Abstract
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•A facile synthesis of FOX-7 based nitramines was developed.•Title compounds were fully characterized by IR, NMR, EA, and, X-ray analysis.•Newly synthesized compounds have high chemical and mechanical stabilities.•Propellant formulations suggest that compounds 9a-b are green AP replacements.•Compounds 9a-b are able to improve the efficiency of ethanol-based fuel.
A variety of amine derivatives was found to react with FOX-7 to give triazine derivatives, which upon nitration gave rearranged nitramines in good to excellent yields. The structures of these triazines and nitramines were determined by various spectroscopic techniques, and elemental analyses. Further the structure of selected compounds namely 4-(dinitromethylene)-1-methyl-1,3,5-triazinane (8a), 4-(((methyl(nitro)amino)methyl)imino)-3,5-dinitro-5,6-dihydro-4H-1,2λ4,5-oxadiazin-2-olate (9a) and 3,5-dinitro-4-(((nitro(2-(nitrooxy)ethyl)amino)-methyl)imino)-5,6-dihydro-4H-1,2λ4,5-oxadiazin-2-olate (9b) were unambiguously confirmed by single crystal X-ray analysis. These compounds have good thermal stabilities with their decomposition temperatures in the range of 119–188 °C and experimental densities between 1.38 g cm−3 to 1.75 g cm−3. The enthalpies of formation of the new compounds were calculated (Gaussian-03) and combined with their experimental densities to evaluate the propulsive and detonation properties. Compounds 9a and b are found to have excellent energetic properties (9aP = 31.48 GPa, D = 8542 m/s; 9b, P = 31.83 GPa, D = 8518 m/s) that exceed those of TNT, HNS and are comparable to FOX-7 and RDX. The potential of these compounds as solid propellants/oxidizers was explored in detail; compounds (9a, Isp,vac 290.74 s; 9b, Isp,vac 293.00 s; with AP, Isp,vac 291.66 s (9a) and Isp,vac 292.57 s (9b)) were found to be suitable oxidizers for solid rocket propulsion.