Computational Study on Spirocyclic Compounds as Energetic Materials (I)

摘要

The molecular structures of 2,6-diaza-1,3,5,7-tetraoxaspiro[3,3]heptane (1) and its dinitro derivative, 2,6-dinitro-2,6-diaza-1,3,5,7-tetraoxaspiro[3,3]heptane (2), were fully optimized without symmetry constraints at HF/6-31G* level of theory. A bisected conformation with respect to the ring is preferred with a C2 symmetric structure. The density of each molecule in the crystalline state was estimated to 1.12 and 2.36 g/cm~3 using PM3/ VSTO-3G calculations from the molecular volume. The heat of formation was calculated for two compounds at the CBS-4M level of theory. The detonation parameters were computed using the EXPL05 software: D = 6282 m/s, P_(C-J)= 127 kbar for compound 1, D = 7871 m/s, P_(C-J)= 307 kbar for compound 2, and D= 6975 m/s, P_(C-J) =170 kbar for 60% compound 2 with 40% TNT. Specific impulse of compound 1 in aluminized formulation when used as monopropellants was very similar to that of the conventional ammonium perchlorate in the same formulation of aluminum.