Catalysis in oxidation reactions. 3. The oxalic acid catalyzed chromic acid oxidation of tris(1,10-phenanthroline)iron(II)

Hintze, Ray E.; Rocek, Jan

doi:10.1021/ja00443a025

Cited by 19 publications

(8 citation statements)

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“…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]. Some of the chelating agents as catalysts like oxalic acid, -hydroxy acids experience cooxidation [19].…”

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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“…They attributed this rate acceleration to the phenomenon called cooxidation wherein both substrates undergo oxidation simultaneously. On the other hand, oxalic acid acts as a catalyst in the Cr(V1) oxidations of iodide (2) and ferroin (3). Recently the mechanisms of oxidation of alkyl aryl sulfoxides (4) and diaryl sulfoxides (5) by Cr(V1) have been reported and therefore the study of the influence of oxalic acid on the rates of Cr(V1) oxidation of sulfoxides will be of particular interest.…”

Section: Introductionmentioning

confidence: 99%

Substituent effects in cooxidation: Cr(VI) – oxalic acid – sulfoxides systems

Srinivasan¹,

Jegatheesan²,

Rajagopal³

et al. 1987

Can. J. Chem.

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The kinetics of cooxidation of several substituted phenyl methyl sulfoxides and oxalic acid with Cr(V1) have been carried out in the presence of perchloric acid. The reaction is first order each in sulfoxide, oxalic acid, Cr(VI), and H'. The products of oxidation are sulfones and carbon dioxide. Electron-releasing groups in the phenyl ring accelerate the rate while electron-withdrawing groups retard it. The Hammett correlation yields a reaction constant of -0.927 +-0.08 ( r = 0.994) at 313 K. Addition of aluminium nitrate prevents the occurrence of cooxidation. Based on the kinetic information a suitable mechanism has been proposed. Diary1 sulfoxides behave in an analogous manner in the cooxidation.C. SRINIVASAN, P. PANDARAKUTTY JEGATHEESAN, S. RAJAGOPAL et N. ARUMUGAM. Can. J. Chem. 65, 2421Chem. 65, (1987.Operant en presence d'acide perchlorique, on a mesure les cinetiques de cooxydation de l'acide oxalique et de plusieurs phenyl methyl sulfoxydes substitues par le Cr(V1). La reaction est du premier ordre en sulfoxyde, en acide oxalique, en Cr(V1) et en H +.Les produits d'oxydation sont les sulfones et le dioxyde de carbone. La presence sur le noyau phenyle de groupements ~lectrodonneurs provoque une augmentation de la vitesse de la reaction alors que les groupements electroaffinitaires la diminue.A 313 K, la correlation de Hamrnett conduit i une constante de reaction de -0,927 + 0,08 (r = 0,994). L'addition de nitrate d'aluminium empkche la reaction de se produire. Sur la base des informations cinetiques, on propose un mecanisme approprie. Les sulfoxydes de diaryles se cornportent d'une fason similaire lors de cooxydations.[Traduit par la revue] Introduction A dramatic rate acceleration was observed by Hasan and RoEek (I) in the Cr(V1) oxidation of a mixture of isopropanol and oxalic acid compared to the Cr(V1) oxidations of either of the above substrates. They attributed this rate acceleration to the phenomenon called cooxidation wherein both substrates undergo oxidation simultaneously. On the other hand, oxalic acid acts as a catalyst in the Cr(V1) oxidations of iodide (2) and ferroin (3). Recently the mechanisms of oxidation of alkyl aryl sulfoxides (4) and diaryl sulfoxides (5) by Cr(V1) have been reported and therefore the study of the influence of oxalic acid on the rates of Cr(V1) oxidation of sulfoxides will be of particular interest. In this paper we wish to report the salient features of the Cr(V1) oxidation of sulfoxides in the presence of oxalic acid.

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“…A similar reaction mechanism is known for the reaction with the 1e-reductants of transition metal ions [41] and [Fe(phen) 3 ] 2+ [107]. In some other cases, this mechanism has also been suggested [82,97,[108][109][110][111].…”

Section: The Common Pathways Leading To Reduction Of Chromium(vi) To mentioning

confidence: 54%

Micellar effect on the kinetics and mechanism of chromium(VI) oxidation of organic substrates

Das

2004

Coordination Chemistry Reviews

117

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Catalysis in oxidation reactions. 3. The oxalic acid catalyzed chromic acid oxidation of tris(1,10-phenanthroline)iron(II)

Cited by 19 publications

References 1 publication

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

Substituent effects in cooxidation: Cr(VI) – oxalic acid – sulfoxides systems

Micellar effect on the kinetics and mechanism of chromium(VI) oxidation of organic substrates

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