Formation of aromatics during the pyrolysis of oligocyclic naphthenes: Indications for a mechanistic alternative

It is known that aromatics are formed in much higher yields in the pyrolysis of di- and oligocyclic naphthenes than in that of alkanes and monocyclic naphthenes. To study the mechanisms of the formation of aromatics from naphthenes, the thermal decomposition of dicyclohexyl, decalin, dodecahydrofluorene, tetradecahydroanthracene, hexadecahydropyrene and 9,10-¹⁴C]tetradecahydroanthracene was studied in different laboratory tubular furnaces from 800 to 850°C. The reaction products were analysed by conventional and radio gas chromatography. As an important consequence of the results, a new hypothesis for the formation of aromatics via acyclic, multiply unsaturated hydrocarbon species as precursors is presented.