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Preparation method of m-phenylenediamine

A technology of m-phenylenediamine and nitroaniline, which is applied in the preparation of carboxylic acid amides, organic compounds, nitro compounds, etc. It can solve the problems of small-scale experiments, difficult temperature control, and the explosive nature of dinitrobenzene and other problems to achieve the effect of avoiding the explosive compound dinitrobenzene, stabilizing the production process, and avoiding dangerous processes

Inactive Publication Date: 2020-04-17
SHANGHAI JIAO TONG UNIV
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  • Abstract
  • Description
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Problems solved by technology

[0003] At present, the method of industrial preparation of m-phenylenediamine mainly uses mixed acid nitration of benzene to prepare m-dinitrobenzene, and then reduces m-phenylenediamine. In this process route, there are mainly two temperature processes, and mononitrobenzene is produced at 35 ° C. , and then raise the temperature to about 90°C to produce dinitrobenzene, and release a large amount of heat at the same time, the temperature is difficult to control, and it is easy to cause temperature runaway. Numerous highly destructive explosions
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 focus of many researchers is still to continue to optimize 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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preparation example Construction

[0034] A kind of preparation method of m-phenylenediamine, this method takes benzoic acid as starting raw material, first reacts esterification with alcohol reagent under the action of acid, then nitrates to obtain m-nitrobenzoate, or with benzoic acid As the starting material, it is first nitrated, and then esterified with alcohol reagents under the action of acid to obtain m-nitrobenzoate; and then ammonolysis of m-nitrobenzoate to obtain 3-nitrobenzoate Amide, m-nitroaniline is prepared after reacting with hypohalite or halogen in an alkaline solvent, and the m-phenylenediamine is obtained after reduction.

[0035] The reaction process is as follows:

[0036]

[0037] Wherein, compound 1 is benzoic acid, compound 2 is m-nitrobenzoate (or 3-nitrobenzoate), compound 3 is 3-nitrobenzamide (or m-nitrobenzamide), Compound 4 is m-nitroaniline (or 3-nitroaniline), and target product 5 is m-phenylenediamine.

[0038] As the preferred technical scheme of the present invention, ...

Embodiment 1

[0062] 61g of benzoic acid (compound 1) was dissolved in 200g of methanol, 2g of sulfuric acid was added, the temperature was raised to reflux, and the generated water was continuously evaporated. After the temperature reached 66.5°C, the methanol was evaporated to dryness, and 180ml of dichloroethane was added, and the temperature was raised to 30°C. Add 35g of fuming nitric acid dropwise, detect with thin-layer chromatography, after methyl benzoate disappears, add 100g of ice water, neutralize with alkali, evaporate the solvent, filter and wash, and obtain 81.1g of methyl m-nitrobenzoate after recrystallization (compound 2). Yield 89.6%.

Embodiment 2

[0064] Dissolve 61g of benzoic acid (compound 1) in 200g of ethanol, add 2g of p-toluenesulfonic acid, heat up and reflux, and continuously evaporate the formed water. After the temperature reaches 79-80°C, evaporate the ethanol to dryness, and add 180ml of dichloroethane , the temperature was raised to 30°C, 35g of fuming nitric acid was added dropwise, detected by thin-layer chromatography, after the methyl benzoate disappeared, 100g of ice water was added, the lower organic liquid layer was separated, washed, the solvent was distilled off, filtered and washed, and weighed After crystallization, 82.9 g of methyl m-nitrobenzoate (compound 2) were obtained. Yield 91.6%.

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Abstract

The invention relates to a preparation method of m-phenylenediamine, which comprises the following steps: by using benzoic acid as an initial raw material, reacting with an alcohol reagent under the action of an acid to esterify, and nitrifying to obtain a m-nitrobenzoate, or by using benzoic acid as an initial raw material, nitrifying, and reacting with an alcohol reagent under the action of an acid to esterify to obtain the m-nitrobenzoate; carrying out aminolysis of the m-nitrobenzoate to obtain 3-nitrobenzamide, reacting with a hypohalite or a halogen in an alkaline solvent to obtain m-phenylenediamine. Compared with the prior art, the method has the advantages that generation of explosive compound dinitrobenzene and generation of a large amount of waste acid are avoided, the whole production process is stable, and the yield is high.

Description

technical field [0001] The invention relates to the industrial production of m-phenylenediamine, in particular to a preparation method of m-phenylenediamine. Background technique [0002] M-phenylenediamine is a very important intermediate, mainly used as a dye intermediate for the manufacture of dyes such as basic orange, basic brown G, direct sunfast black G, etc., and can also be used as a curing agent for epoxy resin, cement It is widely used in the fields of coagulant accelerator, petroleum additive and raw material for manufacturing medicine. [0003] At present, the method of industrial preparation of m-phenylenediamine mainly uses mixed acid nitration of benzene to prepare m-dinitrobenzene, and then reduces m-phenylenediamine. In this process route, there are mainly two temperature processes, and mononitrobenzene is produced at 35 ° C. , and then raise the temperature to about 90°C to produce dinitrobenzene, and release a large amount of heat at the same time, the t...

Claims

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Application Information

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IPC IPC(8): C07C211/51C07C209/36
CPCC07C201/08C07C209/36C07C209/50C07C231/02C07C211/51C07C205/57C07C233/65C07C211/52
Inventor 罗先金
Owner SHANGHAI JIAO TONG UNIV
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