Novel Imidazole Derivative Complexes That Catalyze the Thermal Decomposition of AP, CL-20, and BNFFO

In this study, three energetic complexes, namely Cu(1-MIM)₂(N₃)₂ (1) (1-MIM=1-methylimidazole), [Cu(1-VIM)₂(N₃)₂]_n (2) (1-VIM=1-vinylimidazole), and Cu(2-MIM)₃(N₃)₂ (3) (2-MIM=2-methylimidazole), were synthesized via a simple and mild method. The complexes were characterized by single-crystal X-Ray diffraction, Fourier transform infrared (FTIR) spectroscopy, and elemental analysis. The thermal behavior and sensitivity of the complexes were analyzed by DSC, TG, and BAM methods, and their catalytic performances with respect to AP (ammonium perchlorate), CL-20 (hexanitrohexaazaisowurtzitane), and BNFFO (3,4-dinitrofurazanfuroxan) thermal decomposition were studied by differential scanning calorimetry (DSC). The obtained results indicate that complex 1 exhibits the best catalytic performance for AP thermal decomposition, as it reduces the decomposition (high-temperature) peak temperature by 101.0 °C compared to pure AP. Moreover, this complex alters the shape of the decomposition peak, which suggests that it speeds up the decomposition process and renders it more intense. In terms of CL-20 and BNFFO thermal decomposition, complex 3 shows the best catalytic performance, and it reduces the peak decomposition temperatures by 18.4 and 108.2 °C, respectively, compared to the pure samples. The activation energies of the AP/complex, CL-20/complex, and BNFFO/complex mixtures were calculated using the Kissinger and Ozawa equations. Considering that the calculated values are lower than those corresponding to the pure substrates, the complexes can be employed as combustion catalysts for composite propellants.