Kinetic Modeling of Overlapping Thermal Decomposition of 2,6-Diamino-3,5-dinitropyrazine-1-oxide: Two Consecutive Autocatalytic Reactions and the Thermal Safety Assessment

Abstract

The practical application of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) highly requires the understanding of its thermal decomposition kinetics and thermal hazard prediction. In this study, by combining nonisothermal analysis and the advanced kinetic-based approach, a kinetic model comprised of two consecutive autocatalytic reactions was successfully identified to describe the complex overlapping thermal decomposition behavior of LLM-105, and the contribution of each step to the overall reaction was revealed. The established kinetic model enables the thermal safety evaluation of LLM-105 under different conditions, and the simulated results indicate that the adiabatic time to maximum rate after 24 h (TD24) and 8 h (TD8) of LLM-105 are 257.47 and 268.14 °C, respectively. In addition, the thermal hazard simulations of LLM-105 under mass storage further demonstrate that the self-accelerating decomposition temperature strongly depends on the storage quality, packaging material, and stacking forms of the explosives.

Effects of N‐oxide on the thermal stability of energetic materials: A case study of 2,6‐Diamino‐3,5‐dinitropyrazine‐1‐oxide

“…The difference in TMR iso values between the two explosives was mainly attributed to the reaction kinetics. According to the kinetic model of ANPZO, the first step of its thermal decomposition is a typical autocatalytic reaction [27, 28]. As can be seen from Figure 3, the thermal decomposition of ANPZO experienced a long induction period before the onset of exotherm was detected.…”