New Energetic Complexes as Catalysts for Ammonium Perchlorate Thermal Decomposition

In this study, four new energetic complexes (1) [Cu(vimi)₄]DCA₂, (2) [Co(vimi)₄]DCA₂, (3) [Ni(vimi)₄]DCA₂, and (4) [Cu(vimi)₄]CBH₂ (vimi: 1-vinylimidazole, DCA: dicyanamide anion, CBH: cyanoborohydride anion) were prepared, and their structures were characterized via single-crystal X-ray diffraction, elemental analysis, and Fourier-transform infrared spectroscopy. The catalytic effects of the complexes on ammonium perchlorate thermal decomposition were studied via thermal analysis methods, including differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Among the complexes, complex 2 showed the best catalytic performance. The two decomposition peaks in the DSC curve of the pure ammonium perchlorate—low-temperature decomposition (LTD) peak: 295 °C and high-temperature decomposition (HTD) peak: 418 °C—were merged into a lower decomposition peak (325 °C) in the curve of AP with complex 2. Moreover, the heat released by ammonium perchlorate with complex 2 (1661.7 J g⁻¹) was significantly higher than that released by the pure ammonium perchlorate (814.5 J g⁻¹). The kinetic parameters calculated using Kissinger's method revealed that the complexes had a significant effect on the activation energy of ammonium perchlorate decomposition (223.5 kJ mol⁻¹), and complex 2 lowered the activation energy to 115.6 kJ mol⁻¹. The results indicate that complex 2 is a potential energetic additive for ammonium perchlorate-based solid propellants.