Oxidation of manganese(II) by ozone and reduction of manganese(III) by hydrogen peroxide in acidic solution

✍ Scribed by Frank Jacobsen; Jerzy Holcman; Knud Sehested

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 182 KB
• Volume: 30
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/(sici)1097-4601(1998)30:3<207::aid-kin6>3.0.co;2-w

✦ Synopsis

Manganese(II) is oxidized by ozone in acid solution, k ϭ (1.5 Ϯ 0.2) ϫ in HClO 4 and in H 2 SO 4 . The plausible mechanism is 3 Ϫ1 Ϫ1 3 Ϫ 1 Ϫ 1 10 M s k ϭ (1.8 Ϯ 0.2) ϫ 10 M s an oxygen atom transfer from O 3 to producing the manganyl ion which subse-2ϩ 2ϩ Mn MnO , quently reacts rapidly with to form Mn(III). No free OH radicals are involved in the 2ϩ Mn mechanism. The spectrum of Mn(III) was obtained in the wave length range The 200-310 nm. activation energy for the initial reaction is Manganese(III) is reduced by hydrogen 39.5 kJ/mol. peroxide to Mn(II) with at pH 0-2. The mechanism of 3 Ϫ1 Ϫ1 k(Mn(III) ϩ H O ) ϭ 2.8 ϫ 10 M s 2 2

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.