Preparation method of p-chlorophenylhydrazine sulfate

Abstract

The invention discloses a preparation method of p-chlorophenylhydrazine sulfate, which comprises the following steps of by taking p-chloroaniline as a raw material, carrying out diazotization, reduction, acidolysis and crystallization centrifugation to obtain the p-chlorophenylhydrazine sulfate. According to diazotization, sulfate reacts with aniline, and then reacts with nitrososulfuric acid at low temperature to generate diazonium liquid; the obtained diazonium liquid reacts with sulfur dioxide under a certain pressure to generate an intermediate, then pressure is released, heating and refluxing are conducted for 1 hour, cooling, crystallizing and centrifuging are conducted to obtain p-chlorophenylhydrazine sulfate, the centrifuged mother liquor isadsorbed by carbon fibers, and the mother liquor is reused in diazotization synthesis; the purity of the p-chlorobenzene phenylhydrazine sulfate is more than 97%, the yield is more than 85%, compared with the prior art, the process has the advantages that no other metal cations are introduced, the centrifuged mother liquor can be applied to diazotization synthesis after being treated, no wastewater is generated, clean production is realized, and the requirements of safe production of current industrial production are met.

Description

technical field [0001] The invention relates to a production method of a compound, in particular to a preparation method of p-chlorophenylhydrazine sulfate. Background technique [0002] Pyraclostrobin is a new type of spectrum fungicide with broad-spectrum and high-efficiency bactericidal properties. What is more prominent is its low toxicity to non-target organisms, the environment and the safety of users. It is mainly used for spraying stems and leaves, which can effectively control Crop diseases caused by almost all types of fungal pathogens, such as Cysticomycetes, Basidiomycetes, Deuteromycetes and Oomycetes. Among them, phenylhydrazine salt is an important intermediate in the synthesis of pyraclostrobin. [0003] At present, phenylhydrazine hydrochloride is used as an intermediate for the synthesis of pyraclostrobin, and most of the methods for synthesizing phenylhydrazine hydrochloride introduce sodium nitrite and sodium sulfite. Acidic wastewater, which contains m...

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Problems solved by technology

[0003] At present, phenylhydrazine hydrochloride is used as an intermediate for the synthesis of pyraclostrobin, and most of the methods for synthesizing phenylhydrazine hydrochloride introduce sodium nitrite and sodium sulfite. Acidic wastewater, which contains miscellaneous salts, is difficult to treat;

[0004] U.S. Patent (US0047023) adopted p-chloroaniline, hydrochloric acid and sodium nitrite to react to generate diazonium liquid, then react with suitable reducing agent (sodium sulfite, sodium thiosulfate, etc.), and obtain phenylhydrazine hydrochloric acid after the reaction Salt; after the reaction, there will be more miscellaneous salt wastewater, which is more difficult to deal with

[0005] European patent (EP0959067) adopts p-chloroaniline, hydrochloric acid and n-butanol as solvents to synthesize p-chlorophenylhydrazine hydrochloride, and obtain the collection of p-chlorophenylhydrazine hydrochloride, which is as low as 36.2%, and the post-treatment is complicated

[0006] The Chinese patent (CN106187811A) uses p-chloroaniline, hydrochloric acid and sodium nitrite to synthesize p-chlorophenylhydrazine hydrochloride. Sodium nitrite is used as a reducing agent at high temperature, which is risky, and the patent does not propose a post-treatment method.

[0007] Chinese patent (CN106278937A) is to use hydrogen to reduce diazonium liquid under the action of catalyst, the three wastes that this method produces are few, but catalyst cost is high, still has more hydrochloric acid containing waste water to produce

[0008] Bibliographical reports: Synthetic process of p-chlorophenylhydrazine hydrochloride [J]. Applied Chemistry, 2001, 18 (12): 1001-1003. It is reported that p-chloroaniline is diazotized with hydrochloric acid and sodium nitrite, and then used After reduction and hydrolysis of sodium sulfite, the crude product is obtained by filtration, then filtered with alkali to obtain p-chlorophenylhydrazine, and then acid is added to obtain p-chlorophenylhydrazine hydrochloride. The product obtained in this process has high purity, but it is complicated and unfavorable for industry Production

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