Formation of Naphthalene, Indene, and Benzene from Cyclopentadiene Pyrolysis:  A DFT Study

Four new reaction pathways for polycyclic aromatic hydrocarbon growth from cyclopentadiene pyrolysis are proposed and investigated using the B3LYP/6-31G(d,p) level of theory. These pathways allow for the production of indene, naphthalene, and benzene through intramolecular addition, C−H β-scission, and C−C β-scission reaction mechanisms, respectively. Results show that the intramolecular addition channel is favored at low temperatures, and the C−H β-scission channel and the newly identified C−C β-scission pathway become significant when the temperature increases. These results are in qualitative agreement with the experimental results previously obtained by this research group indicating that the main product at low temperature is indene, while benzene and naphthalene production dominate at the high-temperature end.