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Mansour, Mohamed A.

doi:10.1023/a:1021326228930

Cited by 8 publications

(6 citation statements)

References 2 publications

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“…Thus formation of sulfoxide radical ( 5 ) is proposed as a result of nucleophilic attack of water on sulfonium cation intermediate ( 4 ) (Eqn 5) which then transfers its electron to another [Fe(NN) 3 ] 3+ (Eqn 6) that leads to the formation of sulfoxide cation. Such type of attack by water followed by second electron transfer to another [Fe(NN) 3 ] 3+ is already shown in the oxidation of sulfur compounds by polypyridyl complexes . The sulfoxide cation then undergoes rearrangement to form phenylsulfonyl free radical via cleavage of a C‐S bond β to the aromatic ring .…”

Section: Resultsmentioning

confidence: 72%

“…[52] It is also shown that the increase in absorbance is more pronounced in Phen complexes than in Bpy complexes. The observed Michaelis-Menten kinetics [53] with PSAA can be taken as the kinetic evidence for the formation of adduct (3). The strong one electron nature of the oxidant [Fe(NN) 3 ] 3+ and formation of a new peak characteristic of [Fe(NN) 3 ] 2+ as one of the products of the reaction clearly confirm the formation of sulfoxide radical cation (4) as the transient species by electron transfer from PSAA to Fe(III).…”

Section: Failure Of the Hammett Linear Free Energy Relationshipmentioning

confidence: 99%

“…Thus formation of sulfoxide radical (5) 3+ is already shown in the oxidation of sulfur compounds by polypyridyl complexes. [6,53] The sulfoxide cation then undergoes rearrangement to form phenylsulfonyl free radical via cleavage of a C-S bond β to the aromatic ring. [58] Srinivasan et al [59] showed a fairly intense peak corresponding to C 6 H 5 SO 2 • radical in the mass spectrum of phenylsulfonylacetic acid by the loss of • CH 2 COOH.…”

Section: Failure Of the Hammett Linear Free Energy Relationshipmentioning

confidence: 99%

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A paradigm shift in rate determining step from single electron transfer between phenylsulfinylacetic acids and iron(III) polypyridyl complexes to nucleophilic attack of water to the produced sulfoxide radical cation: a non‐linear Hammett

Subramaniam¹,

Rose

Rathinakumari

2016

J of Physical Organic Chem

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Mechanism of oxidative decarboxylation of phenylsulfinylacetic acids (PSAAs) by iron(III) polypyridyl complexes in aqueous acetonitrile medium has been investigated spectrophotometrically. 3+ is rationalized on the basis of coordination of a water molecule at the carbon atom adjacent to the ring nitrogen of the metal polypyridyl complexes by nucleophilic attack at higher concentrations. Electron-withdrawing and electron-releasing substituents in PSAA facilitate the reaction and Hammett correlation gives an upward 'V' shaped curve. The apparent upward curvature is rationalized based on the change in the rate determining step from electron transfer to nucleophilic attack, by changing the substituents from electron-releasing to electron-withdrawing groups. Electron-releasing substituents in PSAA accelerate the electron transfer from PSAA to the complex and also stabilize the intermediate through resonance interaction leading to negative reaction constants (ρ). Conversely, electron-withdrawing groups, while retarding the electron transfer exert an accelerating effect on the nucleophilic attack of H 2 O which leading to low magnitude of ρ + compared to high ρ À values of electron-releasing groups. Marcus theory is applied, and a fair agreement is seen with the experimental values.

