Nitro Groups vs. N-Oxide Linkages: Effects Upon Some Key Determinants of Detonation Performance

Abstract

Abstract:Increasing the nitrogen/carbon ratios in the molecular frameworks of C,H,N,O explosives has attracted considerable attention because it tends to result in more positive heats of formation and often greater densities. In conjunction with this, there has been a growing interest in N-oxide linkages,, as another source of oxygen in these compounds, in addition to or even possibly replacing NO2 groups. In this study, for a series of polyazines and polyazoles, we have compared the effects of introducing a single N-oxide linkage or NO2 group upon key properties that affect detonation velocity and detonation pressure. We found that: (1) The heats of formation per gram of compound, which is what is relevant for this purpose, are almost always higher for the N-oxides. (2) The nitro derivatives have greater densities and detonation heat releases. In relation to the latter, it must be kept in mind that increasing detonation heat release tends to be accompanied by increasing sensitivity. (3) The N-oxides produce more moles of gaseous detonation products per gram of compound.

Theoretical Prediction of the Heats of Formation, Densities and Relative Sensitivities, and/or Synthetic Approaches Toward the Synthesis of High Energy Dense Materials (HEDMs): 3,5-Dinitro-1,3,5-Oxadiazinane, Bis-Adjacent RDX, Bis-Adjacent HMX, 4,4',6,6'-Tetranitro-1,1'-Bis(N-oxide)-5,5',6,6'-4H,4'H-5,5'-Bisimidazo Oxadiazole, and the Open-Cage Derivative of CL-20

“…RDX has a crystalline density of 1.80 cm 3 , a detonation pressure of 34.7 GPa, and a detonation velocity of 8754 m/s. 10 The comparable performance of this molecule to HMX, and its predicted moderate sensitivity make it an interesting target for synthesis (NB: HMX has a crystalline density of 1.90 cm 3 , a detonation velocity of 9150 m/s, and a detonation pressure of 39.3 GPa). It was believed that glycoluril was a logical starting point toward the synthesis of bis-adjacent RDX.…”

Computational design of tetrazolone‐based high‐energy density energetic materials: Property prediction and decomposition mechanism

“…Compounds 10, 16, 17, and 24 have higher V D than that of high-energy explosive ONC (9.50 km/s) and 17 has a value of P D comparative to explosive CL-20 (44.10 GPa). Results show that compounds 6,10,11,12,15,16,17,22,23, and 24 own better performance than widely used explosive HMX and may serve as promising candidates of environmentally friendly HEDMs.…”

“…For tetrazolone derivatives with the linkage of -NH-(8-13) and -NHNH- (14)(15)(16)(17)(18)(19), the N atoms are not coplane and the bond lengths of C═O are about 1.208 Å. The remaining tetrazolone derivatives (20)(21)(22)(23)(24)(25) show centrosymmetric configurations with double tetrazolones linked by the azo bond and 2 substituted groups crossed arranged around the rings. All the optimized geometries are summarized in Supporting Information.…”

“…All the tetrazolone-based compouds FIGURE 4 Overall performance of tetrazolone-based compounds (TOs) compared with RDX and HMX in this work except 5, 7, 8, and 14 have similar or even better detonation properties compared to HMX, which is one of the most commonly used high-performance energetic ingredients. Compound 6,10,11,15,16,17,22,23, and 24 own excellent performance with detonation velocity of about 9.5 km/s and detonation pressure of about 41.0 GPa making them potential candidates of new green HEDMs.…”

“…These newly designed tetrazolone-based compounds show high densities (up to 2.08 g/cm 3 ) and highly positive heats of formation (407.0-1377.9 kJ/mol) due to all right content of nitrogen and oxygen. Most of them exhibit good detonation velocity (8.31-9.62 km/s) and detonation pressure (32.40-43.86 GPa), and some are comparative to excellent explosive 10,11,12,15,16,17,22,23, and 24 own superior detonation performance than widely used explosive HMX and may be promising candidates of green high-performance energetic materials. …”