OH Radical‐Initiated Oxidation of 1‐Dimethylamino‐2‐Nitroethylene: A Theoretical Study

Abstract 1‐Dimethylamino‐2‐nitroethylene (DMANE) is a nitroenamine, a building block of commonly used pesticides. In the present work, the OH‐initiated oxidation reaction of DMANE is investigated by performing electronic structure calculations using M06‐2X and ɷB97X‐D level of theories with 6‐311+G(d,p) basis set, and the single‐point energy calculations at the CCSD(T)/aug‐cc‐pVDZ level of theory. The initial OH‐radical addition and H‐atom abstraction reactions of DMANE are studied. The results obtained from initial reactions show that the OH‐addition reaction is more favorable than the H‐abstraction reaction. The rate constant for the formation of DMANE‐OH‐adduct intermediates, I1 and I2, is 1.58 × 10 −10 and 2.54 × 10 −09 cm 3 molecule −1 s −1 , which are about seven orders of magnitude higher than the rate of ozonolysis of nitroalkenes and other nitroenamines, showing the significance of OH‐initiated reactions of nitroenamines. The secondary reactions from the initially formed radicals are studied in detail to identify the products of the reaction and assess their toxicity. The toxicity assessment results show that DMANE is not harmful to aquatic organisms. The absorption spectra calculated for DMANE and favorable products show that the degradation of these compounds through photolysis is unlikely. The calculated photochemical ozone creation potential shows the significant role of these compounds in the formation of ozone in the atmosphere.