A method for preparing aromatic amines by catalytic hydrogenation of aromatic nitro compounds

An aromatic nitro, catalytic hydrogenation technology, applied in the preparation of amino compounds, the preparation of amino hydroxy compounds, the preparation of organic compounds, etc., can solve problems such as insignificant effects, and achieve a wide range of applications, reduced content, and simple use methods. Effect

Active Publication Date: 2011-12-21
ZHEJIANG UNIV OF TECH
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Problems solved by technology

However, this method has no effect when applied to the catalytic hydrogenation of aromatic nitro compounds to prepare aromatic amines. When the amount of cocatalyst acidic carbon is small or the acidity of acidic carbon is weak, the effect of inhibiting the formation of azo is not obvious. When the dosage increases or the acidity of the acid carbon increases, it will lead to the formation of benzidine

Method used

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  • A method for preparing aromatic amines by catalytic hydrogenation of aromatic nitro compounds
  • A method for preparing aromatic amines by catalytic hydrogenation of aromatic nitro compounds
  • A method for preparing aromatic amines by catalytic hydrogenation of aromatic nitro compounds

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1 5

[0026] Examples 1 to 5 investigated the influence of inhibitor types on the inhibitory effect of azo compounds. In a 500ml stainless steel reaction kettle, add 100ml nitrobenzene, 200ml ethanol, 0.5g 5% Pd / C catalyst (produced by Degong Chemical Co., Ltd., Deqing County, Zhejiang Province), no inhibitor or 0.01g inhibitor, close the reaction kettle , Replace the air in the reactor with nitrogen three times, and then replace it with hydrogen three times; raise the temperature to 60°C, hydrogen pressure to 2MPa, start stirring at a stirring rate of 900r / min, and react for 1h; stop the reaction, and wait until the temperature drops to room temperature , The reaction solution was taken out, the catalyst was removed by filtration, and the filtrate was analyzed by gas chromatography. The experimental results are shown in Table 1.

[0027] Table 1 Inhibitor Types Influence on the Inhibitory Effect of Azo Compounds

[0028]

Embodiment 6 10

[0030] Embodiments 6 to 10 investigated the influence of inhibitor dosage on the inhibitory effect of azo compounds. In a 500ml stainless steel reaction kettle, add 100ml o-nitrotoluene, 200ml methanol, 2g Raney-Ni catalyst (produced by Zhejiang Kony Alloy Manufacturing Co., Ltd.), add different amounts of inhibitors, close the reaction kettle, and replace the inside of the reaction kettle with nitrogen. The air was replaced three times with hydrogen; the temperature was raised to 70°C, the hydrogen pressure was 1MPa, stirring was started, the stirring rate was 900r / min, and the reaction was 1.5h; the reaction was stopped, and after the temperature dropped to room temperature, the reaction solution was taken out and filtered The catalyst was removed and the filtrate was analyzed by gas chromatography. The experimental results are shown in Table 2.

[0031] Table 2 Influence of inhibitor dosage on the inhibitory effect of azo compounds

[0032]

Embodiment 11 2

[0034] Examples 6 to 10 investigated the influence of inhibitors on the inhibitory effect of azo compounds when different aromatic nitro compounds were used as raw materials. In a 500ml stainless steel reactor, add 100ml of aromatic nitro compounds, 200ml of ethanol, 1g of 5% Pt / C catalyst (produced by Degong Chemical Co., Ltd., Deqing County, Zhejiang Province), add inhibitors, close the reactor, and replace the reactor with nitrogen The air was replaced three times with hydrogen; the temperature was raised to 100°C, the hydrogen pressure was 1.5MPa, stirring was started, the stirring rate was 900r / min, and the reaction was 2h; the reaction was stopped, and after the temperature dropped to room temperature, the reaction solution was taken out and filtered The catalyst was removed and the filtrate was analyzed by gas chromatography. The experimental results are shown in Table 3.

[0035] The influence of table 3 inhibitor on the inhibitory effect of different aromatic nitro com...

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Abstract

The invention discloses a method for preparing arylamine by catalytic hydrogenation of an aromatic nitro compound. The method is to obtain the arylamine of a formula (I) by the catalytic hydrogenation of an aromatic nitro compound shown by a formula (II) and hydrogen in the presence of a catalyst and an ammonium compound serving as an inhibitor. The method disclosed by the invention can obviously reduce the generation of azo compounds and improve the yield and quality of the product.

Description

(1) Technical field [0001] The invention relates to a method for preparing aromatic amines by catalytic hydrogenation of aromatic nitro compounds. (2) Background technology [0002] Aromatic amines are an important class of organic chemical intermediates, widely used in the preparation of medicines, materials, dyes, pesticides and other fields. [0003] The method of catalyzing the hydrogenation reduction of nitroaromatic compounds to prepare aromatic amines has attracted much attention and has been widely used because of its advantages such as environmental friendliness and recyclable catalysts. However, when the catalytic hydrogenation reduction method is used to prepare aromatic amines from aromatic nitro compounds, a certain amount of azo compounds such as azo, azo oxide, and hydrazo will be produced under alkaline conditions. can exist stably. For example, Chinese patent CN201010223741.8 discloses a kind of NaOH, KOH, (CH 3 ) 3 CONa or (CH 3 ) 3 When COK is an alk...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/46C07C211/47C07C211/52C07C209/36C07C215/76C07C217/84C07C213/02C07C309/46C07C303/32
Inventor 李小年张群峰马磊卢春山丰枫吕井辉
Owner ZHEJIANG UNIV OF TECH
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