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Catalyst for preparing cyclohexylamine through aniline hydrogenation, preparation method and application

A technology of catalyst and cyclohexylamine, which is applied in the direction of chemical instruments and methods, physical/chemical process catalysts, amino compound preparation, etc., can solve the problems of reduced reaction effect, equipment corrosion, and CHA selectivity drop, so as to improve reaction performance and Stability, meet the needs of industrial applications, and improve the effect of catalyst selectivity

Active Publication Date: 2021-08-24
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage is that the catalyst is not suitable for reaction at higher temperature. As the reaction temperature rises, the selectivity of CHA drops sharply, and the content of by-product DCHA increases significantly. At 200°C, the yield of by-product DCHA reaches more than 30%.
The disadvantage of this method is that the introduction of a relatively large amount of ammonia gas in industrial devices will cause equipment corrosion and bring potential safety hazards; the recovery and analysis of ammonia gas is also required in the post-treatment process, which increases the investment in procedures and equipment; Ammonia waste gas treatment problem
The disadvantage is that the catalyst activity is low, and it is difficult to achieve a satisfactory yield by increasing the space velocity reaction
[0007] 1. The gas-phase hydrogenation reaction of aniline is a strongly exothermic reaction, and the hot spot temperature of the reaction bed is as high as 200°C. According to the existing patent reports, the catalyst has a high content of by-products at a relatively high temperature, and the yield of cyclohexylamine is low, which is difficult to meet industrialization requirements. application needs;
[0008] 2. In order to improve the selectivity of cyclohexylamine, it is usually necessary to add coupling inhibitors such as ammonia, which leads to a series of problems such as complicated process, equipment corrosion, increased reaction process and equipment investment, and treatment of ammonia-containing waste gas, which is not conducive to industrial operation;
[0009] 3. The activity of the catalyst is low, increasing the space velocity of aniline will significantly reduce the reaction effect, which will greatly limit the increase in production capacity of the device in industrial applications

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] 1) Preparation of 1# catalyst:

[0046] a) 12.61g Ce (NO 3 ) 3 ·6H 2 O, 4.94g Co(NO 3 ) 2 ·6H 2 O and 17.41g NaBH 4 Dissolve in 360 ml of deionized water, then add 1.83 g of melamine, and heat in a water bath to disperse in the solution. The solution was transferred to a three-necked flask, and the crystallization reaction was stirred in a water bath at 90 °C for 24 h. The obtained precipitate was washed with deionized water for several times until neutral, and then placed in a vacuum oven at 70° C. to be fully dried to obtain a catalyst precursor.

[0047] b) 0.11g Zn(NO 3 ) 2 ·6H 2 O was dissolved in 40 ml of anhydrous ethanol, the pre-ground catalyst precursor was added, and the mixture was continuously stirred for 1 h. After suction filtration, washing, and vacuum drying at 70 °C, the solid was calcined in a muffle furnace at 500 °C for 4 h to obtain the present invention. Invented 1# catalyst.

[0048] 2) Evaluation of 1# catalyst at different temperatu...

Embodiment 2

[0057] 1) Preparation of 2# catalyst:

[0058] a) 12.61g Ce (NO 3 ) 3 ·6H 2 O, 6.17g Co(NO 3 ) 2 ·6H 2 O and 15.21g NaBH 4 Dissolve in 320 ml of deionized water, then add 2.44 g of dicyandiamide, and heat in a water bath to disperse in the solution. The solution was transferred to a three-necked flask, and the crystallization reaction was stirred in a water bath at 90 °C for 24 h. The obtained precipitate was washed with deionized water for several times until neutral, and then placed in a vacuum oven at 70° C. to be fully dried to obtain a catalyst precursor.

[0059] b) 0.16g Mg(NO 3 ) 2 ·6H 2 O was dissolved in 40 ml of anhydrous ethanol, the pre-ground catalyst precursor was added, and the mixture was continuously stirred for 1 h. After suction filtration, washing, and vacuum drying at 70 °C, the solid was calcined in a muffle furnace at 500 °C for 4 h to obtain the present invention. Invented 2# catalyst.

[0060] 2) Evaluation of 2# catalyst at different temp...

Embodiment 3

[0069] 3# catalyst preparation:

[0070] a) 12.61g Ce (NO 3 ) 3 ·6H 2 O, 7.41g Co(NO 3 ) 2 ·6H 2 O and 24.75g NaBH 4 Dissolve in 520 ml of deionized water, then add 0.49 g of cyanamide, and heat it in a water bath to disperse it in the solution. The solution was transferred to a three-necked flask, and the crystallization reaction was stirred in a water bath at 90 °C for 24 h. The obtained precipitate was washed with deionized water for several times until neutral, and then placed in a vacuum oven at 70° C. to be fully dried to obtain a catalyst precursor.

[0071] b) 0.12g Ca(NO 3 ) 2 ·6H 2 O was dissolved in 40 ml of anhydrous ethanol, the pre-ground catalyst precursor was added, and the mixture was continuously stirred for 1 h. After suction filtration, washing, and vacuum drying at 70 °C, the solid was calcined in a muffle furnace at 500 °C for 4 h to obtain the present invention. Invented 3# catalyst.

[0072] 2) Evaluation of 3# catalyst at different temperat...

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PUM

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Abstract

The invention provides a catalyst for preparing cyclohexylamine through aniline hydrogenation as well as a preparation method and application of the catalyst. The catalyst comprises a carrier, an active component Co and an auxiliary agent, wherein the carrier is modified CeO2, and the auxiliary agent is at least one of Mg, Ca and Zn. The catalyst can catalyze aniline hydrogenation reaction in a high-activity, high-selectivity and stable manner to prepare cyclohexylamine, has good reaction performance under the conditions of high space velocity and high temperature, and is more suitable for industrial application.

Description

technical field [0001] The invention relates to a hydrogenation catalyst, in particular to a catalyst for preparing cyclohexylamine by hydrogenation of aniline, a preparation method and application thereof, and belongs to the technical field of organic catalysis. Background technique [0002] Cyclohexylamine is an important organic chemical and fine chemical intermediate, widely used in rubber auxiliaries, food additives, metal corrosion inhibitors, anti-corrosion, papermaking, plastic processing and textile industries. Due to the rapid development of food additives and rubber accelerators , cyclohexylamine as a raw material has been in short supply for a long time. At present, the production of cyclohexylamine at home and abroad mostly adopts the gas-phase hydrogenation process of aniline. [0003] Patent US5728883A discloses an unsupported cobalt catalyst and a method for synthesizing cyclohexylamine. The catalyst contains Co, Mn, alkaline earth metal and other transitio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J27/24C07C209/72C07C211/35
CPCB01J27/24C07C209/72C07C2601/14C07C211/35
Inventor 张立娟张聪颖刘振国姜瑞航王震海周亚文曹娜
Owner WANHUA CHEM GRP CO LTD