From BTO2− to HBTO− insensitive energetic salt: a route to boost energy

Abstract

A promising strategy was utilized to boost the detonation performance of energetic salts. The desired 4,4′,5,5′-tetraamino-4H,4′H-[3,3′-bi(1,2,4-triazole)]-1,1′-diium 1′-hydroxy-1H,1′H-[5,5′-bitetrazol]-1-olate [TABT²⁺(HBTO⁻)₂] was synthesized by controlling the ratio between the cation and anion (1 : 2) during the synthesis of 4,4′,5,5′-tetraamino-4H,4′H-[3,3′-bi(1,2,4-triazole)]-1,1′-diium 1H,1′H-[5,5′-bitetrazole]-1,1′-bis(olate) (TABT²⁺BTO²⁻). The bivalent cation-bivalent anion salt changed into bivalent cation-univalent anion salt easily as confirmed by single-crystal X-ray diffraction, NMR spectroscopy, IR spectroscopy, DSC, and elemental analysis. Compared with TABT²⁺BTO²⁻, the density, heat of formation, detonation velocity and detonation pressure of TABT²⁺(HBTO⁻)₂ increased by 0.165 g cm⁻³ (10.0%), 1.81 kJ g⁻¹ (111.0%), 549 m s⁻¹ (6.8%) and 11.5 GPa (52.0%), respectively. Meanwhile, the enhanced properties of HBTO⁻ salt do not come at the expense of molecular stability, just from changing one insensitive explosive to another more energetic insensitive explosive (IS > 40 J, FS > 360 N, T_dec.,onset = 271.8 °C). This work provides a promising route to enhance the properties of energetic salts.