Role of alkyl benzenes in the photochemical oxidation of petroleum distillates

Various petroleum distillates differing mainly in their aromatic content were photo-oxidized in the solar UV range and analysed by FTIR and UV spectrophotometry. It appeared that mononuclear alkyl aromatics play a key role owing to the high reactivity of their a carbon in the radical propagation of oxidation chains. They are transformed into phenones whose high molar absorptivities in the UV range explain the observed spectral changes.