Insights into triazole-based energetic material design from decomposition pathways of triazole derivatives†

Nitrogen-rich heterocycles are of great interest for the design of high-energy materials (HEMs) because they offer high density, positive heat of formation, superior detonation properties, and high thermal stability. Among the different types of nitrogen-rich heterocyclic azoles, 1,2,4-triazole provides a remarkable framework for the development of green energetic materials. The presence of functional groups, such as nitro, amino, and nitramino groups, affects the stability, thermal decomposition behavior, and energetic properties of HEMs. In the present study, we chose amino- and nitramino substituted 1,2,4-triazole and triazole containing both amino and carboxymethyl groups to compare their decomposition mechanisms. The decomposition pathways of 3-amino-1,2,4-triazole (1), 2,4-dihydro-3H-1,2,4-triazol-3-ylidene-nitramide (2), and 5-amino-1,2,4-triazol-3-yl-acetic acid (3) were explored using thermal experiments and mass spectrometry. Kinetic parameters were evaluated using a nonlinear integral method, and decomposition pathways were elucidated based on mass fragmentation data obtained from mass spectrometry and tandem mass spectrometry. Furthermore, near-real-time identification of decomposition products that evolved in the form of gases was performed using the TG-FTIR technique. Based on kinetic analysis, mass fragmentation data, and TG-FTIR analysis, the possible degradation pathways of the HEMs following the introduction of different substituents were identified.