A kind of preparation method of chloroacetaldoxime

Abstract

The invention discloses a preparation method of chlorinated acetaldehyde oxime. The preparation method uses acetaldehyde oxime and chlorine gas as reaction raw materials and uses a microreactor as a reaction device to prepare chlorinated acetaldehyde oxime. The preparation method comprises the following steps: acetaldehyde The oxime and chlorine gas are simultaneously and continuously fed into the microreactor for reaction, and the product solution obtained by the neutralization reaction is obtained to obtain a chloroacetaldoxime solution. In the preparation method of the present invention, the microreactor is used as the reaction device, and the reaction can be quickly completed in a relatively short period of time, which can not only significantly reduce energy consumption, but also shorten the residence time, greatly improve the reaction efficiency, and can realize continuous feed and Discharge, remove the target product and reaction heat in time, reduce the decomposition of raw materials and the generation of explosive by-products, greatly improve the reaction yield and production safety, and have the advantages of high safety, simple operation, high yield, economical and environmental protection, etc. , has very good application value and application prospect.

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. [0002] technical background [0003] Chloroacetaldehyde oxime, English name: Chloroacetaldehyde Oxime, is an important intermediate for the synthesis of thiodimethomyl, methomyl, and acetaminocarb. The structural formula is as follows: [0004] [0005] 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 sho...

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Problems solved by technology

[0007] 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

[0008] 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

[0009] 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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