Relationship between the Bond Dissociation Energies and Impact Sensitivities of Some Nitro‐Explosives
ABSTRACT The bond dissociation energy (BDE) for removal of the NO2 group for eleven CHNO nitro-containing explosive molecules is studied to find its correlation with impact sensitivity. The BDE for removal of the NO2 group in nitroaromatic molecules with nitro alkyl, and esters with nitro alkyl, is calculated using the B3LYP method of Density Functional Theory with the 6-31G* basis set. The relationship between the impact sensitivities and the weakest C-NO2 bond dissociation energy values is examined. The results indicate a nearly linear correlation between the impact sensitivity and the ratio of the BDE value to the total molecular energy.
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ABSTRACT: The bond topological and electrostatic properties of nitrogen-rich 4,4′,5,5′-tetranitro-2,2′-bi-1H-imidazole (TNBI) energetic molecule have been calculated from the DFT method with the basis set 6-311G** and the AIM theory. The optimized geometry of this molecule is almost matched with the experimental geometric parameters. The electron density at the bond critical point and the Laplacian of electron density of C–NO2 bonds are not equal, one of them is much weaker than the other. Similar trend exists in the C–N bonds of the imidazole ring of the molecule. The ratio of the bond dissociation energy (BDE) of the weakest bond to the molecular total energy exhibits nearly a linear correlation with the impact sensitivity; its h 50% value is ~32.01 cm. The electrostatic potential around both the nitro groups are found unequal; the NO2 group of weakest C–NO2 bond exhibits an extended electronegative region.Structural Chemistry · 1.77 Impact Factor
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ABSTRACT: A novel polynitro cage compound 10-(5-nitrimino-1,2,3,4-tetrazol-1-yl)methyl-2,4,6,8,12-pentanitro-hexaazaisowurtzitane, composed of CL-20 and tetrazole framework, has been designed. DFT-B3LYP/6-31G(d) and molecular mechanics methods are employed to calculate its IR spectrum, heat of formation, thermodynamic properties, and crystal structure. Besides, the stability of this compound is evaluated using the bond dissociation energy. The result shows that the initial step of thermal decomposition is the rupture of N–NO2 bond in the side chain. This compound is most likely to crystallize in the P-1 space group, and corresponding cell parameters are Z = 2, a = 7.65 Å, b = 14.30 Å, c = 10.36 Å, α = 91.53°, β = 50.83°, γ = 89.44°, and ρ = 2.025 g cm−3. Detonation velocity and detonation pressure of this compound are estimated to be 9.090 km s−1 and 38.078 GPa using the Kamlet–Jacobs equation, similar to those of CL-20. Considering detonation performance and thermal stability, this compound meets the requirements of exploitable high energy density materials.Structural Chemistry 01/2013; · 1.77 Impact Factor
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ABSTRACT: Six density function theory methods (B3LYP, B3P86, MPWB1K1, MPWPW91, PBEPBE, TPSS1KCIS3) were used to calculate bond dissociation enthalpies of nitro compounds, where the B3P86 method was found to give the most accurate predictions. Using the B3P86 method meta- and para-substituted nitroaromatics were systematically studied for the first time. The remote substituent effects, Hammett relationships, and the origin of the substituent effects were discussed on the basis of the calculated results. Both meta- and para-substituted nitromethyl-benzenes showed significant substituent effects and a fair correlation against substituent constants σp+ The ground state effects were found to play the major role in determining the overall substituent effects. Meanwhile, nitroamino- benzenes showed irregular substituent effects and a poorer Hammett correlation, where both ground and radical state effects contributed to the overall substituent effects.Chinese Journal of Chemistry 06/2008; 26(6):1122 - 1128. · 0.92 Impact Factor