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Method for preparing CLT acid by taking m-toluidine as raw material

A technology of toluidine and raw materials, applied in the field of preparing CLT acid, can solve the problems of low yield of salt-forming amino group, and achieve the effects of high yield, few by-products, and no dangerous process

Active Publication Date: 2019-11-22
ZHEJIANG UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the yield of salt-forming amino protection is still low

Method used

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  • Method for preparing CLT acid by taking m-toluidine as raw material
  • Method for preparing CLT acid by taking m-toluidine as raw material
  • Method for preparing CLT acid by taking m-toluidine as raw material

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Embodiment 1

[0054] (1) Acylation operation steps: Add a magnetic stirrer in a 250mL three-necked flask, add m-toluidine (20.00g, 190.00mmol) under nitrogen protection at room temperature, and add acetic anhydride (20.60g ,171.54mmol), after the acetic anhydride was dropped, the temperature was raised to 85°C and stirred for about 1.0h, then the heating was stopped.

[0055] Reaction result: the content of m-acetamidotoluene was analyzed by HPLC to be >99%.

[0056] (2) Chlorination operation steps: Use an ice-water bath to cool down the acylation reaction solution. When the temperature drops to about 20°C, add 25mL of acetic acid and 44.08g (about 38.00mL) of concentrated hydrochloric acid to the acylation reaction solution. Use an ice-water bath to cool down to 15°C, use a constant pressure dropping funnel to add 22.22g of hydrogen peroxide dropwise within 60 minutes, keep stirring at 15-20°C for 2.5h after the hydrogen peroxide drops, then raise the temperature to 20-25°C and keep stirr...

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Abstract

The invention discloses a method for preparing CLT acid by taking m-toluidine as a raw material, and belongs to the field of chemical synthesis. The method solves the problems that existing CLT acid production is low in yield, not environmentally friendly and the like. The method comprises: S01) an acylation step, namely a step of reacting m-toluidine and acetic anhydride to obtain acylation reaction solution; S02) a chlorination step, namely a step of adding acetic acid and concentrated hydrochloric acid into the acylation reaction solution, then adding hydrogen peroxide, and finally adding an aqueous solution containing sodium sulfite to obtain a chlorination reaction solution; S03) a hydrolyzing step to form salt, namely a step of adding concentrated sulfuric acid into the chlorinationreaction solution, and removing the solvent after reaction; S04) a transposition sulfonation step, namely a step of adding chlorobenzene into the solvent-removed reaction solution obtained in the stepS03, heating the mixture, adding dichlorobenzene, heating the mixture again, reacting the mixture for 7-10 hours with the temperature of the system being maintained at a temperature higher than 170 DEG C, and stopping heating; and S05) a step of post-treatment to obtain a finished product that is the CLT acid. The method has the advantages of environmental protection and the like.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, in particular to a method for preparing CLT acid by using m-toluidine as a raw material. Background technique [0002] CLT acid, chemical name: 2-amino-5-chloro-4-methylbenzene, referred to as C acid, white powder, insoluble in water. It is an important red organic pigment intermediate. CLT acid is one of the organic intermediates whose annual consumption exceeds 10,000 tons in the world. In the production process of CLT acid, the main pollutants are waste water, waste gas and waste residue. Due to pollution problems, developed countries in the world have shut down some production equipment or restricted production to reduce pollution. Some enterprises in my country have been forced to stop production due to pollution problems. As the country pays more and more attention to environmental protection, the problem of "three wastes" treatment will be related to the fate of my country's CLT acid ind...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C303/04C07C309/48C07C209/62C07C211/52C07C231/12C07C231/02C07C233/15C07C209/00
CPCC07C303/04C07C209/62C07C231/12C07C231/02C07C209/00C07C309/48C07C211/52C07C233/15
Inventor 贾建洪李益珠冯东
Owner ZHEJIANG UNIV OF TECH
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