Premium
Oxidation of manganese(II) by ozone and reduction of manganese(III) by hydrogen peroxide in acidic solution
Author(s) -
Jacobsen Frank,
Holcman Jerzy,
Sehested Knud
Publication year - 1998
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/(sici)1097-4601(1998)30:3<207::aid-kin6>3.0.co;2-w
Subject(s) - chemistry , manganese , disproportionation , hydrogen peroxide , radical , ozone , inorganic chemistry , peroxide , oxygen , photochemistry , reaction mechanism , catalysis , organic chemistry
Manganese(II) is oxidized by ozone in acid solution, k =(1.5±0.2)×10 3 M −1 s −1 in HClO 4 and k =(1.8±0.2)×10 3 M −1 s −1 in H 2 SO 4 . The plausible mechanism is an oxygen atom transfer from O 3 to Mn 2+ producing the manganyl ion MnO 2+ , which subsequently reacts rapidly with Mn 2+ to form Mn(III). No free OH radicals are involved in the mechanism. The spectrum of Mn(III) was obtained in the wave length range 200–310 nm. The activation energy for the initial reaction is 39.5 kJ/mol. Manganese(III) is reduced by hydrogen peroxide to Mn(II) with k (Mn(III)+H 2 O 2 )=2.8×10 3 M −1 s −1 at pH 0–2. The mechanism of the reaction involving formation of the manganese(II)‐superoxide complex and reaction of H 2 O 2 with Mn(IV) species formed due to reversible disproportionation of Mn(III), is suggested. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 207–214, 1998.