Molecular design of N–NO2 substituted cycloalkanes derivatives Cm(N–NO2)m for energetic materials with high detonation performance and low impact sensitivity

Abstract

For novel high-energy low-sensitivity energetic materials, a series of novel cycloalkanes derivatives C_m(N–NO₂)_m (m = 3–8) were theoretically designed by substitution of the hydrogen atoms with N–NO₂ group. Density functional theory (DFT) calculations in combination with the isodesmic reaction and the Kamlet–Jacobs equations were employed to predict the heats of formation (HOFs) and the detonation properties. We found that the designed compounds have large positive HOFs, which are proportional to the amount of N–NO₂ groups. Importantly, these compounds possess high crystal densities (1.85–1.95 g cm⁻³) and heats of detonation (1811–2054 kJ g⁻¹), which lead to remarkable detonation properties (detonation velocities = 9.37–9.61 km s⁻¹ and detonation pressures = 38.03–42.48 GPa) that are greater than those of the well-known energetic compounds 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20), 1,3,5-trinitro-1,3,5-triazinane (RDX), and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX). Moreover, the bond dissociation energy and the impact sensitivity index h₅₀ values suggest that the title molecules are less sensitive than CL-20, and comparable to HMX and RDX. Therefore, our results show that the designed compounds may be promising candidates for energetic materials with notable detonation performance and low impact sensitivity.