Method and device for producing p-phenylenediamine by using liquid phase continuous hydrogenation method

A technology of p-phenylenediamine and hydrogenation method, which is applied in chemical instruments and methods, preparation of organic compounds, preparation of amino compounds, etc., can solve the problems of low production capacity of equipment, high labor intensity of operation, serious environmental pollution, etc., and achieve Low equipment cost, low labor intensity, and the effect of reducing environmental pollution

Inactive Publication Date: 2011-12-14
JIANGSU KESHENG CHEM MACHINERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: the product yield is low, and the total yield is less than 85%; the environmental pollution is serious, and the iron sludge generated is difficult to handle; the operating environment is poor
[0003] There are also domestic reports on the production of p-phenylenediamine

Method used

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  • Method and device for producing p-phenylenediamine by using liquid phase continuous hydrogenation method
  • Method and device for producing p-phenylenediamine by using liquid phase continuous hydrogenation method
  • Method and device for producing p-phenylenediamine by using liquid phase continuous hydrogenation method

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Effect test

Embodiment 1

[0040] Embodiment 1: produce p-phenylenediamine according to the following steps:

[0041] (1) In the first-stage hydrogenation reactor 5 and the second-stage hydrogenation reactor 8, methanol corresponding to 50% of the total volume of the reactor was first added, and then a nickel catalyst equivalent to 1.5% of the above-mentioned methanol weight was added;

[0042] (2) Turn on the cooling water of the heat exchange coil and keep the reaction temperature at 90°C;

[0043] (3) When stirring at 90°C, continuously feed hydrogen into the primary hydrogenation reactor 5 and the secondary hydrogenation reactor 8; The pressure in the stage hydrogenation reactor 8 remains on 1.3MPa;

[0044] (4) When the hydrogen pressure in the kettle reaches 1.3 MPa, continuously add methanol and p-nitroaniline into the first-stage hydrogenation reactor 5, and the speed of adding methanol is 15.5 minutes when methanol passes through the first-stage hydrogenation reactor 5. Calculated, the volu...

Embodiment 2

[0049] Embodiment 2: produce p-phenylenediamine according to the following steps:

[0050] (1) In the first-stage hydrogenation reactor 5 and the second-stage hydrogenation reactor 8, methanol corresponding to 60% of the total volume of the reactor was first added, and then a nickel-based catalyst equivalent to 1% of the above-mentioned methanol weight was added;

[0051] (2) Turn on the cooling water of the heat exchange coil and keep the reaction temperature at 100°C;

[0052] (3) When stirring at 100°C, continuously feed hydrogen into the primary hydrogenation reactor 5 and the secondary hydrogenation reactor 8; The pressure in the stage hydrogenation reactor 8 remains on 2.0MPa;

[0053] (4) When the hydrogen pressure in the kettle reaches 2.0MPa, continuously add methanol and p-nitroaniline into the primary hydrogenation reactor 5, and the speed of adding methanol is 10 hours when the methanol passes through the primary hydrogenation reactor. Calculated, the volume ra...

Embodiment 3

[0058] Embodiment 3: produce p-phenylenediamine according to the following steps:

[0059] (1) In the first-stage hydrogenation reactor 5 and the second-stage hydrogenation reactor 8, methanol corresponding to 70% of the total volume of the reactor was first added, and then a nickel-based catalyst equivalent to 0.5% of the above-mentioned methanol weight was added;

[0060] (2) Turn on the cooling water of the heat exchange coil and keep the reaction temperature at 120°C;

[0061] (3) At 120°C under agitation, continuously feed hydrogen into the primary hydrogenation reactor 5 and the secondary hydrogenation reactor 8; The pressure in the stage hydrogenation reactor 8 remains on 2.0MPa;

[0062] (4) When the hydrogen pressure in the kettle reaches 2.0MPa, continuously add methanol and p-nitroaniline into the first-stage hydrogenation reactor 5, and the rate of adding methanol is based on the residence time of methanol passing through the first-stage hydrogenation reactor at...

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Abstract

The invention discloses a method and device for producing p-phenylenediamine by using a liquid phase continuous hydrogenation method. The reaction is carried out in first-stage and second-stage hydrogenation reaction kettles which are connected in series. The method comprises the following steps of: adding methanol which is 50-70% of the volume of the reaction kettles into the first-stage and the second-stage hydrogenation reaction kettles, adding a catalyst which is 0.5-1.5% of the methanol, and continuously introducing hydrogen into the first-stage and the second-stage hydrogenation reaction kettles in a stirring state; after reaching a certain pressure in the first-stage and the second-stage hydrogenation reaction kettles, continuously adding methanol and paranitroaniline into the first-stage hydrogenation reaction kettle, continuously keeping the pressure in the first-stage and the second-stage hydrogenation reaction kettles, meanwhile, discharging from the first-stage hydrogenation reaction kettle to the second-stage hydrogenation reaction kettle, and continuously discharging from the second-stage hydrogenation reaction kettle; recycling the catalyst from the reaction liquid from the second-stage hydrogenation reaction kettle through a settling tank; and removing methanol and water by rectifying the reaction liquid after the catalyst is recycled so as to obtain the p-phenylenediamine. The method and the device disclosed by the invention have the advantages of low cost, high yield, good safety and environment friendliness.

Description

technical field [0001] The invention relates to a production method and device for p-phenylenediamine, in particular to a method and a device for producing p-phenylenediamine by a liquid-phase continuous hydrogenation method. Background technique [0002] p-Phenylenediamine is one of the simplest aromatic diamines, and it is also a widely used intermediate, which can be used to prepare azo dyes, high molecular polymers, and can also be used to produce fur dyes, rubber antioxidants and photo In addition, p-phenylenediamine is a sensitive reagent commonly used to detect iron and copper. P-phenylenediamine is an extremely important dye intermediate, mainly used in aramid fiber, azo dyes, sulfur dyes, acid dyes, etc. At present, the main production process of p-phenylenediamine in China is obtained by reducing iron powder with p-nitroaniline as raw material. The disadvantages of this method are: the product yield is low, and the total yield is less than 85%; the environmental...

Claims

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Application Information

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IPC IPC(8): C07C211/51C07C209/36
CPCY02P20/584
Inventor 王武谦许如海王在良庄绕林
Owner JIANGSU KESHENG CHEM MACHINERY
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