Radical decomposition of 2,4-dinitrotoluene (DNT) at conditions of advanced oxidation. Computational study

At the present time one of the main remediation technologies for such environmental pollutant as 2,4-dinitrotoluene (DNT) is advanced oxidation processes (AOPs). Since hydroxyl radical is the most common active species for AOPs, in particular for Fenton oxidation, the study modeled mechanism of interaction between DNT and hydroxyl radical at SMD(Pauling)/M06-2X/6-31+G(d,p) level. Computed results allow to suggest the most energetically favourable pathway for the process. DNT decomposition consists of sequential hydrogen abstractions and hydroxyl attachments passing through 2,4-dinitrobenzyl alcohol, 2,4-dinitrobenzaldehyde, and 2,4-dinitrobenzoic acid. Further replacement of nitro- and carboxyl groups by hydroxyl leads to 2,4-dihydroxybenzoic acid and 2,4-dinitrophenol, respectively. Reaction intermediates and products are experimentally confirmed. Mostly of reaction steps have low energy barriers, some steps are diffusion controlled. The whole process is highly exothermic.