Effect of Nitrogen-Doping on Detonation and Stability Properties of CL-20 Derivatives from a Theoretical Viewpoint

Six nitrogen-doping CL-20 derivatives were designed and investigated as energetic materials at B3LYP/6-31G** level based on the density functional theory method. Results show that nitrogen-doping derivatives exhibit high crystal densities (1.98∼2.18 g cm⁻³) and positive heats of formation (451.68∼949.68 kJ mol⁻¹). Among nitrogen-doping derivatives, 2,4,6,8,10,12-hexanitro-2,4,6,8,9,10,12-heptaazaisowurtzitane(A1), 2,4,6,8,10,12-hexanitro-2,3,4,6,8,9,10,12-octaazaisowurtzitane(B1) and 2,4,6,8,10,12-hexanitro-1,2,3,4,6,8,9,10,12-nonaazaisowurtzitane(C1) possess better detonation velocity and pressure than CL-20, and A1 gives the best performance (D_K-J•A1=9.6 km s⁻¹; P_K-J•A1=43.07 GPa). Moreover, the specific impulse, brisance, and power of N-doping CL-20 derivatives are also higher than that of CL-20. The thermal stability and sensitivity of nitrogen-doping molecules were analyzed via the bond dissociation energy (BDE), the characteristic height (h₅₀) and electrostatic sensitivity (E_ES). The results indicate that the stability of A1, B1 and 2,4,6,8,10,12-hexanitro-1,2,3,4,6,7,8,9,10,12-decaazaisowurtzitane(D1) is comparable with that of CL-20. Considering detonation performance and stability, A1 and B1 may be promising candidates as energetic materials with superior detonation performance and favorable stability.