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2 Central European Journal of Energetic Materials

2 2017

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Thermal Decomposition Characteristics of Ammonium Nitrate(V) in the Presence of Mn2O3/Graphene Oxides

Xu Z., Xu G., Fu X., Wang Q.

Central European Journal of Energetic Materials

2017

Vol. 14, no. 3

636--659

Nano-composites (Mn2O3, Mn2O3/graphene oxides (GO)) were prepared by a new method. The nano-composites were characterized by XRD and HRTEM. The catalytic performance of the nano-composites on the thermal decomposition of ammonium nitrate(V) (AN) was investigated by TG-DSC and TG-MS. The reaction of AN with the nano-composites in the condensed phase was investigated by RSFTIR. The results of TG-DSC experiments indicated that the nano-composites significantly catalyze the thermal decomposition of AN, especial Mn2O3/GO. The exothermic reaction of AN with Mn2O3/GO commenced at about 185 °C. Based on the TG-MS results, it was ascribed to N2O formation. In the RSFTIR experiments, the dissociation reaction and ionization reaction of AN were both detected. NOx formation at low temperature was also found. NH2 was directly oxidized by HNO3/NO3− at low temperature. The interaction between Mn2O3 and NH3 was detected according to DRIFT experiments. At elevated temperature, the functional groups of GO are destroyed, which had an influence on the interaction between Mn2O3 and GO. A probable mechanism for the exothermic reaction and then its disappearance is proposed. HNO3 gas was absorbed on the surface of solid AN, which can markedly catalyze the thermal decomposition of AN. Perhaps the HNO3 plays a key role in the exothermic reaction and then the reaction of AN disappears at very low temperatures.

A Facile Synthesis of 3,3'-Dinitro-5,5'-diamino-bi-1,2,4-triazole and a Study of Its Thermal Decomposition

Ma Q., Lu H., Qu Y., Liao L., Li J., Fan G., Chen Y.

Central European Journal of Energetic Materials

2017

Vol. 14, no. 2

281--295

3,3’-Dinitro-5,5’-diamino-bi-1,2,4-triazole (DABNT) was synthesized by a facile method and its crystalline density was determined as 1.839 g·cm−3 at 293(2) K by X-ray diffraction. Its thermal decomposition kinetics and mechanism were studied by means of differential scanning calorimetry-thermogravimetry (DCS-TG), in situ thermolysis by rapid-scan Fourier transform infrared spectroscopy (RSFTIR) and simultaneous TG-IR technology. The results showed that the apparent activation energies obtained by the Kissinger, Ozawa and Starink methods were 122.9 kJ·mol−1, 123.2 kJ·mol−1 and 123.5 kJ·mol−1, respectively. The thermodynamic parameters of ΔS≠, ΔH≠ and ΔG≠ were −37.5 J·K−1·mol−1, 118.4 kJ·mol−1 and 138.7 kJ·mol−1, respectively. The decomposition reaction process of DABNT starts with the transformation from a primary amine to a secondary amine and then the loss of one nitro-group from the DABNT structure. Gaseous products, such as N2O and H2O, were detected from decomposition in the range of 50-300 °C. Density functional theory (DFT) calculations were further employed to illustrate the decomposition mechanism. The above-mentioned information on the synthesis and thermal behaviour is quite useful for the scale-up and evaluation of the thermal safety of DABNT.