Experimental and kinetic modeling investigation on anisole pyrolysis: Implications on phenoxy and cyclopentadienyl chemistry

In this work, the flow reactor pyrolysis of anisole was studied at pressures of 0.04 and 1 atm and temperatures from 850 to 1160 K. Comprehensive speciation was achieved using synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). A detailed kinetic model for anisole combustion was developed and validated against experimental results in the present work. Fuel decomposition and aromatics formation processes were investigated based on modeling analyses. The results show that the dominant decomposition pathway of anisole is the unimolecular O–CH₃ bond dissociation reaction at both pressures, while the role of bimolecular reactions becomes significant at 1 atm. At lower temperatures, phenoxy radical is mainly consumed via the reactions with methyl radical, producing methylcyclohexadienone. At higher temperatures, it is mainly consumed via the unimolecular decomposition reaction producing cyclopentadienyl. Cyclopentadienyl is responsible for the abundant production of aromatic products such as benzene, toluene, styrene and naphthalene. Furthermore, the bimolecular reactions of anisole also contribute to the formation of aromatic products at lower temperatures. Possible formation pathways of oxygenated aromatics such as benzofuran and dibenzofuran were also analyzed in this work. The present model was also validated against literature experimental data of anisole combustion, including global combustion parameters like ignition delay times and speciation profiles in flow reactor pyrolysis and jet stirred reactor pyrolysis and oxidation.