A new route to silicon alkoxides from silica

A novel route to tetraethoxysilane and other silicon alkoxides is described, from amorphous silica (SiO2. nH(2)O) as the raw material. The reaction of amorphous silica with triethanolamine is enhanced by using an alkali metal hydroxide catalyst, to form a range of triethanolamine-substituted silatrane species. These can undergo alkoxide exchange in acidic alcohols to form alkoxysilatranes, tetraalkoxysilanes, hexaalkoxydisiloxanes and higher siloxanes. Reaction of triethanolamine-substituted silatranes with acetic anhydride produces acetoxysilatrane. Products were identified by multinuclear (H-1, C-13 and Si-29) magnetic resonance spectroscopy, electrospray mass spectrometry or high-resolution gas chromatography electron impact mass spectrometry.