Experimental fluctuations are excellent tools for elucidation of reaction mechanisms.
Microkinetic analysis was performed for the ethanol to 1,3-butadiene reaction.
The rate-limiting step changed as a function of reaction temperature.
From 300 to 400 °C, acetaldehyde condensation controls the reaction system.
From 400 to 450 °C, ethanol dehydrogenation becomes the slowest reaction rate.