Infrared Study of the Adsorption of Ethyl Cyanoacetate on Silica Immersed in Carbon Tetrachloride

Abstract

Infrared spectra are reported of silica immersed in solutions of ethyl cyanoacetate in carbon tetrachloride. The surface–adsorbate interaction for silica which had been preheated at 1073 K involved the formation of hydrogen bonds between pairs of isolated surface silanol groups and both the cyano and carbonyl groups in each adsorbed ethyl cyanoacetate molecule. For silica which had been evacuated at 298 K adjacent interacting surface silanol groups also provided sites for the adsorption of ethyl cyanoacetate. The adsorbed molecules were again bonded to the surface via both their cyano and carbonyl groups. Each carbonyl group was involved in a hydrogen bonding interaction with a single surface silanol group. This contrasts with the observation that pairs of adjacent interacting silanol groups each formed two hydrogen bonds with the carbonyl oxygen atom of a single ethyl acetate molecule adsorbed on silica immersed in carbon tetrachloride.