Preparation method of chloroacetaldehyde oxime

Abstract

The invention discloses a preparation method of chloroacetaldehyde oxime. Chloroacetaldehyde oxime is prepared with acetaldehyde oxime and chlorine gas as raw reaction materials and a micro reactor asa reaction device; the preparation method comprises the following steps of simultaneously and continuously introducing acetaldehyde oxime and the chlorine gas into the micro reactor for a reaction, and conducting a neutralization reaction on an obtained product solution to obtain a chloroacetaldehyde hydrazine solution. According to the preparation method, the micro reactor is used as the reaction device, the reaction can be completed quickly within a short time, the energy consumption can be significantly reduced, the staying time can be shortened, the reaction efficiency is greatly improved, continuous feeding and discharging can be achieved, a target product and reaction discharged heat are timely removed, the decomposition of raw materials and the production of explosive by-products are reduced, the reaction yield is greatly increased, the production safety is greatly improved, and the method has the advantages of high safety, simple operation, high yield, economical performance,environmental protection and the like, and has good application value and application prospects.

Description

technical field [0001] The invention relates to a preparation method of chloroacetaldehyde oxime, in particular to a method for preparing chloroacetaldehyde oxime by using a microreactor. technical background [0002] Chloroacetaldehyde oxime, English name: Chloroacetaldehyde Oxime, is an important intermediate for the synthesis of thiodimethomyl, methomyl, and acetaminocarb. The structural formula is as follows: [0003] [0004] At present, most domestic manufacturers use acetaldehyde oxime aqueous solution and chlorine gas to chlorinate at low temperature in the reactor. After the reaction is completed, add soda ash to neutralize to obtain chloroacetaldoxime. Decomposition, so the reaction yield is low, and the reaction produces a large amount of saline waste water; Simultaneously, the tank reaction increases the opportunity of chloroacetaldoxime to continue to contact with chlorine, and it is very easy to generate explosive dichloronitroso by-products (as shown below...

AI Technical Summary

Problems solved by technology

[0006] US4327033 discloses a preparation method of using N-methylpyrrolidone as a solvent and acetaldehyde oxime as a raw material through chlorine chlorination to synthesize chloroacetaldehyde oxime in a kettle-type reaction equipment. This method reduces waste water, but cannot avoid acetaldehyde Acid Decomposition of Oxime and Formation of Dichloronitroso by-product

[0007] CN106757137A and CN107916446A disclose the clean preparation of chloroacetaldehyde oxime by combining electrolysis and organic chlorination. This method can effectively avoid salty wastewater, but the process is complicated and the conditions are harsh. It is currently difficult to be used in industrial production and the production cost is relatively high. high

[0008] In summary, there are the following problems in the existing method for preparing chloroacetaldoxime: (1) the chlorination reaction process is difficult to control, and it is easy to generate explosive dichloronitroso by-products, which will pose a serious threat to production safety; (2) The electrolysis process is complicated, the conditions are harsh, and the production cost is high, so it is difficult to realize large-scale industrial production and utilization; (3) The raw materials are easily decomposed in an acidic system, and the reaction yield is low; (4) The neutralization process produces a large amount of Salt wastewater, which greatly increases the cost of wastewater treatment and the pressure on environmental protection

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