Photochemical excitation of (nBu4N)4W10O32 in the presence of oxygen (760 torr) leads to the formation of C6H11• and OH• radicals which can be revealed by ESR spin-trapping investigations. Cyclohexane is transformed in cyclohexanone and cyclohexanol with an overall photooxidation quantum yield of 0.35 at 325 nm photoexcitation wavelength. A strong influence of oxygen pressure on the concentration ratio of these products is observed; in that, at low oxygen pressure (15 torr), the yield of cyclohexanone is negligible and the photocatalytic oxidation of cyclohexane mainly leads to the formation of cyclohexanol. The photocatalyst investigated does not suffer irreversible modifications allowing the oxygenation of cyclohexane by O2 itself under mild conditions with good turnover values.
CATALYTIC OXYGENATION OF CYCLOHEXANE BY PHOTOEXCITED (nBu4N)4W10O32: THE ROLE OF RADICALS
MALDOTTI, Andrea;AMADELLI, Rossano;CARASSITI, Vittorio;MOLINARI, Alessandra
1997
Abstract
Photochemical excitation of (nBu4N)4W10O32 in the presence of oxygen (760 torr) leads to the formation of C6H11• and OH• radicals which can be revealed by ESR spin-trapping investigations. Cyclohexane is transformed in cyclohexanone and cyclohexanol with an overall photooxidation quantum yield of 0.35 at 325 nm photoexcitation wavelength. A strong influence of oxygen pressure on the concentration ratio of these products is observed; in that, at low oxygen pressure (15 torr), the yield of cyclohexanone is negligible and the photocatalytic oxidation of cyclohexane mainly leads to the formation of cyclohexanol. The photocatalyst investigated does not suffer irreversible modifications allowing the oxygenation of cyclohexane by O2 itself under mild conditions with good turnover values.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
