds are better termed as promoter instead of catalyst.…”

Section: Introductionmentioning

confidence: 99%

“…These heteroaromatic N-bases compounds are better termed as promoter instead of catalyst. 35,36 In our recent work we have manifested the oxidation kinetic of 4-chlorobenzyl alcohol in single micellar medium following pseudo-rst order condition. 33 Herein, we have uncovered the role of SDS/TX-100 mixed micellar media on the oxidation of same aromatic alcohol by chromic acid at 30°C.…”

Section: Introductionmentioning

confidence: 99%

A synergistic combination of SDS and TX-100 for the catalytic oxidation of an aromatic alcohol in aqueous media

Rakshit

Chowdhury

Acharjee

et al. 2023

Preprint

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In aqueous medium, oxidation of an aromatic alcohol (4-chlorobenzyl alcohol) was carried out in aqueous mixed micellar media under pseudo first order condition by chromic acid at 30 ºC. The micellar microenvironment constituted by anionic SDS and nonionic TX-100 surfactants showed excellent catalytic performance in course of oxidation, individually. In addition to that the nanomicelle produced by combination of SDS and TX-100 was found to be effective microheterogeneous catalyst for the aforementioned oxidation process. Use of two organic precursors, Phen and Bpy, entitled as promoter, made the reaction faster in presence of single micelle and mixed micelle. The fabrication of mixed micelle was confirmed by UV, 1H-NMR and 2D NOESY study. The maximum improvement in reaction kinetic was noticed when SDS/TX-100 surfactants mixture introduced along with Bpy promoter.

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Heteroaromatic N-base ligands in 1,10-phenanthroline- and 2,2′-bipyridyl-assisted chromic acid oxidation of (−)-l-sorbose in aqueous micellar acid media: a kinetic study

Islam

Das

2008

Carbohydrate Research

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Micellar Effects on the Reactions of Chromium(VI) Oxidation of Lactic Acid and Malic Acid in the Presence and Absence of Picolinic Acid in Aqueous Acid Media

Cited by 4 publications

References 15 publications

Kinetics and Mechanism of Oxidation of D-Galactose by Chromium(VI) in Presence of 2,2’-Bipyridine Catalyst in Aqueous Micellar Media

Kinetics and Mechanism of Oxidation of D-Galactose by Chromium(VI) in Presence of 2,2’-Bipyridine Catalyst in Aqueous Micellar Media

A synergistic combination of SDS and TX-100 for the catalytic oxidation of an aromatic alcohol in aqueous media

Heteroaromatic N-base ligands in 1,10-phenanthroline- and 2,2′-bipyridyl-assisted chromic acid oxidation of (−)-l-sorbose in aqueous micellar acid media: a kinetic study

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