Abstract
The initial channels of thermal decomposition mechanism of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) molecule were investigated. The results of quantum chemical calculations revealed four candidates involved in the reaction pathway, including the C–NO2 bond homolysis, nitro–nitrite rearrangement followed by NO elimination, and H transfer from amino to acyl O and to nitro O with the subsequent OH or HONO elimination, respectively. In view of the further kinetic analysis and ab initio molecular dynamics simulations, the C–NO2 bond homolysis was suggested to be the dominant step that triggered the decomposition of LLM-105 at temperatures above 580 K. Below this temperature, two types of H transfer were considered as the primary reactions, which have advantages including lower barrier and high rate compared to the C–NO2 bond dissociation. It could be affirmed that these two types of H transfer are reversible processes, which could buffer against external thermal stimulation. Therefore, the excellent thermal stability of LLM-105, that is nearly identical to that of 1,3,5-triamino-2,4,6-trinitrobenzene, can be attributed to the reversibility of H transfers at relatively low temperatures. However, subsequent OH or HONO elimination reactions occur with difficulty because of their slow rates and extra energy barriers. Although nitro–nitrite rearrangement is theoretically feasible, its rate constant is too small to be observed. This study facilitates the understanding of the essence of thermal stability and detailed decomposition mechanism of LLM-105.
Highlights
Thermal decomposition mechanisms for energetic materials, and their corresponding series of intermediates and products, are extremely important because they guide systematic predictions about unknown explosives, influence feasibility of large-scale synthesis, predict long-term stability for purposes of storage, and predict sensitivity to various stimuli, such as heat and mechanical impact [1].The safety and performances of explosives are intimately associated with the thermal decomposition processes; knowledge of mechanistic pathways can assist researchers to understand the behaviors of explosives rather than by empirical ways.Molecules 2019, 24, 125; doi:10.3390/molecules24010125 www.mdpi.com/journal/molecules2,6-Diamino-3,5-dinitropyrazine-1-oxide first synthesized synthesizedby byP.F
There are four reaction channels as candidates the initial pathways in2 the gashomolysis; phase decomposition of LLM-105 according to our calculated for results
The results of quantum chemical calculations revealed four steps involved in the reaction pathway, including the C–NO2 bond homolysis, nitro–nitrite rearrangement followed by NO elimination, and H transfer from amino to acyl
Summary
Thermal decomposition mechanisms for energetic materials, and their corresponding series of intermediates and products, are extremely important because they guide systematic predictions about unknown explosives, influence feasibility of large-scale synthesis, predict long-term stability for purposes of storage, and predict sensitivity to various stimuli, such as heat and mechanical impact [1].The safety and performances of explosives are intimately associated with the thermal decomposition processes; knowledge of mechanistic pathways can assist researchers to understand the behaviors of explosives rather than by empirical ways.Molecules 2019, 24, 125; doi:10.3390/molecules24010125 www.mdpi.com/journal/molecules2,6-Diamino-3,5-dinitropyrazine-1-oxide first synthesized synthesizedby byP.F. Thermal decomposition mechanisms for energetic materials, and their corresponding series of intermediates and products, are extremely important because they guide systematic predictions about unknown explosives, influence feasibility of large-scale synthesis, predict long-term stability for purposes of storage, and predict sensitivity to various stimuli, such as heat and mechanical impact [1]. The safety and performances of explosives are intimately associated with the thermal decomposition processes; knowledge of mechanistic pathways can assist researchers to understand the behaviors of explosives rather than by empirical ways. (code: LLM-105), LLM-105), which which was was first Pagoria [2] in. 1995, is an explosive material with good performance. It was found to be a stable species
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
