Theoretical analysis of the effects of nitration of the explosive properties of triazoles: 4-nitro-2H-l,2,3-triazole and 4,5-dinitro-2H-l,2,3-triazole

摘要

At the molecular level, the ground-slate intrinsic energies of the C-NO; and N-N bonds and the excited-state bond (Clarities of the 4-nitro- and 4,5-dinitro-2H-l,2,3-triazoles have been compared with one another using their theoretical jpumized geometries. Their enthalpies of formation have been calculated using a modified Xcv approach and, finally hcit explosive characteristics have been studied at the macroscopic level with the help of the thermodynamic code of Kondrikov-Sumin. With respect to the planar mononitro derivative, the second nitration provokes, (i) a torsion of Ibout 30° of the two nitro groups, (ii) a significant lowering of the C-N bond dissociation energy, by about 9 kcal mol~', igether with a weakening of the N-N bonds thus reducing thermostability. (iiij an increase of the C-NCK and N-N wnd polarities in the electronic excited states, correlated with a lowering of shock sensitivity, and (iv) an increase of the as-phase enthalpy of formation from -25kcal mol (or -51kcalmor estimated for the condensed phase) for the nononilro derivative to +65 kcal mol"' (viz. +50 kcal mol~') for the dinitro compound. Using these enthalpy results and Kondrikov-Sumin-like equation of state, one can describe the ideal velocity of detonation Da as a function of the lensity pt, by DCJ = 0.337 + 3.86p0 and Da = 2.246 + 3.61p0 for the mononitro and dinitro derivatives, respectively, hus giving the corresponding velocities of 6.5 and 8.0 km s~(-1) for an assumed density of 1.6g cm~(-3).