Theoretical Investingation On Properties Of C/N-NO₂dynamites With External Fields And The Design Of Detonation Velocity Device

In this dissertation, we show the application of the quantum chemistry theory on properties of C/N-NO2 dynamites under the influence of external electrical fields and design a detonation device. Firstly, nitromethane(C H3NO2) containing C-NO2, nitramide(NH2NO2) including N-NO2, and methyl nitrate(C H3ONO2) containing C-O-NO are chosen to research the influence of the intermolecular hydrogen-bonding interaction with HF. Then, the initiation decomposition of the nitromethane as well as N H2NO2/H2 O complexes with fields was theoretically investigated by the frist-principle calculations. The structures and energies of nitroimidazoles under the external electrical fields are also discussed. Additionaly, we design the device to measure the velocities of explosives with electrical fields. It shall be very important for safe using and the synthesis of novel energetic material.Specific research contents as follows:1. Fully optimized geometries of R-NO2(R=-CH3、-NH2、-OCH3) and R-NO2···HF complexes in external electric field have been obtained with B3 LYP methods at the 6-311++G(2d,p) level. And the energies have been calculated by the B3 LYP and MP2(full) methods at the 6-311++G(2d,p) and aug-cc-pVTZ levels, especially when the ones of monomer molecules by the CCSD(T) method for more details. The nature of differences between structures and properties have been revealed by the analysis of AIM and molecular electrostatic potential exploratory. The results indicate that the molecular relative energies and the bond lengths of the solicitation bond decrease while the dipole moment and the bond dissociation energies increase in a certain rate and direction of electric field. What‘s more, the bond lengths of the solicitation bond become more shorter and the bond dissociation energies more bigger when the monomer molecules become intermolecular hydrogen-bonded complex.2. The decomposition of the nitromethane as well as NH2NO2/H2 O complexes under the influence of external e lectric fields was theoretically investigated by using B3 LYP and MP2 methods. It is found that the initiation of reactions involves proton transfer, C –N bond rupture and isomerization. With the electric field along the C –NO2direction of nitromethane, nitromethane dissociation occurs via the C–NO2bond rupture in the range beween ?0.0100~0.0060 a.u. but via isomerization when the field is above + 0.0060 a.u. When fields antiparallel to the vertical direction of C–NO2plane, the decomposition of nitromethane prefers intermolecular proton transfer. In addition, the fields control selectivity for NH2NO2/H2 O competitive reaction between intramolecular and intermolecular proton transfer.3. The structure optimization of nitroimidazoles and their complexes of intermolecular hydrogen-bonding interaction and molecule-cation interaction between the nitro group under the influence of external electrical fields by using DFT-B3 LYP and MP2(full) method on 6-311++G(2d,p) set level. The lowest potential energy was got(NImag = 0).The influence of fields on properties of nitroimidazoles explosive are discussed and the detonation velocity device is designed as well in this paper. It shows that different external fields effect the monomer and dimers with HF of nitroimidazoles: With the electric field along the C–NO2direction of nitroimidazoles, the changes is bigger than those of the fields along the direction of N-O bond; the order of intermolecular hydrogen-bonding energies is 4-NI<2-NI<5-NI in the same electrical fields. Based on the calculations and analyzed, the energies of nitroimidazoles explosive might be increased but the sensitivity decreased under the influence of external electrical fields.