Search Results (10)

5-aminotetrazole (5AT)-based gas generators, particularly the 5AT/NaIO₄ system, have garnered interest for their high gas production and energy potential. This study investigates the impact of various metal oxides (MnO₂, Al₂O₃, TiO₂, CuO, Fe₂O₃, MgO, ZnO, and MoO₃) on the thermal decomposition and combustion performance of 5AT/NaIO₄. The REAL calculation program was used to infer reaction products, which indicated that the gas products are almost all harmless, with negligibly low percentages of NO and CO. Thermogravimetric analysis revealed that metal oxides, especially MoO₃, significantly advance the decomposition process above 400 °C, reducing the activation energy by 130 kJ/mol and lowering critical ignition and thermal explosion temperatures. Combustion performance tests and closed bomb tests confirmed MoO₃’s positive effect, accelerating reaction rates and enhancing decomposition efficiency. The system’s high Gibbs free energy indicates non-spontaneous reactions. These findings provide valuable insights for designing environmentally friendly gas generators, highlighting MoO₃’s potential as an effective catalyst. Full article

5-aminotetrazole (5AT) has been widely used as a fuel in SPGGs for its high nitrogen content, heat resistance, and environmentally friendly product. However, 5AT-based propellants still have disadvantages, such as a high exhaust temperature and unstable combustion rate, which somewhat limit their application. Given that transition metal oxides are typically employed in small quantities to enhance the performance of solid propellants, this study selected nickel oxide (NiO) nanoparticles as a catalyst and employed them in conjunction with 5AT via mechanical ball milling to investigate their impact on the pyrolysis behavior of 5AT. It was found that the nanoscale NiO particles can significantly reduce the thermal degradation temperature of 5AT according to TG-DSC tests. The calculation of the energy required to initiate the pyrolysis of 5AT using three kinetic methods, namely Friedman (FR), Flynn–Wall–Ozawa (FWO), and Kissinger–Akahira–Sunose (KAS), indicated that the use of NiO nanoparticles can reduce the energy required by more than 46 kJ mol⁻¹, thereby increasing the likelihood of 5AT pyrolysis. Meanwhile, the reduced thermal safety parameters indicated that NiO makes 5AT more susceptible to thermal decomposition due to thermal explosion transition, so more care is needed for the storage of 5AT. Moreover, the TG-FTIR test was conducted to study the pyrolysis mechanism with or without NiO; the results showed that NiO exerts different catalytic effects on the gas products. The results from this study can offer direction and recommendations for future research on solid propellants. Full article

5-aminotetrazole is one of the most marked high-nitrogen tetrazole compounds. However, the structural modification of 5-aminotetrazole with nitro groups often leads to dramatically decreased molecular stability, while the N-bridging functionalization does not efficiently improve the density and performance. In this paper, we report on a straightforward approach for improving the density of 5-aminotetrazole by introducing 4-amino-3,5-dinitropyrazole. The following experimental and calculated properties show that nitropyrazole functionalization competes well with energetic performance and mechanic sensitivity. All compounds were thoroughly characterized using IR and NMR spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). Two energetic compounds (DMPT-1 and DMPT-2) were further confirmed by implementing single-crystal X-ray diffraction studies. Compound DMPT-1 featured a high crystal density of 1.806 g cm⁻³, excellent detonation velocity (v_D = 8610 m s⁻¹), detonation pressure (P = 30.2 GPa), and impact sensitivity of 30 J. Full article

An N-glycidyl-5-aminotetrazole homopolymer was synthesized herein by nucleophilic substitution of 5-aminotetrazole heterocycles for chlorine atoms in poly-(epichlorohydrin)-butanediol. Copolymers of N-glycidyl-5-aminotetrazole and glycidyl azide with a varied ratio of energetic elements were synthesized by simultaneously reacting the 5-aminotetrazole sodium salt and the azide ion with the starting polymeric matrix. The 5-aminotetrazole-based homopolymer was nitrated to furnish a polymer whose macromolecule is enriched additionally with energy-rich terminal ONO₂ groups and nitrate anions. The structures of the synthesized polymers were characterized by ¹H and ¹³C NMR and IR spectroscopies, elemental analysis and gel-permeation chromatography. The densities were experimentally measured, and thermal stability data were acquired by differential scanning calorimetry. The insertion of aminotetrazole heterocycles into the polymeric chain and their modification via nitration provides an acceptable thermal stability and a considerable enhancement in density and nitrogen content compared to azide homopolymer GAP. By the 1.3-dipolar cycloaddition reaction, we demonstrated the conceptual possibility of preparing spatially branched, energy-rich polymeric binders bearing 5-aminotetrazole and 1,2,3-triazole heterocycles starting from the plasticized azide copolymers. The presence of the aforesaid advantages makes the reported polymers attractive candidates for use as a scaffold of energetic binders. Full article

