Theoretical study of the stabilities and detonation performance of 5-nitro-3-trinitromethyl-1H-1,2,4-triazole and its derivatives.

5-Nitro-3-trinitromethyl-1H-1,2,4-triazole (NTMT, A) and its substituted derivatives A-CH3, A-OCH3, A-NH2, A-OH, A-NO2, and A-ONO2 were studied using density functional theory (DFT). For all of the molecules except for A-ONO2, the C-NO2 bond in the trinitromethyl group was found to be the weakest, and no transition state occurred during the scission of this bond. The weakest C-NO2 of the trinitromethyl group bond dissociation energies for all of the molecules were all very similar. Most of the title molecules had similar frontier orbital distributions and comparable energy gaps between the frontier orbitals. The impact sensitivity (h 50, in cm), predicted at various levels of theory, decreased in the order A-NH2 (53.0-71.0) > A-CH3 (53.0) > A (36.7) > A-OCH3 (32.6-42.3) > A-OH (26.7-53.0) > A-NO2 (5.6-7.4) > A-ONO2 (4.6-6.1). Their detonation velocities (D), detonation pressures (P), and specific impulses (I s) were 8.02-8.82 km/s, 29.92-35.54 GPa, and 214-260 s, respectively. Composite explosives made from hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and A, A-OH, A-NH2, A-NO2, or A-ONO2 as an oxidizer were found to possess much better detonation performance (D = 9.04-9.29 km/s, P = 37.25-39.26 GPa, and I s = 270-281 s). Thus, introducing -OCH3, -OH, and -NH2 groups into A produced new explosives with acceptable stability and good detonation performance. A-OH and A-NH2 appear to be promising candidates for oxidizers in composite explosives.