Abstract
A new structural type for melt cast materials was designed by linking nitrotetrazole ring with 1,2,4-oxadiazole through a N-CH2-C bridge for the first time. Three N-CH2-C linkage bridged energetic compounds, including 3-((5-nitro-2H-tetrazol-2-yl) methyl)-1,2,4-oxadiazole (NTOM), 3-((5-nitro-2H-tetrazol-2-yl)methyl)-5-(trifluoromethyl)-1,2,4 -oxadiazole (NTOF) and 3-((5-nitro-2H-tetrazol-2-yl)methyl)-5-amine-1,2,4-oxadiazole (NTOA), were designed and synthesized through a two-step reaction by using 2-(5-nitro-2H-tetrazole -2-yl)acetonitrile as the starting material. The synthesized compounds were fully characterized by NMR (1H, 13C), IR spectroscopy and elemental analysis. The single crystals of NTOM, NTOF and NTOA were successfully obtained and investigated by single-crystal X-ray diffraction. The thermal stabilities of these compounds were evaluated by DSC-TG measurements, and their apparent activation energies were calculated by Kissinger and Ozawa methods. The crystal densities of the three compounds were between 1.66 g/cm3 (NTOA) and 1.87 g/cm3 (NTOF). The impact and friction sensitivities were measured by standard BAM fall-hammer techniques, and their detonation performances were computed using the EXPLO 5 (v. 6.04) program. The detonation velocities of the three compounds are between 7271 m/s (NTOF) and 7909 m/s (NTOM). The impact sensitivities are >40 J, and the friction sensitivities are >360 N. NTOM, NTOF and NTOA are thermally stable, with decomposition points > 240 °C. The melting points of NTOM and NTOF are 82.6 °C and 71.7 °C, respectively. Hence, they possess potential to be used as melt cast materials with good thermal stabilities and better detonation performances than TNT.
Highlights
Melt cast explosives are widely used in military and civilian fields such as grenades, mortars, warheads and antipersonnel mines [1]
The C-N bond length and the N-N bond length in oxadiazole and tetrazole rings are found to be shorter than the normal C-N single bond (1.47 Å) and longer than the C = N double bond (1.22 Å). These results indicate that electronic conjugation is formed in amino-1,2,4-oxadiazole and 5-nitrotetrazole structure
The three compounds were fully characterized by nuclear magnetic resonance (NMR), IR spectroscopy and elemental analysis
Summary
Melt cast explosives are widely used in military and civilian fields such as grenades, mortars, warheads and antipersonnel mines [1]. 2,4,6-Trinitrotoluene (TNT) and dinitroanisole (DNAN) are two kinds of widely investigated and applied melt cast materials. Their further applications are limited by their relative shortcomings, such as the toxicity and environmental problems of TNT [3,4]. Low detonation performances of DNAN [5,6]. There is continued interest in developing new melt cast materials with better explosive performances. Significant progress has been made in the field of melt cast explosives.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
