Detonation Velocities and Pressures, and their Relationships with Electric Spark Sensitivities for Nitramines

Abstract

AbstractThe DFT‐B3LYP method, with basis set 6–31G*, is employed to optimize molecular geometries and electronic structures of eighteen nitramines. The averaged molar volume (V) and theoretical density (ρ) are estimated using the Monte‐Carlo method based on 0.001 electrons/bohr3 density space. Subsequently, the detonation velocity (D) and pressure (P) of the explosives are estimated by using the Kamlet‐Jacobs equation on the basis of the theoretical density and heat of formation (ΔfH), which is calculated using the PM3 method. The reliability of this theoretical method and results are tested by comparing the theoretical values of ρ and D with the experimental or referenced values. The theoretical values of D and P are compared with the experimental values of electric spark sensitivity (EES). It is found that for the compounds with metylenenitramine units (CH2N(NO2)) in their molecules (such as ORDX, AcAn and HMX) or with the better symmetrical cyclic nitramines but excluding metylenenitramine units (such as DNDC and TNAD), there is a excellent linear relationship between the square of detonation velocity (D2) or the logarithm of detonation pressure (lg P) and electric spark sensitivity (EES). This suggests that in the molecular design of energetic materials, such a theoretical approach can be used to predict their EES values, which have been proven to be difficult to predict quantitatively or to synthesize.