[CH2:1]([SiH:5]([CH2:10][CH2:11][CH2:12][CH3:13])[CH2:6][CH2:7][CH2:8][CH3:9])[CH2:2][CH2:3][CH3:4].Cl[SiH](Cl)Cl.C([Mg]Cl)CCC.[H][H].[CH3:26][OH:27]>[Pd].O>[CH2:10]([Si:5]([CH2:1][CH2:2][CH2:3][CH3:4])([CH2:6][CH2:7][CH2:8][CH3:9])[O:27][CH3:26])[CH2:11][CH2:12][CH3:13]In a 500 ml four-neck flask provided with reflux condenser, precision glass stirrer and thermometer, 1.2 g of 5% palladium on activated carbon, water-free (commercially available from Sigma-Aldrich Corp., USA) were suspended in 23.7 g of methanol. 124 g of tri-n-butylsilane (prepared from trichlorosilane and n-butylmagnesium chloride by a method customary in organic chemistry) were subsequently introduced at room temperature over a period of one hour while stirring. After addition of the first drops of the SiH-functional siloxane, spontaneous hydrogen evolution commenced. The temperature of the reaction mixture rose to a maximum of 35° C. After the addition was complete, the mixture was allowed to react further until gas evolution could no longer be observed at the attached bubble counter, the black precipitate was filtered on a pressure filter and the colorless clear filtrate was distilled via a 20 cm Vigreux column. After the first fraction, which according to gas-chromatographic analysis consisted mainly of methanol, 134 g of tributylmethoxysilane having a GC purity of 99.5% by area distilled over at a boiling temperature of 112° C. at 10 hPa.
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