Theoretical study on the thermal decomposition mechanism of 2-nitro-[1,2,4]triazolo[1,5-a][1,3,5]triazine-5,7-diamine.

Context: High nitrogen and high-density compounds have become popular research objects in the energetic materials in recent years. Among them, compounds composed of triazine and azole skeleton rings have received attention due to their good stability and nitrogen content. The triazine imidazole-based condensed ring energetic derivatives have good properties and lack research on the direction of thermal decomposition. By exploring the thermal decomposition mechanism of energetic materials, their safety and thermal stability can be effectively analyzed. 2-Nitro-[1,2,4]triazolo[1,5-a][1,3,5]triazine-5,7-diamine has excellent thermal stability and low mechanical sensitivity, making it a potential candidate for heat-resistant and insensitive energetic materials. So this article chooses 2-nitro-[1,2,4] triazolo[1,5-a][1,3,5]triazine-5,7-diamine as the research object and uses density functional theory (DFT) to study its thermal decomposition mechanism. The thermal decomposition mechanism is helpful to deepen the understanding of these substances. This work calculated the key information such as the reaction potential barrier of the substance and gradually derived it. The research shows that its decomposition path includes ring cleavage, hydrogen atom rearrangement, and free radical detachment.

Methods: Based on the density functional theory (DFT), all substances in this work were subjected to structural optimization and energy calculations using the B3LYP/6-311 + G(d,p) and M06-2X/def2TZVPP methods. After optimizing convergence, perform vibration analysis without imaginary frequencies to obtain a stable structure.