Preparation method of high-purity bromoxynil octanoate

Abstract

The invention discloses a preparation method of high-purity bromoxynil octanoate. According to a reaction sequence, the preparation method successively comprises bromination reaction and esterification reaction steps, and comprises the following steps: adding water and cyanophenol into a reaction container, and dropwise adding hydrogen peroxide and bromine, controlling a dropwise adding temperature to be 20-100 DEG C, heat-insulating reacting for 1-2 hours, sampling, after the reaction is qualified, adding sodium carbonate to break the excessive hydrogen peroxide, and then adding a solvent, dropwise adding caustic soda liquid and caprylyl chloride simultaneously, controlling a reaction temperature to be 0-50 DEG C, after dropwise adding, heat-insulating reacting for 1-2 hours, sampling, controlling by neutralizing, washing by the water after qualified, recovering the solvent, sampling and detecting, discharging and barreling after qualified. The bromination is firstly performed, and the esterification is performed in the reaction. The reaction is controllable. Existing problems that the esterification reaction is firstly performed so that the space resistance of an octoate group islarge and the reaction activity thereof is weaker than the reaction activity of a phenolic hydroxyl group are solved. The bromination is also performed firstly without using an expensive catalyst, and excessive caprylyl chloride does not need to be recovered by warming at the same time, so the recovery difficulty is reduced.

Description

technical field [0001] The invention relates to a method for synthesizing the original pesticide, in particular to a method for preparing high-purity octanoyl bromoxynil. Background technique [0002] At present, the synthesis of bromoxynil octanoyl is generally divided into two steps, bromoxynil is synthesized by bromoxynil first, and then it is subjected to acylation reaction to obtain bromoxynil octanoyl. Since the bromoxynil produced by bromination is a solid, centrifugation is required, and the transfer requirements after centrifugation are extremely high. Once leaked, it will cause serious environmental pollution accidents, and the bromine mother liquor needs to be recovered, which is labor-intensive and low in production automation. [0003] There is a known and disclosed preparation process of bromoxynil octanoyl, patent number: CN201510293082.8, which has certain disadvantages: 1. The esterification reaction needs to be carried out at high temperature, and after the...

AI Technical Summary

Problems solved by technology

Since the bromoxynil produced by bromination is a solid, it needs to be separated by centrifugation, and the transfer requirements after centrifugation are extremely high. Once it leaks, it will cause serious environmental pollution accidents, and the bromide mother liquor needs to be recycled, which is labor-intensive and low in production automation.

[0003] There is a known and disclosed preparation process of bromoxynil octanoyl, patent number: CN201510293082.8, which has certain disadvantages: 1. The esterification reaction needs to be carried out at high temperature, and after the first step of esterification, it needs Recover excess octanoyl chloride by heating; 2. Using the process of esterification first, the octanoyl ester group has a large steric resistance, and its reactivity is weaker than that of the phenolic hydroxyl group, which increases the difficulty of the bromination reaction and requires the use of expensive catalysts, otherwise the reaction will fail. conduct

Octanoyl chloride is poisonous, the recovery process is not easy to carry out, and the use of expensive catalysts greatly increases the cost and prolongs the time of the entire process

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