Synthesis process of trimethyl orthoacetate

A technology of trimethyl orthoacetate and synthesis method, applied in the preparation of organic compounds, chemical instruments and methods, organic chemistry, etc., can solve the problems of uneven dispersion, trimethyl orthoacetate quality, low yield, and reaction yield Instability and other problems can be achieved to improve the mixing state and increase the reaction yield

Active Publication Date: 2014-02-19
JIANGSU YANGNONG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When we carried out the process research of synthesizing trimethyl orthoacetate with reference to this method, we directly passed hydrogen chloride gas according to the conventional method, and found that the reaction yield was only between 72% and 80% and was unstable. When entering the reaction system, due to uneven dispersion, the formed hydrochloride becomes lumpy or attached to the reactor wall, which contains a certain amount of raw material acetonitrile, resulting in lower quality and yield of the final product trimethyl orthoacetate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] 1) In a 1.5m high 1000L enamel reaction kettle equipped with a stirrer and a temperature measuring probe, a circle of hydrogen chloride gas distribution tube made of polytetrafluoroethylene is attached to the inner wall, and the tube has uniformly distributed holes. 4cm, wall thickness 0.2cm, opening rate 8.5%, the lower edge of the pipe wall is 40cm from the bottom of the reactor. Put 82kg (2kmol) of acetonitrile, 67.2kg (2.1kmol) of anhydrous methanol and 300kg of n-hexane into the kettle, stir and cool the reaction solution to -10°C, and slowly pass dry hydrogen chloride gas through the hole of the distribution tube for about 8 hours 85kg, fully stirred and reacted for 6 hours to form a salt after passing through, and obtained alkyliminoacetate hydrochloride;

[0021] 2) Add 160kg of anhydrous methanol to the alkylimino acetate hydrochloride obtained in step 1), and pass ammonia gas to adjust the pH of the reaction solution to 5.5-6.0. Keep it unchanged for 15 minut...

Embodiment 2

[0023] 1) In a 1.5m high 1000L enamel reaction kettle equipped with a stirrer and a temperature measuring probe, a circle of hydrogen chloride gas distribution tube made of polytetrafluoroethylene is attached to the inner wall, and the tube has uniformly distributed holes. 4cm, wall thickness 0.2cm, opening rate 9%, the lower edge of the tube wall is 35cm away from the bottom of the reactor. Put 82kg (2kmol) of acetonitrile (2kmol), 67.2kg (2.1kmol) of anhydrous methanol and 310kg cyclohexane into the kettle, stir the reaction solution and cool it to -5°C, and slowly pass it through the hole of the distribution tube for about 6h. Hydrogen chloride gas 73kg, fully stirred and reacted for 4 hours to form a salt after passing through, and obtained alkyliminoacetate hydrochloride;

[0024] 2) Add 160kg of anhydrous methanol to the alkylimino acetate hydrochloride obtained in step 1), and pass ammonia gas to adjust the pH of the reaction solution to 5.0-6.0. Keeping it unchanged f...

Embodiment 3

[0026] 1) In a 1.5m high 1000L enamel reaction kettle equipped with a stirrer and a temperature measuring probe, a circle of hydrogen chloride gas distribution tube made of polytetrafluoroethylene is attached to the inner wall, and the tube has uniformly distributed holes. 5cm, wall thickness 0.22cm, opening rate 7%, and the lower edge of the tube wall is 35cm from the bottom of the reactor. Put 82kg (2kmol) of acetonitrile, 80kg (2.5kmol) of anhydrous methanol and 360kg of n-hexane into the kettle, stir and cool the reaction solution to -20°C, and slowly pass dry hydrogen chloride gas through the hole of the distribution tube for about 6 hours 73kg, fully stirred and reacted for 8 hours to form a salt after passing through, and obtained alkyl imino acetate hydrochloride;

[0027] 2) Add 180 kg of anhydrous methanol to the alkylimino acetate hydrochloride obtained in step 1), and feed ammonia gas to adjust the pH of the reaction solution to 5.5-6.5. Keeping it unchanged for 1...

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Abstract

The invention provides a synthesis method of trimethyl orthoacetate. The synthesis method comprises the following steps: 1) mixing acetonitrile, methanol and a non-polar solvent in a reaction kettle, cooling to between minus 20 and minus 5 DEG C, introducing hydrogen chloride gas through a distribution pipe fixed on the inside wall of the reaction kettle, and fully stirring for reacting to generate hydrochloride, wherein, the mol ratio of the acetonitrile to the methanol to hydrogen chloride is 1:(1-2):(1.05-1.5), and the mass ratio of the acetonitrile to the non-polar solvent is 1:(2-5); and 2) adding 2-4-fold methanol based on the molar weight of the starting acetonitrile to the hydrochloride generated in step 1), adjusting the pH value of the system to 5-6.5, carrying out alcoholysis reaction at the temperature of 25-40 DEG C, filtering and refining the obtained alcoholysis product to finally obtain the trimethyl orthoacetate. In the method, the hydrogen chloride gas is introduced into feed liquid through the distribution pipe fixed on the inside wall of the reaction kettle. By utilizing the synthesis method, the quality and yield of the trimethyl orthoacetate are obviously improved.

Description

technical field [0001] The invention relates to a compound synthesis method, in particular to a new synthesis process of trimethyl orthoacetate. Background technique [0002] Trimethyl orthoacetate, also known as trimethoxyethane, is an important orthoester. Molecular formula C 5 h 12 o 3 , relative molecular weight 120.14, boiling point 107~109℃, density 0.944, soluble in alcohol, ether and other organic solvents, mainly used in the synthesis of medicine, pesticide, spices, etc. [0003] Trimethyl orthoacetate is an important intermediate for synthesizing DV chrysanthemic acid and Kungfu chrysanthemic acid by the Sagami method. The method for synthesizing cyanogen chloride with triethyl orthoacetate can greatly reduce production costs and simplify the process route, so its synthesis has high economic value. It was previously reported that trimethyl orthoacetate was prepared from acetonitrile by alcoholysis of alkylimino acetate hydrochloride, and the synthesis yield wa...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C43/32C07C41/60
Inventor 戚明珠冯广军赵鹏张斌丁剑剑张可谢邦伟杨凡张敏
Owner JIANGSU YANGNONG CHEM
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