Comparative theoretical synthesis of high-energy explosive 1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin

Abstract

Reaction mechanisms were proposed in this study for the theoretical synthesis of high-energy 1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin (TNAD). Corresponding computations were performed using density functional theory (DFT) and the Hartree Fock (HF) method with the same 6-31G(d,p) base function. Glyoxal and ethylenediamine were used as the raw materials and were placed into respective gaseous and solvated (water or ethanol) environments to proceed the condensation reaction to form the precursor 1,4,5,8-tetraazadecalin, which subsequently underwent four stages of nitro-group substitution to obtain the target TNAD compound. A whole reaction scheme closely related to the experimental processes was successfully constructed, and the corresponding energy barriers were estimated for each elementary reaction. The findings revealed that the overall activation energy by B3LYP/6-31G(d,p) calculation is 2660.4 kJ/mol, which is lower than the 2832.1 kJ/mol calculated by HF/6-31G(d,p) computation. Furthermore, the reaction has a lower overall energy barrier in the solvated environment than in the gaseous system, being 2389.6 kJ/mol in ethanol, 2428.7 kJ/mol in water and 2660.4 kJ/mol in the gaseous phase. The ethanol-solvated system is suggested to be the most suitable medium for the synthesis of TNAD.