Synthesis and Characterization of Fluorodinitrobenzenes with Tunable Melting Point: Potential Low Sensitive Energetic Plasticizer and Melt-Cast Carrier^†

In order to explore the effects of fluoro substituents on the energy and safety of energetic compounds, a series of fluorodinitrobenzenes including 1,3-difluoro-2,4-dinitrobenzene (1), 1,5-difluoro-2,4-dinitrobenzene (2), 1,2,3-trifluoro-4,6-dinitrobenzne (3) and 1,3,5-trifluoro-2,4-dinitrobenzene (4) were prepared. All the compounds were fully characterized. The structures of 2 and 3 were further confirmed by single crystal X-ray diffraction analysis. The results show that these compounds exhibit comparable detonation properties (D = 6703-6978 m·s^–1, and p = 21.3—23.7 GPa) to those of 2,4,6-trinitrotoluene (TNT) due to the significantly increased density of fluorine introduced. Low sensitivity (IS > 40 J, and FS > 360 N) of these compounds along with different melting points make them potential candidates for different allocation. Among them, 1 and 4 with the melting point of 42.5 °C and 55.2 °C, respectively, show promise for application in the field of energetic plasticizer. Compounds 2 and 3 are potential low sensitive melt-cast carrier due to their similar melting point and superior detonation performance to that of TNT.