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A kind of method for preparing m-phenylenediamine

A technology of m-phenylenediamine and isophthalamide, which is applied in the preparation of carboxylic esters, carboxylic acid amides, and oxidized carboxylic acids. Scale experiments and other issues to achieve the effect of avoiding dangerous processes and high yield

Active Publication Date: 2021-01-22
SHANGHAI JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the industry mainly uses mixed acid nitrobenzene to prepare m-dinitrobenzene, and then reduces it to obtain m-phenylenediamine. In this process route, there are mainly two temperature processes. Mononitrobenzene is produced at 35°C, and then the temperature is raised to 90°C. Dinitrobenzene is produced from left to right, and a large amount of heat is released at the same time. The temperature is difficult to control, and it is easy to cause temperature out of control. Dinitrobenzene is very easy to explode. If the temperature is out of control, explosion accidents will occur. This process has happened many times. destructive explosion
At the same time, this process will produce a large amount of waste acid (the production of one ton of dinitrobenzene produces about ten tons of waste acid)
At present, the research focus of many researchers is still limited to the benzene nitration process, using solid acid catalysis to avoid the generation of a large amount of waste acid, but the yield is very low and the effect is not good
There is also the use of microchannel reactors to nitrate benzene to avoid the risk of explosion due to temperature out of control, the yield is not high and only small-scale experiments can not be mass-produced

Method used

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  • A kind of method for preparing m-phenylenediamine
  • A kind of method for preparing m-phenylenediamine
  • A kind of method for preparing m-phenylenediamine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0081] Embodiment 1 (route one)

[0082] The first step: the preparation of isophthalonitrile (compound 2)

[0083] use figure 1 The device prepares isophthalonitrile. In the figure, 1 is a micropump, 2 is an ammonia gas source, 3 is an air compressor, 4 is an air flow meter, 5 is an ammonia gas flow meter, 6 is an air buffer tank, 7 is an ammonia gas buffer tank, and 8 is an air preheating tank. Heater, 9 is an ammonia gas preheater, 10 is a fixed bed reactor, 11 is a condenser, 12 is a receiving tank, and 13 is an acid liquid tank. Ammonia gas source 2, ammonia gas flowmeter 5, ammonia gas buffer tank 7 and ammonia gas preheater 9 are connected in sequence, and air compressor 3, air flow meter 4, air buffer tank 6 and air preheater 8 are connected in sequence, and the air The outlet of preheater 8 and air preheater 8 is connected with fixed bed reactor 10, and fixed bed reactor 10 is connected with condenser 11, receiving tank 12 and acid liquid tank 13 successively, and ...

Embodiment 2

[0085] Route one: the second step: the preparation of isophthalamide (compound 3)

[0086] Dissolve 128 g of isophthalonitrile in 600 ml of methanol solution, add 20 g of sodium carbonate aqueous solution, heat up and reflux for 5 to 6 hours to reach the end point, evaporate methanol to dryness, and recrystallize to obtain 156 g of isophthalamide (compound 3). Yield 95.1%.

Embodiment 3

[0087] The preparation of embodiment 3 isophthalamide (compound 3)

[0088] Isophthalonitrile 128g is dissolved in 500ml ethanol solution, adds 5g sodium hydroxide, adds dropwise 50ml ammoniacal liquor, heats up and refluxes and reaches the end point after 5~6 hours, evaporates solvent, and recrystallization obtains 157.6g isophthalamide (compound 3). Yield 96.1%.

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PUM

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Abstract

The invention relates to a method for preparing m-phenylenediamine, comprising the following steps: (1) using m-xylene as a starting material to prepare isophthalamide; (2) mixing isophthalamide in an alkaline solvent Hypohalite or halogen reaction to prepare m-phenylenediamine. Compared with the prior art, the method for preparing m-phenylenediamine in the present invention completely avoids the mixed acid nitration process, does not produce waste acid, and does not produce the highly explosive compound dinitrobenzene, and is safe, clean and efficient.

Description

technical field [0001] The invention relates to a method for industrially producing m-phenylenediamine, in particular to a method for preparing m-phenylenediamine. Background technique [0002] M-phenylenediamine is an important raw material for organic synthesis. It is mainly used as a dye intermediate, a curing agent for epoxy resin, a coagulant for cement, a petroleum additive, and a raw material for the manufacture of medicines. It has a wide range of uses. [0003] At present, the industry mainly uses mixed acid nitrobenzene to prepare m-dinitrobenzene, and then reduces it to obtain m-phenylenediamine. In this process route, there are mainly two temperature processes. Mononitrobenzene is produced at 35°C, and then the temperature is raised to 90°C. Dinitrobenzene is produced from left to right, and a large amount of heat is released at the same time. The temperature is difficult to control, and it is easy to cause temperature out of control. Dinitrobenzene is very easy ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C209/50C07C211/51C07C231/06C07C231/02C07C233/65C07C253/28C07C255/51C07C67/08C07C69/80C07C51/16C07C63/24
CPCC07C51/16C07C67/08C07C209/50C07C231/02C07C231/06C07C253/28C07C211/51C07C233/65C07C255/51C07C69/80C07C63/24
Inventor 罗先金
Owner SHANGHAI JIAOTONG UNIV
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