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The thermal decomposition of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) is studied using a quantum-based molecular dynamics (MD) method at several temperatures, to uncover its fundamental reaction mechanism and kinetic properties. The primary decomposition pathways, key intermediate products and their population evolutions are systematically investigated. For the first time, we uncover four sequential reaction stages during the thermal dissociation of TATB: (1) C–NO2 bond cleavage and amino dehydrogenation; (2) hydrogen transfer to nitro or NO2, with further conversion to NO and H2O; (3) carbon oxidation and molecular ring deep fission to generate CO and small –CN fragments; (4) final formation of gaseous N2 and CO2. The fission and formation rate constants and reaction energy barriers of the main chemical bonds are obtained by exploring the kinetic process. We confirm that C–NH2 bond breaking is the rate-controlling step for carbon oxidation, while N–N bond formation is the rate-controlling step for N2 generation. Besides, we obtain the global exothermic reaction rate and reaction heat based on an analysis of the changes in potential energy. The results not only give a deep insight into the chemical performance of TATB, but also provide prerequisite parameters for improving the macroscopic physical models for explosive reactivity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Thermolysis mechanisms of β-HMX under different thermodynamics states are investigated. • The special hydrogen transfer mechanism induced by NO 3 molecule is uncovered. • The reaction kinetics properties are compared with different reaction conditions. The thermolysis of β-HMX under different thermodynamics states are investigated using quantum-based molecular dynamics method. The reaction is mainly initiated with molecular ring breaking and alkyl dehydrogenation. The cleavages of N-N and C-N bonds are impeded under high pressure, while that of C-H bond is significantly enhanced. NO 3 is more favorably produced under low pressure, which can promote the hydrogen transfer to form H 2 O or OH. The reaction kinetics constants reflect that the initial endothermic reaction is really slower under high pressure, but the following exothermic reaction is significantly accelerated with a larger reaction heat of 368.05 cal·g−1. [ABSTRACT FROM AUTHOR]