The study of 1-ethylnaphthalene pyrolysis in a flow reactor

Ethylnaphthalenes (ENs) and other alkylated naphthalenes exist in a variety of fuels such as coal and petroleum, and their decomposition is closely related to soot and polycyclic aromatic hydrocarbons (PAHs) formation in fuel combustion. In this paper, 1-EN pyrolysis was studied experimentally in a quartz tube reactor in the temperature range of 600–850 °C. The products quantified include 1-vinylnaphthalene (VN), 1-methylnaphthane (MN), acenaphthalene (AceN), naphthalene, 2-MN, 2-VN, and acenaphthene, with 1-VN as the most abundant. Ethane, ethylene and methane have also been identified as gaseous products. The results suggested that the reactivity of 1-EN is higher than that of the MNs. Possible product formation pathways are discussed, which gives rise to hypothesized reaction mechanisms. There are three decomposition routes for 1-EN: hydrogen abstraction from the ethyl group forming naphthylethyl radicals (both primary and benzylic) and then forming 1-VN, homolytic cleavage of the bond between the α- and β-carbons forming 1-MN, and hydrogen displacement of the ethyl group forming naphthalene.