Method for synthesizing lufenuron intermediate through continuous reactions

Abstract

The invention discloses a method for synthesizing a lufenuron intermediate through continuous reactions. According to the method, a micro-channel reactor is adopted, three steps of continuous reactions of addition, nitration and pressurized hydrogenation without separation can be implemented for the lufenuron intermediate, continuous product can be achieved, the total yield of the lufenuron intermediate is greater than 92%, the purity of the lufenuron intermediate is greater than 99% or greater, meanwhile the production cycle is greatly shortened, the conversion rate is increased, side reactions are reduced, the amount of an expensive gas, namely perfluoropropylene, used in a first step of an addition process, is reduced, and thus the production cost can be greatly reduced; the danger thatexplosion can be easily caused by dangerous hydrogenation and nitration processes is also avoided; meanwhile, the problem that an expensive catalyst, namely Pt / C used in a conventional kettle type hydrogenation process, is low in reuse time, is also solved.

Description

technical field [0001] The invention relates to a method for synthesizing a lufenuron intermediate by continuous reaction. Background technique [0002] The trade name of lufenuron is Meichu, which is a substituted urea insecticide produced by Syngenta, and 2,5-dichloro-4-(1,1,2,3,3,3-hexafluoropropane Oxygen) aniline is an indispensable important intermediate for the synthesis of lufenuron, and its structural formula is as follows for I: [0003] [0004] Lufenuron is the largest product among benzoylurea insecticides. In 1993, Syngenta first launched lufenuron in France. It is used in corn. The main market of lufenuron is in the field of animal health. It is used to prevent fleas on cats and dogs, and the trade name is Program. [0005] In agriculture, lufenuron has been registered on many crops, especially soybean, cotton, corn and vegetables; it has also been registered in many countries, especially Japan and Brazil; Brazil has become the main market for lufenuron. ...

AI Technical Summary

Problems solved by technology

[0010] There are the following disadvantages in using the first method to carry out the kettle reaction: there are many wastes to be reduced, the loss of the expensive gas perfluoropropylene is large and the yield is low, and the nitrification reaction is dangerous, resulting in high costs, so this route is generally not used in industry

[0020] At present, lufenuron technical is not only used as a herbicide, but also used in the prevention and control of fleas on pet cats and dogs and termite control; under this background, large foreign companies such as Syngenta have particularly high quality requirements for lufenuron technical , it is required that the content of all individual impurities in the sample is less than 0.1%, while the traditional kettle reaction is an early backward technology, the quantitative content of the original drug product is low, and there are many impurities; many impurities are difficult to remove through post-treatment purification, which not only increases the The environmental pollution caused by purification has also greatly increased the manufacturing cost, so seeking new synthesis methods has become an unstoppable trend

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