Transient isotopic studies in the Temporal Analysis of Products (TAP) reactor evidenced a clear mechanistic regularity between methane and propane for N₂O reduction over Fe-silicalite in the temperature range of 623-773 K. The lifetime of the oxygen species generated by N₂O decomposition on extraframework iron sites was found to be crucial for alkane oxidation. When N₂O and CH₄ or C₃H₈ were pulsed together over Fe-silicalite, oxygen species deposited on iron sites effectively activated the hydrocarbon. However, these oxygen species become inactive for alkane oxidation if the pulses of N₂O and the alkane were separated by more than 0.1 s. Transient studies have indicated that C₃H₈ is more efficient for N₂O reduction than CH₄, as expected from the facilitated activation of the CH bond upon increasing the carbon number in alkanes. The performance derived from the TAP reactor agrees well with experiments under flow conditions at ambient pressure.