Thermal characterization of the promising energetic material TKX-50

Abstract

The thermal behavior of dihydroxylammonium 5,5 0 -bistetrazole-1,1 0 -diolate (TKX-50) was measured by differential scanning calorimetry (DSC), thermal gravimetric analysis-Fourier transform infrared spectroscopy (TG-FTIR) and thermal gravimetric analysisdifferential scanning calorimetry-mass spectrometry (TG-DSC-MS). The critical temperature of thermal explosion (T b ) and the initial decomposition temperature (T p0 ) were determined to be 523.39 and 513.80 K, respectively. The apparent activation energy (E) and preexponential factor (A) of the exothermic decomposition reaction, and activation entropy (DS = ), activation enthalpy (DH = ), activation Gibbs free energy (DG = ) at T P0 of the reaction and the critical temperature of thermal explosion (T b ) were calculated: E K = 237.59 kJ mol -1 , E O = 234.11 kJ mol -1 , DS = = 209.83 J K -1 mol -1 , DH = = 233.32 kJ mol -1 , DG = = 126.53 kJ mol -1 . TG-DSC-FTIR/MS analysis of thermal decomposition products of TKX-50 reveals that the main decomposition products are N 2 , H 2 O, NH 3 , NH 2 , N 2 O and NO.

DFT Study of the Decomposition Pathways of 5,5'-bitetrazole-1,1'-diide as a Parent Anion in the Family of Highly Energetic Green Explosives

“…For this purpose we have replaced the 5,5'-bistetrazole-1,10-diolate moiety by a more symmetric 5,5'-bitetrazole-1,1'-diide ion (BTEZ) and obtained relaxed scans of all possible routs of the bond breaking followed by the transition state search. As a result, we have obtained the activation energy equal 229.1 kJ mol -1 , which is rather close to the Yang's value [9]. The formation of an azide anion was found to be the most exothermic path of the BTEZ decomposition.…”

“…To date, a two-step process initiated by a proton transfer from hydroxylammonium cations to 5,5'-bistetrazole-1,10-diolate is generally accepted [8][9][10][11][12][13][14][15]. Early molecular dynamics studies of thermal decomposition of TKX-50 revealed that the latter decays with release of molecular nitrogen or N2O with the activation energies of 188.7 and 302.1 kJ mol -1 , respectively [8].…”

“…Early molecular dynamics studies of thermal decomposition of TKX-50 revealed that the latter decays with release of molecular nitrogen or N2O with the activation energies of 188.7 and 302.1 kJ mol -1 , respectively [8]. More recent experimental studies, however, give the activation energy value obtained by the Kissinger's method been equal to 237.6 kJ mol -1 [9]. The latter is strongly dependent on the experimental conditions (heating rate) and can be decreased even to 112 kJ mol -1 [10].…”

Crystal structure transformation and step-by-step thermal decomposition behavior of dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate

“…The calculated mainly using Kissinger and Ozawa's method and the results were in different ranges depending on the test condition. [21][22][23]29 The structural stability and chemical stability of TKX-50 under high pressure and high temperature were discussed based on Raman spectroscopy results and the intermediates at high pressure were attributed to a suppression of H-transfer. 24 The structural response of TKX-50 under high pressure was studied and the experimental results showed that TKX-50 exhibits a highly anisotropic compression, with an anomalous compression of the a-axis, which was explained by the hydrogen bonds.…”

Thermolysis, nonisothermal decomposition kinetics, calculated detonation velocity and safety assessment of dihydroxylammonium 5, 5′-bistetrazole-1, 1′-diolate

“…However, the thermal stability and safety of energetic material itself play crucial roles in application. Up till now, although many properties have been studied [5][6][7], the thermal decomposition, nonisothermal kinetic and safety assessment of TKX-50 have been rarely reported. Hence, in order to understand the stability and safety of TKX-50 for its application, it is extremely important to know the thermal decomposition, kinetic and safety parameters.…”