Synthesis and thermal behaviors of 1,8-dihydroxy-4,5-dinitroanthraquinone barium salt

A novel energetic green combustion catalyst, 1,8-dihydroxy-4,5- dinitroanthraquinone barium salt (DHDNEBa), was firstly synthesized by the process of metathesis reaction with a yield of 95.7%, and its structure and thermal behavior were characterized by IR, elemental analysis, thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). The thermal decomposition kinetics and mechanism were studied by means of different heating rate DSC, thermolysis in situ rapid-scan FTIR and simultaneous TG-MS technology. The results show that the apparent activation energy and pre-exponential factor of the exothermic decomposition reaction of DHDNEBa obtained by Kissinger's method are 177.3 kJ mol^-1 and 1013.5 s^-1. The entropy (ΔS^≠), enthalpy (ΔH^≠) and free energy of activation (ΔG^≠) of the first step thermal decomposition are found to be 8.16 J mol^-1 K^-1, 168.0 kJ mol ^-1 and 163.4 kJ mol^-1, respectively. The self-accelerating decomposition temperature (T_SADT) and critical temperature of thermal explosion (T_b) are 555.0 and 570.2 K. The decomposition reaction process of DHDNEBa begins with four-molecule combined water lost in the DHDNEBa structure. The gaseous products such as H₂O, CO, CO ₂ and NO are detected from decomposition of DHDNEBa at 606 K. The residue is mainly composed of BaO and some carbon black. The above-mentioned information on thermal behavior is quite useful for analyzing and evaluating the stability and thermal safety of DHDNEBa.