Simple relationship for predicting onset temperatures of nitro compounds in thermal explosions

Abstract

Nitro compounds are capable of rapid chemical decompositions with a large amount of energy releases and hence pose significant thermal explosion hazards. Molecular simulation has been well established and demonstrated as an effective tool to predict physical and/or chemical properties of energetic materials, such as onset temperature, heat of reaction, and shock sensitivity. In this work, a simple relationship for predicting the onset temperature of nitro aromatic compounds containing other functional groups is developed based on their molecular structures. The results have shown that the thermal onset temperature of a specific nitro aromatic compound is strongly related to its excitation energy (a singlet state to triplet state). The predicted onset temperatures show very good agreement with respect to the measured onset temperatures by differential scanning calorimetry. Deviations compared to the experimental values are very small. These correlations can be used to computationally screen new nitro compounds for their thermal explosion hazards. These correlations can also be applied as a preliminary thermal analysis method and expedite the evaluation process of new energetic materials.