DFT M06-2X investigation of alkaline hydrolysis of nitroaromatic compounds

[Display omitted] ► TNT hydrolysis reaction was modeled along with simulation of UV–VIS and NMR spectra. ► The most plausible initial intermediates are TNT anion and Meisenheimer complexes. ► Reaction proceeds toward polynegative complexes and Janovsky complexes. ► Polymeric compounds and cycle cleavage species are products of later stages. ► Alkaline hydrolysis of DNT and DNAN are energetically less favorable than the corresponding TNT reaction. The nitroaromatic compounds 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (DNT) and 2,4-dinitroanisole (DNAN) are potential environmental contaminants and their transformations under a variety of environmental conditions are consequently of great interest. One possible method to safely degrade these nitrocompounds is alkaline hydrolysis. A mechanism of the initial stages of this reaction was investigated computationally. Simulations of UV–VIS and NMR spectra for this mechanism were also produced. The results obtained were compared to available experimental data on the alkaline hydrolysis of TNT and suggest that the formation of Meisenheimer complexes and an anion of TNT are potential first-step intermediates in the reaction path. As the reaction proceeds, computational results indicate that polynegative complexes dominate the degradation pathway, followed by cycles of carbon chain opening and breaking. A second possible pathway was identified that leads to polymeric products through Janovsky complex formation. Results from this study indicate that the order of increasing resistance to alkaline hydrolysis is TNT, DNT and DNAN.