Unimolecular Decomposition Reactions of Picric Acid and its Methylated Derivatives — A DFT Study

Author
Wiik, Kristine
Høyvik, Ida-Marie
Unneberg, Erik
Jensen, Tomas Lunde
Swang, Ole
Date Issued
2022-04-26
Keywords
Pikrinsyre
Energetiske materialer
Dekomponering
Tetthetsfunksjonalteori
Aktiveringsenergi
Beregningskjemi
Permalink
http://hdl.handle.net/20.500.12242/3032
DOI
10.1021/acs.jpca.1c10770
Collection
Articles
Description
Journal of Physical Chemistry A 2022 ;Volum 126. s. 2645-2657
2016810.pdf
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Abstract
To handle energetic materials safely, it is important to have knowledge about their sensitivity. Density functional theory (DFT) has proven a valuable tool in the study of energetic materials, and in the current work, DFT is employed study the thermal unimolecular decomposition of 2,4,6-trinitrophenol (picric acid, PA), 3-methyl-2,4,6-trinitrophenol (methyl picric acid, mPA), and 3,5-dimethyl-2,4,6-trinitrophenol (dimethyl picric acid, dmPA). These compounds have similar molecular structures, but according to the literature, mPA is far less sensitive to impact than the other two compounds. Three pathways believed important for the initiation reactions are investigated at 0 K and 298.15 K. We compare the computed energetics of the reaction pathways with the objective of rationalizing the unexpected sensitivity behavior. Our results reveal few if any significant differences in the energetics of the three molecules, and thus do not reflect the sensitivity deviations observed in experiments. These findings point towards the potential importance of crystal structure, crystal morphology, bimolecular reactions, or combinations thereof on the impact sensitivity of nitroaromatics.
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