The generation of singlet oxygen by petroleum and its fractions

Quantum yields of singlet oxygen formation by diesel oil, samples of four different crude petroleum and some fractions of a Brazilian intermediate petroleum were measured at 315 nm, 355 nm, 400 nm and 450 nm both by pulsed LASER or Xe lamp, with analysis of singlet oxygen emission at 1270 nm. All samples generated singlet oxygen in dilute solution. Diesel oil has the highest quantum yield (0.49) and a Venezuelan crude the poorest (0.17). The aromatic, polar, asphaltene and maltene fractions of the Brazilian crude all generate singlet oxygen. Singlet oxygen formation was also observed when undiluted crude petroleum was analyzed.