Partial oxidation of light alkanes by reductively activated oxygen in Eu-catalytic system at 40 degrees C

Oxidation of light alkanes, CH4, C2H6, and C3H8, could be performed at 40 d egrees C by using the EuCl3-catalytic system (EuCl3, O-2, Zn-0, and CF3CO2H ). In the case of CH4 oxidation, MeOH was produced from CH4 but CO2 from CF 3CO2H could not be avoided. However, selective oxygenations of C2H6 (89% se lectivity) and C3H8 (91%) could be performed. In the oxidation of C2H6, EtO H was primary product and the successive oxidation of EtOH gave MeCHO and C O2. Regio-selectivities (1 degrees:2 degrees) observed in the oxidation of C3H8 suggested that an electrophilic active oxygen species was generated in the EuCl3-catalytic system. This active oxygen could not oxidize C-H bonds of MeOH (CF3CO2Me) because of a strong electron-withdrawing effect of CF3C O-group. Eu2+ species produced by the reduction with Zn-0 was studied by UV -visible spectra. The spectral data proposed that O-2 was reductively activ ated through the redox of Eu3+/Eu2+.