Environment-friendly clean production method of high-purity cyanoacetic acid, cyanoacetate and malonate

A high-purity cyanoacetic acid and cyanoacetate technology, which is applied in chemical instruments and methods, carboxylate/lactone preparation, carboxylate preparation, etc., can solve the problem of cyanoacetic acid purification or high energy consumption and unclean salt separation , cumbersome operation and other problems, to achieve the effect of solving unclean salt separation, saving investment and reducing processing load

Inactive Publication Date: 2020-07-10
高春燕
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0016] Aiming at the deficiencies of current technology, the object of the present invention is to provide a kind of environment-friendly clean production method of high-purity cyanoacetic acid and cyanoacetic ester and malonate, to solve the problem of cyanoacetic acid purification or high energy consumption in the prior art, or operation cumbersome, serious decomposition, or unclean salt separation, etc. At the same time, high-purity cyanoacetate and malonate can be produced from high-purity cyanoacetic acid to avoid bringing too much chlorine into the esterification water phase, greatly reducing esterification It is difficult to recover the by-product salt in the water phase, and realize the clean production of the whole process

Method used

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  • Environment-friendly clean production method of high-purity cyanoacetic acid, cyanoacetate and malonate

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] Embodiment 1: Carry out neutralization reaction through chloroacetic acid and sodium carbonate in water, carry out cyanidation reaction with sodium cyanide solution 1159.4kg (containing sodium cyanoacetate 23.33wt%, sodium chloride 12.88% , water 61.47%), acidified with 296.4L of 31wt% hydrochloric acid to obtain an acidified solution containing cyanoacetic acid and sodium chloride (cyanoacetic acid 14.19wt%, sodium chloride 21.18wt%, water 63.43%), adding a salt-removing agent The mass ratio of the amount of tert-butanol to the amount of water in the acidification solution is 0.25:1, precipitate and filter about 80% of the sodium chloride in the acidification solution at 25°C, and wash the sodium chloride solid with tert-butanol for use. Remove the next salt analysis, and the filtrate after separating sodium chloride is about 1453kg (containing cyanoacetic acid 14.64wt%, sodium chloride 4.31wt%, water 64.89wt%, tert-butanol 16.00wt%), and the filtrate is pretreated by f...

Embodiment 2

[0057] Embodiment 2: same as embodiment 1, utilize above-mentioned electrodialysis desalting process to obtain the desalination liquid that the salt content is lower than 0.05% from the desalination room, carry out negative pressure evaporation and concentration to the water content in the concentrated liquid of about 8wt%, add cyanoacetic acid 1.8 times moles A certain amount of anhydrous methanol, drop an appropriate amount of 98wt% concentrated sulfuric acid catalyst, control the temperature at 60~70°C for esterification reaction, after the reaction is completed, steam the excess methanol under negative pressure, add sodium carbonate solution for washing, neutralization, phase separation, and purification Distillation yields 234.7kg of high-purity methyl cyanoacetate with a content ≥ 99.5%.

Embodiment 3

[0058] Embodiment 3: same as embodiment 1, utilize above-mentioned electrodialysis desalination treatment to obtain from the desalting liquid of desalination chamber that the salt content is lower than 0.05%, carry out negative pressure evaporation concentration to the water content in the concentrate liquid about 12wt%, add cyanoacetic acid 1.85 times moles amount of anhydrous ethanol, add an appropriate amount of 98wt% concentrated sulfuric acid catalyst dropwise, and control the temperature at 60-70°C to carry out esterification reaction. Distillation yields 264.4kg of high-purity ethyl cyanoacetate with a content ≥ 99.5%.

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Abstract

The invention discloses an environment-friendly clean production method of high-purity cyanoacetic acid, cyanoacetate and malonate. The method comprises the following steps: carrying out an acidification reaction on sodium cyanoacetate and hydrochloric acid or HCl gas to obtain an acidified solution, carrying out salt precipitation by using a salt precipitation agent, filtering to obtain a filtrate, carrying out electrodialysis and other desalination treatments to obtain a desalted solution, concentrating the desalted solution, and crystallizing to prepare high-purity cyanoacetic acid, or esterifying to prepare cyanoacetate, or carrying out acidolysis and esterification to prepare malonate. According to the method, cyanoacetic acid and sodium chloride are well separated by desalting methods such as electrodialysis after salt precipitation; and the problems of cyanoacetic acid decomposition caused by concentration separation of cyanoacetic acid and salt and sulfuric acid consumption andmixed salt wastewater treatment caused by residual sodium chloride during esterification in the prior art are avoided, so that the method is the environment-friendly and clean production method.

Description

technical field [0001] The invention relates to an environment-friendly and clean production method of high-purity cyanoacetic acid, cyanoacetate and malonate, belonging to the field of fine chemicals. Background technique [0002] Cyanoacetic acid is an important organic chemical intermediate with a wide range of uses. Its main downstream products include cyanoacetate and malonate. Cyanoacetate is an important intermediate of acrylic quick-drying adhesives. Malonate It is an important pharmaceutical and pesticide intermediate. [0003] At present, the industrial production of cyanoacetic acid uses chloroacetic acid as a raw material. The usual route is: neutralization reaction of chloroacetic acid and sodium carbonate (or sodium hydroxide) to obtain sodium chloroacetate, and then react with sodium cyanide to obtain sodium cyanoacetate and sodium chloride. , and then acidified with hydrochloric acid to obtain cyanoacetic acid and sodium chloride. It can be known from this ...

Claims

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Application Information

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IPC IPC(8): C07C253/30C07C253/34C07C255/19C07C51/09C07C55/08C07C67/08C07C69/38
CPCC02F2001/427C02F2103/36C07C51/09C07C67/08C07C253/30C07C253/34C07C255/19C07C55/08C07C69/38
Inventor 高春燕其他发明人请求不公开姓名
Owner 高春燕
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