Experimental and kinetic modeling study of α-methyl-naphthalene pyrolysis: Part II. PAH formation

摘要

α-Methyl-naphthalene plays an important role as a functional material in petrochemical industries andas a precursor of soot particles. The formation chemistry of polycyclic aromatic hydrocarbons (PAHs)from α-methyl-naphthalene, therefore, warrants detailed investigations. In this work, we studied PAHformation from its pyrolysis using experiments and kinetic models. Flow reactor pyrolytic experiments atlow and atmospheric pressures (30 and 760 Torr) were performed using synchrotron vacuum ultravioletphotoionization molecular beam mass spectrometry (SVUV-PI-MBMS). A kinetic model was then developedto predict PAH formation from α-methyl-naphthalene. According to the kinetic analysis of the proposedmodel, naphth-1-yl-methyl, benzo-fulvenallene, and benzo-fulvenallenyl are three critical intermediatesin the formation of large PAHs. Other than the traditional H-abstraction acetylene-/vinylacetyleneadditionmechanisms, three prototypical PAH formation pathways are identified in α-methyl-naphthalenepyrolysis: 1) addition and cyclization reactions of naphth-1-yl-methyl and naphth-1-yl radicals; 2) recombinationof resonance stabilized radicals (indenyl, benzo-fulvenallenyl, phenalenyl, etc.) and the subsequentring expansion reactions; 3) sequential propargyl addition reactions.