Thermal decomposition mechanism study of 1-acetyl-3,5-dinitro-1,3,5-triazacyclohexane (TAX)

1-Acetyl-3,5-dinitro-1,3,5-triazacyclohexane, codenamed TAX, is a by-product of the RDX/HMX production process. The thermal decomposition process of TAX has not been studied at present. Understanding the decomposition mechanism of TAX can improve the understanding of its performance, which is helpful for the treatment of RDX/HMX production wastewater. The thermal decomposition process of 1-acetyl-3,5-dinitro-1,3,5-triazacyclohexane (TAX) was studied by TG-DSC and ReaxFF molecular dynamics (ReaxFF MD) simulation. The results showed that the activation energy of TAX calculated by the Kissinger and Flynn-Wall-Ozawa methods is 140 kJ center dot mol-1, and the activation energy obtained by the Friedman method is 154 kJ center dot mol-1; The thermal decomposition of TAX may generate the main intermediate products C5H9N4O3, C5H9N3O, C3H5NO, C2H3O, HNO2, N2O2 and NO, etc. and the intermediate products continued to decompose to generate the final products CH2O, CO2, CO, H2O and N2; The reaction rate constants of each stage of TAX were calculated, and the possible thermal decomposition pathways of TAX were obtained: TAX -> C5H9N4O3 + NO2 -> C5H9N3O + C3H5NO + C2H4N3O2 + NO2 -> C2H3O + CH2N + HNO2 + N2O2 + NO2 + NO + H + OH + horizontal ellipsis -> CH2O + CO2 + CO + H2O + N2 + horizontal ellipsis This study contributes to a deeper understanding of the decomposition process of TAX after heating and has specific significance for reducing the thermal hazard of the TAX pyrolysis process.