Properties of the ADN/ANTA cocrystal based on theoretical simulation

Abstract

Ammonium dinitramide (ADN) is highly hygroscopic which poses significant challenges in its practical applications. Consequently, mitigating this hygroscopic nature has been a primary focus in the research and development of ADN. This study investigated the properties of the ADN/3-amino-5-nitro-1,2,4-triazole (ANTA) cocrystal using density functional theory, molecular dynamics, and Monte Carlo methods. The research involved analyzing binding energies, radial distribution functions, and molecular interaction energies, predicting the crystallographic properties of the cocrystal, and theoretically assessing the hygroscopicity of ADN, stability and detonation properties. The results indicated that the cocrystal achieved relative stability at a 1 : 1 molar ratio of ADN to ANTA, driven by favorable conditions for cocrystal formation. The primary forces facilitating this cocrystal formation were hydrogen bonds and van der Waals interactions. The predicted space group for the cocrystal was P, with a calculated crystal density of 1.8353 g cm⁻³. Additionally, the cocrystal demonstrated a calculated saturated moisture absorption rate of 3.67%, which contrasted significantly with the 18.12% absorption rate observed for pure ADN. The cohesive energy density and trigger bond length indicated that the stability of the ADN/ANTA cocrystal was higher than that of ADN. Theoretical calculations indicated that the detonation performance of the cocrystal is close to that of the pure component ADN, suggesting that the ADN/ANTA cocrystal is a new type of high-energy material with low hygroscopicity.