Combining potassium with positive oxygen-balanced polynitropyrazole: a promising way to develop green primary explosives

Abstract

Combining potassium and a nitrogen-rich heterocycle with a positive oxygen balance is an efficient strategy to develop new lead-free green primary explosives. In this study, we successfully synthesized dipotassium 3,5-dinitro-4-nitramino-1-(dinitromethyl)pyrazole (6) and monopotassium 3,5-dinitro-4-nitramino-1-(dinitromethyl)pyrazole (8·2H₂O). These compounds were characterized by IR spectroscopy, elemental analysis, NMR spectroscopy, differential scanning calorimetry (DSC), and single crystal X-ray diffraction. Compound 6 has attractive properties, including positive oxygen balance (Ω_CO = 24.1%, Ω_CO2 = 4.0%), high density (2.068 g cm⁻³), good thermal stability (T_d = 270 °C), superior detonation properties (D = 7572 m s⁻¹, P = 27.54 GPa), and appropriate sensitivity for primary explosives (FS = 42 N, IS = 0.25 J). The superior properties of compound 6 make it a competitive replacement as a green primary explosive.