A pulse radiolysis study of the OH radical induced autoxidation of methanesulfinic acid

K. Sehested, J. Holcman

    Research output: Contribution to journalConference articleResearch


    Methanesulfinic acid, CH3SO2H, reacts with OH radicals at pH 7 forming CH3SO2 radicals with a rate constant k = (6.0 +/- 1.0) x 10(9) M(-1) s(-1). The CH3SO2 radical absorbs at 325 nm with an extinction coefficient of 900 +/- 100 M(-1) cm(-1) and disappears in a second order self-reaction with k = (1.0 +/- 0.2) x 10(9) M(-1) s(-1). This radical reacts with oxygen, k = (1.2 +/- 0.3) x 10(9) M(-1) s(-1), forming a peroxy radical which absorbs in the UV below 300 nm. The peroxy radical reacts in turn with methanesulfinic acid reforming the CH3SO2 radical whereby a chain oxidation of sulfinic acid takes place. During the course of the chain oxidation a peroxyacid, presumably methaneperoxymonosulfonic acid, is formed and accumulated. This acid absorbs in the UV and eventually decays by reaction with excess methanesulfinic acid k = 5 x 10(3) M(-1) s(-1). The final product of the chain autoxidation is methanesulfonic acid. The chain is very efficient and proceeds until either oxygen or methanesulfinic acid is exhausted. The mechanism is compared to the chain autoxidation of sulfite.
    Original languageEnglish
    JournalRadiation Physics and Chemistry
    Issue number3
    Pages (from-to)357-360
    Publication statusPublished - 1996
    Event8th Tihany Symposium of Radiation Chemistry - Balatonszéplak, Hungary
    Duration: 3 Sep 19948 Sep 1994
    Conference number: 8


    Conference8th Tihany Symposium of Radiation Chemistry


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