The post-synthesis modification is a highly efficient method for the modification of Metal-organic framework (MOF) materials, which has been used to synthesize MOF materials purposefully that cannot be prepared by direct synthesis and impregnation method. In this work, amino modified ZIF8 with 5-aminotetrazole was prepared by the post synthesis modification method and was employed to reversibly remove SO₂ from flue gas. Based on the characterization and analysis of X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and Brunner Emmet Teller (BET), it was found that the functionalized ZIF8 (Zn(5-ATZ)_1.5) was a microporous material with a two-dimensional nano-layered structure. According to the SO₂ adsorption experiments, the adsorption capacity of SO₂ at the concentration of 1.6% vol can reach to 122 mg/g under the optimal conditions (25 °C, 2865 h⁻¹). Five successive adsorption-desorption experiments exhibited that Zn(5-ATZ)_1.5 had excellent regeneration performance. The characterization results of Raman Spectra (Raman) and X-ray photoelectron spectroscopy (XPS) as well as the DFT simulation calculations revealed that SO₂ mainly interacted with Zn(5-ATZ)_1.5 by hydrogen bonds between O of SO₂ and amino H in the Zn(5-ATZ)_1.5, and the interaction of SO₂ with amino N and 5-aminotetrazole N by forming a non-covalent charge transfer complex. This work suggested that Zn(5-ATZ)_1.5 is an excellent potential sorbent for SO₂ removal. Full article

Excesses and shortages of some metal ions such as Fe³⁺ and Cr₂O₇²⁻ pose a threat to human life. A Zn-based two-dimensional MOF has proven to be sensitive for Fe³⁺ and Cr₂O₇²⁻ in water with Ksv values of 1.8 × 10⁴ and 6.5 × 10⁴, respectively. The limit of detection (LOD) for these ions was found to be 2.5 μM and 0.15 μM for Fe³⁺ and Cr₂O₇²⁻ ions, respectively. A comparative study was conducted using two 3D MOFs in terms of their detection ability, synthesis and structure. Full article

A derivative of dihydrotetrazolopyrimidine has been successfully synthesized through a cyclocondensation reaction between a chalcone derivative with 5-aminotetrazole. The molecular structure of the title compound was established based on Fourier transform infrared spectra (FTIR), high-resolution mass spectrometry (HRMS), 1D and 2D nuclear magnetic resonance (NMR) spectrum. Full article

A new compound belonging to a dihydrotetrazolopyrimidine derivative, that is, ethyl 5-methyl-7-(4-morpholinophenyl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylate, was successfully synthesized using a Biginelli reaction between 4-morpholinobenzaldehyde, ethyl acetoacetate, and 5-aminotetrazole with p-toluenesulfonic acid (pTSA) as a catalyst in ethanol under reflux. The molecular structure of the title compound was characterized on the basis of spectroscopic evidence, using FTIR, HRESI-MS, ¹H- and ¹³C-NMR, and 2D NMR. Full article

The crystal structures of three salts of anionic 5-aminotetrazole are described. The tetramethylammonium salt (P ) forms hydrogen-bonded ribbons of anions which accept weak C–H···N contacts from the cations. The cystamine salt (C2/c) shows wave-shaped ribbons of anions linked by hydrogen bonds to screw-shaped dications. The tetramethylguanidine salt (P2₁/c) exhibits layers of anions hydrogen-bonded to the cations. Full article

The crystal structures of four salts of 1,4-diazabicyclo[2.2.2]octane (DABCO) and 5-aminotetrazole are described. Anhydrous 1:1 (Pbca, R_gt = 0.041) and 1:2 (P, R_gt = 0.038) salts form hydrogen-bonded layers of anions and cations. The monohydrate of the 1:1 compound (P2₁/c, R_gt = 0.038) shows infinite chains of DABCO cations and an undulated layer of anions and water molecules. The octahydrate of the 3:2 compound (P2₁/c, R_gt = 0.042) features DABCO triples and clusters of four tetrazolate ions in a network of water molecules. Full article