Transition Metal Complexes Based on Hypergolic Anions for Catalysis of Ammonium Perchlorate Thermal Decomposition

On the basis of hypergolic dicyandiamide (DCA) and cyanoborohydride (CBH) anions, 1-methyl-1,2,4-triazole (MTZ) ligand, and transition metal (Co/Ni/Cu) cations, five hypergolic coordination compounds (HCCs) were synthesized and characterized. Their molecular formulas were expressed as [Co(MTZ)4](DCA)2 (1), [Ni(MTZ)4](DCA)2 (2), [Cu(MTZ)2](DCA)2 (3), [Co(MTZ)4](CBH)2 (4), and [Ni(MTZ)4](CBH)2 (5). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) instruments were used to investigate the thermal decomposition behaviors of compounds 1-5, and the DSC instrument was used to investigate the catalytic effect of HCCs on the thermal decomposition of ammonium perchlorate (AP). High-temperature decomposition (HTD) of AP samples with 5% catalyst occurred immediately after low-temperature decomposition (LTD), and their HTD temperatures were lowered by 60-116 °C. The heat release of all samples is improved observably and is 2-3 times that of pure AP. Among them, compound 1 shows the best catalytic performance. The heat release of sample AP + compound 1 can reach 2291 J g-1, and the decomposition temperature can be advanced by 116 °C. The kinetic/thermodynamic parameters were calculated to further study the catalytic mechanism of HCCs on the thermal decomposition of AP. The research in this paper shows that HCCs were suggesting for a class of novel additives of composite propellants with improved combustion and energetic performances.