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Method for preparing aromatic amine from mixed nitrochlorobenzene

A technology of nitrochlorobenzene and nitroaniline, which is applied in the field of preparing aromatic amines, can solve the problems of short process flow, high separation cost, and large amount of three wastes, and achieve low energy consumption, lower production costs, and less generation of three wastes Effect

Active Publication Date: 2013-05-08
ZHEJIANG HONGSHENG CHEM IND +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for preparing aromatic amines with mixed nitrochlorobenzene as raw material for the high investment, high separation cost, large amount of three wastes and difficult treatment in the current production process. The method has a process flow Short, fast reaction, high selectivity, simple separation process, low production cost, safe and reliable, and no three wastes in the production process

Method used

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  • Method for preparing aromatic amine from mixed nitrochlorobenzene
  • Method for preparing aromatic amine from mixed nitrochlorobenzene

Examples

Experimental program
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Effect test

Embodiment 1

[0023] 615kg of molten mixed nitrochlorobenzene (made by chlorobenzene through mixed acid adiabatic nitration, contains trace impurities, wherein the mass content of p-nitrochlorobenzene is 65.3%, the mass content of o-nitrochlorobenzene is 33.2%, and the mass content of m-nitrochlorobenzene chlorobenzene mass content is 0.8%) pumped into 3M 3 In a stirred reactor, mix it with 2220kg of 30% (w / w) ammonia water from the ammonia distribution tank under stirring, raise the temperature and control the temperature at 170-185°C and the pressure at 3.5-4.9MPa. Decomposition reaction for 10 hours, then lowered to about 145°C and began to discharge ammonia, the discharged gas was absorbed by water, used to prepare raw ammonia water for ammonolysis, the reactor material after ammonia discharge was pumped into the stripping tower, and stripped with 0.5MPa steam, Ammonia and nitrochlorobenzene are recovered by condensation at the top of the tower. The material after stripping was cooled,...

Embodiment 2

[0026] 650kg of molten mixed nitrochlorobenzene (made by chlorobenzene through mixed acid adiabatic nitration, contains trace impurities, wherein the mass content of p-nitrochlorobenzene is 64%, the mass content of o-nitrochlorobenzene is 34.5%, and the mass content of m-nitrochlorobenzene chlorobenzene mass content is 0.7%) pumped into 3M 3 In a stirred reactor, mix it with 2350kg of 33% (w / w) ammonia water from the ammonia distribution tank under stirring, raise the temperature and control the temperature at 160-182°C and the pressure at 4.0-4.9MPa. Decompose reaction for 10 hours, then cool down to about 145°C and start to discharge ammonia. The reactor material after ammonia discharge is pumped into the stripping tower, stripped with 0.5MPa steam, and the ammonia and nitrochlorobenzene are recovered by condensation at the top of the tower. After cooling, the material was cooled down to 35°C to crystallize, settled, and centrifuged to obtain 552 kg of mixed nitroaniline.

...

Embodiment 3

[0029] Pump 615kg of molten mixed nitrochlorobenzene (65.3% for p-nitrochlorobenzene, 33.2% for o-nitrochlorobenzene, 0.8% for m-nitrochlorobenzene) into 3M 3 In a stirred reactor, mix it with 2220kg of 30% ammonia water from the ammonia distribution tank under stirring, raise the temperature and control the temperature at 170-185°C and the pressure at 3.5-4.9MPa for 10 hours of ammonolysis reaction, Then it drops to about 145°C and starts to discharge ammonia. The discharged gas is absorbed by water, and is used to prepare raw ammonia water for ammonolysis. The reactor material after ammonia discharge is pumped into the stripping tower, stripped with 0.5MPa steam, and the ammonia is recovered by condensation at the top of the tower. and nitrochlorobenzene. The material after stripping was cooled, cooled to 30°C to crystallize, left to settle, and centrifuged to obtain 527 kg of mixed nitroaniline. The centrifuged mother liquor could be further processed to concentrate and cry...

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Abstract

The invention provides a method for preparing aromatic amine by using mixed nitrochlorobenzene as a raw material. The method comprises the steps that: mixed nitrochlorobenzene is subjected to ammonolysis, deamination stripping, cooling crystallization, and centrifugal separation, such that a material comprising mixed nitroanilide is obtained; the material can be subjected to catalytic hydrogenation in an alcohol solvent, and p-phenylenediamine and o-phenylenediamine products can be prepared through separation; or before catalytic hydrogenation, part of p-nitroanilide is separated; and hydrogenation is carried out, such that p-phenylenediamine and o-phenylenediamine products can be prepared. According to the aromatic amine preparation method, the mixed nitrochlorobenzene raw material can be used in phenylenediamine production without separation, such that a product material separation process of a traditional production process is simplified, and energy consumption during production process is reduced. The method is economical and highly efficient, and the product has high purity.

Description

(1) Technical field [0001] The invention relates to a method for preparing aromatic amines from mixed nitrochlorobenzenes. (2) Background technology [0002] Chlorobenzene is an important intermediate of dyes and pesticides. Starting from it, after a series of organic synthesis unit processes, various intermediates with complex structures can be obtained. For example, chlorobenzene can obtain a mass fraction of 60~ 65% p-nitrochlorobenzene, 34-39% o-nitrochlorobenzene and a small amount of m-nitrochlorobenzene. The current industrial practice is to separate the above isomers for subsequent synthesis or processing, but the difference in the boiling points of the three isomers of the nitrochlorobenzene system, ortho, para, and meta, is very small, and nitrochlorobenzene is a heat-sensitive substance, which is a difficult-to-separate system in the field of rectification; for traditional crystallization separation, Since the isomers of nitrochlorobenzene can form eutectics, com...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/51C07C209/36
CPCY02P20/584
Inventor 何旭斌苏建军陶建国朱敬鑫孟明
Owner ZHEJIANG HONGSHENG CHEM IND
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