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Theoretical Calculation and Molecular Design for High Explosives: Theoretical Study on Polynitropyrazines and Their N ‐oxides
Author(s) -
Li Jinshan,
Huang Yigang,
Dong Haishan
Publication year - 2004
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.200400052
Subject(s) - isodesmic reaction , detonation , explosive material , standard enthalpy of formation , oxide , detonation velocity , density functional theory , chemistry , basis set , standard enthalpy change of formation , pyrazine , sensitivity (control systems) , computational chemistry , materials science , thermodynamics , stereochemistry , organic chemistry , physics , electronic engineering , engineering
The geometries of polynitropyrazines and their N ‐oxides have been fully optimized employing the density functional B3LYP method and the 6‐31++G** basis set. For polynitropyrazines and their N ‐oxides we have obtained the enthalpies of formation (at p =1.013×10 5 Pa and T =298.15 K) by designing isodesmic reactions and the detonation velocities by using the Stine method. Calculated results show that the aromaticity of the pyrazine ring of polynitropyrazine is lower than that of its N ‐oxide. From the acquired relationship between the experimental impact sensitivity H 50 (12B type) and the least CNO 2 bond order the predicted H 50 values for compounds 2,5‐diamino‐3,6‐dinitropyrazine and 2,5‐diamino‐3,6‐dinitropyrazine‐1‐oxide are 83 cm and 59 cm, respectively, implying that they are low sensitive explosives. The enthalpy of formation of polynitropyrazine is much less than that of its N ‐oxide. The calculated density (1.90 g/cm 3 ) for 2,6‐diamino‐3,5‐dinitropyrazine‐1‐oxide (LLM‐105) is close to the experimental value (1.918 g/cm 3 ), and from both sensitivity and detonation velocity it has been deduced that LLM‐105 is superior to other diaminodinitropyrazines and their N ‐oxides. The largest density and detonation velocity obtained in this work are 2.02 g/cm 3 (2‐amino‐3,5,6‐trinitropyrazine) and 9.34 km/s (2,3,5,6‐tetranitropyrazine), respectively.