Theoretical Study on the Gas‐Phase Oxidation Mechanism of Ethylene by Nitrous Oxide

Abstract The application of nitrous oxide (N 2 O) as a candidate oxidant provides a new opportunity for green propellants and propulsion systems. In this study, reaction paths are calculated by the DFT method in the B3LYP/6‐31++G** approximation for direct oxidation of ethylene with nitrous oxide. The results indicate that the reaction between N 2 O and C 2 H 4 proceeds by a chain reaction mechanism. The reaction prefers the mechanism including 1,3‐dipolar cycloaddition of N 2 O to the double bond with the formation of unstable 4,5‐dihydro‐[1,2,3] oxadiazole intermediate via a transition state with an activation energy barrier of 102.54 kJ/mol, which is far below than that of N 2 O or C 2 H 4 decomposition. Subsequently, the next step is the decomposition of these intermediates through hydrogen transfer within the hydrocarbon backbone and the formation of the final products.