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dc.contributor.authorPérez de Benito, Joaquín F.-
dc.contributor.authorFerrando Benítez, Jordi-
dc.description.abstractThe reduction of permanganate ion to MnO2 Mn2O3 soluble colloidal mixed oxide by L-phenylalanine in aqueous phosphate-buffered neutral solutions has been followed by a spectrophotometric method, monitoring the decay of permanganate ion at 525 nm and the formation of the colloidal oxide at 420 nm. The reaction is autocatalyzed by the manganese product and three rate constants have been required to fit the experimental absorbance-time kinetic data. The reaction shows base catalysis and the values of the activation parameters at different pHs have been determined. A mechanism including both the non-autocatalytic and the autocatalytic reaction pathways, and in agreement with the available experimental data, has been proposed. Some key features of this mechanism are the following: (i) of the two predominant forms of the amino acid, the anionic form exhibits a stronger reducing power than the zwitterionic form; (ii) the non-autocatalytic reaction pathway starts with the transfer of the hydrogen atom in the  position of the amino acid to permanganate ion; and (iii) the autocatalytic reaction pathway involves the reduction of Mn(IV) to Mn(II) by the amino acid and the posterior re-oxidation of Mn(II) to Mn(IV) by permanganate ion.-
dc.format.extent12 p.-
dc.publisherAmerican Chemical Society-
dc.relation.isformatofVersió postprint del document publicat a:
dc.relation.ispartofJournal of Physical Chemistry B, 2014, vol. 118, num. 51, p. 14949-14960-
dc.rights(c) American Chemical Society , 2014-
dc.subject.classificationCinètica química-
dc.subject.otherChemical kinetics-
dc.subject.otherAmino acids-
dc.titleThree rate-constant kinetic model for permanganate reactions autocatalyzed by colloidal manganese dioxide: the oxidation of L-phenylalanine-
Appears in Collections:Articles publicats en revistes (Ciència dels Materials i Química Física)

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