A kind of preparation method of 2,5-dimethoxy-4-chloroacetoacetanilide

A kind of technology of chloroacetoacetanilide and dimethoxy, applied in 2 fields, can solve the problems of large energy consumption, large material loss and the like

Active Publication Date: 2019-03-01
NANTONG ACETIC ACID CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to obtain a high-quality product with a low content of enol structure, secondary refining and purification must be carried out, resulting in large material loss and high energy consumption, and the content of enol isomers in the product is usually only guaranteed to be below 100ppm

Method used

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  • A kind of preparation method of 2,5-dimethoxy-4-chloroacetoacetanilide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Add ethanol and 100 grams of 2,5-dimethoxy-4-chloroaniline to a 500ml three-necked flask equipped with a stirrer and a thermometer, control the temperature at 50°C, add 44.8 grams of diketene dropwise, and continue After 4 hours of reaction, the reaction was completed. The pH of the reaction solution was adjusted to 3.0 with hydrochloric acid, and the reaction solution was rapidly cooled at a rate of 35°C / min. Filter, wash and dry at 5°C to obtain the product. According to HPLC analysis, the content of enol isomer in 2,5-dimethoxy-4-chloroacetoacetanilide is 28 ppm.

Embodiment 2

[0033] Add methanol and 100 grams of 2,5-dimethoxy-4-chloroaniline to a 500ml three-necked flask equipped with a stirrer and a thermometer, control the temperature at 25°C, add 53.7 grams of diketene dropwise, and continue After reacting for 2 hours, the reaction was completed. The pH of the reaction solution was adjusted to 3.0 with hydrochloric acid, and the reaction solution was rapidly cooled at a speed of 30°C / min. Filter, wash and dry at 10°C to obtain the product. According to HPLC analysis, the content of enol isomer in 2,5-dimethoxy-4-chloroacetoacetanilide is 20 ppm.

Embodiment 3

[0035] Add 100 grams of isopropanol and 2,5-dimethoxy-4-chloroaniline to a 500ml three-necked flask equipped with a stirrer and a thermometer, control the temperature at 60°C, add 51.2 grams of diketene dropwise, and continue After reacting for 2.5 hours, the reaction was completed. The pH of the reaction solution was adjusted to 2.5 with hydrochloric acid, and it was rapidly cooled at a rate of 40°C / min. °C, filtered, washed, and dried to obtain the product. According to HPLC analysis, the content of enol isomer in 2,5-dimethoxy-4-chloroacetoacetanilide was 34 ppm.

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Abstract

The invention discloses a preparation method of 4-Chloro-2,5-dimethoxyacetoace tanilide. The preparation method particularly comprises the following steps: adding an alcohols solvent or an acetic acid solvent into a reactor, meanwhile, adding 2,5-dimethoxy-4-chloroaniline, controlling the temperature to be 10-100 DEG C, dripping acetyl ketene, and finishing adding after 0.5-4 h, wherein the molar ratio of 2,5-dimethoxy-4-chloroaniline to acetyl ketene is 1:1-1:1.2; and after finish of dripping, preserving the temperature for 0.5-4 h, keeping the material in a fully-dissolved state after finish of reaction, adjusting the pH to be 0.5-5.0, quickly cooling with a refrigerating fluid, quickly stirring, controlling the cooling speed to be 5-40 DEG C / min, enabling 4-Chloro-2,5-dimethoxyacetoace tanilide to be quickly separated out as powder, cooling to -10 DEG C to 20 DEG C, filtering and drying obtain 4-Chloro-2,5-dimethoxyacetoace tanilide. The preparation method is simple, and the enolic isomer content in obtained 4-Chloro-2,5-dimethoxyacetoace tanilide can be controlled to be 50 ppm or below.

Description

technical field [0001] The invention relates to the field of chemical purification, in particular to a preparation method of 2,5-dimethoxy-4-chloroacetoacetanilide. Background technique [0002] 2,5-dimethoxy-4-chloroacetoacetanilide, its English name: 4-Chloro-2,5-dimethoxyacetoace tanilide, alias: naphthol AS-IRG, its molecular formula and molecular weight are C 12 h 14 ClNO 4 , 271.7. Appearance: white to off-white crystalline powder, melting point: 102-104°C (228K); boiling point: 432.7°C at 760mmHg; relative density: 1.277; color index: 37613, flash point: 215.5°C, molar refractive index: 68.07; isotonic specific volume ( 90.2K): 544.8; surface tension (dyne / cm): 43.1; polarizability (10-24cm 3 ): 26.98. [0003] 2,5-dimethoxy-4-chloroacetoacetanilide is an intermediate for the preparation of organic dyes and pigments, and can be used to prepare C.I.83 organic yellow pigments, pigment yellow 83 and ice dyes, C.I. pigment yellow 75, 152 and other varieties It can a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C231/04C07C235/80
CPCC07C231/04C07C235/80
Inventor 丁彩峰庆九朱小刚刘芳孙赵姚俊生
Owner NANTONG ACETIC ACID CHEM
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