Preparation method of dimethylethoxysilane

A technology of dimethyldiethoxysilane and dimethyldichlorosilane is applied in the field of preparation of dimethyldiethoxysilane, and can solve the problem of increasing by-products and waste residues, increasing the amount of neutralizing agent, and generating The problem of increasing the amount of waste residue, etc., achieves the effect of improving the rectification yield, easy control, and reducing investment.

Inactive Publication Date: 2012-10-10
XINYAQIANG SILICON CHEM JIANGSU
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The biggest problem of the traditional preparation process is that there are side reactions in the reaction process, and water is produced after the side reactions occur, so that the raw materials (or products) are hydrolyzed to form linear organosiloxanes
At the same time, because there is a large amount of hydrogen chloride in the system, it is not easy to remove, and the occurrence of side reactions is promoted at a certain temperature, resulting in a vicious circle.
In addition, due to the large amount of hydrogen chloride contained in the system, the amount of neutralizing agent added increases, and the amount of waste residue generated also increases. As a result, the operation is difficult to control, the process flow is long, the product yield is greatly reduced, and by-products and waste residues increase.

Method used

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  • Preparation method of dimethylethoxysilane
  • Preparation method of dimethylethoxysilane
  • Preparation method of dimethylethoxysilane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] 1. Response: first at 1m 3 Put 500kg of dimethyldichlorosilane and 300kg of urea into the enamel stirred kettle, mix and stir; then add 130kg of ethanol dropwise into the stirred kettle, and the dropwise addition is completed within one hour. The reaction is carried out at -200mm Hg, and the temperature is controlled at 60 Below ℃, the temperature control is realized by the dropping speed or jacket cold water cooling; the hydrogen chloride gas that has not reacted with the urea is absorbed by the ammonia gas in the hydrogen chloride absorber; after the reaction is completed, stop stirring, keep the stratification for 20 minutes, and release the acidic liquid at the bottom , import the upper crude product into the neutralization kettle.

[0035] 2. Neutralization: analyze the content of dimethyldiethoxychlorosilane and hydrogen chloride before neutralization to determine the amount of potassium ethoxide added. The amount of potassium ethoxide added should be over 5%. In ...

Embodiment 2

[0039] 1. Response: first at 1m 3 Put 500kg of dimethyldichlorosilane and 500kg of urea into the enamel stirred tank, mix and stir; then add 315kg of ethanol dropwise into the stirred tank, and the dropwise addition is completed within one and a half hours. Below 60°C, the temperature control is realized by dropping speed or jacketed cold water cooling; the hydrogen chloride gas that has not reacted with urea is absorbed by the amine in the hydrogen chloride absorber; after the reaction, stop stirring, stand still for 40 minutes, and release the acidic liquid at the bottom , import the upper crude product into the neutralization kettle.

[0040] 2. Neutralization: analyze the content of dimethyldiethoxychlorosilane and hydrogen chloride before neutralization to determine the amount of sodium ethoxide added. The amount of sodium ethoxide added should be over 5%. In this process, in order to improve Reaction speed, add 3kg of ethanol to increase the reactant concentration. Whe...

Embodiment 3

[0044] 1. Response: first at 1m 3 Put 500kg of dimethyldichlorosilane and 700kg of urea into the enamel stirred tank, mix and stir; then add 500kg of ethanol dropwise into the stirred tank, and the dropwise addition is completed within two hours. The reaction is carried out at 0mm mercury column, and the temperature is controlled at 60°C Below, the temperature control is achieved by dropping the speed or cooling the jacket cold water; the hydrogen chloride gas that has not reacted with the urea is absorbed by the alkaline earth metal in the hydrogen chloride absorber; after the reaction is completed, stop stirring, and keep the stratification for 60 minutes to release the acidic liquid at the bottom. The upper crude product is introduced into the neutralization kettle.

[0045] 2. Neutralization: analyze the content of dimethyldiethoxychlorosilane and hydrogen chloride before neutralization to determine the amount of alkaline earth metal added. The amount of alkaline earth met...

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Abstract

The invention discloses a preparation method of dimethylethoxysilane, which comprises the following specific steps of: (1) reaction: firstly adding dimethyldichlorosilane and urea in a stirring kettle, mixing and stirring; then dropwise adding ethanol into the stirring kettle, standing and layering, discharging bottom acid liquid and introducing an upper coarse product into a neutralization kettle; (2) neutralization: analyzing the contents of the dimethyldichlorosilane and hydrogen chloride in the upper coarse product before neutralization and ensuring that the addition amount of a neutralization agent exceeds above 5 percent; when a system is neutral or alkalescent, terminating the neutralization reaction; standing and settling after reaction and rectifying supernatant liquor; and (3) rectification: adding the supernatant liquor into an intermittent rectifying tower kettle to produce the trimethylethoxysilane. The preparation method has the beneficial effects that the reaction can be carried out at a normal temperature, so that the concentration of the hydrogen chloride in the system is reduced, the generation of secondary reaction is avoided; and therefore, the preparation method has the advantages of short reaction process, less investment, easiness in neutralization reaction control, greatly improved rectification yield and reduced production cost.

Description

technical field [0001] The invention relates to a preparation process of dimethyldiethoxysilane. Background technique [0002] The traditional preparation process of dimethyldiethoxysilane adopts the direct alcoholysis fatification method, that is, under the condition of heating and vaporization, ethanol directly reacts with dimethyldichlorosilane (or adopts double-tower fatification, that is, adopts two-stage reaction, carried out at different lipidation temperatures), after the product is condensed, ethanol is added to remove the hydrogen chloride, and at the same time, the unreacted product is continued to complete the reaction, the slag is removed by filtration, and the liquid is rectified to obtain the product. [0003] The biggest problem of the traditional preparation process is that there are side reactions in the reaction process, and water is generated after the side reactions occur, so that the raw materials (or products) are hydrolyzed to form linear organosiloxa...

Claims

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Application Information

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IPC IPC(8): C07F7/18
Inventor 初亚军
Owner XINYAQIANG SILICON CHEM JIANGSU
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