A nitrogen-doped carbon-coated catalyst, its preparation method and application

A nitrogen-doped carbon and catalyst technology, which is applied in the field of halogenated nitroaromatics to prepare halogenated aromatic amines by catalytic hydrogenation, can solve the problems of ammonium shedding and affecting product quality, achieve stable hydrogenation activity, reduce process costs, The effect of chemical structure stabilization

Active Publication Date: 2021-04-30
XIAMEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The shortcoming of these methods is: need constantly add dechlorination inhibitor in reaction system
Modifying Pt or Pd with inorganic ammonium will cause ammonium to fall off when the catalyst is used, which will affect the quality of the product. If it is used mechanically, it is necessary to add inorganic ammonium

Method used

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  • A nitrogen-doped carbon-coated catalyst, its preparation method and application
  • A nitrogen-doped carbon-coated catalyst, its preparation method and application
  • A nitrogen-doped carbon-coated catalyst, its preparation method and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Weigh 1g of supported metal catalyst Pt / C, wherein the loading of Pt is 0.85%, according to the mass ratio of supported noble metal catalyst and nitrogen-containing compound of 1:4, weigh 4g of urea, after physical mixing, place in a 50mL crucible , placed in a muffle furnace, raised to 400°C, kept for 5h, and then lowered to room temperature to obtain nitrogen-doped carbon-coated platinum-on-carbon catalyst 1 (CN@Pt / C), wherein the thickness of nitrogen-doped carbon is 2nm.

[0035] figure 1 It is the TEM picture of supported metal catalyst 0.85%Pt / C, figure 2 TEM image of nitrogen-doped carbon-coated platinum carbon catalyst 1 (CN@Pt / C) in Example 1, for comparison figure 1 and figure 2 , the nitrogen-doped carbon layer wraps the Pt metal active sites on the platinum-carbon catalyst well.

[0036] image 3 It is the supported metal catalyst 0.85%Pt / C and the Raman spectrum of nitrogen-doped carbon-coated platinum carbon catalyst 1 (CN@Pt / C) obtained in this exam...

Embodiment 2

[0041] Weigh 1g of supported metal catalyst Pt / Al 2 o 3 , wherein the loading capacity of Pt is 0.85%, according to the mass ratio of supported noble metal catalyst and nitrogen-containing compound 1:6, take by weighing 6g melamine, after physical mixing, place the crucible of 50mL, put into the muffle furnace, rise to 600°C, kept for 3h, then cooled down to room temperature, and nitrogen-doped carbon-coated platinum-on-carbon catalyst 2 (CN@Pt / Al 2 o 3 ), where the nitrogen-doped carbon has a thickness of 5 nm.

Embodiment 3

[0043] Take by weighing 1g supported metal catalyst Pt / Y type molecular sieve, wherein the loading capacity of Pt is 0.85%, according to the mass ratio 1:10 of supported noble metal catalyst and nitrogen-containing compound, take by weighing 10g dicyandiamide, after physically mixing, place In a 50mL crucible, put it into a muffle furnace, raise it to 800°C, keep it for 1h, and cool it down to room temperature to obtain nitrogen-doped carbon-coated platinum carbon catalyst 3 (CN@Pt / Y molecular sieve), in which nitrogen-doped The carbon has a thickness of 10 nm.

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Abstract

A nitrogen-doped carbon-coated catalyst, its preparation method and application. The invention provides a nitrogen-doped carbon-coated catalyst for the catalytic hydrogenation of halogenated nitroaromatics to prepare halogenated aromatic amines, including a supported metal catalyst and a coating layer, and the supported metal catalyst includes a carrier and a metal active group The cladding layer is a nitrogen-doped carbon layer, and the thickness of the nitrogen-doped carbon layer is 0.1nm-10nm. The metal active component is G-M, G is one or more of noble metals Pt, Pd, Rh or Ru, and M includes at least one of Fe, Co, Ni, Sn, and Mo metals. The catalyst provided by the invention is applied to the catalytic hydrogenation of halogenated nitroaromatics to prepare halogenated aromatic amines, the conversion rate of halogenated nitrobenzene is as high as 100%, and the catalyst coated with nitrogen-doped carbon has high activity and excellent stability, and can be obtained High-purity halogenated aniline, the selectivity can reach more than 99.7%, and the dehalogenation is less than 0.3%, which effectively inhibits dehalogenation; and does not need to add dechlorination inhibitors in the reaction system, which reduces the cost and reduces the complexity of the reaction system. Reduce possible side reactions.

Description

technical field [0001] In a preferred solution, the catalyst of the present invention can be loaded on a carrier, and the carrier can be activated carbon, molecular sieve, silicon dioxide, aluminum oxide, graphene to form a supported catalyst. [0002] The invention belongs to the technical field of catalysts and catalyst applications, and relates to a nitrogen-doped carbon-coated catalyst, its preparation method and its application in the catalytic hydrogenation of halogenated nitroaromatics to prepare halogenated aromatic amines. Background technique [0003] Halogenated aromatic amines are important chemical intermediates for medicine, pesticides, dyes, spices, etc., and have a wide range of uses. Its production method is mainly obtained by reducing the corresponding halogenated nitroaromatic compounds. The reduction methods include iron powder reduction method, alkali sulfide reduction method and catalytic hydrogenation reduction method. The iron powder reduction method...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J27/24B01J29/12B01J35/02C07C209/36C07C211/52
CPCB01J27/24B01J29/126B01J35/0086B01J35/023B01J2229/18C07C209/365C07C211/52
Inventor 郑南峰李凯佳刘锟隆刘圣杰陈洁
Owner XIAMEN UNIV
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