From FOX-7 to H-FOX to insensitive energetic materials with hypergolic properties†
Nitrogen/halogen rich derivatives, 3, 4, 8, and 9 of FOX-7 (1,1-diamino-2,2-dinitroethene), and H-FOX (1-hydrazinyl-2,2-dinitroethenamine) have been synthesized, characterized and found to exhibit good energetic properties. Compound 4 displays hypergolic properties with commonly utilized fuels such as monomethyl hydrazine (MMH), and hydrazine hydrate (HH), as well as with ethylenediamine (EN), and 1,3-diaminopropane (DAP) showing ignition delay times between 2.5 to 10 ms. Additionally, the hypergolic properties of 4 and 8 were further studied by using ammonia borane as a fuel solubilized in a green ionic liquid, 1-allyl-3-methyl imidazolium dicyanamide, (1 : 1 molar ratio). This is a new role for a derivative of H-FOX. The energetic and physical properties of all the molecules were either measured or calculated. All of materials were characterized by NMR, and infrared spectra, elemental analyses, and differential scanning calorimetry. Single crystal X-ray structural measurements for 4 and 9 were helpful in their confirmation.