Infra-red studies of reactions on oxide surfaces. Part 3.—HCN and C2N2 on silica

Abstract

Infra-red spectroscopy has been used to investigate the nature of the chemisorbed species which form on the surface of silica after high temperature reaction with gaseous HCN or C₂N₂. Three distinct surface species are formed with either reactant and force constant calculations combined with experimental isotopic shift data have indicated that these are a silyl isocyanate, a silyl cyanide and a silyl isocyanide. A fourth species is unique to the C₂N₂ reaction when very high temperatures are employed and its identity is unknown. The surface SiCN and SiNC species are converted to SiNCO after heating in oxygen. Acetonitrile behaves like HCN in its reaction with silica and gaseous methane is a reaction product.