Decomposition mechanisms of dinitrotoluene

To develop a viable detection system for 2,4‐dinitrotoluene (DNT), its unimolecular decomposition mechanisms were studied by using the density functional theory. Three decomposition mechanisms were investigated: (1) homolytic cleavage; (2) migration of one of the O atoms in the NO 2 groups to its neighboring C atoms; (3) migration of one of the H atoms in the methyl group to a neighboring O atom in the NO 2 group. Only homolytic cleavage of the CN bond yields NO 2 radicals with a total energy of 61 kcal/mol or more. Initial migration of the O atom to its second‐nearest‐neighbor C atom requires about 56 kcal/mol, but subsequent homolysis produces NO fragments with less energy ∼15 kcal/mol. NO formation from both NO 2 groups in 2,4‐DNT is possible with a total energy of ∼63 kcal/mol. The H‐migration has the lowest energy barrier of 39 kcal/mol among the three initial decomposition mechanisms. Removing O directly from 2,4‐DNT requires ∼90 kcal/mol, while NO 2 radical decomposes to NO and O with ∼73 kcal/mol. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008