Process for concurrent preparation of organosiloxanes and methyl chloride
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsKiichi Habata, Kesazi Ichikawa, Mutsuo Shimizu
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AssigneeShin-Etsu Chemical Co., Ltd.
InventorsKiichi Habata, Kesazi Ichikawa, Mutsuo Shimizu
Estimating the term…
The invention provides a novel continuous process for concurrently producing methyl chloride and organosiloxanes by the reaction of an organochlorosilane and methyl alcohol in an aqueous reaction medium at 70.degree. to 150.degree. C. Different from conventional processes, the aqueous reaction medium contains no catalyst so that the problems inherent to the use of a large amount of a catalyst can be avoided. In the inventive process, the feed rates of the reactants are controlled so as to keep the concentration of hydrogen chloride in the aqueous reaction medium not to exceed the azeotropic concentration thereof at the temperature and under the pressure of operation. These conditions are critical to reduce the loss of hydrogen chloride by dissipation into the gaseous phase resulting in a remarkably high yield of methyl chloride from the standpoint of both the conversion of chlorine content and the space-time yield of the reaction vessel. The inventive process is advantageous also in the excellent quality of the organosiloxane product and markedly decreased formation of dimethyl ether as an undesirable by-product.
A process for concurrently producing methyl chloride and organosiloxanes from an organochlorosilane and methyl alcohol in a continuous operation which comprises introducing simultaneously the organochlorosilane and methyl alcohol in such a proportion that the amount of introduction of the methyl alcohol is substantially equimolar to the silicon-bonded chlorine atoms in the organochlorosilane into an aqueous reaction medium comprising methyl alcohol and hydrogen chloride kept at a temperature of 70.degree. to 150.degree. C. and under a pressure of atmospheric or higher and contained in a reaction vessel at or near the bottom thereof, the rates of introduction of the organochlorosilane and methyl alcohol being controlled such that the concentration of hydrogen chloride in the aqueous reaction medium does not substantially exceed the azeotropic concentration at the temperature and under the pressure of operation at least at or in the vicinity of the surface of the aqueous reaction medium.
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