Reaction mechanism from quantum molecular dynamics for the initial thermal decomposition of 2,4,6-triamino-1,3,5-triazine-1,3,5-trioxide (MTO) and 2,4,6-trinitro-1,3,5-triazine-1,3,5-trioxide (MTO3N), promising green energetic materials

摘要: Klapotke and co-workers recently designed two new materials, 2,4,6-triamino-1,3,5-triazine-1,3,5-trioxide (MTO) 2,4,6-trinitro-1,3,5-triazine-1,3,5-trioxide (MTO3N), envisioned as candidates for green high-energy materials. However, all attempts at synthesis have failed. In order to validate the expected properties these systems determine why materials are too unstable synthesize, we used PBE flavor of Density Functional Theory (DFT) predict crystal structures MTO MTO3N then carried out DFT molecular dynamics simulations (DFT-MD) initial reaction mechanisms decomposition. estimated that would a density ρ = 1.859 g cm−3 with an detonation velocity (Dv) 8.979 km s−1, making it comparable RDX (ρ 1.82 cm−3, Dv 8.75 s−1) β-HMX 1.91 9.10 s−1). His impact sensitivity >30 J, make much better than HMX (7 J) (7.5 J). Our predicted structure (P2(1) space group) leads in good agreement expectations. DFT-MD studies find first step decomposition is intermolecular hydrogen-transfer (barrier 3.0 kcal mol−1) which followed quickly by H2O NO release barriers 46.5 35.5 mol−1. contrast (P2(1)/c group), steps bimolecular NO2 (ΔH 44.1 mol−1, ΔG 54.7 simultaneous unimolecular cleavage 59.9 58.2 unique among EMs. These results suggest be significantly more thermally stabile > 6.0 mol−1 higher) HMX, excellent candidate insensitive energetic However very favorable hydrogen transfer reactions may complicate crystallization, promising system.