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Preparation method of asymmetric aromatic azo compound

An aromatic azo and asymmetric technology, applied in the field of preparation of asymmetric aromatic azo compounds, can solve the problems of high operation requirements, easy environmental pollution, poor selectivity, etc., and achieves good selectivity, safe and simple operation, and reduced processing intensity. Effect

Active Publication Date: 2014-12-24
SINOPHARM CHEM REAGENT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the above-mentioned problems, the purpose of the present invention is to provide a method for preparing an asymmetric aromatic azo compound, so as to overcome the complicated operation, poor selectivity, high operation requirements and easy pollution of the environment in the preparation process of aromatic azo compounds in the prior art. etc., the product yield of the obtained asymmetric aromatic azo compound is greater than 85% and above, and the purity of the product reaches 98% and above

Method used

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  • Preparation method of asymmetric aromatic azo compound
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  • Preparation method of asymmetric aromatic azo compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Preparation of 4-nitrophenylazobenzene:

[0034] The structural formula is:

[0035]

[0036] Preparation process: Add 1.0mol phenylhydrazine (108.1g), 500ml dichloromethane, and 8g potassium carbonate-modified alumina solid base to a reaction vessel equipped with stirring and a thermometer in sequence, control the temperature at 20-40°C, and add dropwise 1.05mol of 4-nitrochlorobenzene (165.4g), after dropping, place the reaction vessel under ultrasonic conditions at 38-40°C for 1 hour, filter to remove the solid, add 200ml of 10wt% sodium hypochlorite solution to the filtrate, and stir at room temperature for reaction After 6 hours, the layers were left to stand, and the water phase was removed. The dichloromethane layer was concentrated again to obtain the crude product, and the crude product was recrystallized with dichloromethane to obtain 196g of 4-nitrophenylazobenzene with a purity of 98.8% (total yield 86.3%), the recovered dichloromethane can be recycled a...

Embodiment 2

[0038] Preparation of 4-nitrophenylazo 4-methoxybenzene:

[0039] The structural formula is:

[0040]

[0041] Preparation process: Add 1.0mol 4-nitrophenylhydrazine (153.1g), 1000ml dichloromethane, and 20g potassium carbonate-modified alumina solid base to a reaction vessel equipped with stirring and a thermometer, and control the temperature at 20-40°C , add 1.10mol of 4-methoxybromobenzene (205.7g) dropwise, after dropping, place the reaction bottle under ultrasonic conditions at 38-40°C for 2 hours, filter to remove the solid, add 200ml of 10wt% sodium hypochlorite solution to the filtrate , stirring and reacting at room temperature for 5 hours, standing to separate layers, removing the water phase, and then concentrating the dichloromethane layer to obtain a crude product, which was recrystallized with dichloromethane to obtain 4-nitrophenylazo 4- Methoxybenzene 225g (total yield 87.5%), the dichloromethane recovered can be recycled after treatment.

Embodiment 3

[0043] Preparation of 2,4-dinitrophenylazo 4-nitrobenzene:

[0044] The structural formula is:

[0045]

[0046] Preparation process: Add 1.0mol 2,4-dinitrophenylhydrazine (198.2g), 1500ml dichloromethane, and 20g potassium nitrate-modified alumina solid base to a reaction vessel equipped with stirring and a thermometer, and control the temperature at 20 -40°C, add 1.20mol of 4-nitrochlorobenzene (189.0g) dropwise, after dropping, place the reaction bottle under ultrasonic conditions at 38-40°C for 1.5 hours, filter to remove the solid, add 300ml of filtrate, 25% Hydrogen peroxide, stirred and reacted at room temperature for 4 hours, let stand to separate layers, removed the water phase, concentrated the dichloromethane layer to obtain the crude product, and recrystallized the crude product with dichloromethane to obtain 4-nitrophenylazobenzene with a purity of 99.3% 288g (total yield 90.8%), the recovered dichloromethane can be recycled after treatment.

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Abstract

The invention discloses a preparation method of an asymmetric aromatic azo compound. The preparation method comprises the following steps: performing condensation on aromatic hydrazine and aryl halide which are used as raw materials in a dichloromethane two-phase system of a solid base catalyst to obtain asymmetric disubstituted hydrazine, and performing catalytic oxidation on the asymmetric disubstituted hydrazine to prepare the asymmetric aromatic azo compound. The asymmetric aromatic azo compound prepared by the preparation method has the yield of above 85% and the purity of 98% and above; compared with the prior art, the preparation method is safe, simple and convenient to operate, greatly improves an operating environment, and avoids of a dangerous diazotization step; moreover, the method is mild in reaction condition, good in selectivity, easy in process control and stable in product quality, can recycle and reuse unreacted organic raw materials, and greatly reduces the treatment intensity of environment-friendly COD, thereby being suitable for industrial production.

Description

technical field [0001] The invention relates to a preparation method of an unsymmetrical aromatic azo compound. Background technique [0002] Aromatic azo compounds have a long history of development, production, and application. There are many varieties and series, and they are widely used in analytical testing, printing and dyeing, biomedicine and other fields. The traditional manufacturing process is to couple aromatic amines, phenol (ether), pyrrole, active methylene compounds, etc. after diazotization with sodium nitrite. [0003] However, the diazonium salt in the diazotization step in the traditional process is usually unstable. It will decompose and release nitrogen when encountering certain ions under the conditions of light and heat. It is very likely to generate high pressure and explode. Because the reaction system is large (water is aromatic amine More than 10 times that of aromatic amines, the amount of acid used is more than 2.5 times that of aromatic amines)...

Claims

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Application Information

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IPC IPC(8): C07C245/08
Inventor 郭建国顾金凤郑琦杜志友凌芳
Owner SINOPHARM CHEM REAGENT
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