Carbon-13 and nitrogen-15 nuclear magnetic resonance and infrared spectroscopic investigations of pyridine adsorbed on silica-gel surfaces

Abstract

Carbon-13 and nitrogen-15 high-resolution n.m.r. measurements have been combined with i.r. spectroscopic investigations to study the interaction of pyridine molecules with OH groups on a partially dehydroxylated and phosphorus-modified silica-gel surface. On partially dehydroxylated silica gel strong hydrogen bonds are formed between the nitrogen atoms and the protons of the hydroxyl groups. The number of active sites is ca. 1.2 nm^–2. The formation of pyridinium ions was observed in the case of adsorption on phosphorus-modified silica gel. The number of ions was estimated to be 0.05 nm^–2.