CHEMISORPTION AND CLEAVAGE OF ALKYL BENZOATES ON ALUMINA SURFACE STUDIED BY INELASTIC ELECTRON-TUNNELING SPECTROSCOPY

The technique of inelastic electron tunneling spectra (IETS) has been used to study the surface reaction of ethyl, isobutyl, and tert-butyl benzoates on alumina. The ethyl and isobutyl benzoates decompose to th e corresponding alcohols where the net reaction accounts for the hydro lysis of the benzoate, and the ultimate products of chemisorption on a lumina surface are detected to be the corresponding alkoxide anions. I n the case of tert-butyl benzoate, the chemisorbed species on the alum ina surface is benzoic acid rather than tert-butyl alcohol. In both ca ses, the surface reactions are identified as the dissociative chemisor ption of the hydrolysis products of the original benzoate molecule. Th ese phenomena are explained by the cleavage of the acyl-oxygen bond an d of the alkyl-oxygen bond, respectively, both proceeding via acid-cat alyzed hydrolysis.