Revisiting the kinetics of pyridine pyrolysis. Part 2: Model development and validation

High-temperature pyrolysis of pyridine, C 5 H 5 N, starts with its decomposition forming pyridyls + H and subsequent reactions of H atom abstraction from C 5 H 5 N by H, CH 3 , CN, C 2 H 3 , CHCHCN and nC 4 H 3 radicals. These abstraction reactions were theoretically investigated in Part 1 of the present work. In Part 2, the rate constants of many other reactions were revisited aiming at the development of a consistent detailed kinetic mechanism. Moreover, thermodynamic data of open-chain C 5 H 4 N radicals and other intermediates important in pyrolytic reactions of pyridine decomposition and formation have been calculated at the G4 theoretical level. The new rate constants and thermodynamic data obtained, together with the rate constants from the literature allow for the development of a new kinetic model of pyridine pyrolysis. The model was validated using experimental data for the formation of major and minor products previously obtained in a single pulse shock tube and a well-stirred reactor and was found in good agreement with these measurements over 1550 – 1800 K and 1100 – 1220 K ranges of temperature, respectively. The pathways of pyridine pyrolysis via pyridyl isomers conversion into the final products were discussed using sensitivity and rate-of-production analyses.