A computational study of the kinetics and mechanism of the gas phase pyrolysis of allyl methyl amine

A density functional theory (DFT) study has been carried out at the B3LYP/6-31G(d) level on the gas-phase retro-ene reaction of allyl methyl amine (AMN). The results were compared with single point calculations at a high level of the theory, using the G3MP2 method. Two mechanisms for this kind of reaction are possible, one involves a six-membered cyclic transition state (TS) and the other is a multistep, free radical mechanism. Both DFT and high level calculations show that propene and imine formation are in accordance with a concerted cyclic mechanism. Natural bond orbital analysis (NBO) and atoms-in-molecule (AIM) procedures show that the reaction achieves a synchronicity value of 90%. The calculated kinetic parameters for AMN pyrolysis agree with the available experimental results.