Zun-Ning Zhou

Synthesis, crystal structure, thermal decomposition, and non-isothermal reaction kinetic analysis of an energetic complex: [Mg(CHZ)3](ClO4)2 (CHZ = carbohydrazide)

An energetic complex [Mg(CHZ)3](ClO4)2 was synthesized by the reaction of carbohydrazide (CHZ) with magnesium perchlorate. The product was characterized by X-ray single-crystal diffraction, elemental analysis, and IR spectroscopy. The crystal belongs to the monoclinic system with space group P2(1)/n. Cell parameters: a = 10.034(2) Å, b = 8.5069(16) Å, c = 21.285(4) Å, β = 100.901(3)°, V = 1784.1(6) Å3, Z = 4. The central magnesium is six-coordinate with three oxygen atoms of carbonyl groups and three terminal nitrogen atoms of the hydrazine groups from three CHZs to form a distorted octahedron. Differential scanning calorimetry and thermogravimetric-differential thermogravimetric analysis were applied to assess the thermal decomposition behavior. The kinetic parameters were obtained by non-isothermal reaction kinetics. The equation can be expressed as . Moreover, the values of critical temperature of thermal explosion, ΔS≠ , ΔH≠ , ΔG≠ , and the energy of combustion were obtained as 284°C, −169.76 J mol−1 K−1, 65.46 kJ mol−1, 154.27 kJ mol−1, and 6759 kJkg−1, respectively.

Nitrogen-rich salts based on the energetic [monoaquabis(N,N-bis(1H-tetrazol-5-yl)amine)-zinc(II)] anion: a promising design in the development of new energetic materials.

Nitrogen-rich energetic salts involving various cations (lithium, 1; ammonium, 2; hydrazinium, 3; hydroxylammonium, 4; guanidinium, 5; aminoguanidinium, 6; diaminoguanidinium, 7; and triaminoguanidinium, 8) based on nitrogen-rich anion [Zn(BTA)2(H2O)](2-) (N% = 65.37, BTA = N,N-bis[1H-tetrazol-5-yl]amine anion) were synthesized with a simple method. The crystal structures of all compounds except 1, 2, and 6 were determined by single-crystal X-ray diffraction and fully characterized by elemental analysis and FT-IR spectroscopy. The thermal stabilities were investigated by differential scanning calorimetry (DSC). The DSC results show that all compounds exhibit high thermal stabilities (decomposition temperature >200 °C). Additionally, the heats of formation were calculated on the basis of the experimental constant-volume energies of combustion measured by using bomb calorimetry. Lastly, the sensitivities toward impact and friction were assessed according to Bundesamt für Materialforschung (BAM) standard methods.

Synthesis, structure, and thermal behavior of a 2-D polymeric Ca(II) compound with tetrazole-1-acetic acid

A 2-D polymeric Ca(II) compound, [Ca(tza)2(H2O)2] n , was synthesized by the reaction of tetrazole-1-acetic acid with calcium carbonate. The product was characterized by X-ray single-crystal diffraction, elemental analysis, and IR spectroscopy. The calcium center is six-coordinate in a slightly distorted octahedral configuration by four carboxylic oxygens from four different tza− ligands and two waters. The 2-D supramolecular laminar structure in b-axis × c-axis plane was constructed via four bridging tza− ions connecting one Ca(II) with four adjacent Ca(II) ions. Differential scanning calorimetry and thermogravimetric–differential thermogravimetric analysis were applied to assess the thermal decomposition behavior. The kinetic parameters were obtained by non-isothermal reaction kinetics, and the Arrhenius equation can be expressed as lnk = 21.96–262.2 × 103/RT. The values of critical temperature of thermal explosion, ΔS≠ , ΔH≠ , and ΔG≠ were obtained as 574 K, −67.62 J mol−1 K−1, 257.52 kJ mol−1, and 295.59 kJ mol−1, respectively.

Research on thermal decomposition of trinitrophloroglucinol salts by DSC, TG and DVST

AbstractThe thermal decomposition of the four nitrogen-rich salts of ammonia (NH4), aminoguanidine (AG), carbohydrazide (CHZ) and 5-aminotetrazo (ATZ) based on trinitrophloroglucinol (H3TNPG) was investigated using the differential scanning calorimetry (DSC), thermogravity (TG), and dynamic vacuum stability test (DVST). DSC and TG methods research the complete decomposition, while DVST method researches the very early reaction stage. The peak temperatures of DSC curves are consistent with the temperatures of maximum mass loss rates of TG curves. The apparent activation energies of these H3TNPG-based salts obtained by DSC and DVST have the same regularity, i.e., (ATZ)(H2TNPG)·2H2O < (CHZ)(HTNPG)·0.5H2O < NH4(H2TNPG) < (AG)(H2TNPG). The thermal stability order is (ATZ)(H2TNPG)·2H2O < (CHZ)(HTNPG)·0.5H2O < (AG)(H2TNPG) < NH4(H2TNPG), which was evaluated by DVST according to the evolved gas amount of thermal decomposition. DVST can monitor the real-time temperature and pressure changes caused by thermal decomposition, dehydration, phase transition and secondary reaction, and also evaluate the thermal stability and kinetics.

