AEROBIC OXIDATION OF SATURATED-HYDROCARBONS INTO ALKYL HYDROPEROXIDESINDUCED BY VISIBLE-LIGHT AND CATALYZED BY A QUINONE-COPPER ACETATE SYSTEM

Irradiation in air of an alkane solution in MeCN in the presence of ca talytic amounts of quinone and copper(II) acetate (ratio 5:1) affords mainly alkyl hydroperoxide which by the action of triphenylphosphine m ay be easily converted into the corresponding alcohol and ketone (alde hyde) (in the case of cyclohexane oxidation the ratio cyclohexanol:cyc lohexanone was 50:1 after 10 h). The main peculiarities (the rate depe ndencies on initial concentrations of a substrate and the catalyst as well as of some additives and the effective activation energy) of the reaction are described. The proposed mechanism includes the abstractio n of the hydrogen atom from ail;ane, RH, by photo-excited quinone to p roduce radicals R(.) and HOC6H4O.. The former then reacts rapidly with O-2 to give RO(2)(.), and the latter may be reoxidized by copper(II). A copper(I) derivative thus formed may be converted into copper(II) w hen oxidized either by RO(2)(.) or O-2.