A method for simultaneously preparing 2,6-dichloro-4-nitroaniline by direct chlorination of chlorine gas and oxidative chlorination of hydrogen peroxide

A technology of nitroaniline and p-nitroaniline, which is applied in the field of preparation of 2,6-dichloronitro-4-aniline, can solve the problems of inability to recycle, low product yield, high production cost, etc.

Active Publication Date: 2016-03-16
昌邑新澳化工有限公司
View PDF0 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

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 post-treatment amount is large, resulting in high production costs
The dichlorosulfuryl method produces a large amount of sulfur dioxide and hydrogen chloride gas, and it is difficult to treat the three wastes
Hydrogen peroxide oxidative chlorination method, due to the water brought in and the water generated during the oxidation process, the concentration of hydrochloric acid gradually decreases, making the later stage chlorination more difficult, resulting in low product yield and low purity

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

specific Embodiment approach

[0021] The present invention will be further illustrated below through specific embodiments, but it is not limited thereto.

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

Embodiment 1

[0024] A method for preparing 2,6-dichloro-4-nitroaniline simultaneously by direct chlorination of chlorine gas and oxidative chlorination of hydrogen peroxide, including the following steps:

[0025] Add 450mL of 25wt% hydrochloric acid mother liquor and 69g (0.5mol) of p-nitroaniline into a 1000mL reaction flask equipped with stirring, thermometer, chlorine, hydrogen peroxide and reflux condenser. The temperature is raised to 60℃ and stirred for 30min to make the Nitroaniline is completely dissolved. Chlorine 52.54g (0.74mol) was introduced slowly. After 10min of chlorine gas, 40.8g (0.36mol) of 30wt% hydrogen peroxide was slowly added dropwise. The time for both chlorine and hydrogen peroxide was maintained within 3h. After the addition, the reaction was continued for 30 minutes. Cool to 30°C, filter, and collect the filtrate. The hydrochloric acid concentration of the filtrate is maintained at 25wt%. 450 mL of the hydrochloric acid mother liquor can be taken for reuse; the f...

Embodiment 2

[0027] A method for preparing 2,6-dichloro-4-nitroaniline simultaneously by direct chlorination of chlorine gas and oxidative chlorination of hydrogen peroxide, including the following steps:

[0028] Add 500 mL of 20wt% hydrochloric acid mother liquor and 69 g (0.5 mol) of p-nitroaniline to a 1000 mL reaction flask equipped with a stirring, thermometer, chlorine, hydrogen peroxide and reflux condensation device. The temperature is raised to 65°C, and stirred for 30 min. Nitroaniline is completely dissolved. Chlorine 45.57g (0.67mol) was introduced slowly. After 10min of chlorine gas, 44.88g (0.33mol) of 25wt% hydrogen peroxide was slowly added dropwise. The time for both chlorine and hydrogen peroxide was maintained within 3.5h. After the addition, the reaction was continued for 30 minutes. Cool down to 30°C, filter, and collect the filtrate. The hydrochloric acid concentration of the filtrate is maintained at 20wt%. 500 mL of the mother liquor of hydrochloric acid can be taken...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

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 preparing 2,6-dichloro-4-nitroaniline simultaneously by direct chlorination of chlorine gas and oxidative chlorination of hydrogen peroxide. It belongs to the field of organic intermediate chemical technology. Background technique [0002] 2,6-Dichloronitro-4-aniline (alias: 2,6-dichloro-p-nitroaniline; nitroaniline), 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 crystals, hardly soluble in water, easily soluble in ethanol and ether, slightly soluble in acetone, chloroform, ethyl acetate, melting point: 186-190℃. 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, and disperse blue S-BBL, dis...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Patents(China)
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
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products