Preparation method for cyanoacetic acid and derivatives thereof

A technology of cyanoacetic acid and sodium cyanoacetate, applied in the field of preparation of cyanoacetic acid and its derivatives, can solve the problems of cumbersome operation, high cost, large amount of organic solvent, etc., and achieve simple operation, low production cost, and less three wastes Effect

Inactive Publication Date: 2016-04-13
CHONGQING UNISPLENDOUR CHEM
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the amount of organic solvent used is large (the ratio of solvent to mixed solution is

Method used

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  • Preparation method for cyanoacetic acid and derivatives thereof

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[0022] Example 1

[0023] Reference figure 1 , To further explain the present invention:

[0024] (1) Cyanation reaction: Dissolve 96.8g of chloroacetic acid (content 98%, 1.0mol) and 70g of water under stirring, and neutralize with 25% sodium carbonate aqueous solution (215g) to pH=6.5-7.0 to produce sodium chloroacetate 354.8 g (content 32.8%); the temperature is raised to 50°C, and then 165.0g (1.01mol) of sodium cyanide aqueous solution with a mass concentration of 30% is added dropwise. When the reaction temperature reaches 85-90°C, stop heating and start cooling. When the reaction temperature When the temperature reaches 105°C, the reaction is completed, and it is cooled to room temperature to obtain an aqueous solution of sodium cyanoacetate;

[0025] (2) Acidification reaction: add 30% hydrochloric acid (127.8g, 1.05mol) by mass concentration to the sodium cyanoacetate aqueous solution obtained in step (1) for acidification to obtain 495.1g of a mixed solution of cyanoaceti...

Example Embodiment

[0028] Example 2

[0029] (1) Cyanation reaction: Dissolve 96.8g of chloroacetic acid (content 98%, 1.0mol) and 70g of water under stirring, and neutralize with 25% sodium carbonate aqueous solution (215g) to pH=6.5-7.0 to produce sodium chloroacetate 354.8 g (content 32.8%); the temperature is raised to 50°C, and then 179.7g (1.1mol) of sodium cyanide aqueous solution with a mass concentration of 30% is added dropwise. When the reaction temperature reaches 85-90°C, stop heating and start cooling. When the reaction temperature When the temperature reaches 105°C, the reaction is completed, and it is cooled to room temperature to obtain an aqueous solution of sodium cyanoacetate;

[0030] (2) Acidification reaction: adding 5% by mass hydrochloric acid (729.2g, 1.0mol) to the sodium cyanoacetate aqueous solution obtained in step (1) for acidification to obtain 1095.5g of a mixed solution of cyanoacetic acid and sodium chloride;

[0031] (3) Separate the mixed solution of cyanoacetic ac...

Example Embodiment

[0033] Example 3

[0034] (1) Cyanation reaction: Dissolve 96.8g of chloroacetic acid (content 98%, 1.0mol) and 70g of water under stirring, and neutralize with 25% sodium carbonate aqueous solution (215g) to pH=6.5-7.0 to produce sodium chloroacetate 354.8 g (content 32.8%); the temperature is raised to 50°C, and then 171.5g (1.05mol) of sodium cyanide aqueous solution with a mass concentration of 30% is added dropwise. When the reaction temperature reaches 85-90°C, stop heating and start cooling. When the reaction temperature When the temperature reaches 105°C, the reaction is completed, and it is cooled to room temperature to obtain an aqueous solution of sodium cyanoacetate;

[0035] (2) Acidification reaction: Adding 20% ​​hydrochloric acid (200.5g, 1.1mol) by mass concentration to the sodium cyanoacetate aqueous solution obtained in step (1) for acidification to obtain 564.8g of a mixed solution of cyanoacetic acid and sodium chloride;

[0036] (3) Separate the mixed solution ...

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Abstract

The invention discloses a preparation method for cyanoacetic acid and derivatives thereof. According to the invention, a mixed solution of cyanoacetic acid and sodium chloride is subjected to continuous chromatographic separation so as to obtain a cyanoacetic acid solution and sodium chloride; so the cyanoacetic acid solution with low chloride ion content or high-content solid cyanoacetic acid products and derivatives thereof are obtained, and the disadvantages of considerable decomposition and low yield of cyanoacetic acid in traditional distillation, concentration and separation are overcome. The preparation method is simple to operate, low in production cost, high in product yield and low in the amounts of waste gas, waste water and industrial residues, is an environment-friendly clean production method and can prepare the cyanoacetic acid solution with low chloride ion content or high-content solid cyanoacetic acid products and derivatives thereof.

Description

technical field [0001] The invention belongs to the technical field of organic chemical synthesis and separation, and relates to a preparation method of cyanoacetic acid and derivatives thereof. Background technique [0002] Cyanoacetic acid is an important intermediate in the production of medicines, dyes, and pesticides, and is used in the production of malonic acid, cyanoacetate, malonate, α-methyl cyanoacrylate, vitamin B6, caffeine, and cream uran . [0003] The traditional production process uses chloroacetic acid, sodium carbonate, and sodium cyanide as raw materials, and is obtained through neutralization, cyanation, acidification, and dehydration under reduced pressure. However, the content of the solid cyanoacetic acid product obtained by this method is only about 90%, and the water content and salt content are relatively high, which limits its application. Because the concentration of cyanoacetic acid in the cyanoacetic acid mixed solution is low, and the conten...

Claims

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Application Information

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IPC IPC(8): C07C253/30C07C255/19C07C67/22C07C69/38C07C67/08C07C51/08C07C55/08
CPCC07C51/08C07C67/08C07C67/22C07C253/14C07C253/30C07C255/19C07C69/38C07C55/08
Inventor 丁永良张飞刘佳徐代行何咏梅唐大家陈依柔王颖
Owner CHONGQING UNISPLENDOUR CHEM
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