High-resolution NMR studies of methyl acrylate adsorbed on silica and TiCl4-modified silica

Abstract

High-resolution ¹³ C and ¹ H NMR measurements on methyl acrylate adsorbed on silica and TiCl ₄ -modified silica are reported. In both cases, samples with methyl acrylate adsorbed at equilibrium pressures of 38 or 2 Torr, then desorbed under vacuum have been studied. NMR spectra of both nuclei show clearly the adsorption of the methyl acrylate on unmodified silica and on the TiCl ₄ -modified silica. Our results indicate the existence of two adsorbed species which demonstrates the existence of two types of acid sites on the TiCl ₄ -modified silica. We also characterized the effect of adsorption on the methyl acrylate molecules.