Density functional theory study on the gas-phase pyrolysis mechanisms of N'-benzylidene-benzohydrazide

The gas-phase pyrolytic decomposition mechanisms of N'-benzylidene-benzohydrazide with the production of benzene nitrile and benzamide were studied by density functional theory. The geometries of the reactant, transition states, intermediates and products were optimized at the B3LYP/6-31G (d, p) level. Vibration analysis was carried out to confirm the transition state structure, and the intrinsic reaction coordinate (IRC) method was performed to search the minimum energy path. Three possible reaction channels are shown, including one concerted reaction of direct pyrolytic decomposition and two indirect channels in which the reactant first becomes a ring-like intermediate, followed by concerted pyrolytic decomposition. The concerted reaction of direct pyrolytic decomposition has the lowest activation barrier among all the three channels and therefore it occurs more often than the others.