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Oxidation of lactic acid by water soluble (colloidal) manganese dioxide
Author(s) -
Khan Zaheer,
Akram Mohd.
Publication year - 2004
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.20010
Subject(s) - chemistry , manganese , autocatalysis , lactic acid , potassium permanganate , inorganic chemistry , colloid , redox , permanganate , catalysis , aqueous solution , kinetics , organic chemistry , physics , quantum mechanics , biology , bacteria , genetics
Spectrophotometric method has been used to characterize water‐soluble colloidal manganese dioxide obtained by the redox reaction between sodium thiosulphate and potassium permanganate in neutral aqueous medium which shows a single peak in the visible region with λ max = 425 nm. The kinetics of the oxidation of lactic acid by colloidal manganese dioxide (oxidant) has been investigated spectrophotometrically under pseudo‐first‐order conditions of excess lactic acid. The rate of the noncatalytic reaction pathway was slow which increased with increasing lactic acid concentration. The reaction was first‐order with respect to [oxidant] as well as [lactic acid]. In presence of manganase(II) and fluoride ions, the noncatalytic path disappeared completely while the oxidation rate of autocatalytic path increased and decreased, respectively with increasing [Mn(II)] and [F − ]. A mechanistic scheme in conformity with the observed kinetics has been proposed with the rate‐law:© 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 359–366 2004