Methyltrimethoxysilane → methyltrimethoxysilane KOH

A 500 ml 5-neck round-bottom flask, inertized with nitrogen and fitted with paddle stirrer, dropping funnel, thermometer, and water separator with reflux condenser, is charged with 30 g (0.22 mol) of methyltrimethoxysilane (available commercially from Wacker Chemie AG) and 50 g of Isopar E (isoparaffinic hydrocarbon mixture with 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 8.7 g (0.13 mol) of potassium hydroxide (85% form, available commercially from AppliChem) in 9.1 g (0.5 mol) of demineralized water is metered in over 12 minutes. The mixture heats up to 50° C. It is heated to boiling temperature and the stirrer speed is reduced to 50 rpm as soon as distillation begins. The distillate separates off as the bottom phase in the water separator. Up to a boiling temperature of 119° C., 25.4 g of clear colorless distillate accumulate, containing—according to analysis by gas chromatography—80.4% of methanol, 18.4% of water, and 1% of Isopar E. During the distillation, a pastelike white solid separates out in the reaction mixture, and breaks down increasingly into fine particles and forms a suspension. The suspension is filtered through a Beco KD3 filter plate in a pressure suction filter, and nitrogen is passed through until the weight is constant. This gives 19.8 g of fine, white, free-flowable powder with a solids content of 100% (determined using the HR73 halogen moisture analyzer from Mettler Toledo at 160° C.). A 50% strength aqueous solution prepared with this solid exhibits no precipitation even after storage at room temperature for two weeks in the absence of air.