Detailed kinetic mechanism of thermal decomposition of furyl radicals: Theoretical insights

[Display omitted] •The detailed kinetic mechanism is theoretically reported in 500–2000 K and 1–76000 Torr.•Mechanistic inconsistency and incompleteness in previous studies are resolved.•Unimolecular decomposition dominates (2-furyl ↔ 3-furyl) isomerization.•Well-skipping reactions are observed at high temperatures and/or low pressures. This study presents the detailed kinetic mechanism of the thermal decomposition of furyl radicals, which play an essential role in the production of the second-generation lignocellulosic biofuels. In particular, the accurate composite method W1U was used to explore the main reaction pathways on which the temperature- and pressure-dependent kinetic behaviors were analyzed in the range of 500–2000 K and 1–76000 Torr using a complementary deterministic/stochastic Rice-Ramsperger-Kassel-Marcus based master equation rate model. Corrections of tunneling and hindered internal rotation treatments were included in the rate model. Detailed kinetic analyses, including time-resolved species profile and flux analysis, reveal that: (i) the decomposition pathways are more favorable than the (2-furyl ↔ 3-furyl) isomerization; and (ii) the well-skipping reactions, accounting for the formation of the products in a shorter time scale, are observed at high temperature and/or low pressure. The calculated thermodynamic and kinetic parameters are in good agreement with literature data; thus, the reported detailed kinetic mechanism can be confidently used to investigate furyl-related systems in different conditions. Also, among the selected composite methods, CBS-QB3 and CBS-APNO have shown to be cost-effective methods in replacing the higher level W1U for constructing the reaction mechanisms for larger similar systems.