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Method for preparing 4,4'-diaminodiphenylmethane

A technology of diaminodiphenylmethane and aniline, which is applied in the field of chemical production, can solve the problems of complex post-processing of products, high reaction temperature, complex catalyst preparation, etc., achieve high catalytic activity and stability, mild synthesis reaction conditions, suitable for The effect of widely promoting the application

Active Publication Date: 2018-04-20
SHANDONG YUHUANG CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above patents have solved the problems of difficult separation and reuse of catalysts, complex post-processing of products, and pollution of the environment by waste liquid discharge to varying degrees.
However, the above process still has the disadvantages that the preparation of the catalyst is complicated or expensive, and the condensation reaction requires a higher reaction temperature and a longer reaction time, resulting in a high content of by-products in the product and a decrease in product selectivity.

Method used

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  • Method for preparing 4,4'-diaminodiphenylmethane
  • Method for preparing 4,4'-diaminodiphenylmethane
  • Method for preparing 4,4'-diaminodiphenylmethane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Prepare a mixed solution of inorganic strong acid and dichromate or chromate, and take 200mL of the mixed solution and 50g of activated carbon, and place them in a 500mL three-necked flask. Place the three-neck flask in a magnetic stirring heating mantle, heat and reflux at a certain temperature for a certain period of time, take out the modified activated carbon, filter, wash until neutral, and dry it in a vacuum oven at 105°C to constant weight to obtain the acid-modified Activated carbon, numbered uniformly and placed in a desiccator for later use. The acid-modified activated carbons prepared under different conditions are shown in Table 1.

[0021] Table 1 Acid-modified activated carbon prepared under different conditions

[0022]

Embodiment 2

[0024] Place 6.0g of acid-modified activated carbon SGXT-01, SGXT-02, SGXT-03, SGXT-04, SGXT-05, SGXT-06, SGXT-07, and 168.3g of freshly distilled aniline in a 250mL reactor, Fully replace the air in the kettle. Add 48.9 g of 37% formaldehyde aqueous solution into the kettle dropwise through a metering pump, and stir thoroughly for 30 minutes after the addition is completed, during which the temperature is controlled at 30-50°C. After completing the above operations, set the reaction temperature to 120° C. and the reaction time to 6 hours to carry out the reaction. After the reaction is completed, the catalyst and the reaction product are separated through a sand core funnel, and the catalyst is recycled. The reaction product was purified by vacuum distillation, the unreacted aniline was recycled, and the bottom product was analyzed by liquid chromatography. The results are shown in Table 2.

[0025] Product liquid chromatography analysis under different catalysts in table 2...

Embodiment 3

[0028] Put 6.0g of acid-modified activated carbon SGXT-03 and 168.3g of freshly distilled aniline in a 250mL reaction kettle, and fully replace the air in the kettle with nitrogen. Add 48.9 g of 37% formaldehyde aqueous solution into the kettle dropwise through a metering pump, and stir thoroughly for 30 minutes after the addition is completed, during which the temperature is controlled at 30-50°C. After completing the above operations, set the reaction temperature to 80°C, 120°C, and 160°C respectively, and the reaction time to 6h to carry out the reaction. After the reaction is completed, the catalyst and the reaction product are separated through a sand core funnel, and the catalyst is recycled. The reaction product was purified by vacuum rectification, the unreacted aniline was recycled, and the bottom product was analyzed by liquid chromatography. The results are shown in Table 3.

[0029] Product liquid chromatography analysis under table 3 different reaction temperatur...

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Abstract

The invention relates to the technical field of chemical production, in particular to a method for preparing 4,4'-diaminodiphenylmethane. The method for preparing 4,4'-diaminodiphenylmethane is characterized by comprising the steps of; adopting a mode of soaking activated carbon in a mixed solution of excessive dichromate salt or chromate salt with an inorganic strong acid to prepare acid-modifiedactivated carbon; putting the acid-modified activated carbon and aniline in a reaction kettle, adding a formaldehyde aqueous solution dropwise in a nitrogen atmosphere, performing full stirring at the same time, and performing an initial reaction after the addition; and performing vacuum rectification to purify the reaction product so as to obtain the product. The method for preparing 4,4'-diaminodiphenylmethane has a simple preparation process and mild synthesis reaction conditions, the adopted catalyst has low cost, high catalytic activity and stability, high product selectivity, can be separated from the product easily, and can be used repeatedly, and therefore the method for preparing 4,4'-diaminodiphenylmethane is suitable for wide promotion and application.

Description

(1) Technical field [0001] The invention relates to the technical field of chemical production, in particular to a preparation method of 4,4'-diaminodiphenylmethane. (2) Background technology [0002] 4,4′-Diaminodiphenylmethane is an important organic synthesis intermediate, which is widely used in the production of epoxy resin toughening agent, rubber antioxidant, polyurethane MDI, polyesterimide insulating paint and other products. Therefore, the synthesis process of 4,4′-diaminodiphenylmethane has always been one of the hot spots of domestic and foreign researchers. [0003] At present, in industrial production, aniline and formaldehyde are mainly prepared through condensation reaction under the action of liquid strong acid (mainly hydrochloric acid), which is reflected in patents US3260751, US3297759, US3857890, CN101583591A, and CN102666474A. Using a liquid strong acid as a catalyst has the advantages of simple synthesis process and mild reaction conditions. However,...

Claims

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Application Information

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IPC IPC(8): C07C209/78C07C211/50B01J23/26
CPCB01J23/26C07C209/78C07C211/50
Inventor 杨鹏飞谢恒来苟永霞侯红霞王建伟王胜伟
Owner SHANDONG YUHUANG CHEM CO LTD
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