Methyltrimethoxysilane → methyltri-methoxysilane 3,3,3-trifluoropropyltrimethoxysilane KOH

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A 500 ml 5-neck round-bottom flask, rendered inert with nitrogen and equipped with paddle stirrer, dropping funnel, thermometer, and water separator with reflux condenser, is charged with 50 g (0.36 mol) of methyl-trimethoxysilane (available commercially from Wacker Chemie AG), 8.8 g (0.04 mol) of 3,3,3-trifluoro-propyltrimethoxysilane (available commercially from Fluka), and 39.7 g of Isopar E (isoparaffinic hydro-carbon mixture having a boiling range of 113-143° C., available commercially from ExxonMobil). The water separator is filled to the brim with Isopar E. Accompanied by stirring at 350 rpm, a solution of 17.2 g of potassium hydroxide (85% strength, available commercially from AppliChem) (0.26 mol of potassium hydroxide) and 15.3 g of demineralized water is metered in over 12 minutes. During this metered addition, the mixture heats up to 67° C. The mixture is heated to boiling temperature (70° C.). The distillate separates out as the bottom phase in the water separator. Up to a boiling temperature of 119° C., 48.5 g of colorless, slightly turbid distillate accumulate. The suspension which remains is subsequently evaporated to dryness with stirring under a full oil-pump vacuum (5 hPa) to 70° C. This gives 45.9 g of fine, white, free-flowable powder with a solids content of 99.7% (determined using the HR73 halogen moisture analyzer from Mettler Toledo at 160° C.). A 50% strength aqueous solution prepared with this powder exhibits no precipitation even after being stored at room temperature for two weeks in the absence of air.

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