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Preparation method of 2,6-dihydroxybenzoic acid

A technology of dihydroxybenzoic acid and dichlorobenzaldehyde, applied in the chemical industry, can solve the problems of high raw material prices, cumbersome operation steps, and difficult treatment of phenol-containing strong acid wastewater, and achieve the effect of cheap raw materials, simple operation, and easy production

Inactive Publication Date: 2018-12-28
石家庄绿田科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] This method has problems such as cumbersome operation steps, high raw material price, and difficult treatment of phenol-containing strong acid wastewater.

Method used

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  • Preparation method of 2,6-dihydroxybenzoic acid
  • Preparation method of 2,6-dihydroxybenzoic acid
  • Preparation method of 2,6-dihydroxybenzoic acid

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0050] 1) Chlorination: Put 1L of organic solvent and 350g of 2,6-dichlorobenzaldehyde into the reaction kettle, and pass chlorine gas under the condition of temperature control at 50-150°C for chlorination. After passing the test, stop the chlorine flow, and the chlorination is over .

[0051] 2) Rectification: Put the chlorinated liquid into the rectification kettle, heat up the rectification and separate it, first distill out the solvent for recycling, and when the temperature at the top of the tower reaches 140-143°C, distill out qualified 2,6-dichlorobenzoyl chloride, 393.6 g of 2,6-dichlorobenzoyl chloride was weighed, and the conversion rate was 93.9%.

[0052] 3) Hydrolysis: Slowly add 1L of water to 2,6-dichlorobenzoyl chloride, slowly raise the temperature to reflux, cool down and filter to obtain 357.4 g of hydrolyzed product 2,6-dichlorobenzoic acid, with a conversion rate of 99.6%.

[0053] 4) Alkaline hydrolysis: Put the 2,6-dichlorobenzoic acid-base solution in...

example 2

[0056] 1) Chlorination: 1.5L of organic solvent and 525g of 2,6-dichlorobenzaldehyde were put into the reaction kettle, and chlorine gas was introduced into the reactor at a temperature of 50-150°C for chlorination. Finish.

[0057] 2) Rectification: Put the chlorinated liquid into the rectification kettle, heat up the rectification and separate it, first distill out the solvent for recycling, and when the temperature at the top of the tower reaches 140-143°C, distill out qualified 2,6-dichlorobenzoyl chloride, 586.6 g of 2,6-dichlorobenzoyl chloride was weighed, and the conversion rate was 93.7%.

[0058] 3) Hydrolysis: 1.5 L of water was slowly added to 2,6-dichlorobenzoyl chloride, and the temperature was raised slowly to reflux, and the temperature was lowered and filtered to obtain 532.7 g of hydrolyzed product 2,6-dichlorobenzoic acid, with a conversion rate of 99.6%.

[0059] 4) Alkaline hydrolysis: Put the 2,6-dichlorobenzoic acid-base solution into the reaction kettl...

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PUM

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Abstract

The invention discloses a preparation method of 2,6-dihydroxybenzoic acid. According to the synthetic method, 2,6-dichlorobenzaldehyde is taken as a raw material and subjected to chlorination in an organic solvent by adopting chlorine as a chlorinating agent, 2,6-dichlorobenzoyl chloride is obtained and subjected to hydrolysis, alkaline hydrolysis and acidification, and 2,6-dihydroxybenzoic acid is prepared. The method has the advantages that raw materials are cheap, the operation is simple and the product is easy to separate.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a preparation method of 2,6-dihydroxybenzoic acid. Background technique [0002] 2,6-Dihydroxybenzoic acid is an important organic synthesis intermediate for the production of pesticides, pharmaceuticals and photoinitiators. The key intermediate, the product is widely used in agricultural chemistry, pharmaceutical industry and other fields and has broad market prospects. [0003] The synthesis of 2,6-dihydroxybenzoic acid is currently mainly based on resorcinol and CO 2 As a raw material, in an organic solvent, react under the action of an alkali metal to obtain a high-purity target product through steps such as solvent recovery, organic solvent extraction, acidification, and recrystallization. Specifically, the general preparation method is to dissolve resorcinol In an organic solvent, add an alkali metal to the solution, heat it to 140 ° C, and pass through carbon dioxide to ...

Claims

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Application Information

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IPC IPC(8): C07C51/02C07C65/05
CPCC07C51/02C07C51/04C07C51/412C07C51/58C07C65/05C07C63/70
Inventor 肖俊兰王铁招张宇峰康志军陈中强董玉刚
Owner 石家庄绿田科技有限公司
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