Preparation, crystal structures, thermal decompositions and explosive properties of two new high-nitrogen azide ethylenediamine energetic compounds

Two new multi-ligand coordination compounds of copper(II) ethylenediamine (en) azide and cobalt(III) ethylenediamine azide, [Cu2(en)2(N3)4]n (1) and Co(en)2(N3)2(NO3) (2), were synthesized and characterized by elemental analysis and FT-IR spectroscopy. The crystal structures were determined by X-ray single crystal diffraction. The obtained results show that the crystals of 1 and 2 belong to the monoclinic, C2/c space group. The metal cations are six-coordinated with the azido ligands and ethylenediamine molecules through nitrogen atoms. The coordination modes of the azido-groups were μ-1, μ-1,1 and μ-1,1,3 modes for 1, and μ-1 mode for 2. Under a nitrogen atmosphere, with a heating rate of 5 K min−1, the thermal decompositions contain two main exothermic stages in the DSC curves corresponding to the TG-DTG curves. The non-isothermal kinetics parameters were calculated by the Kissingers method and Ozawas method, respectively. The energies of combustion, enthalpies of formation, critical temperature of thermal explosion, entropies of activation (ΔS≠), enthalpies of activation (ΔH≠), and free energies of activation (ΔG≠) were measured and calculated. The sensitivity properties were also determined with standard methods and the results showed that 1 had a much higher flame sensitivity and lower impact sensitivity.

Energetic Salts Based on Tetrazole N-Oxide

Energetic materials (explosives, propellants, and pyrotechnics) are used extensively for both civilian and military applications and the development of such materials, particularly in the case of energetic salts, is subject to continuous research efforts all over the world. This Review concerns recent advances in the syntheses, properties, and potential applications of ionic salts based on tetrazole N-oxide. Most of these salts exhibit excellent characteristics and can be classified as a new family of highly energetic materials with increased density and performance, alongside decreased mechanical sensitivity. Additionally, novel tetrazole N-oxide salts are proposed based on a diverse array of functional groups and ions pairs, which may be promising candidates for new energetic materials.

Synthesis, crystal structure, thermal decomposition, and explosive properties of [Bi(tza)3] n (tza = tetrazole acetic acid)

A coordination compound based on tetrazole acetic acid (Htza) and bismuth(III), [Bi(tza)3] n , was synthesized and characterized by single crystal X-ray diffraction analysis, elemental analysis, FT-IR, and 1H NMR spectroscopy. The crystallographic data show that the crystal belongs to monoclinic, P21/n space group, a = 0.91968(19) nm, b = 0.94869(19) nm, c = 1.7824(4) nm, β = 101.488(3)°, and Z = 4. The central bismuth(III) is nine-coordinate by three nitrogens from three tetrazole rings and six oxygens of the carboxylate of another three tza− ions, with each tza− tridentate, chelating, bridging coordination. The coordination bonds and the intramolecular hydrogen bonds make the complex pack into a layered structure in polymer form. The thermal decomposition mechanism of the title complex was investigated by DSC and TG-DTG techniques. Under nitrogen at a heating rate of 10°C min−1, thermal decomposition of the complex contains two intense exothermic processes between 217.4°C and 530.3°C in the DSC curve; the final decomposed residue at 570°C was Bi2O3. Sensitivity tests showed that [Bi(tza)3] n was sensitive to impact and flame stimulus.

Synthesis, structure, thermal behavior and energetic properties of a new 2D polymeric Ba(II) compound with tetrazole-1-acetic acid

A new energetic Ba(II) coordination polymer [Ba(tza)2]n (where tza = tetrazole-1-acetic acid anion) was synthesized and characterized by X-ray single crystal diffraction, elemental analysis and IR spectroscopy. In the molecule, the central Ba(II) cation was coordinated by eight carboxylic O atoms from six different tza ions. Quadridentate tza anion bridged three various Ba(II) atoms and formed a 2D supramolecular network. Differential scanning calorimetry (DSC) and thermogravimetric differential thermogravimetric (TG DTG) analyses were applied to assess the thermal decomposition behavior. The kinetic parameters were obtained by non-isothermal reaction kinetics, and the Arrhenius equation can be expressed as lnk = 22.47 – 291× 103/RT. Critical temperature of thermal explosion, thermodynamic parameters, energy of combustion, enthalpy of formation and sensitivities of [Ba(tza)2]n were measured or calculated to argue that as a potential energetic material.

The facile synthesis of graphene nanoplatelet–lead styphnate composites and their depressed electrostatic hazards

Graphene nanoplatelet–lead styphnate composites (GLS) were prepared either by adding graphene nanoplatelets (GNP) to the reaction solution or by coating normal lead styphnate (LS) with GNP. The composites exhibited excellent anti-electrostatic performance with depressed electrostatic spark sensitivity and static electricity accumulation.

Preparation, crystal structure, and thermal decomposition of an azide energetic compound [Cd(IMI)2(N3)2]n (IMI = imidazole)

Cadmium(II) imidazole (IMI) azide [Cd(IMI)2(N3)2]n (1) was synthesized using imidazole and azide, and was characterized by the elemental analysis and FTIR spectrum. The crystal structure was determined by X-ray single crystal diffraction, and the crystallographic data show that the crystal belongs to orthorhombic, Pba2 space group, α = 10.780(4) Å, b = 13.529(5) Å, and c = 3.6415(12) Å. Its crystal density is 2.080 g·cm–3. Cd(II) is a six-coordinate with six nitrogens from four imidazoles and two azides with μ–1,1 coordination. The thermal decomposition mechanism was determined based on differential scanning calorimetry (DSC) and thermogravimetry-derivative thermogravimetry (TG-DTG) analysis, and the kinetic parameters of the first exothermic process were studied using Kissinger’s method and Ozawa’s method, respectively. The energy of combustion, enthalpy of formation, critical temperature of thermal explosion, entropy of activation (ΔS ≠), enthalpy of activation (ΔH ≠), and free energy of activation (ΔG ≠) were measured and calculated. In the end, impact sensitivity was also determined by standard method.