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Nitration separation method of 2,5-dichloronitrobenzene

A technology of dichloronitrobenzene and a separation method, which is applied in the field of preparation of dichloronitrobenzene, can solve problems such as the increase of polychlorides, and achieve the effects of improving recovery rate, reducing preparation cost and eliminating impurities

Inactive Publication Date: 2017-01-11
JIANGSU PENGYU CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the depth of chlorination is not well controlled, the by-product polychlorides will multiply

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0010] Take out the dichlorobenzene solution, add toluenesulfonic acid in the dichlorobenzene solution, the addition amount of toluenesulfonic acid is 1kg-5kg, fully mix the dichlorobenzene solution and toluenesulfonic acid, then add Add concentrated nitric acid into the mixed solution, keep the temperature between 180°C and 200°C, let the mixed solution undergo nitration reaction, the nitration reaction time is 5-7 hours, and obtain the crude product of 2,5 dichloronitrobenzene, then The dichloronitrobenzene crude product is placed in the reactor, and caustic soda is added in the reactor, and the addition amount of caustic soda accounts for 2%-5% in the mixture of the dichloronitrobenzene crude product, so that caustic soda and dichloronitrobenzene Crude benzene is reacted, and the reaction time is 0.5 hours to 1.5 hours. Then, palladium carbon series is added to the reaction kettle, and then toluene is added thereto. The proportion is 1.5%-3%, the pressure of the reactor is ...

Embodiment 2

[0012] The dichlorobenzene solution is taken out, and toluenesulfonic acid is added in the dichlorobenzene solution, and the addition of toluenesulfonic acid is 1kg, and the dichlorobenzene solution and toluenesulfonic acid are fully mixed, and then mixed solution Concentrated nitric acid was added dropwise into the medium, and the temperature was kept between 180°C, and the mixed solution was allowed to undergo nitration reaction. The nitration reaction time was 5 hours to obtain the crude product of 2,5 dichloronitrobenzene, and then the crude product of dichloronitrobenzene Place in the reactor, add caustic soda in the reactor, the proportion of caustic soda in the dichloronitrobenzene crude product mixture is 2%, allow caustic soda and dichloronitrobenzene crude product to react, the time of reaction is 0.5 hour, then Add palladium-carbon series to the reactor, and then add toluene therein, the amount of toluene added is 1.5% in the dichloronitro mixture treated with causti...

Embodiment 3

[0014] Dichlorobenzene solution is taken out, in dichlorobenzene solution, add toluenesulfonic acid, the addition of toluenesulfonic acid is 3kg, dichlorobenzene solution and toluenesulfonic acid are fully mixed, then to mixed solution Concentrated nitric acid was added dropwise into the medium, and the temperature was kept between 190°C, and the mixed solution was allowed to undergo nitration reaction. The nitration reaction time was 6 hours to obtain the crude product of 2,5 dichloronitrobenzene, and then the crude product of dichloronitrobenzene Place in the reactor, add caustic soda in the reactor, the proportion of caustic soda in the dichloronitrobenzene crude product mixture is 3%, allow caustic soda and dichloronitrobenzene crude product to react, the time of reaction is 1.1 hours, then Add palladium-carbon series to the reactor, and then add toluene therein, the amount of toluene added accounts for 2.1% in the dichloronitro mixture that has been treated with caustic so...

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PUM

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Abstract

The invention relates to a nitration separation method of 2,5-dichloronitrobenzene. The method comprises the following steps: adding a catalyst methyl benzenesulfonic acid into a dichlorobenzene solution to carry out reaction; and after the dichlorobenzene and methyl benzenesulfonic acid are thoroughly mixed, dropwisely adding 95% concentrated nitric acid into the mixed solution, and carrying out nitration reaction at 180 DEG C for 5-7 hours to obtain the 2,5-dichloronitrobenzene crude product. By adding the catalyst methyl benzenesulfonic acid into the dichlorobenzene, the dichlorobenzene can react more sufficiently, and the reaction time is greatly shortened. The concentrated nitric acid dropwisely added into the dichlorobenzene liquid can quickly obtain dichloronitrobenzene, so the dichloronitrobenzene preparation time is shortened.

Description

technical field [0001] The invention relates to a preparation method of dichloronitrobenzene, in particular to a nitration separation method of 2,5-dichloronitrobenzene. Background technique [0002] 2,5-Dichloronitrobenzene is an important intermediate in organic synthesis and is widely used in the manufacture of fluorochloroaniline, fluorochloronitrobenzene and 2,5-dichloroaniline. The existing production process of 2,5-dichloronitrobenzene is as follows: p-nitrochlorobenzene is chlorinated by introducing chlorine gas at a temperature of 100°C to 105°C in the presence of a catalyst anhydrous ferric chloride reaction. When the chlorination reaches a certain depth, the chlorine gas flow is stopped; then water washing is carried out, and the crude product of 2,5-dichloronitrobenzene is obtained by layering. The crude product of 2,5-dichloronitrobenzene is rectified to obtain the finished product of 2,5-dichloronitrobenzene. Under the condition that the chlorination depth i...

Claims

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Application Information

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IPC IPC(8): C07C205/12C07C201/08C07C201/16
Inventor 沈正阳
Owner JIANGSU PENGYU CHEM
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