Method for preparing 2,6-dichloro-4-nitroaniline through direct chlorination of chlorine gas and oxidative chlorination of hydrogen peroxide

A technology of nitroaniline and p-nitroaniline, applied in the field of preparation of 2,6-dichloronitro-4-aniline, which can solve the problems of low purity, increased difficulty in chlorination, and high production cost

Active Publication Date: 2015-05-13
昌邑新澳化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the formation of hydrochloric acid as a by-product, the concentration of hydrochloric acid gradually increases as the reaction progresses, resulting in dark color and low purity of the product
Sodium chlorate chlorination method and sodium hypochlorite chlorination method generate a large amount of inorganic salt waste liquid due to the by-product sodium chloride, forming waste hydrochloric acid containing a large amount of inorganic salt that cannot be recycled, and the po

Method used

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Examples

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specific Embodiment approach

[0021] The present invention will be further described below through specific examples, but not limited thereto.

[0022] The raw materials used in the examples are conventional raw materials, and the equipment used are conventional equipment, commercially available products.

Embodiment 1

[0024] A method for the simultaneous preparation of 2,6-dichloro-4-nitroaniline by direct chlorine chlorination and hydrogen peroxide oxidative chlorination, comprising the following steps:

[0025] Add 450mL of 25wt% hydrochloric acid mother liquor, p-nitroaniline 69g (0.5mol) in the 1000mL reaction flask that has stirring, thermometer, logical chlorine, hydrogen peroxide dripping and reflux condensation device, heat up to 60 ℃, stir 30min, make p-nitroaniline Nitroaniline is completely dissolved. Slowly feed 52.54 g (0.74 mol) of chlorine gas. After 10 minutes of feeding chlorine gas, slowly add 40.8 g (0.36 mol) of 30 wt % hydrogen peroxide dropwise. The time for feeding chlorine gas and dripping hydrogen peroxide is maintained within 3 hours. Continue to react for 30 minutes after the addition. Cool down to 30°C, filter, and collect the filtrate. The concentration of hydrochloric acid in the filtrate is maintained at 25wt%, and 450 mL of the mother liquor of hydrochloric ...

Embodiment 2

[0027] A method for the simultaneous preparation of 2,6-dichloro-4-nitroaniline by direct chlorine chlorination and hydrogen peroxide oxidative chlorination, comprising the following steps:

[0028] Add 500mL of 20wt% hydrochloric acid mother liquor and 69g (0.5mol) of p-nitroaniline into a 1000mL reaction flask equipped with stirring, thermometer, chlorine feeding, hydrogen peroxide dripping and reflux condensing device, heat up to 65°C, stir for 30min, and make p-nitroaniline Nitroaniline is completely dissolved. Slowly feed 45.57 g (0.67 mol) of chlorine gas. After 10 minutes of feeding chlorine gas, slowly add 44.88 g (0.33 mol) of 25 wt % hydrogen peroxide dropwise. The time for feeding chlorine gas and dripping hydrogen peroxide is maintained within 3.5 h. Continue to react for 30 minutes after the addition. Cool down to 30°C, filter, and collect the filtrate. The concentration of hydrochloric acid in the filtrate is maintained at 20wt%, and 500 mL of the mother liquor ...

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PUM

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Abstract

The invention relates to a method for preparing 2,6-dichloro-4-nitroaniline through direct chlorination of chlorine gas and oxidative chlorination of hydrogen peroxide. The method comprises the following steps: (1) adding paranitroaniline into hydrochloric acid at the concentration of 5-35wt%, heating to 40-80 DEG C, stirring for uniformly mixing, slowly inflating the chlorine gas within 0.5-5h, slowly adding hydrogen peroxide dropwise, and after adding the chlorine gas and the hydrogen peroxide, continuing to preserve heat and react for 0.3-1.5h; (2) filtering a product obtained in the step (1), washing a filter cake to be neutral, and drying to obtain the 2,6-dichloro-4-nitroaniline. By regulating a dosage ratio of the chlorine gas to the hydrogen peroxide, the concentration of the hydrochloric acid in a reaction system can be kept unchanged, the reaction process is steady and easily controlled, and the product is high in yield and purity.

Description

technical field [0001] The present invention relates to a preparation method of 2,6-dichloronitro-4-aniline, in particular to a method for simultaneously preparing 2,6-dichloro-4-nitroaniline by direct chlorine chlorination and hydrogen peroxide oxidative chlorination, The invention belongs to the technical field of organic intermediate chemical industry. Background technique [0002] 2,6-Dichloronitro-4-aniline (alias: 2,6-dichloro-p-nitroaniline; Chloronitroamine), English name: 2,6-Dichloro-4-nitroaniline, molecular formula: C 6 h 4 Cl 2 N 2 o 2 , Molecular weight: 207, Appearance: Yellow needle-like crystal, hardly soluble in water, easily soluble in ethanol and ether, slightly soluble in acetone, chloroform, ethyl acetate, melting point: 186-190°C. 2,6-Dichloronitro-4-aniline is an important dye intermediate, mainly used in the production of disperse dyes such as disperse yellow brown 3GL, disperse yellow brown 2RFL, disperse brown 3R, disperse orange S-4RL, disper...

Claims

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Application Information

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IPC IPC(8): C07C211/52C07C209/74
Inventor 付忠东高建伟徐丕法万克玲徐少华
Owner 昌邑新澳化工有限公司
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