Alcoholysis Equilibria of Dialkoxydimethylsilanes Catalyzed by Iodine or Iodine Monobromide

Article abstract of DOI:10.1246/bcsj.56.295

Iodine or iodine monobromide was found to be an especially favorable catalyst for the study of the alcoholysis equilibria of dialkoxydimethylsilanes by gas chromatography.Iodine monobromide was employed to promote the reactions associated with tertiary alcohols, and iodine was used for the other reactions.Eight alcohols were allowed to react with diethoxydimethylsilane, and successive equilibrium constants, K₁ and K₂, were determined at 20 deg C.K₁=2.36-2.75 and K₂=0.66-0.69 (by the use of primary alcohols), K₁=1.34-1.38 and K₂=0.28-0.30 (secondary alcohols), and K₁=0.15-0.16 (tertiary alcohols) were observed.These values express precisely the difference of reactivities of the three groups of alcohols with diethoxydimethylsilane.Out of the dialkoxydimethylsilanes used in this study, eight unreported compounds were isolated and characterized.