Crystal Structure and Improved Synthesis of 1-(2 H -Tetrazol-5-yl)guanidium Nitrate

Energetic derivatives of tetrazoles are one of the key areas of research focus in pursuit of novel high energy materials, useful as propellants and explosives. Herein, the crystal structure and an improved synthetic procedure of 1-(2H-tetrazol-5-yl)guanidine (1) and its nitrate salt (2) are reported. The compounds were structurally characterized by spectroscopic (FT-IR, 1H NMR, 13C NMR) and elemental analysis. The molecular structure of tetrazolyl guanidium nitrate (2) was solved using low temperature single-crystal X-ray diffraction. 2 crystallized as its hemihydrate in the orthorhombic space group Fdd2, with a crystal density of 1.69 g cm−3. Thermal behavior and decomposition of the molecules were studied with differential scanning calorimetry (DSC). Molar enthalpy of formation (ΔfHm) of compound 2 was back calculated from heat of combustion (ΔcH0) value obtained experimentally using bomb calorimetric measurements. Lattice enthalpy of 1-(2H-tetrazol-5-yl)guanidium nitrate was directly calculated from measured crystal density using Jenkins equation. Preliminary ballistic parameters of the compound were predicted and compared with reported high nitrogen tetrazole derivatives.Accepted versio

1-(2 H -Tetrazolyl)-1,2,4-triazole-5-amine(TzTA) : a thermally stable nitrogen rich energetic material : synthesis, characterization and thermo-chemical analysis

The targeted high nitrogen energetic material 1-(2H-tetrazol-5-yl)-1,2,4-triazol-5-amine (TzTA) was synthesized from 3-amino-1,2,4-triazole via a two-step procedure using cyanogen bromide and sodium azide. TzTA was prepared in good yields and characterized using analytical (elemental) and spectroscopic (IR, Raman, NMR) techniques. The crystal structure of sulfate salt of the molecule was solved by means of low temperature X-ray crystallography, which showed the co-planarity of the two rings. The sulfate salt of the molecule crystallized in monoclinic system P21/n, with a crystal density of 1.856 g cm−3. The thermal stability of the molecule was assessed by DSC. The molecule showed excellent thermal stability better than many known nitrogen rich energetic molecules and showed comparable thermal stability with HMX. Non-isothermal kinetics was performed on the molecule to derive the activation energy. Constant volume combustion energy was determined using oxygen bomb calorimeter and back calculated the heat of formation. Preliminary insight on the gas generating capability of the molecule was tested by measuring the dynamic pressure generated inside a closed bomb. Dynamic pressure of an oxygen balanced system (TzTA and ADN) was also measured using the Parr dynamic pressure measurement system

3-Amino-1,2,4(4H)-oxadiazol-5-one (AOD) and its nitrogen-rich salts: a class of insensitive energetic materials

The targeted energetic material 3-amino-1,2,4(4H)-oxadiazol-5-one (AOD) was synthesized from sodium dicyanamide using hydroxylamine hydrochloride in a one-step procedure. AOD was prepared by a novel procedure in good yield and characterized using spectroscopic (IR, Raman, NMR) techniques. The high nitrogen-containing hydroxylamine and hydrazine salts of AOD (3) were prepared from their respective nitrogen bases in good yields. The solid state structures of the synthesized molecules were confirmed by single X-ray crystallography. 3-Amino-1,2,4(4H)-oxadiazol-5-one (AOD, 3), 3-amino-1,2,4(4H)-oxadiazol-5-one-hydroxylamine (AOD-HyAm, 5) and 3-amino-1,2,4(4H)-oxadiazol-5-one-hydrazine (AOD-Hy, 6) showed densities of 1.76, 1.73 and 1.64 g cc−1 respectively. The thermal stabilities of the molecules were assessed by thermogravimetric analysis. Non-isothermal kinetics was performed on the molecules to derive the activation energy. Constant volume combustion energy was determined using oxygen bomb calorimetry and the heat of formation was calculated from the experimental values. Sensitivities of the molecules were measured by using impact and friction tests.Accepted versio