A kind of preparation method of cyanoacetic acid and derivatives thereof
A technology of cyanoacetic acid and sodium cyanoacetate, which is applied in the field of preparation of cyanoacetic acid and its derivatives, can solve the problems of high cost, large amount of organic solvent, cumbersome operation, etc., and achieve low production cost, less amount of three wastes, and simple operation Effect
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Embodiment 1
[0025] Reference figure 1 , To further explain the present invention:
[0026] (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;
[0027] (2) Acidification reaction: adding 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 mixture containing cyanoacetic acid and sod...
Embodiment 2
[0032] (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;
[0033] (2) Acidification reaction: adding 33% hydrochloric acid (110.6g, 1.0mol) by mass concentration to the sodium cyanoacetate aqueous solution obtained in step (1) for acidification to obtain 474.9g of a mixture containing cyanoacetic acid and sodium chloride;
[0034] (3) Desalination of distilled water: turn on the vac...
Embodiment 3
[0038] (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;
[0039] (2) Acidification reaction: adding 36% hydrochloric acid (111.5g, 1.1mol) by mass concentration to the sodium cyanoacetate aqueous solution obtained in step (1) for acidification to obtain 439.8g of a mixture containing cyanoacetic acid and sodium chloride;
[0040] (3) Desalination of distilled water: turn on the va...
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