Alcoholysis Equilibria of Triethylalkoxysilanes Catalyzed by Iodine or Iodine Monobromide

Article abstract of DOI:10.1246/bcsj.55.2973

The equilibrium constants K of alcoholysis of triethylalkoxysilanes were determined at 20 degC and 40 degC.Iodine monobromide was used to promote the reactions associated with the tertiary alkoxyl groups, while the other reactions proceeded in the presence of iodine.The K values of the reaction systems with ethoxyl or propoxyl-primary, secondary, and tertiary alkoxyl pairs were 1 or above, about 0.5, and about 0.05, respectively.These values reflect the extent of the binding abilities of the alkoxyl groups to silicon, which is in the expected order of primary>secondary>tertiary alkoxyl groups.A mechanism is postulated for the reaction which involves participation by the iodine or iodine monobromide.