Transient behavior of the system ethanol-diethyl ether-water-alumina
1984; Elsevier BV; Volume: 87; Issue: 2 Linguagem: Inglês
10.1016/0021-9517(84)90205-7
ISSN1090-2694
Autores Tópico(s)Catalysis and Hydrodesulfurization Studies
ResumoThe reactions of ethanol and diethyl ether on alumina have been studied by stopped-feed, started-feed, and pulse-flow techniques at 250 °C. In pulse-flow experiments, the reactants were introduced both on a fresh alumina surface and on a surface covered by reaction components during steady-state operation. The results indicate that surface ethoxide is the reaction intermediate in all transformations. From the alcohol, it is formed by the substitution of the surface hydroxyl groups under liberation of water and then decomposes relatively slowly into ethylene; also 2-butanol and 2-methyl-2-propanol behaved in this way. A general scheme for reversible surface reactions of alcohols, ethers, and water with surface hydroxyl and alkoxide groups is proposed. The possibility of the participation of alkoxides in the steady-state dehydration of alcohols is discussed. The distinction between fresh and working surfaces of alumina is stressed.
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