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Creation Steps Of Hexamethyldisiloxane

Update:2022-05-07 00:00
Summary:

Steps to create Hexamethyldisiloxane :

(1) in 1L four-necked flask, add 325g pure water, and 400g trimethylmonochlorosilane (purity 99.540%) is added dropwise to pure water, by controlling the rate of addition and heat exchange conditions, the temperature of the reaction is kept at 30 ° C, vigorous stirring makes the container peripheral liquid linear velocity reach 8m/s, sampling gas chromatography analysis after dripping, analysis result: dimethyl-fluoro silane: 5.949%, dimethyl Silanol: 0.138%, TK methyl-siloxane: 93.204%.

(2) Gas chromatographic analysis results after stirring for 1 h: trimethylmonochlorosilane: 1.093%, trimethylsilyl: 0.162%, hexamethyldisiloxane: 97.890%. The lower layer of acid water was separated, and the concentration of hydrochloric acid was determined by titration to be 30.86%.

(3) in the oil phase, add 325g pure water, wash with high-speed stirring for 0.5h, gas chromatography analysis result: trimethylmonochlorosilane: 0.001%, trimethylsilyl: 0.180%, hexamethyldisiloxane: 98.978%. Total chlorine content: 78^111. The same washing process was repeated once and the total chlorine content dropped to 17ppm. The second dilute acid water obtained during the washing process is used for the first washing, the acid water after the first washing is used for the previous hydrolysis.

(4) The obtained oil phase is transferred into a 5L glass spring packing type rectifying tower for rectification. By collecting 99~102°C fractions, hexamethyldisiloxane can be obtained. Wherein yield reaches 97.5%, hexamethyldisiloxane 99.99%, trimethylmonochlorosilane cannot detect (less than 1ppm), total chlorine content cannot detect (less than 1ppm), silanol (with Trimethylsilanol) content 0.01%, a product with a moisture content of 38ppm.