Chemistry and thermal decomposition of trinitropyrazoles

Abstract

New energetic compounds-3,4,5-1H-trinitropyrazole (TNP), 1-methyl-3,4,5-1H-trinitropyrazole (MTNP) and ammonium 3,4,5-1H-TNP have been synthesized and characterized by thermal analysis. These new compounds can be considered as promising since the high heat of formation for them. To estimate the process of their thermal decomposition, the original technique for computer simulation was used. We generated the models for the mechanisms of thermal decay of synthesized compounds which allowed obtaining comprehensive spectrum of transformations of intermediates on the way to the final products of thermolysis. The preferred pathways were determined based on the results of activation energy (Ea) calculations (DFT 6-311++G** method) of thermal decay reactions for each generated pathways. The thermal decomposition has been studied also experimentally by thermogravimetry (TG) and differential scanning calorimetry. Kinetic parameters of thermolysis were evaluated by model-free and -fitting methods using TG data. Model-free method has given not reliable data for TNP and MTNP compounds, whereas model-fitting yields kinetic equations with the good correlation with experimental TG data.