Method for producing p-fluoroaniline by solvent-free catalytic hydrogenation method

A technology for p-fluoroaniline and catalytic hydrogenation, applied in chemical instruments and methods, preparation of organic compounds, chemical recovery and other directions, can solve problems such as difficulties in industrialization, and achieve the effects of reducing production costs, simple preparation and high yield

Inactive Publication Date: 2018-12-14
济南和润化工科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is limited by the source of raw materials or needs to use strong corrosive hydrofluoric acid, etc., so it is difficult to industrialize

Method used

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  • Method for producing p-fluoroaniline by solvent-free catalytic hydrogenation method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] (1) Put 200g of p-fluoronitrobenzene, 1g of 1%Pt / C catalyst, and 1g of sodium hypophosphite into the autoclave, and replace with nitrogen and hydrogen three times respectively.

[0026] (2) Turn on the stirring, raise the temperature to 60°C, pass in hydrogen gas at 0.9Mpa, start the reaction, and control the reaction temperature to 85°C.

[0027] (3) During the reaction process, measure the instantaneous reaction speed of the reaction, expressed as the hydrogen pressure drop per minute, and the reaction speed is: 0.12Mpa / min.

[0028] (4) The reaction time is 3 hours. At the end of the reaction, the reaction pressure increases, the reaction temperature decreases, and the reaction speed is zero.

[0029] (5) The catalyst is separated from the reaction solution by suction filtration, the reaction solution is simply separated from water, and the final product p-fluoroaniline is obtained after vacuum distillation. The conversion rate of the reaction is 100%, the product pu...

Embodiment 2

[0031] Under the premise of embodiment 1, carry out the mechanical experiment of catalyst (that is, catalyst recycles):

[0032] (1) Put 200g of p-fluoronitrobenzene, add 0.2g of 1%Pt / C catalyst, and 1g of sodium hypophosphite into the autoclave, and replace with nitrogen and hydrogen three times respectively.

[0033] (2) Turn on the stirring, raise the temperature to 60°C, pass in hydrogen gas at 0.9Mpa, start the reaction, and control the reaction temperature to 85°C.

[0034] (3) During the reaction process, measure the instantaneous reaction speed of the reaction, expressed as the hydrogen pressure drop per minute, and the reaction speed is: 0.13Mpa / min.

[0035] (4) The reaction time is 2 hours and 45 minutes. At the end of the reaction, the reaction pressure increases, the reaction temperature decreases, and the reaction speed is zero.

[0036] (5) The catalyst is separated from the reaction solution by suction filtration, the reaction solution is simply separated from...

Embodiment 3

[0038] Under the premise of embodiment 1, embodiment 2, continue to apply mechanically 10 batches and obtain result as follows:

[0039] Wherein sequence number 8 is to change the sodium hypophosphite in embodiment 1 into sodium phosphate, other conditions are constant;

[0040] Sequence number 9 is to change the sodium hypophosphite in embodiment 1 into disodium hydrogen phosphate, and other conditions are constant;

[0041] Sequence number 10 is to change the sodium hypophosphite in embodiment 1 into sodium biphosphite, and other conditions are constant;

[0042] Sequence number 11 is that the control reaction temperature in embodiment 1 is 30 ℃, other conditions are unchanged;

[0043] No. 12 is to control the reaction temperature in Example 1 to 150° C., and keep other conditions unchanged.

[0044]

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Abstract

The invention provides a method for producing p-fluoroaniline by a solvent-free catalytic hydrogenation method. The method comprises that p-fluoronitrobenzene as a raw material undergoes a catalytic hydrogenation reaction in an autoclave under the condition of no solvent and use of a catalyst and a phosphate to produce p-fluoroaniline. The method utilizes a solvent-free hydrogenation method. Compared with the existing solvent hydrogenation method, the method greatly increases reaction efficiency, obviously improves the equipment utilization rate, effectively prevents the energy consumption andequipment cost caused by the solvent recovery, belongs to the pollution-free environment-friendly processes and effectively prevents the production of a large amount of wastewater and waste slag. Thenoble metal catalyst Pt / C is prepared through simple processes and can be recycled in the catalyst reaction and the metal in the catalyst can be recovered and recycled so that the production cost isfurther reduced. The phosphate can be used as a dehydrogenation inhibitor and can improve a reaction conversion rate.

Description

technical field [0001] The invention belongs to the technical field of catalytic hydrogenation, and in particular relates to a method for producing p-fluoroaniline by a solventless catalytic hydrogenation method. Background technique [0002] p-Fluoroaniline is an important fine chemical intermediate, mainly used in medicine, dyestuffs and pesticides, etc. The development of this product was earlier in foreign countries, and it started in the early 1990s in China. [0003] There are two kinds of production methods about p-fluoroaniline in the prior art: one is by azidobenzene (US Patent US4145364) or N-phenyl ammonium hydroxide (US Patent US4291991) or p-chloronitrobenzene (US Patent US3900519) etc. are used as raw materials to directly synthesize p-fluoroaniline through one-step reaction. This method is difficult to industrialize due to the limitation of raw material sources or the need to use strong corrosive hydrofluoric acid. Another method is to prepare p-fluoroanilin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/36C07C211/52
CPCC07C209/36C07C211/52Y02P20/584
Inventor 侯卫波韩龙凯
Owner 济南和润化工科技有限公司
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