Using trichlorosilane as a probe to investigate the role of the preadsorbed amine in a two-step amine-promoted reaction of chlorosilanes on silica

Low frequency infrared data is critical for identifying the chemisorbed species that are formed when HSiCl3 reacts with the surface of silica, That information is now used to probe an important aspect of the two-step amine-promoted room temperature reaction of chlorosilanes on silica. In the reaction of HSiCl3 with a silica whose surface contains preadsorbed NH3, it is shown that the ammonia that is liberated from the surface is consumed exclusively by the HCl that is generated as a byproduct of the surface reaction, The ammonia liberated from the surface is not ''free'' to react with the adsorbed HSiCl3 species, This has implications in using preadsorbed amines to control the amount and spatial distribution of a chlorosilane on the surface.