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High-yield ethyl chrysanthemate preparation method

A high-yield technology of ethyl chrysanthemum acid, applied in the field of chemical technology, can solve the problem of low chemical yield, and achieve the effects of reducing poisoning and excellent environmental protection performance

Active Publication Date: 2020-11-24
湖北中灏科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Use ethyl diazoacetate and 2,5-dimethyl-2,4-hexadiene as raw materials to prepare ethyl chrysanthemum acid, usually using copper powder as catalyst, toluene or halogenated hydrocarbon as solvent, but there is a chemical yield not high problem

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] A high-yield preparation method of ethyl chrysanthemum acid, comprising the following steps:

[0039] (1) Diazotization: Put 600 parts of water, 490 parts of glycine ethyl acetate and 35 parts of glacial acetic acid into the diazotization kettle, stir to dissolve the solid, and use glacial acetic acid to keep the pH value of the diazotization reaction at 3.5~ Between 4.5, then put 800 parts of dimethyl carbonate as a solvent into the diazotization kettle, turn on the freezer, reduce the temperature of the diazotization kettle to 20-25°C, and then add the sodium nitrite aqueous solution dropwise into the diazotization kettle , the sodium nitrite addition time is controlled within 4-5 hours, after the addition, the temperature is kept for 60 minutes, after the reaction is completed, the layers are static, and the lower water layer is discharged to the waste liquid collection tank to obtain the diazonium liquid;

[0040](2) Cyclization: put 1100 parts of 2,5-dimethyl-2,4-h...

Embodiment 2

[0052] The difference between embodiment 2 and embodiment 1 is:

[0053] (1) Diazotization: Put 500 parts of water, 480 parts of glycine ethyl acetate and 36 parts of glacial acetic acid into the diazotization kettle, stir to dissolve the solid, and use glacial acetic acid to keep the pH value of the diazotization reaction at 3.5~ Between 4.5, then put 800 parts of dimethyl carbonate as a solvent into the diazotization kettle, turn on the freezer, reduce the temperature of the diazotization kettle to 20-25°C, and then add the sodium nitrite aqueous solution dropwise into the diazotization kettle , the sodium nitrite dropping time is controlled within 4-5 hours, after the dropping, keep warm for 45 minutes, after the reaction is completed, static layering, the lower water layer is discharged to the waste liquid collection tank, and the diazonium liquid is obtained;

[0054] (2) Cyclization: Put 1,100 parts of 2,5-dimethyl-2,4-hexadiene into the cyclization kettle, use 3.5 parts...

Embodiment 3

[0056] The difference between embodiment 3 and embodiment 1 is:

[0057] (1) Diazotization: Put 700 parts of water, 470 parts of glycine ethyl acetate and 37 parts of glacial acetic acid into the diazotization kettle, stir to dissolve the solid, and use glacial acetic acid to keep the pH value of the diazotization reaction at 3.5~ Between 4.5, then put 800 parts of dimethyl carbonate as a solvent into the diazotization kettle, turn on the freezer, reduce the temperature of the diazotization kettle to 20-25°C, and then add the sodium nitrite aqueous solution dropwise into the diazotization kettle , the sodium nitrite addition time is controlled within 4-5 hours, after the addition, the temperature is kept for 60 minutes, after the reaction is completed, the layers are static, and the lower water layer is discharged to the waste liquid collection tank to obtain the diazonium liquid;

[0058] (2) Cyclization: Put 1100 parts of 2,5-dimethyl-2,4-hexadiene into the cyclization kettl...

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Abstract

The invention belongs to the technical field of chemical processes, and specifically relates to a high-yield ethyl chrysanthemate preparation method. The high-yield ethyl chrysanthemate preparation method comprises the following steps: (1) diazotization: a step of adding water, glycine ethyl ester acid salt, glacial acetic acid and dimethyl carbonate as solvents into a diazotization kettle, dropwisely adding a sodium nitrite aqueous solution into the diazotization kettle, and carrying out a reaction so as to a diazo liquid; (2) cyclization: a step of putting 2,5-dimethyl-2,4-hexadiene into a cyclization kettle, and carrying out a reaction with cuprous chloride as a catalyst so as to obtain a cyclized solution; (3) desolventizing: a step of sending the cyclized solution into a high-yield desolventizing tower to remove the solvents so as to obtain a crude ethyl chrysanthemate product; and (4) distillation: a step of putting the crude ethyl chrysanthemate product into a distillation kettle, and carrying out vacuum distillation so as to obtain the high-purity ethyl chrysanthemate. The high-yield ethyl chrysanthemate preparation method provided by the invention has the following beneficial effects: when the dimethyl carbonate is used as a solvent, a diazotization reaction can be carried out more completely, so the loss of raw materials is reduced; and meanwhile, the yield of ethyl chrysanthemate in the subsequent cyclization reaction can be improved.

Description

technical field [0001] The invention belongs to the technical field of chemical technology, in particular to a high-yield preparation method of ethyl chrysanthemum acid. Background technique [0002] Ethyl permethrin, like methyl permethrin, is also an important intermediate of pyrethroids, which can be used to prepare a variety of hygienic pyrethroids, including allethrin, tetramethrin, phenethrin, and pyrethrin and other pesticides. The reaction between ethyl diazoacetate and 2,5-dimethyl-2,4-hexadiene is one of the most important and industrially applicable synthetic routes. Use ethyl diazoacetate and 2,5-dimethyl-2,4-hexadiene as raw materials to prepare ethyl chrysanthemum acid, usually using copper powder as catalyst, toluene or halogenated hydrocarbon as solvent, but there is a chemical yield Not a high question. Contents of the invention [0003] The purpose of the present invention is to provide a high-yield preparation method of ethyl chrysanthemum acid, which...

Claims

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Application Information

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IPC IPC(8): C07C67/343C07C67/52C07C67/54C07C69/747C07C245/20B01J27/122
CPCC07C67/343C07C67/52C07C67/54C07C245/20B01J27/122C07C2601/02C07C69/747
Inventor 黄金铨李国江丁作艳
Owner 湖北中灏科技有限公司
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