阅读说明：本技术 一种2,3-二氰基丙酸乙酯的合成工艺 (Synthesis process of ethyl 2, 3-dicyanopropionate ) 是由 邵新华 王荣洲 何正江 徐亚华 于 2020-06-02 设计创作，主要内容包括：一种2,3-二氰基丙酸乙酯的合成工艺,在溶解釜中加入二甲基甲酰胺和氰化钠,高速搅拌后与二甲基甲酰胺、多聚甲醛合成,滴加氰乙酸乙酯后搅拌静置分层,分层后的水层继续蒸馏,有机层进入精馏釜中得到本发明2,3-二氰基丙酸乙酯产品。本发明工艺合理、产生的危险废物小,收率高,废水通过减压蒸馏后再通过精馏釜精馏回收原料,这样节约了生产成本,再剩余的废水做进一步废水处理,减少了废水的排放,保护了环境。(A process for synthesizing 2, 3-dicyanopropionic acid ethyl ester includes such steps as adding dimethyl formamide and sodium cyanide to dissolving kettle, high-speed stirring, synthesizing with dimethyl formamide and paraformaldehyde, dropping ethyl cyanoacetate, stirring, laying aside for layering, continuously distilling the layered water layer, and rectifying the organic layer in rectifying kettle to obtain the product of 2, 3-dicyanopropionic acid ethyl ester. The invention has reasonable process, less produced hazardous waste and high yield, the waste water is distilled under reduced pressure and then rectified by the rectifying still to recover the raw material, thus saving the production cost, and the residual waste water is further treated, reducing the discharge of waste water and protecting the environment.)

1. A synthesis process of ethyl 2, 3-dicyanopropionate is characterized by comprising the following steps:

1) adding 50-80 parts of dimethylformamide and 40-45 parts of sodium cyanide into a dissolving kettle, and stirring at a high speed to obtain suspended matters;

2) adding 160-180 parts of dimethylformamide and 25-30 parts of paraformaldehyde into a synthesis reaction kettle, adding the prepared suspended substance obtained in the step 1), heating and refluxing for 2 hours, cooling to 30 ℃, starting to dropwise add 80-100 parts of ethyl cyanoacetate, keeping the dropwise adding temperature at 28-31 ℃, and keeping the temperature at 30 ℃ for 4 hours; after the reaction is finished, cooling to 0 ℃, neutralizing to be neutral by using hydrochloric acid, adding 80-100 parts of water, stirring, standing and layering;

3) extracting the water layer separated by layers for 3 times by 200-220 parts of 1, 2-dichloroethane, separating the water layer and the organic layer, recovering the 1, 2-dichloroethane from the water layer by distillation, and feeding the separated organic layer into a rectifying still;

4) washing the layered organic layer once by 20-40 parts of water, continuously standing for layering, allowing the layered organic layer to enter a rectifying still, and allowing the layered water layer to enter wastewater treatment;

5) and 3) pumping the organic layer obtained in the step 4) into a rectifying still for vacuum distillation, and taking a fraction at 150-154 ℃ to obtain a light yellow oily liquid with the content of 98.5%, namely ethyl 2, 3-dicyanopropionate.

2. The process for synthesizing ethyl 2, 3-dicyanopropionate according to claim 1, wherein the proportion of parts extracted 3 times by 1, 2-dichloroethane in step 3) is 8: 8: 5.

3. the process for synthesizing ethyl 2, 3-dicyanopropionate according to claim 1, wherein the water separated layer in the step 3) is distilled under reduced pressure to a rectifying still and then rectified to obtain dimethylformamide.

Technical Field

The invention relates to the technical field of chemical industry, in particular to a synthesis process of ethyl 2, 3-dicyanopropionate.

Background

At present, the yield of chemical products such as medicines, pesticides and the like in China is continuously and stably increased all the time, so that the continuous and stable increase of synthetic intermediates is driven, the market demand of the intermediates is further expanded, the temperature of a reaction system is controlled to be higher to 20-30 ℃ in the original synthesis process of the ethyl 2, 3-dicyanopropionate, side reactions are more in the reaction process, materials are easy to polymerize, and the generated hazardous wastes are more and the yield is low.

Disclosure of Invention

The invention aims to provide a synthesis process of 2, 3-dicyanopropionic acid ethyl ester, which aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a synthesis process of ethyl 2, 3-dicyanopropionate comprises the following steps:

1) adding 50-80 parts of dimethylformamide and 40-45 parts of sodium cyanide into a dissolving kettle, and stirring at a high speed to obtain suspended matters;

2) adding 160-180 parts of dimethylformamide and 25-30 parts of paraformaldehyde into a synthesis reaction kettle, adding the prepared suspended substance obtained in the step 1), heating and refluxing for 2 hours, cooling to 30 ℃, starting to dropwise add 80-100 parts of ethyl cyanoacetate, keeping the dropwise adding temperature at 28-31 ℃, and keeping the temperature at 30 ℃ for 4 hours; after the reaction is finished, cooling to 0 ℃, neutralizing to be neutral by using hydrochloric acid, adding 80-100 parts of water, stirring, standing and layering;

3) extracting the water layer separated by layers for 3 times by 200-220 parts of 1, 2-dichloroethane, separating the water layer and the organic layer, recovering the 1, 2-dichloroethane from the water layer by distillation, and feeding the separated organic layer into a rectifying still;

4) washing the layered organic layer once by 20-40 parts of water, continuously standing for layering, allowing the layered organic layer to enter a rectifying still, and allowing the layered water layer to enter wastewater treatment;

5) and 3) pumping the organic layer obtained in the step 4) into a rectifying still for vacuum distillation, and taking a fraction at 150-154 ℃ to obtain a light yellow oily liquid with the content of 98.5%, namely ethyl 2, 3-dicyanopropionate.

Preferably, the proportion of parts extracted 3 times by using 1, 2-dichloroethane in the step 3) is 8: 8: 5.

preferably, the water layer removed in the step 3) is distilled to a rectifying still under reduced pressure and then rectified to obtain the dimethylformamide.

The invention has reasonable process, less produced hazardous waste and high yield, the waste water is distilled under reduced pressure and then rectified by the rectifying still to recover the raw material, thus saving the production cost, and the residual waste water is further treated, reducing the discharge of waste water and protecting the environment.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.