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Preparation method of cyanoacetic acid

A technology of cyanoacetic acid and sodium cyanoacetate, applied in cyanide reaction preparation, organic chemistry, etc., can solve the problems of large energy consumption and high production cost, and achieve the effects of reducing production energy consumption, reducing water content, and simplifying the production process

Inactive Publication Date: 2012-02-01
WEIFANG BAILI CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The use of hydrochloric acid acidification has the following disadvantages: due to the influence of the solubility of hydrogen chloride in water, the concentration of hydrochloric acid currently used is generally about 30wt%, so that when acidifying sodium cyanoacetate, a large amount of water is inevitably brought in, and then it has to be removed Water is extracted, obviously, the whole process consumes a lot of energy, resulting in high production costs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Put 289g of 98wt% chloroacetic acid into a 2000ml round-bottomed flask, add an appropriate amount of water to dissolve, add 400g of 30wt% sodium hydroxide for neutralization reaction to generate sodium chloroacetate, then add 30wt% of 490g of sodium cyanide for cyanidation reaction, and prepare Get sodium cyanoacetate aqueous solution, prepare hydrogen chloride by hydrolysis with phosphorus trichloride, pass the obtained hydrogen chloride into a round-bottomed flask, keep the temperature at 40°C, stop after feeding 109.5g, and dehydrate under reduced pressure to obtain 70wt% cyanoacetic acid 357g.

Embodiment 2

[0020] Put 289g of 98wt% chloroacetic acid into a 2000ml round-bottomed flask, add an appropriate amount of water to dissolve, add 530g of 30wt% sodium carbonate for neutralization reaction to generate sodium chloroacetate, then add 490g of 30wt% sodium cyanide for cyanation reaction, and obtain Sodium cyanoacetate aqueous solution, hydrolyzed with phosphorus trichloride to prepare hydrogen chloride, put the obtained hydrogen chloride into a round bottom flask, keep the temperature at 30°C, stop after feeding 109.5g, and dehydrate under reduced pressure to obtain 414g of 60wt% cyanoacetic acid .

Embodiment 3

[0022] Put 98wt% chloroacetic acid 1445kg in a 10000l glass-lined reactor, add appropriate amount of water to dissolve, add 30wt% sodium hydroxide 2000kg neutralization reaction to generate sodium chloroacetate, then add 30wt% sodium cyanide 2450kg cyanide reaction, Sodium cyanoacetate aqueous solution is prepared, the reaction material is pumped into the hydrochloric acid absorption tower in the production process of chloroacetic acid, and the pump is used to circulate continuously. The hydrogen chloride from the chloroacetic acid chlorination kettle is continuously absorbed, and the temperature is maintained at 35 ° C. After measurement After passing the test, stop feeding the hydrogen chloride, pump to the dehydration device, and dehydrate under reduced pressure to obtain 1780kg of 70wt% cyanoacetic acid.

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PUM

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Abstract

The invention discloses a preparation method of cyanoacetic acid, which comprises the following steps that: chloroacetic acid and alkali take neutralization reaction to generate sodium chloroacetate, in addition, the sodium chloroacetate and sodium cyanide carry out cyaniding reaction to obtain sodium cyanoacetate water solution, hydrogen chloride gas is absorbed by the sodium cyanoacetate water solution, and cyanoacetic acid water solution is obtained through reaction. The sodium cyanoacetate water solution is used for directly absorbing the hydrogen chloride gas. Compared with the prior art, the preparation method has the advantages that the production process is simplified, the equipment investment is also not increased, and in addition, the production consumption is greatly reduced, so the production cost is reduced.

Description

technical field [0001] The present invention relates to a kind of preparation of cyanoacetic acid, be specifically related to a kind of method of using chloroacetic acid to prepare cyanoacetic acid. Background technique [0002] Cyanoacetic acid is the main raw material for preparing fine chemical products such as cyanoacetate, malonate and caffeine. The traditional method of preparing cyanoacetic acid is to use chloroacetic acid as a raw material, first neutralize it with alkali such as sodium hydroxide or sodium carbonate, then add sodium cyanide for cyanation, then add hydrochloric acid for acidification, and then dehydrate to obtain different concentrations of cyanide acetic acid. The use of hydrochloric acid acidification has the following disadvantages: due to the influence of the solubility of hydrogen chloride in water, the concentration of hydrochloric acid currently used is generally about 30wt%, so that when acidifying sodium cyanoacetate, a large amount of water...

Claims

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Application Information

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IPC IPC(8): C07C255/19C07C253/14
Inventor 郭希田马会楼
Owner WEIFANG BAILI CHEM
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