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A kind of preparation method of hexamethyldisiloxane

A technology of hexamethyldisilazane and hexamethyldisilazane is applied in the field of preparation of silylation reagents, and can solve the problems of increasing production time, affecting reaction time, limited cycle times, etc., thereby reducing production costs and shortening The effect of reaction flow and short reaction time

Active Publication Date: 2021-07-06
JIANGSU FOOD & PHARMA SCI COLLEGE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, the above method has the following defects: (1) For the preparation method without using a solvent, an excess of hexamethyldisilazane (HMDZ) is required, generally more than 3 times the excess, but due to the high price of HMDZ, when it is necessary to use Excessive amounts of HMDZ will lead to increased production costs. Although the existing technology provides that HMDZ can be recycled, the number of cycles is limited due to the continuous accumulation of impurities, which will still lead to an increase in production costs.
(2) For the preparation method using a solvent, the choice of solvent will greatly affect the reaction time, and after the reaction is completed, the filtrate needs to be processed, which will increase the production time
In addition, the amount of solvent used in the existing technology is relatively large, for example, a solvent with a stoichiometric ratio of more than 2 times is required, which increases the production cost
(3) For the use of the catalyst, since it will remain in the product, it will affect the storage stability of the product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Under nitrogen protection, under stirring, 520ml (5mol) of ethylene glycol dimethyl ether, 807g (5mol) of hexamethyldisilazane, 300g (5mol) of urea, and 5ppm of chlorine were charged into the reactor Ammonium chloride was reacted at 70° C., and the reaction was stopped when the nitrogen escape was over, and the reaction time was 30 minutes. The reactant was cooled, filtered, and the filter cake was dried under reduced pressure to obtain 1014 g of the product hexamethyldisiloxane, with a yield of 99.2% and a purity of 99.85%. After testing, the product does not contain ammonium chloride. Collect the filtrate for later use.

Embodiment 2

[0025] Under nitrogen protection, under stirring, 1040ml (10mol) of ethylene glycol dimethyl ether, 807g (5mol) of hexamethyldisilazane, 300g (5mol) of urea, and 10ppm of chlorine were charged into the reactor Ammonium chloride was reacted at 80° C., and the reaction was stopped when the nitrogen escape was over, and the reaction time was 35 minutes. The reactant was cooled, filtered, and the filter cake was dried under reduced pressure to obtain 1016 g of the product hexamethyldisiloxane with a yield of 99.3% and a purity of 99.82%. After testing, the product does not contain ammonium chloride. Collect the filtrate for later use.

Embodiment 3

[0027] Under nitrogen protection, under stirring, 624ml (6mol) of ethylene glycol dimethyl ether, 1130g (7mol) of hexamethyldisilazane, 300g (5mol) of urea, and 25ppm of chlorine were charged into the reactor Ammonium chloride was reacted at 90° C., and the reaction was stopped when the nitrogen escape was over, and the reaction time was 40 minutes. The reactant was cooled, filtered, and the filter cake was dried under reduced pressure to obtain 1017 g of the product hexamethyldisiloxane with a yield of 99.4% and a purity of 99.79%. After testing, the product does not contain ammonium chloride. Collect the filtrate for later use.

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PUM

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Abstract

A preparation method of hexamethyldisilazane, said method comprising the steps of: in the presence of an inert gas, in a reactor, first add ethylene glycol dimethyl ether, then add hexamethyldisilazane, and then Add urea, and the catalyst ammonium chloride or ammonium sulfate, and heat up to 70-90°C for reaction. The reaction time is 30-40 minutes, and the ammonia gas evolution is over at this time. The reactant was cooled to room temperature, filtered to recover the precipitated hexamethyldisiloxane, and then dried under reduced pressure to obtain hexamethyldisiloxane. The filtrate sets were collected for use in the next batch of production. The method of the invention has the advantages of short reaction time, less solvent consumption and high product stability.

Description

[0001] field of invention [0002] The invention relates to a preparation method of a silylating agent, in particular to a preparation method of hexamethyldisiloxane. Background technique [0003] Hexamethyldisiloxane, also known as bis-trimethylsilylurea (BSU), is an excellent silylating agent that can convert active hydrogen atoms (-OH, -COOH, -NH, -SH) into organic molecules Replacement by trimethylsilane groups, and the formation and removal reaction conditions are mild, essentially quantitative. Because the stability of the protected compound can be improved after silanization protection, it is widely used in organic synthesis and pharmaceutical industry. It is an indispensable group protecting agent in the synthesis of semi-synthetic antibiotics that has developed rapidly in recent years. It has a large industrial production value. Hexamethyldisiloxane is the most ideal silane protective agent in the synthesis of β-lactam antibiotics. Taking the semi-synthesis of ceph...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07F7/10
CPCC07F7/10
Inventor 李思阳陶陈泷其他发明人请求不公开姓名
Owner JIANGSU FOOD & PHARMA SCI COLLEGE