Synthesis Of Two Kinds Of Energetic Compounds Containing Pyrazole And Theoretical Study On Its Related Compounds

Looking for the high energetic insensitivity explosives is one of subjects about synthesis of energetic materials. Nitropyrazoles have received a great deal of attention from researchers because of their good detonation performances, low sensitivities and excellent molecular stabilities. The main content of this paper is the synthesis of 1-amino-3,5-dinitropyrazole (ADNP) and 1-methyl-3,4,5-trinitro-pyrazole (MTNP) and the theoretical research for the designed nitrodiazolesDensity functional theory (DFT) calculation method was used to investigate electronic structures and properties of 1, 1’-azobis-polynitrodiazole-N-oxides at B3LYP/aug-cc-pVDZ level. The gas-phase heats of formation (HOFs) were predicted based on the atomization approach and the condensed-phase HOFs were estimated in the framework of the Politzer model; thermal stabilities, were investigated by calculating bond dissociation energies (BDEs), and Kamlet-Jacob equations were employed to determine detonation properties of the title compounds. Calculated results indicate that the designed compounds present high and positive HOFs, good stabilities and excellent explosive and thermodynamic performances, especially R3 (9.13 km·s-1,37.81 GPa) and R6 (9.11 km·s-1,37.87 GPa) exhibit comparable detonation properties to HMX (9.1 km·s-1,39.00 GPa) R3 and R6 may be regarded as potential candidates for high energy density compounds (HEDCs).1-amino-3,5-dinitropyrazole (ADNP) was synthesized by aminating 3,5-dinitropyrazole with O-mesitylene sulfonyl hydroxylamine (MSH). Its structure was characterized by MS, IR, NMR and element analysis. The single crystal of ADNP was cultivated in ethanol and its crystal structure was determined by a four-cirde X-ray diffactometer. The results show that the crystal is orthorhombic, space group P2(1)/n with crvstal parameters α= 5.543(2) A, b= 9.866(4) A, c= 11.745(5) A, Z= 4, Dc= 1.79 g/cm3, V= 642.3(4) A3, Dc= 1.790 g/cm3. The thermal behavior of ADNP was studied by DSC, the melting point and composition peak are 113℃ and 310℃, respectively. And an optional reaction conditions were obtained:reaction at 20℃, reaction time 5h, ratio of n(3,5-DNP):n(MSH)= 1:2.0. The yield is 59.1%.1-methyl-3,4,5-trinitropyrazole (MTNP) was synthesized by aminating 3,4,5-trinitropyrazole with dimethyl sulfate. Its structure was characterized by MS, IR, NMR and element analysis. The thermal behavior of MTNP was studied by DSC, the melting point and composition peak are 91.6℃ and 223.5 ℃, respectively. And an optional process conditions were determined as follow:ratio of n(3,5-DNP):n(MSH)=1:2.0, reaction time 5 h, reaction temperature 20℃. The yield is 89.5%.Thermal decomposition and kinetics of ADNP were studied by using DSC under non-isothermal. When the heating rate close to zero, decomposition temperature of ADNP was 271.89℃, and the apparent activation energy was 139.485 kJ·mol-1. The mechanical sensitivity of ADNP and MTNP was tested. Theoretical calculations of detonation properties of ADNP and MTNP were calculated theoretically.