Oxidation of Benzidine on Low-Iron Smectites: A Proposed Mechanism

McBride, Murray B.

doi:10.1346/ccmn.1986.0340611

Cited by 3 publications

(6 citation statements)

References 7 publications

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“…Because of the linkage through the apical oxygen of the tetrahedral and octahedral sheets, any change in the octahedral cation-oxygen ligand bondlength would result in tilting of silica tetrahedra to maintain structural integrity (9). This hypothesis is consistent with the results obtained by other indirect spectroscopic techniques such as FTIR (35,37) and the interpretation of 29 Si MAS NMR (36).…”

Section: Effect Of Fe Reduction On Clay Structure: Exafssupporting

confidence: 85%

“…These results are in contrast to other reactive organics at clay surfaces, such as benzene and nitrobenzene, where greater than monolayer water contents impede the reactivity of the clay surface by preventing direct sorption of the reactant to the surface (28). In addition, these results are in general agreement with sorption from aqueous solution of other large polar (or weakly polar) aromatics, such as benzidene and its derivatives (29).…”

Section: Effect Of Water Content On Reaction Kineticssupporting

confidence: 65%

“…Such interactions have been documented in other phenyl containing compounds (5, 29). McBride and Johnson (29) provided evidence of changes in the conformation of benzidene ions upon sorption from aqueous solution to smectite surfaces. The conformational changes of sorbed benzidene are believed to be responsible for the electron transfer and blue color of benzidene-smectite complexes (29).…”

Section: Effect Of Water Content On Reaction Kineticsmentioning

confidence: 99%

“…McBride and Johnson (29) provided evidence of changes in the conformation of benzidene ions upon sorption from aqueous solution to smectite surfaces. The conformational changes of sorbed benzidene are believed to be responsible for the electron transfer and blue color of benzidene-smectite complexes (29). The splitting of the 1430 cm" 1 band for solution TPB into two distinct bands at 1410 and 1400 cm" 1 ( Figure 11) indicate the possibility of a similar change in conformation for sorbed TPB.…”

Section: Effect Of Water Content On Reaction Kineticsmentioning

confidence: 99%

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Degradation of Tetraphenylboron at Hydrated Smectite Surfaces Studied by Time Resolved IR and X-ray Absorption Spectroscopies

Hunter

Gates

Bertsch

et al. 1999

ACS Symposium Series

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The surface catalyzed redox reactivity of an organoboron probe molecule (tetraphenylboron, or TPB) with fully hydrated clay mineral surfaces is described wherein one or both of two degradation pathways can occur. Attenuated total reflectance Fourier transform infrared (ATR-IR) spectroscopy can quantitatively measure, in situ, both acid hydrolytic and oxidative degradation of TPB as controlled by the exchange cation identity and the structural octahedral Fe content of the clay mineral. Oxidation of TPB at smectite surfaces is directly attributable to octahedral Fe(III) in the clay structure.The concomitant reduction of Fe(III) during TPB oxidation can be analytically measured by X-ray absorption near edge structure (XANES) spectroscopy. The resultant distortion of the clay mineral structure during the reduction of structural Fe could be probed directly by extended X-ray absorption fine structure (EXAFS) spectroscopy. The lack of evidence for clay mineral dissolution during the reaction with TPB permits defining the clay as a catalyst. The combination of these three in situ spectroscopic techniques to measure the reaction in real time, provides powerful insight into the reactivity of clay mineral surfaces.

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Section: Effect Of Fe Reduction On Clay Structure: Exafssupporting

confidence: 85%

Section: Effect Of Water Content On Reaction Kineticssupporting

confidence: 65%

Section: Effect Of Water Content On Reaction Kineticsmentioning

confidence: 99%

Section: Effect Of Water Content On Reaction Kineticsmentioning

confidence: 99%

See 2 more Smart Citations

Degradation of Tetraphenylboron at Hydrated Smectite Surfaces Studied by Time Resolved IR and X-ray Absorption Spectroscopies

Hunter

Gates

Bertsch

et al. 1999

ACS Symposium Series

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“…[14] Also, a few papers present semi-empirically calculated data regarding to the oxidation of aniline [12,13] along with the pioneering work where the molecular orbital (MO) energies of Bzd and N,N,N′,N′-tetramethylbenzidine are calculated by the extended Hückel method. [60] Moreover, the optical properties of BBC are quite poorly studied from the theoretical point of view. Only two papers we have found in the literature.…”

Section: Assignment Of Absorption Bands In Electronic Spectrum Of Thementioning

confidence: 99%

Electronic descriptors for analytical use of the benzidine‐based compounds and the mechanism of oxidative coupling of anilines

Bondarchuk

Minaev

2014

J of Physical Organic Chem

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A number of hybrid exchange-correlation functionals, namely, B3LYP, BMK, M06-2X, PBE0, CAM-B3LYP, BH&HLYP, and HSE06, have been employed to calculate the electronic spectra of a series of the N,N′-derivatives of benzidine, their radical cations, and dications; the results are compared with available experimental data. In most cases studied, the timedependent density functional theory results based on the CAM-B3LYP and BMK functionals indicate a better agreement with the experimental absorption bands in the UV-Vis spectra. The other five functionals provide statistically comparable but lower accuracy. On the basis of the time-dependent density functional theory calculations with both the CAM-B3LYP and BMK functionals and the 6-311 + G(d,p) basis set including effect of polar medium simulation, the electronic spectrum of the benzidine dication has been completely assigned. Because the latter dication is formed during oxidative coupling of two aniline molecules, as the reductive reagents for analytical determination of strong oxidants, the mechanism of this reaction has been clarified on the ground of density functional theory calculations including effect of dispersion for all possible reaction paths and intermediates. By the analysis of spectral properties and ionization energies of several aniline derivatives, a few simple electronic descriptors that help to justify a reagent molecule as a potentially favorable for colorimetric use have been proposed.

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Praktische Verwendung und Einsatzmöglichkeiten von Tonen

Lagaly¹

1993

Tonminerale Und Tone

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Oxidation of Benzidine on Low-Iron Smectites: A Proposed Mechanism

Cited by 3 publications

References 7 publications

Degradation of Tetraphenylboron at Hydrated Smectite Surfaces Studied by Time Resolved IR and X-ray Absorption Spectroscopies

Degradation of Tetraphenylboron at Hydrated Smectite Surfaces Studied by Time Resolved IR and X-ray Absorption Spectroscopies

Electronic descriptors for analytical use of the benzidine‐based compounds and the mechanism of oxidative coupling of anilines

Praktische Verwendung und Einsatzmöglichkeiten von Tonen

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