Preparation method of oxadiazon intermediate 2, 4-dichloro-5-isopropoxyphenylhydrazine

A technology for isopropoxyphenylhydrazine and intermediates, which is applied in the field of preparing 2,4-dichloro-5-isopropoxyphenylhydrazine, can solve the problems of difficult waste water treatment, expensive raw materials, difficult recovery and the like

Active Publication Date: 2021-04-20
湖南兴同化学科技有限公司
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  • Description
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  • Application Information

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Problems solved by technology

[0008] In order to overcome the above problems, the present invention aims to provide a novel preparation method of 2,4-dichloro-5-isopropoxyphenylhydrazine to solve the pr

Method used

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  • Preparation method of oxadiazon intermediate 2, 4-dichloro-5-isopropoxyphenylhydrazine
  • Preparation method of oxadiazon intermediate 2, 4-dichloro-5-isopropoxyphenylhydrazine
  • Preparation method of oxadiazon intermediate 2, 4-dichloro-5-isopropoxyphenylhydrazine

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Example Embodiment

[0029]Example 1

[0030]200g of 2,4-dichloro-5-isopropoxyenylamine content of 35% was added to 200 g of a 500 ml of a four-mouth flask inserted with a condensation pipe, and 40% hydrochloric acid was slowly poured at room temperature. After stirring 0.5 h, potassium cyanate was 33.5 g, then slowly warmed to 100 ~ 105 ° C, refluxed for 2 h, gas chromatographic tracking of raw materials 2,4-dichloro-5-isopropoxyine <1%, the reaction end , Cool down, intermediate (phenyl urea), to be added to the sodium chlorite solution.

[0031]When the temperature drops to 20 ~ 25 ° C, 372 g (urea, hypochlorite, sodium alkali), 1: 1.25: 2.6 of the alkali is started, and the temperature of the entire process is not more than 25 ° C, and add After completing, the insulation reaction is 40 min, then the temperature is slowly warmed to 80 ~ 85 ° C, continue the insulation reaction for 1 h, the liquid chromatography tracking raw material peak is less than 1% to the end point of the reaction, 2,4-dichloro-5-iso...

Example Embodiment

[0033]Example 2

[0034]Preparation of phenylurea (intermediate) is in Example 1, the second step degradation re-row process replaces sodium hypochlorite to sodium bromate, 2,4-dichloro-5-isopropoxy iscylate purity 98.8%, 2,4-dichloro-5-isopropylamine to the 2nd step yield of benzide reached 92.69%.

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Abstract

The invention provides a preparation method of a herbicide oxadiazon intermediate 2, 4-dichloro-5-isopropoxy phenylhydrazine, which comprises the following steps: by taking a toluene solution of 2, 4-dichloro-5-isopropoxy aniline as a raw material, stirring to form a salt under an acidic condition, reacting with cyanate at a certain temperature to generate urea, degrading and rearranging by Hofmann in an alkaline environment, filtering, after recovering a solvent at normal pressure, taking 2, 4-dichloro-5-isopropoxy phenylhydrazine as a raw material, adding chloroform for extraction, and obtaining a chloroform solution of the 2, 4-dichloro-5-isopropoxy phenylhydrazine which can be directly used for an acylation process to synthesize the oxadiazon key intermediate 2, 4-dichloro-5-isopropoxy phenylhydrazine. According to the method disclosed by the invention, a complicated tin recovery process caused by reduction of diazonium salt by stannous chloride in a traditional synthesis process is effectively avoided, and generation of a large amount of high-salt wastewater in a recovery section is avoided; on the other hand, alkalization operation is avoided, solid materials are not added, the labor intensity is greatly reduced, and the production efficiency is effectively improved.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a method for preparing 2,4-dichloro-5-isopropoxyphenylhydrazine. Background technique [0002] Oxadiazone is a high-efficiency broad-spectrum herbicide for controlling various annual monocotyledonous and dicotyledonous weeds. Its structural formula is: [0003] [0004] Both 2,4-dichloro-5-isopropoxyaniline and 2,4-dichloro-5-isopropoxyphenylhydrazine are key intermediates for the synthesis of oxadiazone. [0005] In the prior art, the synthetic method of 2,4-dichloro-5-isopropoxyphenylhydrazine generally needs 2,4-dichloro-5-isopropoxyaniline to generate diazonium salt through diazotization, and then The 2,4-dichloro-5-isopropoxyphenylhydrazine hydrochloride was prepared by reduction with a reducing agent, and then the product 2,4-dichloro-5-isopropoxyphenylhydrazine was obtained by alkalinization. The thermal stability of the diazonium salt in the diazotization p...

Claims

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Application Information

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IPC IPC(8): C07C241/02C07C243/22
Inventor 廖丽莎朱有为熊运畅李华轩甘娟王宇
Owner 湖南兴同化学科技有限公司
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