Rates of reaction in a recycling system—dehydration of ethanol and diethyl ether over alumina

A new method for measuring isothermal rates of heterogeneously catalyzed gas reactions is described. The method involves a differential reactor incorporated in a recycling system and affords ease of control, accuracy, and many rate measurements in one run. The results for the reaction system investigated show that four reactions are important: the dehydration of ethanol to ethylene, the reaction of ethanol to form diethyl ether, the dehydration of diethyl ether to ethylene, and the reaction of diethyl ether to form ethanol. It is also shown that the rate controlling steps are the monomolecular surface reactions for the two dehydrations and for the formation of ethanol from diethyl ether, and the bimolecular surface reaction for the formation of diethyl ether from ethanol. The values and the temperature dependence of all pertinent rate and adsorption constants are determined and reported, and they are shown to correlate very well the data up to 80% conversion.