Preparation, Crystal and Properties of Nitrogen-Rich Energetic Salt of Bis(semicarbazide) 5,5′-Bitetrazole-1,1′-diolate
A novel energetic salt of Bis(semicarbazide) 5,5 1 -bitetrazole-1,1 1 -diolate [2(SCZ)¨BTO] was synthesized by using semicarbazide hydrochloride and 1H,1'H-5,5'-bitetrazole-1,1'-diol (BTO) as raw materials, and its structure was characterized by elemental analysis, Fourier Transform infrared spectroscopy (FT-IR) spectroscopy, 13 C NMR spectrum and mass spectrum. The single crystal of the title salt was obtained and its structure was determined by an X-ray single-crystal diffractometer. Results
... actometer. Results show that 2(SCZ)¨BTO belongs to the monoclinic space group P2 1 /c with a density of 1.685 g¨cm´3. The thermal decomposition behavior was investigated by differential scanning calorimetry (DSC) and thermogravimetry-derivative thermogravimetry (TG-DTG) analyses, and non-isothermal kinetic parameters were also calculated. The results indicated that it has a good thermal stability with a decomposition temperature above 200˝C. The apparent activation energies were 231.2 kJ¨mol´1 (Kissinger's method) and 228.1 kJ¨mol´1 (Ozawa-Doyle's method), respectively, and the critical temperature of thermal explosion is 240.6˝C. The enthalpy of formation for the salt was calculated as 158.1 kJ¨mol´1. The detonation pressure (P) and detonation velocities (D) of the salt were determined by using the Kamlet-Jacobs equation. The results indicated that the title salt has potential applications in the field of energetic materials. Crystals 2016, 6, 21 2 of 10 2012  . The nitrogen content of BTO is 65.88%, and its oxygen balance is´28.22% since introducing two hydroxyl groups in the tetrazoles, making it easy to form intra-or intermolecular bonds, which contributed to increasing the thermal and structural stability. Additionally, the hydroxyl hydrogen of BTO has a strong acid, making it easy to dissociate back into salts. Therefore, it has attracted significant attention as a good energetic anion. In this contribution, a novel energetic salt, 2(SCZ)¨BTO, based on BTO and semicarbazide (SCZ), was obtained and fully characterized. The crystal structure, thermal decomposition, and heat of combustion of the salt were investigated. In addition, its detonation properties were also determined. Results and Discussion Synthesis of the Energetic Salt 2(SCZ)¨BTO The starting material, 1H,1'H-5,5'-Bitetrazole-1,1'-diolate (BTO), was prepared according to the literature  . As shown in Scheme 1, the salt 2(SCZ)¨BTO was synthesized by the reaction between BTO and SCZ in water with 1:2 molar quantities.