Theoretical Studies Of The Structrue And Performance Of Rich-Nitrogen Energetic Ionic Salts

A series of nitrogen-rich energetic1,2,4-triazole-, tetrazole-, and tetrazine-based ionic salts were designed in this thesis. Density functional theory (DFT) and volume-based thermodynamics (VBT) methods were used to predict their densities, heats of formation, and detonation properties. The effects of different substituents and different energetic ions on the properties of the ionic salts were investigated. The Born-Haber Cycles for the formation of energetic salts were established and the possibility of their formation was predicted by using Gibbs free energy changes of their formation reactions. By comparing their detonation performance, the potential candidates with good performance were selected. This study is organized as follows:1. A series of1,2,4-triazole-based molecules and their corresponding ionic salts containing1,2,4-triazolium cations or1,2,4-triazolide anions were designed in this part. DFT and VBT methods were used to calculate their densities, heats of formation, energetic properties, and thermodynamics of salt formation. The differences between the substituted1,2,4-triazole molecules and their corresponding ionic salts were analyzed. The effects of different substituent’s positions and the numbers of the substituents on the properties of their properties were investigated. The thermodynamic cycles for salt formation were established to calculate the free energy changes of their formation reactions and the possibility of synthesizing the salts was predicted.2. The structures of a series of tetrazole-based cations and anions were optimized using the B3LYP/6-31G**method. Then the average volumes of the tetrazole-based ionic salts were calculated to estimate their crystal densities. The effects of different substituents on the densitis of the ionic salts were investigated. The isodesmic reaction method was used to calculate the heats of formation of the tetrazole-based ions. The effects of different tetrazole-based ions and substituents on the properties of the ionic salts were discussed. The semiempirical Kamlet-Jacobs equations were used to calculate the detonation velocities and pressures of the ionic salts. The detonation properties of two series of the salts were compared. The thermodynamic cycles for salt formation were established to calculate the free energy changes of their formation reactions and the possibility of synthesizing the salts was predicted.3. The geometry structure of a seies of anions based on substituted mono-tetrazine derivatives, directly connected di-tetrazine derivatives, and bridged di-tetrazine derivatives were optimizd at the B3LYP/6-31++G*level. Their average volumes were estimated to predict the crystal densities of the salts. The single-point energies of the ions were obtained at the MP2/6-311++G**level to calculate the HOFs of the tetrazine-based slats by the isodesmic reactions. Their detonation velocities and pressures were calculated by the semiempirical Kamlet-Jacobs equations. The effects of different substituents and bridges on the densities, heats of formation, and the detonation properties of the tetrazine-based salts were discussed. The Born-Haber cycles for the formation of the tetrazine-based salts were established to judge whether the synthesis is possible.