Computational Studies on the Crystal Structure, Thermodynamic Properties, Detonation Performance, and Pyrolysis Mechanism of 2,4,6,8-Tetranitro-1,3,5,7-tetraazacubane as a Novel High Energy Density Material

Abstract

Studies have suggested that octanitrocubane (ONC) is one of the most powerful non-nuclear high energy density material (HEDM) currently known. 2,4,6,8-Tetranitro-1,3,5,7-tetraazacubane (TNTAC) studied in this work may also be a novel HEDM due to its high nitrogen content and crystal density. Density functional theory and molecular mechanics methods have been employed to study the crystal structure, IR spectrum, electronic structure, thermodynamic properties, gas-phase and condensed-phase heat of formation, detonation performance, and pyrolysis mechanism of TNTAC. The TNTAC has a predicted density of about 2.12 g/cm(3), and its detonation velocity (10.42 km/s) and detonation pressure (52.82 GPa) are higher than that of ONC. The crystalline packing is P2(1)2(1)2(1), and the corresponding cell parameters are Z = 4, a = 8.87 Å, b = 8.87 Å, and c = 11.47 Å. Both the density of states of the predicted crystal and the bond dissociation energy of the molecule in gas phase show that the cage C-N bond is the trigger bond during thermolysis. The activation energy of the pyrolysis initiation reaction obtained from the B3LYP/6-311++G(2df,2p) level is 125.98 kJ/mol, which indicates that TNTAC meets the thermal stability request as an exploitable HEDM.

A Theoretical investigation of a potential high energy density compound 3,6,7,8-tetranitro-3,6,7,8-tetraaza-tricyclo[3.1.1.1(2,4)]octane

“…In this study, density functional theory and molecular mechanics methods were employed to study the molecular geometry, electronic structure, IR spectrum, thermodynamic functions, heat of formation, detonation performance and thermal stability of a novel high energy density compound, 3,6,7,8-tetranitro-3,6,7,8-tetraaza-tricyclo [3.1.1.1 2,4 ]octane (TTTO). The most likely packing structure belongs to the P2 1 /C space group.…”

“…[1][2][3] For HEDCs, besides high detonation performance, sensitivity is a prerequisite requirement. [4][5][6][7] HEDCs should be sufficiently safe, stable and reliable to detonate under specific conditions. Thus, good thermal stability and low impact and shock sensitivities are of equal importance to detonation performance, but these requirements are somewhat reciprocally exclusive, with improved insensitivity associated with inferior performance and vice versa.…”

“…350 o C, is likely to be of value as a heat resistant explosive. CL-20 [2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (HNIW)] is another new nitramine explosive, which has 6 N-NO 2 groups in its polycyclic structure, resulting in higher density and heat of formation. [15][16][17] CL-20 is reported as an attractive highly thermally stable explosive with a decomposition temperature of 228 o C. These strained rings of cage compounds possess a concomitant high heat of formation and density, making them powerful explosives.…”

“…Reacting with ammonia, glyoxal yields a precursor 3,6,7,8-tetraaza--tricyclo[3.1.1.1 2,4 ]octane, which provides more N-H sites for introducing nitro substituents, and thus generates the new energetic material 3,6,7,8-tetranitro-3,6,7,8-tetraaza-tricyclo[3.1.1.1 2,4 ]octane. Owing to the difficulties in the synthesis of the molecules under consideration, computer tests become an effective way to design high energy density compounds theoretically.…”

Theoretical studies on the stability, detonation performance and possibility of synthesis of the nitro derivatives of epoxyethane

“…The isodesmic reaction method, which has been employed successfully to predict the gas phase HOFs of many organic compounds with the help of density functional theory (DFT) calculations [31,32] was adopted to predict the HOFs of compounds 1-4 in the gas phase at 298 K: O n (O 2 N) + n CH 4 O + n CH 3 NO 2 (n=1-4)…”