Magnetic multistage nuclear @ shell structure nano-palladium catalyst and preparation method thereof

A technology of core-shell structure and magnetic nanoparticles, applied in chemical instruments and methods, physical/chemical process catalysts, chemical/physical processes, etc.

Inactive Publication Date: 2015-08-05
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, to date, there is no report on a magnetic hierarchical core-shell structured ...

Method used

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  • Magnetic multistage nuclear @ shell structure nano-palladium catalyst and preparation method thereof
  • Magnetic multistage nuclear @ shell structure nano-palladium catalyst and preparation method thereof
  • Magnetic multistage nuclear @ shell structure nano-palladium catalyst and preparation method thereof

Examples

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Embodiment 1

[0039] (1) Preparation of magnetic nanoparticles

[0040] Take 2.16g FeCl 3 ·6H 2 O was dissolved in 80 mL of ethylene glycol in a water bath at 40 °C to obtain a homogeneous and stable solution; 5.76 g of NaAc·3H 2 O, stir slowly until it is completely dissolved, avoiding the generation of air bubbles; transfer to a 100mL polytetrafluoroethylene-lined self-generating pressure bomb, and react at 200°C for 8h. Cool naturally to room temperature, magnetically separate with NdFeB permanent magnets, wash with ethanol for 5 times, then wash with deionized water until neutral, and dry at 60°C for 24 hours to obtain black powdery magnetic nanoparticles, denoted as Fe 3 o 4 . Transmission electron microscopy results (attached figure 1 ) shows that the resulting Fe 3 o 4 The magnetic nanoparticles are spherical particles with a particle diameter of about 400nm; the test results of the magnetic intensity of the vibrating sample show that it has typical superparamagnetism, and the...

Embodiment 2

[0046] (1) Preparation of magnetic nanoparticles

[0047] Take 2.16g FeCl 3 ·6H 2 O was dissolved in 80 mL of ethylene glycol in a water bath at 40 °C to obtain a homogeneous and stable solution; 5.76 g of NaAc·3H 2 O, stir slowly until it is completely dissolved, avoiding the generation of air bubbles; transfer to a 100mL polytetrafluoroethylene-lined self-generating pressure bomb, and react at 200°C for 8h. Cool naturally to room temperature, magnetically separate with NdFeB permanent magnets, wash with ethanol for 5 times, then wash with deionized water until neutral, and dry at 60°C for 24 hours to obtain black powdery magnetic nanoparticles, denoted as Fe 3 o 4 , its size and magnetic properties are the same as in Example 1.

[0048] (2) Preparation of magnetic multi-level core-shell structure hydrotalcite carrier

[0049] Weigh 1.042g Fe 3 o 4The nanoparticles were ultrasonically dispersed in 100 mL of water for 20 min. 2.622g Co(NO 3 ) 2 ·6H 2 O and 1.125g Al...

Embodiment 3

[0053] (1) Preparation of magnetic nanoparticles

[0054] Take 2.16g FeCl 3 ·6H 2 O was dissolved in 80 mL of ethylene glycol in a water bath at 40 °C to obtain a homogeneous and stable solution; 5.76 g of NaAc·3H 2 O, stir slowly until it is completely dissolved, avoiding the generation of air bubbles; transfer to a 100mL polytetrafluoroethylene-lined self-generating pressure bomb, and react at 200°C for 8h. Cool naturally to room temperature, magnetically separate with NdFeB permanent magnets, wash with ethanol for 5 times, then wash with deionized water until neutral, and dry at 60°C for 24 hours to obtain black powdery magnetic nanoparticles, denoted as Fe 3 o 4 , its size and magnetic properties are the same as in Example 1.

[0055] (2) Preparation of magnetic multi-level core-shell structure hydrotalcite carrier

[0056] Weigh 1.042g Fe 3 o 4 The nanoparticles were ultrasonically dispersed in 100 mL of water for 20 min. 2.620g Ni(NO 3 ) 2 ·6H 2 O and 1.125g A...

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Abstract

The invention discloses a magnetic multistage nuclear @ shell structure nano-palladium catalyst and a preparation method thereof, and belongs to the field of magnetic nano-catalysis materials. The general form of the materials is Fe3O4@MAl-LDH@xPd0, wherein the MAl-LDH refers to shell hydrotalcite, the M refers to one or two divalent metal elements, and the x refers to the weight percent load of palladium. By a low-temperature double-dipping co-precipitation method, LDH nano-crystals are assembled on the surface of a Fe3O4 magnetic nuclear surface, shell LDH hexagonal nano-crystals grow in a mutually staggered mode in such a manner that ab surfaces are perpendicular to the magnetic nuclear surface, and the shell LDH hexagonal nano-crystals are honeycomb. By an impregnation reduction method, palladium nano-particles are loaded on a magnetic multistage nuclear @ shell structure carrier to obtain a primary magnetic multistage nuclear @ shell structure nano-palladium catalyst, and the palladium nano-particles are uniformly distributed at edges and staggered positions of the LDH nano-crystals. The obtained catalyst is used for iodobenzene and styrene Heck coupling reaction and has fine catalytic activity, the highest TOF value is 160.5h-1, the catalyst is recycled by an external magnetic field, and the catalytic activity is not obviously reduced after used for ten times.

Description

technical field [0001] The invention belongs to the technical field of magnetic nano-catalysis materials, and in particular relates to a magnetic multi-level core-shell structure nano-palladium catalyst and a preparation method thereof. The magnetic nano-palladium catalyst can be applied to the fields of carbon-carbon coupling, olefin hydrogenation, alcohol oxidation, etc. . Background technique [0002] In the field of organic synthesis, carbon-carbon coupling reaction is a kind of chemical reaction with good substrate applicability, which is widely used in the synthesis of organic intermediates. Common carbon-carbon coupling reaction catalysts mainly use transition metals such as copper, nickel, and palladium as active species. Among them, homogeneous palladium catalysts, especially palladium catalysts containing organophosphine ligands, have attracted much attention due to their excellent catalytic activity, but there are also problems such as sensitivity to air and mois...

Claims

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Application Information

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IPC IPC(8): B01J27/25B01J27/232B01J35/10
Inventor 张慧毕学蒋顺旺
Owner BEIJING UNIV OF CHEM TECH
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