The dehydration of alcohols over alumina: VII. The dependence of reaction direction on the substrate structure

Abstract

The kinetics of the dehydration of n-propanol, benzyl alcohol, isobutanol, and cyclohexanol on γ-Al 2O 3 have been studied and the structures of the adsorption complexes have been investigated by IR spectroscopy. The same rate equation as in the case of the dehydration of methanol and ethanol to ether and of tert-butanol to olefin is found empirically. The selectivity with respect to ether and olefin formation is regarded to be a function of the thermal stability of the respective surface alkoxides. There is IR spectroscopic evidence of such surface alkoxides on the adsorption of alcohols which form ethers, whereas with olefin-forming alcohols no such compounds are detectable.