Low temperature oxidation of biphenyl in an alumina reactor: Possible initiation by O₂ (¹∆)

Oxidation of biphenyl (as a prototype model compound for polychlorinated biphenyls) in an alumina reactor at 490°C yields the initial products dibenzofuran and benzaldehyde which have been confirmed in GC/MS studies. It is postulated that 0₂ (¹∆) whose formation is catalysed by the reactor surfaces, initiates the reaction at this low temperature. Quantum chemical computations of the reaction potential energy surfaces suggest low energy pathways to the observed initial products.