Method for preparing pentamethyl disiloxane

A technology of pentamethyldisiloxane and methyl, which is applied in the field of preparation of pentamethyldisiloxane, can solve the problems of low yield and high product cost, achieve high hydrolysis purity, good industrial value, and increase yield and the effect of purity

Active Publication Date: 2012-07-04
中国中化股份有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to overcome the shortcomings of high product cost and low yield in the existing preparation methods, the present invention is committed to developing a new preparation method

Method used

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  • Method for preparing pentamethyl disiloxane
  • Method for preparing pentamethyl disiloxane
  • Method for preparing pentamethyl disiloxane

Examples

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Embodiment 1

[0029] Add 7.2 grams (0.3 mol) of magnesium powder and 108 grams of ether into a 500 ml four-neck flask equipped with a thermometer, agitator, and condenser, and feed methyl bromide gas under nitrogen protection to control the reaction temperature at 50°C until the magnesium powder All gone. After reacting for 14 hours, 45 g (0.47 mol) of methyl bromide was introduced. Chemical analysis determined that the Grignard reagent content was 96%. Add 100 grams of toluene to the above-mentioned four-necked bottle, cool to about 20°C, add n=20 (molecular weight is about 1300), and 30 grams of high hydrogen-containing silicone oil (hydrogen content 1.56%) with n=20 (molecular weight is about 1300) and both ends are methyl groups (mainly The molar number of content fragments is 0.46 moles), and the reaction was carried out at 20° C. for 5 hours. Then, the temperature was controlled at 15° C., and 200 grams of 20% dilute sulfuric acid was added dropwise to the reactant in the above-ment...

Embodiment 2

[0033]Add 7.2 grams (0.3 mol) of magnesium powder and 108 grams of ether into a 500 ml four-necked bottle equipped with a thermometer, agitator, and condenser, and feed in methyl chloride gas under nitrogen protection, and control the reaction temperature at 50°C until the magnesium powder disappears completely. . The reaction time was 18 hours, 25 g (0.5 mol) of methyl chloride was introduced, and the content of the Grignard reagent was determined to be 95% by chemical analysis. Add 120 grams of toluene to the above-mentioned four-necked bottle, and add 38.4 grams of high hydrogen-containing silicone oil (hydrogen content 1.56%) with n=20 (molecular weight is about 1300) and methyl groups at both ends (main content fragment) dropwise at 30 ° C. The number of moles is 0.6 mol), and the reaction was incubated for 8 hours. Then, the temperature was lowered to 15° C., and 200 grams of 20% dilute sulfuric acid was added dropwise to the above-mentioned four-necked flask. After the...

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Abstract

The invention discloses a method for preparing pentamethyl disiloxane. In a reaction formula below, R may be methyl, ethyl, propyl, phenyl or ethenyl; and X may be a chlorine atom or bromine atom; n is an integer ranging from 4 to 100. Reaction steps include: (1) adding high-hydrogen silicone oil represented by a formula III into a Grignard reagent to perform a Grignard reaction in the presence of an ether solvent and a cosolvent; and (2) adding water to perform a hydrolysis reaction to prepare the pentamethyl disiloxane represented by a formula I. The method has high reaction yield and high product quality and is suitable for industrial preparation.

Description

technical field [0001] The invention belongs to the field of organosilicon chemical synthesis, and in particular relates to a method for preparing pentamethyldisiloxane. Background technique [0002] Pentamethyldisiloxane is an extremely important organosilicon intermediate. This compound has active silicon-hydrogen bonds and can be used as a monomer for the synthesis of organosilicon polymers. It can also be added to carbon compounds to form silicon-carbon Polymers can also link silicone rubber, silicone oil, and silicone resin to modify their properties, and are also raw materials for synthesizing special surfactants. Therefore, pentamethyldisiloxane plays an extremely important role in synthetic silicone products. [0003] The methods for preparing pentamethyldisiloxane disclosed in the prior art all use dimethylchlorosilane or its derivatives as raw materials and prepare by hydrolysis method: Japanese Patent Publication JP64031791 uses dimethylethoxysilane and Trimethy...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07F7/08
Inventor 喻滔刘冬雪贾俊吴玉春付洪娥魏峰肖洋
Owner 中国中化股份有限公司
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