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17477-97-3

tris(Trimethylsilyloxy)silanol synthesis

9synthesis methods
-

Yield:3555-47-3 94.5%

Reaction Conditions:

Stage #1: Hexamethyldisiloxanewith methanol;sulfuric acid at 5 - 10; for 1 h;
Stage #2: tetramethylorthosilicate at 5 - 10; for 1.5 h;
Stage #3: with sulfuric acid;watermore than 3 stages;

Steps:

11

Example 11 A 2000-ml four necked glass flask equipped with a reflux condenser, thermometer and stirrer was purged with nitrogen. The flask was charged with 757.7 g (4.05 mol) of hexamethyldisiloxane and 96.0 g (3.0 mol) of methanol, and cooled in an ice water bath to an internal temperature below 10°C. To the flask kept at an internal temperature of 5-10°C, 14.7 g (0.15 mol) of conc. sulfuric acid was added dropwise over 30 minutes, and stirring was continued at the temperature for 30 minutes. Subsequently, to the flask kept at an internal temperature of 5-10°C, 228.3 g (1.5 mol) of tetramethoxysilane was added dropwise over 30 minutes, and stirring was continued at the temperature for one hour. At an internal temperature of 5-25°C, 108.0 g (6.0 mol) of water was added dropwise over one hour. After the completion of dropwise addition, stirring was continued at 15-25°C for 6 hours. The organic layer of the reaction solution was analyzed by GC, finding that the area percent ratio of the main product to monomethoxy and monohydroxy compounds, Si(OSiMe3)4/[Si(OMe) (OSiMe3)3 + Si(OH) (OSiMe3)3] was 17.2. The total content of monomethoxy and monohydroxy compounds was 0.057 mol, as determined from the area percents by GC. While the organic layer was kept at a temperature of 20-25°C, 34.3 g (0.35 mol) of conc. sulfuric acid was added dropwise over 15 minutes, and stirring was continued at the temperature for 45 minutes. The organic layer after reaction with sulfuric acid was analyzed by GC, finding that the area percent ratio of the main product to monomethoxy and monohydroxy compounds, Si(OSiMe3)4/ [Si(OMe) (OSiMe3)3 + Si(OH)(OSiMe3)3] was 2787.4. The sulfuric acid layer was removed from the reaction solution, after which the organic layer was washed with water, neutralized with aqueous sodium bicarbonate, and washed with water again. On distillation of the resulting organic layer, 545.7 g (1.42 mol) of tetrakis(trimethylsiloxy)silane with a purity of 99.6% was collected as a fraction having a boiling point of 109.0-110.0°C/2.7 kPa. The yield was 94.5%.

References:

EP1510520,2005,A1 Location in patent:Page/Page column 13-14

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