Photochemical Oxidations—iv. The Photooxidation of Cyclohexane With Oxygen

Abstract— –For the photooxidation of cyclohexane, data on the rates of formation of cyclohexanol (I), cyclohexanone (II), and cyclohexylhydroperoxide (III) are presented. There are induction periods for the formation of I and II but not for III. The alcohol (I) is not the precursor of II in this reaction. The photooxidation does not occur when optical filters eliminate wavelengths of 260 nm or less from the incident light, and therefore the contact charge transfer absorption is responsible for the initiation of the reaction. Ozone is not involved to any significant extent in this reaction. The photodecomposition of III produces I and II, and this decomposition is first order during the initial stages. An overall 11 step mechanism is suggested for the photooxidation.