Unexpectedly ambivalent O-2 role in the autocatalytic photooxidation of 2-methoxybenzyl alcohol in water

Vincenzo Augugliaro, Leonardo Palmisano, Andrea Pace, Vittorio Loddo, Sedat Yurdakal, Bilge Sina Tek, Giovanni Palmisano

Risultato della ricerca: Articlepeer review

5 Citazioni (Scopus)

Abstract

tAn unusual autocatalytic photooxidation of 2-methoxybenzyl alcohol has been observed under UV irradi-ation in aqueous medium. The homogeneous oxidation is catalyzed by the corresponding aldehyde that isalso the main oxidation product. The trend of alcohol disappearance rate matches the typical shape of anautocatalytic process, where a crucial and ambivalent role is played by the presence of molecular oxygen.Low oxygen concentrations give rise to a zero-order reaction since the beginning of irradiation, whilehigher amounts of oxygen reduce the alcohol oxidation rate until the aldehyde reaches a concentrationhigh enough to speed up the alcohol’s conversion. Experiments performed by varying alcohol, aldehydeand oxygen concentrations in both aqueous and organic media suggest that the alcohol oxidation is ini-tially favored by the presence of oxygen. Once the formed aldehyde competes for photon absorption,the oxidation is driven by aldehydes alpha cleavage leading to reactive oxygenated species in aqueousmedium. An excess of oxygen quenches the latter processes thus inhibiting/slowing down the reaction.
Lingua originaleEnglish
pagine (da-a)37-42
Numero di pagine6
RivistaJOURNAL OF MOLECULAR CATALYSIS. A: CHEMICAL
Volume403
Stato di pubblicazionePublished - 2015

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Process Chemistry and Technology
  • Physical and Theoretical Chemistry

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