Abstract
Despite the concern about environmental damage caused by toxic polycyclic aromatic hydrocarbons (PAH), the mechanisms that govern thermal build-up of these molecules are hardly known. Only some vague ideas exist, which are equally true for thermally formed hetero-PAH, e.g. benzofurans and dioxins. It is further not clear if complete combustion to H2O, CO2, and NO2, is a realistic goal in the practice of engines or incenerators. Flash vacuum thermolysis (FVT) techniques, provides a tool for description of mechanistic routes and for characterisation of reactive intermediates in PAH and hetero-PAH formation during combustion. On FVT six-membered ring PAH systems were found to undergo thermal transformations to cyclopenta-PAH. Some nitro-PAH gave hydroxy-PAH on FVT. Cyclopenta-PAH can conveniently be synthesized with preparative FVT.