Unimolecular Decomposition Reactions of Propylamine and Protonated Propylamine.

A detailed computational study of the decomposition reaction mechanisms of -propylamine (-PA), -propylamine (-PA), and the cis-isomer of its protonated form (-HPA) has been carried out. Fourteen major pathways with their kinetic and thermodynamic parameters are reported. All reported reactions have been located with a concerted transition state, leading to significant products that agree with previous theoretical and experimental studies. Among six decomposition pathways of -PA, the formation of propene and NH is the significant one, kinetically and thermodynamically, with an activation energy barrier of 281 kJ mol. The production of two carbenes is found via two different transition states, where the reactions are thermodynamically controlled and reversible. Furthermore, five decomposition pathways of -PA have been considered where the formation of ethene, methylimine, and H is the most plausible one with an activation energy barrier of 334 kJ mol. The results show that the formation of propene and NH from the decomposition of -HPA is the most favorable reaction with an activation barrier of 184 kJ mol, that is, the lowest activation energy calculated for all decomposition pathways.