Thermal decomposition and fire-extinguishing mechanism of N(CF₂CF₃)₃ by ReaxFF-based molecular dynamics simulation and density functional theory calculation

Since halon fire-extinguishing agents are forbidden to be used due to environmental concerns, it is necessary to explore new environmentally friendly fire-extinguishing agents. Perfluorotriethylamine (N(CF₂CF₃)₃) with good physicochemical properties is a potential substitute for halons. To evaluate its practicability as the halon substitute, the thermal decomposition performance and mechanism of N(CF₂CF₃)₃ were systematically investigated by combining experiment and theory in this study. The initiation reaction of N(CF₂CF₃)₃ thermal decomposition was calculated by density functional theory. The reactive molecular dynamics simulations based on the reactive force field were used to investigate the thermal decomposition process of N(CF₂CF₃)₃ at different temperatures, including the intermediates, decomposition temperature, and product distribution. To examine the actual fire-extinguishing performance of N(CF₂CF₃)₃, its fire-extinguishing concentration in the n-heptane-air flame was measured by the cup-burner method. Finally, the chemical fire-extinguishing mechanism of N(CF₂CF₃)₃ was proposed. N(CF₂CF₃)₃ was pyrolyzed during the interaction with flame, producing the fire extinguishing radical CF₃·, which further consumed the active H· and OH· radicals by reactions.