Exploration of super heat-resistant monomeric explosive featuring triptycene core structure

Over the last few decades, the research for energetic materials with ultrahigh heat resistance and good energy level has been a highly severe challenge. In this study, a novel heat-resistant compound, 2,3,6,7,14,15-hexanitrotriptycene was developed through triptycene as core structure. Density functional theory (DFT) was employed to predict the energetic properties and synthesis difficulty of five designed triptycene-based compounds. Subsequently, a straightforward and efficient two-step synthesis process was adopted: two isomers of trinitrotriptycene with a yield of 93.8 % were synthesized via an improved Menke nitration method, and then hexanitrotriptycene was obtained with a yield of 74.0 % via an optimized process. Structure characterization confirmed the nitro substitution positions of trinitrotriptycene and trinitrotriptycene. Among them, 2,3,6,7,14,15-hexanitrotriptycene with low sensitivity (IS > 20 J, FS > 360 N) shows an ultrahigh thermal decomposition temperature of 414 °C and exhibits no decomposition after 4 h’ heating at 390 °C, which is extremely rare in the field of heat resistant explosives. Its enhanced density (1.81 g·cm⁻³) and energy level (detonation velocity: 7682 m‧s⁻¹) is comparable to several commonly used heat-resistant explosives such as HNS, PYX, and NONA. These prominent properties of hexanitrotriptycene support it as an advanced heat resistant explosive with great promise.