Theoretical study on nitrogen migration mechanism during the pyrolysis of 2-pyrrolidone

•Possible pathways of 2-pyrrolidone pyrolysis to form NOx precursors are investigated using the DFT method.•The formation of HCN is more advantageous than NH3 during 2-pyrrolidone pyrolysis.•HNCO is inclined to decompose to generate HCN rather than NH3.•The decrease of HNCO release curve with the increase of temperature observed in the experiment is theoretically illustrated.