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

Abstract

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.