Theoreticalinsight intothe mechanisms of the gas-phase decomposition of azidoacetone

Highlights: • Curtius rearrangement plays a central role in the decomposition reaction. • A new and more favored path for the formation of CH₂CO + CH₂ = NH has been proposed. • New reaction pathways leading to CO + CH₃N = CH₂ and CH₃CHO + HCN have been explored. A theoretical study of the mechanisms for the gas-phase decomposition of azidoacetone was performed using ab initio molecular orbital theory based on the QCISD(T)/aug-cc-pVTZ//MP2(full)/6–311++G(d,p) + 0.95 × ZPE method. The calculated results clearly show that the imine CH₃C(O)N = CH₂ formed through Curtius rearrangement route in conjunction with the cyclic amine and the imine CH₃(CO)CH = NH play a crucial role in the gas-phase decomposition of azidoacetone. The fragmentation and/or isomerization these three intermediates giving rise to CH₂CO, CH₂ = NH, CO, CH₃N = CH₂, CH₃CHO and HCN becomes the key reaction pathways. Our calculated results are in excellent consistent with the experimental findings.