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Section: Resultsmentioning

confidence: 72%

Section: Failure Of the Hammett Linear Free Energy Relationshipmentioning

confidence: 99%

Section: Failure Of the Hammett Linear Free Energy Relationshipmentioning

confidence: 99%

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A paradigm shift in rate determining step from single electron transfer between phenylsulfinylacetic acids and iron(III) polypyridyl complexes to nucleophilic attack of water to the produced sulfoxide radical cation: a non‐linear Hammett

Subramaniam¹,

Rose

Rathinakumari

2016

J of Physical Organic Chem

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“…However, it is not clear if the same correlations apply to high Karlovitz number flows where turbulent transport dominates. There, small eddies can broaden the preheat zone and thicken or even break the reaction zone [22][23][24]. The impact on the chemical processes is still not well characterized, especially for heavy hydrocarbon fuels.…”

Section: Independent Of the Lack Of Experimental Data For Heavy Hydromentioning

confidence: 99%

Experimental and numerical studies of fuel and hydrodynamic effects on piloted turbulent premixed jet flames

Smolke

Lapointe

Paxton

et al. 2017

Proceedings of the Combustion Institute

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An experimental and numerical investigation of fuel and hydrodynamic effects is performed on piloted premixed jet flames. The investigation is carried out at a constant laminar flame speed, varying heat losses, jet Reynolds number, fuel molecular weight, and fuel chemical classification. Large Eddy Simulations are performed in an attempt to reproduce the behaviors observed experimentally. Simulations are compared against well-characterized boundary conditions, well-resolved two-dimensional velocity fields from particle image velocimetry, and line-ofsight CH* profiles. Experimental results indicate that small amounts of heat losses may play a significant role on the jet reactivity as the flame heights scale with the heat loss from the jet. However, differences between flames with different fuels can still be seen in the absence of heat losses and these differences are magnified at higher Reynolds numbers. Particularly, methane flames are consistently taller and ethylene flames consistently shorter while other fuels present approximately the same flame height. LES reproduce the experimentally observed trends in global flame heights (effects of heat losses and Reynolds number) but some of the differences between fuels are not captured.

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“…Thus Cr VI compounds seems to be the cause for adverse biological effects. However, interest is generated among the researchers on using Cr VI reagents as oxidizing agent for the study of kinetics of oxidation of organic substrates [5][6][7]. With this intention quinolinium dichromate (QDC), a new chromium reagent, has been used as an oxidant to determine the sensitivity among amino acids towards oxidation.…”

Section: Introductionmentioning

confidence: 99%

A comparative study of quinolinium dichromate oxidation with hydrophobic dependence amino acids. A kinetic and mechanistic approach

Ravishankar

Baba

Rangaswamy

et al. 2007

Transition Met Chem

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A detailed study of kinetics is required to predict the susceptibility of amino acid residues towards metal-catalyzed oxidation. The effect of quinolinium dichromate on the oxidation of a set of amino acid residues with different hydrophobicity in HClO 4 medium at 25°C has been fairly studied. The kinetics of the reaction was followed spectrophotometrically at k max = 440 nm. The reaction has unit dependence on each of the substrates, quinolinum dichromate and acid concentrations. The effect of dielectric constant of the medium on the rate was studied. The induced polymerization of acrylonitrile was observed. The oxidation products were isolated and characterized. Dependence of reaction rate on temperature has been studied and activation parameters were computed. A mechanism consistent with the observed results has been proposed. Of the four amino acid residues, proline is oxidized at a faster rate than all other amino acids. This may be due to the hydrophobic induced oxidation. Therefore, the overall order of amino acid sensitivity to oxidation was found to be Pro > Thr > Ser > Lys.

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Untitled

Cited by 8 publications

References 2 publications

A paradigm shift in rate determining step from single electron transfer between phenylsulfinylacetic acids and iron(III) polypyridyl complexes to nucleophilic attack of water to the produced sulfoxide radical cation: a non‐linear Hammett

A paradigm shift in rate determining step from single electron transfer between phenylsulfinylacetic acids and iron(III) polypyridyl complexes to nucleophilic attack of water to the produced sulfoxide radical cation: a non‐linear Hammett

Experimental and numerical studies of fuel and hydrodynamic effects on piloted turbulent premixed jet flames

A comparative study of quinolinium dichromate oxidation with hydrophobic dependence amino acids. A kinetic and mechanistic approach

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