Theoretical Study of High-nitrogen Salts Composed of Ammonium Cations and Pyrazole-derived Anions

Abstract

Aims: Our primary purpose is investigating the critical role of simple ammonium cations, different substituents and their synergetic effect in the design of efficient pyrazole-derived salts. Study Design: The salts composed of pyrazole-derived anions containing different substituents (–NH2, –NO2, –N3, –NF2, –CN) with some simple energetic cations (NH4+, N2H5+, +NH3OH) were designed. Place and Duration of Study: School of Chemical Engineering, Nanjing University of Science and Technology, between December 2017 and February 2018. Methodology: The densities and heats of formation (HOFs) of the salts were predicted by using DFT-B3LYP and volume-based thermodynamics methods. Several empirical formulas also studied the detonation performance and impacted sensitivity of the salts. Results: The results show that for the promotion of energetic performance of the salts, +NH3OH is the best cation among the three cations. When one substituent is -NO2, another substitution of the –NO2, –N3 or –NF2 group is helpful for enhancing the densities of the salts and the substitution of –NF2 group presents the best density. The attachment of –NO2 group in combination with the –NO2, –N3, –NF2 or –CN group is favorable for improving the HOFs of the salts and the incorporation of –N3 shows the greatest HOFs. The synergy of –N3 and –NF2 group also exhibits the potential to improve the detonation performance of the salts. Conclusion: By comparing with the commonly used explosives RDX and HMX, we screened out the salts with high energy and acceptable sensitivity.