Process for synthesizing p-aminophenol by nitrobenzene catalytic hydrogenation

A technology for p-aminophenol and catalytic hydrogenation, applied in the preparation of organic compounds, preparation of aminohydroxy compounds, organic chemistry, etc., can solve the problems of low catalyst activity, achieve high activity, overcome equipment corrosion, and overcome serious environmental pollution. Effect

Inactive Publication Date: 2008-04-09
HEBEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] US 6028227 proposes to use ion exchange resin and Pt-S / C at the same time, mix nitrobenzene with water and carry out catalytic hydrogenation under the conditions of reaction pressure 20-27atm and reaction temperature 80°C, but the yield of PAP is only 13.9%
CN1562465A discloses with HF-SiO2, H-ZSM5 and load-type heteropolyacid as the method for carrier preparation Pt-solid acid bifunctional catalyst, although this catalyzer has reduced reaction to the demand of sulfuric acid concentration to a certain extent, but in non- Catalyst activity in acidic media is very low

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] In the first step, 0.5g of zinc sulfate, 0.1g of Pt / C catalyst with 2% Pt loading, 3g of nitrobenzene, 0.01g of cetyltrimethylammonium bromide and 50ml of water are put into the high pressure reactor;

[0022] The second step is to use N 2 After replacing the air for 8-12 minutes, pass in H 2 , To a hydrogen partial pressure of 0.6MPa, heat to 120°C and react for 6 hours to convert nitrobenzene to p-aminophenol;

[0023] In the third step, after the reaction of the second step is completed, the reaction solution is filtered while it is hot to filter out the Pt / C catalyst, and the unreacted nitrobenzene and aniline are extracted from the reaction solution with hot toluene. The toluene extract was analyzed by liquid chromatography, and the conversion rate of nitrobenzene was 100%;

[0024] In the fourth step, add 100 ml of absolute ethanol to the reaction solution extracted in the third step to precipitate zinc sulfate, filter, and recycle the precipitated zinc sulfate and th...

Embodiment 2

[0027] In the first step, 5g zinc sulfate, 0.1g Pt loading of 2% Pt / SiO 2 The catalyst, 5g of nitrobenzene, 0.01g of cetyltrimethylammonium bromide and 50ml of water are put into the autoclave;

[0028] The second step is to use N 2 After replacing the air for 8-12 minutes, pass in H 2 , To a hydrogen partial pressure of 0.4MPa, heat to 200°C and react for 6 hours to convert nitrobenzene to p-aminophenol;

[0029] In the third step, after the reaction of the second step is finished, filter the reaction liquid while it is hot to filter out Pt / SiO 2 The catalyst is used to extract unreacted nitrobenzene and aniline with hot toluene. The toluene extract was analyzed by liquid chromatography, and the conversion rate of nitrobenzene was 100%;

[0030] In the fourth step, 100ml of absolute ethanol was added to the reaction solution extracted in the third step to precipitate zinc sulfate, and then filtered, the precipitated zinc sulfate and the Pt / SiO filtered out in the third step 2 The...

Embodiment 3

[0033] The first step is to add 5g zinc sulfate and 0.1gPt to 1% Pt / Al 2 O 3 The catalyst, 1g of nitrobenzene, 0.01g of cetyltrimethylammonium bromide and 50ml of water are put into the autoclave;

[0034] The second step is to use N 2 After replacing the air for 8-12 minutes, pass in H 2 , To a hydrogen partial pressure of 1.0MPa, heat to 200°C and react for 4 hours to convert nitrobenzene to p-aminophenol;

[0035] In the third step, after the reaction of the second step is over, filter the reaction liquid while it is hot to filter out Pt / Al 2 O 3 The catalyst is used to extract unreacted nitrobenzene and aniline with hot toluene. The toluene extract was analyzed by liquid chromatography, and the conversion rate of nitrobenzene was 100%;

[0036]In the fourth step, 100ml of absolute ethanol was added to the reaction solution extracted in the third step to precipitate zinc sulfate, and then filtered, the precipitated zinc sulfate and the Pt / Al filtered out in the third step 2 O 3...

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PUM

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Abstract

The invention relates to a technique of synthesizing paraaminophenol by catalyzing and dydrogenating nitrobenzene, and belongs to the technical field of aminophenol. The invention is the technique of producing the paraaminophenol from the nitrobenzene catalyzing dydrogenating device in the metal salt liquors, wherein, the quality compounding rate of the material has a mass distribution ratio that Lewis acid metal salt: load metal Pt activator: nitrobenzene: hexadecyl trimethyl ammonium bromide: water is equal to 0.5 to 5 : 0.1 to 0.3 : 1 to 5 : 0.01 : 50. The invention has the reacting conditions that: a branch pressure of the hydrogen is 0.1 to 1.0 M Pa, a reacting temperature is 80 to 200 DEG C, and a reacting time is 1 to 10 hours. The reaction which is proceed in the neutral or acidulous metal salt liquors has not high requirements to the device material, thereby preventing using abundant ammonia during the managing process, simplifying the production craftworks and overcoming the problems of the canker of the device and the serious environmental pollution; the metal salt and the activators can be separated from the reaction system for being reused repeatedly; therefore, the invention reduces the production cost, also prevents the discharging of the waste liquids and makes the yield of PAP highly reach to 25 to 73 percents.

Description

Technical field [0001] The technical scheme of the present invention belongs to aminophenol, specifically a process for synthesizing p-aminophenol from nitrobenzene catalytic hydrogenation. Background technique [0002] P-Aminophenol (PAP for short) is an important intermediate in the synthesis of medicines, pesticides and dyes, and can be used as rubber antioxidants. The world's demand for PAP is increasing year by year. There are many reports on the synthesis of p-aminophenol at home and abroad, mainly including: p-nitrophenol iron powder reduction method, nitrobenzene catalytic hydrogenation method and nitrobenzene electrolytic reduction method. The p-nitrophenol iron powder reduction method (also known as the Boqian method) has gradually restricted its production due to high production costs, poor product quality, and serious pollution from the "three wastes". Two processes, catalytic hydrogenation of nitrobenzene and electrolytic reduction of nitrobenzene, are the most advan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C215/76C07C213/00
Inventor 王延吉王淑芳高杨赵新强
Owner HEBEI UNIV OF TECH
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