Preparation method of o-phenylenediamine

A technology of o-phenylenediamine and phthalamide, which is applied in the preparation of carboxylic acid amides, organic compounds, and carboxylic esters, and can solve problems such as waste acid generation, casualty economy, and difficult temperature control

Active Publication Date: 2021-05-18
上海呼龙科技开发有限公司
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AI Technical Summary

Problems solved by technology

[0003] At present, the industry mainly adopts the nitration of chlorinated benzene to prepare o-chloronitrobenzene, then reacts with ammonia gas to obtain o-aminonitrobenzene, and then reduces it to obtain o-phenylenediamine. In this process route, there are mainly the following disadvantages: Two products are produced during the first step of nitration, o-chloronitrobenzene and p-chloronitrobenzene, which need to be separated and refined to obtain high-purity products. Since mixed acids must be used for nitration, a large amount of waste acid must be produced; the second step and The ammonia gas reaction (ammonialysis) process must be completed under high temperature and high pressure. Because the ammonolysis reaction will release a large amount of heat, the temperature is difficult to control, and it is prone to explosion hazards. Several explosion accidents have occurred in our country, resulting in casualties and major economic loss

Method used

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  • Preparation method of o-phenylenediamine

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Effect test

Embodiment 1

[0030] Add 33.2g of phthalic acid to 300ml of methanol, add 1ml of concentrated sulfuric acid, heat up and reflux for 12 hours, and continuously collect fractions below 66°C to remove produced water. When the reflux temperature reaches above 67°C, the esterification is completed, and the remaining methanol, 50ml of ethyl acetate and 20ml of water were added, layered and washed, and after the solvent was distilled, 38.7g of dimethyl phthalate was obtained. The yield is 99.7%.

Embodiment 2

[0032] Add 33.2g of phthalic acid to 300ml of methanol, add 0.5g of p-toluenesulfonic acid, raise the temperature and reflux for 13 hours, and continuously collect fractions below 66°C to remove the produced water. When the reflux temperature reaches above 67°C, the esterification is completed and evaporated Remove remaining methanol, add 50ml of ethyl acetate and 20ml of 0.5% liquid caustic soda, separate layers for washing, and distill to obtain 38.6g of dimethyl phthalate. Yield 99.5%.

Embodiment 3

[0034] Add 33.2g of phthalic acid to 300ml of ethanol, add 3g of solid acid sulfonic acid resin, heat up and reflux for 16 hours, continuously collect fractions below 78°C to remove produced water, when the reflux temperature reaches above 79°C, the esterification is completed, filter , Distilled to obtain 44.2 g of diethyl phthalate. Yield 99.5%.

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Abstract

The invention relates to a preparation method of o-phenylenediamine. The preparation method comprises the following steps: esterifying phthalic acid with alcohol under the catalysis of acid to prepare phthalate, then introducing ammonia gas into an alcohol solvent to obtain phthalic diamide, and then reacting the phthalic diamide with hypohalite or halogen in an alkaline solution to prepare the o-phenylenediamine. Compared with the prior art, the method disclosed by the invention completely avoids a mixed acid nitration process, does not generate waste acid, also does not cause safety accidents during ammonolysis of o-chloronitrobenzene, and is safe, clean and efficient.

Description

technical field [0001] The invention relates to a preparation method of o-phenylenediamine, in particular to a method for industrial production of o-phenylenediamine. Background technique [0002] O-phenylenediamine is mainly used in the manufacture of pesticide fungicides, vat dyes, cationic dyes, polymer stabilizers, heterocyclic compounds, photosensitive materials, surfactants, antifreeze agents, copper anti-corrosion agents, etc., and has a wide range of uses. [0003] At present, the industry mainly adopts the nitration of chlorinated benzene to prepare o-chloronitrobenzene, then reacts with ammonia gas to obtain o-aminonitrobenzene, and then reduces it to obtain o-phenylenediamine. In this process route, there are mainly the following disadvantages: Two products are produced during the first step of nitration, o-chloronitrobenzene and p-chloronitrobenzene, which need to be separated and refined to obtain high-purity products. Since mixed acids must be used for nitratio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/58C07C211/51
CPCC07C209/58C07C231/02C07C67/08C07C211/51C07C233/65C07C69/80
Inventor 罗先金
Owner 上海呼龙科技开发有限公司
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