反应详情

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 27 g (0.198 mol) of methyltrimethoxysilane (available commercially from Wacker Chemie AG), 3.9 g (0.02) of n-propyl(methyl)diethoxysilane (prepared in the laboratory by reacting n-propyl(methyl)dichlorosilane with ethanol) and 20 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 12.4 g (0.188 mol) of potassium hydroxide (85% form, available commercially from AppliChem) in 7.9 g (0.44 mol) of demineralized water is metered in over 12 minutes. The mixture heats up to 48° C. It is heated to boiling temperature. The distillate separates off as the bottom phase in the water separator. Up to a boiling temperature of 95° C., 19.4 g of colorless, slightly turbid distillate accumulate, containing—according to analysis by gas chromatography—78.5% of methanol, 7.5% of ethanol, 3.5% of water, and 8.2% of Isopar E. The bottom phase is drained off from the water separator, which is made up completely with Isopar E again, and water is removed in circulation at a boiling temperature of up to 131° C. This produces 6.2 g of distillate as bottom phase, which according to GC analysis contains 46.9% of methanol, 4.7% of ethanol, and 48.4% of water. During the distillation, a pastelike white solid separates out in the reaction mixture, and breaks down increasingly into fine particles and forms a suspension. 10 g of cyclohexane are added and the suspension is filtered through a Beco KD3 filter plate in a pressure suction filter, and nitrogen is passed through to constant weight. This gives 21.4 g of fine, white, free-flowable powder with a solids content of 99.5% (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.

1. customA 500 ml 5-neck round-bottom flask, inertized with nitrogen and fitted with paddle stirrer
2. temperaturewith reflux condenser
3. customprepared in the laboratory
4. customis metered in over 12 minutes
5. customheats up to 48° C
6. temperatureIt is heated
7. customwater is removed in circulation at a boiling temperature of up to 131° C
8. distillationDuring the distillation
9. temperaturea pastelike white solid separates out in the reaction mixture, and breaks down increasingly into fine particles and forms a suspension
10. addition10 g of cyclohexane are added
11. filtrationthe suspension is filtered through a Beco
12. filtrationKD3 filter plate in a pressure suction
13. filtrationfilter
14. customat 160° C.
15. customA 50% strength aqueous solution prepared with this solid exhibits
16. customno precipitation even after storage at room temperature for two weeks in the absence of air