Characteristic mechanisms of the homogeneous and heterogeneous oxidation of aromatic amines with transition metal-oxalate complexes
Characteristic mechanisms of the homogeneous and heterogeneous oxidation of aromatic amines with transition metal-oxalate complexes
The oxidation-reduction reactions of aromatic amines {o-aminophenol (o-AP), o-phenylenediamine (o-PDA) and p-phenylenediamine (p-PDA)} with Co(III)-, Mn(III)-, and Cu(II)-oxalate complexes have been investigated in homogeneous and heterogeneous systems. The kinetics of the redox reaction of both systems have been studied spectrophotometrically. The redox products were identified and characterised by diffuse reflectance spectroscopy (DRS), and mass spectrometry. The redox reactions follow first-order kinetics with respect to each of the reactants and first order in [amines] in homogeneous and heterogeneous (supported complexes on Amberlite IRA 904 anion-exchange resin) phases, respectively. However, the specific oxidation rate of the amines is found to follow the order, p-PDA > o-AP > o-PDA. The effect of the oxalate anion on the reaction rate of both systems was examined. There is a significant difference in the behaviour of the oxidation of o-AP and o-, p-PDA with all the metal complexes in both systems. Moreover, the oxidation of o-AP and o-, p-PDA appears to follow the outer- and inner-sphere mechanistic classification, respectively.
aromatic amines, amberlite anion-exchange resin, oxalate anions, metal-oxalate complexes, oxidation, homogeneous and heterogeneousl-ascorbic-acid, electron-transfer, aqueous-solution, o-phenylenediamine, ortho-aminophenol, synthase model, inner-sphere, outer-sphere, dioxygen, 2-aminophenol
1317-1328
Zaki, A. B.
d60241c5-b639-4714-ab0f-6aefe73a34cc
El-Sheikh, M. Y.
3ce29d44-2066-40b7-8927-249ed0622ae3
Evans, J.
05890433-0155-49fe-a65d-38c90ea25c69
El-Safty, S. A.
82d1f76a-0131-44a6-802e-de1bd1d2723b
15 June 2000
Zaki, A. B.
d60241c5-b639-4714-ab0f-6aefe73a34cc
El-Sheikh, M. Y.
3ce29d44-2066-40b7-8927-249ed0622ae3
Evans, J.
05890433-0155-49fe-a65d-38c90ea25c69
El-Safty, S. A.
82d1f76a-0131-44a6-802e-de1bd1d2723b
Zaki, A. B., El-Sheikh, M. Y., Evans, J. and El-Safty, S. A.
(2000)
Characteristic mechanisms of the homogeneous and heterogeneous oxidation of aromatic amines with transition metal-oxalate complexes.
Polyhedron, 19 (11), .
(doi:10.1016/S0277-5387(00)00401-0).
Abstract
The oxidation-reduction reactions of aromatic amines {o-aminophenol (o-AP), o-phenylenediamine (o-PDA) and p-phenylenediamine (p-PDA)} with Co(III)-, Mn(III)-, and Cu(II)-oxalate complexes have been investigated in homogeneous and heterogeneous systems. The kinetics of the redox reaction of both systems have been studied spectrophotometrically. The redox products were identified and characterised by diffuse reflectance spectroscopy (DRS), and mass spectrometry. The redox reactions follow first-order kinetics with respect to each of the reactants and first order in [amines] in homogeneous and heterogeneous (supported complexes on Amberlite IRA 904 anion-exchange resin) phases, respectively. However, the specific oxidation rate of the amines is found to follow the order, p-PDA > o-AP > o-PDA. The effect of the oxalate anion on the reaction rate of both systems was examined. There is a significant difference in the behaviour of the oxidation of o-AP and o-, p-PDA with all the metal complexes in both systems. Moreover, the oxidation of o-AP and o-, p-PDA appears to follow the outer- and inner-sphere mechanistic classification, respectively.
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Published date: 15 June 2000
Keywords:
aromatic amines, amberlite anion-exchange resin, oxalate anions, metal-oxalate complexes, oxidation, homogeneous and heterogeneousl-ascorbic-acid, electron-transfer, aqueous-solution, o-phenylenediamine, ortho-aminophenol, synthase model, inner-sphere, outer-sphere, dioxygen, 2-aminophenol
Identifiers
Local EPrints ID: 19060
URI: http://eprints.soton.ac.uk/id/eprint/19060
ISSN: 0277-5387
PURE UUID: 4e720ee9-ce1b-4584-a270-a373c32c5f92
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Date deposited: 16 Dec 2005
Last modified: 29 Oct 2024 02:32
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Author:
A. B. Zaki
Author:
M. Y. El-Sheikh
Author:
S. A. El-Safty
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