Process for synthesizing pyraclostrobin intermediate alpha-bromo-2-nitrotoluene

Abstract

The invention discloses a process for synthesizing a pyraclostrobin intermediate alpha-bromo-2-nitrotoluene. The process method specifically comprises the following steps: adding quantitative chlorobenzene and an HBr aqueous solution into the reactor, raising the temperature to be 40-50 DEG C, simultaneously dropwise adding ortho-nitrotoluene and hydrogen peroxide, and maintaining the temperature for 5-6 hours; transferring into a pH value regulation kettle after the reaction is ended, adding sodium hydroxide to regulate the pH value to be neutral; and transferring into an extraction kettle, standing and layering, extracting the organic phase, thereby obtaining the alpha-bromo-2-nitrotoluene chlorobenzene solution. According to the process disclosed by the invention, the solvent can be effectively recovered from the pyraclostrobin intermediate alpha-bromo-2-nitrotoluene after the primary reaction is ended, the synthetic cost is saved, the economic benefits are improved, the synthetic process design of the pyraclostrobin intermediate alpha-bromo-2-nitrotoluene is optimized, and the requirement on the synthetic process design of the pyraclostrobin intermediate alpha-bromo-2-nitrotoluene is met.

Description

technical field [0001] The invention relates to the technical field of pesticide synthesis, in particular to a synthesis process of pyraclostrobin intermediate o-nitrobenzyl bromide. Background technique [0002] Methoxyacrylate fungicides are a class of low-toxicity, high-efficiency, broad-spectrum, systemic fungicides. They are new fungicides with great development potential and market vitality in the world’s pesticide industry; pyraclostrobin is currently the most active fungicide. A good methoxyacrylate fungicide, which was first developed and researched by BASF in Germany, and was launched in the European market in 2002; pyraclostrobin has the disadvantages of high efficiency, low toxicity, environmental friendliness, and a wide range of crops ; In the short few years since pyraclostrobin was listed, the market of this variety has soared rapidly, and the sales have risen rapidly, and it has been listed as the second place in the market of all bacterial agents, second on...

AI Technical Summary

Problems solved by technology

[0006] 1. There is no agitator in the o-nitrobenzyl bromide synthesis kettle or the setting of stirring parameters is unreasonable, so that the synthesis efficiency of pyraclostrobin intermediate o-nitrobenzyl bromide is low, and the yield is low, which is not conducive to large-scale production ;

[0007] 2. The organic liquid after pH adjustment has not been multi-stage extracted, resulting in various impurities in the final product, affecting the purity and actual use value of the product, which is not conducive to economy, and does not meet the actual requirements of green environmental protection and safety;

[0008] 3. The water layer recovered through extraction is not directly used in the synthesis kettle of o-nitrobenzyl bromide for reaction, which increases the price of sewage treatment, wastes production costs, and is not conducive to economy

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