Premium
A kinetic study of the autocatalytic permanganate oxidation of formic acid
Author(s) -
PerezBenito Joaquin F.,
Arias Conchita,
Brillas Enrique
Publication year - 1990
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550220306
Subject(s) - chemistry , autocatalysis , permanganate , perchloric acid , formic acid , reaction rate constant , manganese , inorganic chemistry , aqueous solution , kinetics , kinetic energy , reaction rate , order of reaction , activation energy , catalysis , organic chemistry , physics , quantum mechanics
The kinetics of the permanganate oxidation of formic acid in aqueous perchloric acid has been studied. The results indicate that this reaction is autocatalyzed by both manganese(II) ion (formed as a reaction product) and colloidal manganese dioxide (formed as an intermediate). The apparent rate constants corresponding to the noncatalytic and autocatalytic reaction pathways are given, respectively, by the following equations\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{l} k_1 = (k_1^{bc} /[{\rm H}^{\rm +}] + k_1^{nc} + k_1^{ac} [{\rm H}^{\rm +}]^3)[{\rm HCOOH]} \\ k_2 = (k_2^{bc} /[{\rm H}^{\rm +}] + k_2^{nc} + k_2^{ac} [{\rm H}^{\rm +}]^3)[{\rm HCOOH]} \\ \end{array} $$\end{document}The activation energies associated with the true rate constants, 1 bc , 1 nc , 1 ac , 2 bc , 2 nc , and 2 acare 37.2, 62.5, 70.9, 52.5, 40.8, and 59.9 kJ mol −1 , respectively. The percentage of the total reaction corresponding to each pathway is given for typical experimental conditions. Mechanisms in agreement with the kinetic data are proposed for the six different reaction pathways observed.