Continuous synthetic method of high-purity p-nitroaniline

A technology of p-nitroaniline and synthesis method, which is applied in the field of fine chemicals, can solve the problems of salty wastewater, high production energy consumption, and long reaction cycle, and achieve the effects of environmental friendliness, stable product quality, and low energy consumption

Inactive Publication Date: 2018-01-23
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Domestic manufacturers generally adopt the first method, but the intermittent ammonolysis production process has the disadvantages of unstable product quality, long reaction cycle, high production energy consumption, and a large amount of saline wastewater. With

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Add spherical molecular sieves (40-60 mesh) into the fixed-bed reactor, the ratio of ammonia to p-nitrochlorobenzene is 3:1, the mass concentration of ammonia water is 35%, and p-nitrochlorobenzene is preheated to 90°C to react The temperature is 182°C, the reaction pressure is 2.5MPa, and the volume space velocity of p-nitrochlorobenzene is 0.5h -1 , the crude product of p-nitroaniline is decompressed, cooled and crystallized at first, and the ammonium chloride mixed solution of p-nitroaniline and ammonia is separated by filtration. According to gas chromatography analysis, the purity of p-nitroaniline is 99.99%, and the conversion rate of p-nitrochlorobenzene is 100%.

Embodiment 2

[0021] Add spherical molecular sieves (40-60 mesh) into the fixed-bed reactor, the ratio of ammonia to p-nitrochlorobenzene is 4:1, the mass concentration of ammonia water is 40%, and p-nitrochlorobenzene is preheated to 85°C to react The temperature is 185°C, the reaction pressure is 3.5MPa, and the volume space velocity of p-nitrochlorobenzene is 0.3h -1 , the crude product of p-nitroaniline is decompressed, cooled and crystallized at first, and the ammonium chloride mixed solution of p-nitroaniline and ammonia is separated by filtration. According to gas chromatography analysis, the purity of p-nitroaniline is 99.99%, and the conversion rate of p-nitrochlorobenzene is 100%.

Embodiment 3

[0023] Add a magnetic ring (20-40 mesh) to the fixed-bed reactor, the ratio of ammonia to p-nitrochlorobenzene is 5:1, the mass concentration of ammonia water is 38.0%, and p-nitrochlorobenzene is preheated to 85°C. The temperature is 190°C, the reaction pressure is 3.5MPa, and the volume space velocity of p-nitrochlorobenzene is 1.2h -1 , the crude product of p-nitroaniline is decompressed, cooled and crystallized at first, and the ammonium chloride mixed solution of p-nitroaniline and ammonia is separated by filtration. According to gas chromatography analysis, the purity of p-nitroaniline is 99.99%, and the conversion rate of p-nitrochlorobenzene is 100%.

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PUM

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Abstract

The invention provides a new process for synthesizing p-nitroaniline. The process comprises: taking p-nitrochlorobenzene and ammonia water as raw materials, in a fixed bed reactor or shell-and-tube reactor and in the presence of a catalyst, carrying out an ammonification reaction to prepare a p-nitroaniline crude product, performing separation recycling to the crude product to prepare p-nitroaniline and obtain ammonium chloride as a by-product, and recycling excess ammonia for cyclic application. According to the process, the p-nitroaniline conversion rate can reach 100%, and the purity of p-nitroaniline can reach 99.9%. The process is green, eco-friendly and new.

Description

technical field [0001] The invention belongs to the field of fine chemical industry and relates to a method for preparing high-purity p-nitroaniline by amination of p-nitrochloroaniline. Background technique [0002] Para-nitroaniline (Para-Nitroanillne) is an important raw material for organic synthesis, mainly used in the manufacture of azo dyes, such as direct dark green B, acid medium brown G, acid black 10B, acid wool ATT, fur black D and direct version D, etc.; can also be used as intermediates for veterinary drugs and pesticides; and can be used to manufacture p-phenylenediamine, which is used as an intermediate for high-strength polymers and has a large export volume; in addition, p-nitroaniline can also be used to prepare antioxidants and preservatives. Due to the wide application and importance of p-nitroaniline, the research on its synthesis process has been paid more and more attention by people. [0003] There are generally two synthesis methods for p-nitroani...

Claims

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Application Information

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IPC IPC(8): C07C209/10C07C211/52C01C1/16
CPCY02P20/584
Inventor 储政袁俊秀徐冬梅封心领
Owner CHINA PETROLEUM & CHEM CORP
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