Thermal Decomposition Kinetics of the Indenyl Radical: A Theoretical Study

Quantum chemistry and statistical reaction rate theory calculations have been performed to investigate the products and kinetics of indenyl radical decomposition. Three competitive product sets are identified, including formation of a cyclopentadienyl radical (c-C₅H₅) and diacetylene (C₄H₂), which has not been included in prior theoretical kinetics investigations. Rate coefficients for indenyl decomposition are determined from master equation simulations at 1800–2400 K and 0.01–100 atm, and temperature- and pressure-dependent rate coefficient expressions are incorporated into a detailed chemical kinetic model for indene pyrolysis. Indenyl is found to predominantly decompose to o-benzyne (o-C₆H₄) + propargyl (C₃H₃), with lesser amounts of fulvenallenyl (C₇H₅) + C₂H₂ and c-C₅H₅ + C₄H₂.