Orthosilicic acid → Tetrakis(N,N,N-trimethylmethanaminium) orthosilicate

Participants

Reaction Conditions

Reaction Steps

About 1250 ml of 10% aqueous tetramethylammonium hydroxide solution are added to 82.2 g of precipitated silicic acid. After the mixture has been stirred at 25° C. for 16 hours and at 50° C. for 8 hours, a clear solution is obtained. The solution is concentrated to two thirds of its starting volume and the resulting tetramethylammonium silicate is crystallized at 4° C. About 359.5 g of tetramethylammonium silicate which still contains water are obtained. About 160 g of tetramethylammonium silicate are added in portions to a well-stirred mixture containing 400 ml of water, 1000 ml of isopropanol, 1500 ml (1136 g) of 1,1,3,3-tetramethyldisiloxane (obtained under the name "HSi2" from Wacker-Chemie GmbH, D-8000 Munich) and 200 ml of 10% hydrochloric acid and the reaction mixture is then stirred at room temperature for 4 hours. The phases are then separated and the organic phase is washed with water until neutral, dried over sodium sulfate and evaporated completely. The residue is recrystallized from acetone. About 52.0 g of octa(hydrogendimethylsiloxy)octasilsesquioxane are obtained.

Provenance & Evidence