Magnetically-separable noble metal catalyst and preparation method thereof

A noble metal catalyst and magnetic separation technology, applied in chemical instruments and methods, preparation of organic compounds, preparation of amino hydroxyl compounds, etc., can solve the problems of unsatisfactory separation efficiency, difficult separation of catalysts, and long time consumption, etc., and achieve excellent catalytic activity , Good recyclability, easy to separate and recycle

Inactive Publication Date: 2012-07-04
FUJIAN INST OF RES ON THE STRUCTURE OF MATTER CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

A large number of articles have reported carbon materials, metal oxides, and zeolites as supports for noble metal nanoparticles. However, their application also encountered the problem of difficult catalyst separation.
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Method used

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  • Magnetically-separable noble metal catalyst and preparation method thereof
  • Magnetically-separable noble metal catalyst and preparation method thereof
  • Magnetically-separable noble metal catalyst and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Example 1: Preparation of magnetic core with core-shell structure

[0016] First, ferric oxide microspheres were prepared. 2.7 g FeCl 3 ·6H 2 O and 7.2 g of sodium acetate were added to 100 mL of ethylene glycol solution, stirred magnetically until a uniform yellow clear solution was formed, then transferred to a polytetrafluoroethylene-lined high-pressure hydrothermal kettle, and reacted at 200 ° C for 8 h. The obtained iron tetroxide magnetic particles were repeatedly washed with water and ethanol, dried under vacuum at 50° C. and then used for future use. Before loading the silica shell layer on the surface of ferric oxide, 0.1 g of ferric oxide was ultrasonically treated with 15 mL of 2M HCl solution for 5 min. Magnetically separated, washed, and then added to a mixed solution of 400mL ethanol, 100mL ultrapure water and 15mL concentrated ammonia water. After mechanical stirring for 15 minutes, 3.5mL tetraethyl orthosilicate was added dropwise, and mechanical stir...

Embodiment 2

[0017] Embodiment 2: Preparation of gold nanoparticles

[0018] 250mL HAuCl 4 ·3H 2 O aqueous solution (1 mM) and 25 mL aqueous sodium citrate solution (38.3 mM) were both heated to boiling with magnetic stirring. Then the boiling sodium citrate solution was quickly added to the gold precursor solution, the mixed solution was stirred for 10 minutes, the heat source was removed, and the solution was stirred for 15 minutes to obtain a purple-red solution containing gold nanoparticles. After cooling, refrigerate and store for later use.

Embodiment 3

[0019] Example 3: Loading of gold nanoparticles on magnetic microspheres

[0020] The loading of gold nanoparticles on magnetic microspheres is carried out by the layer-by-layer self-assembly method according to the following steps: (i) 0.25g of magnetic microsphere carrier with core-shell structure is first added to 10mL concentration of 10mg / mL polyethylene diamine ( PEI) aqueous solution, stirred for 30 minutes, and a layer of PEI polycations was adsorbed on the surface of the microspheres. Then magnetic separation, repeated washing to remove excess PEI. The PEI solution contained 0.5M NaCl as a supporting electrolyte, and the pH of the solution was adjusted to 8.5. (ii) The magnetic microspheres adsorbed by PEI were added to 10mL of the pre-synthesized Au solution, stirred for 30min, and a layer of gold nanoparticles was adsorbed on the surface of the PEI polycation, and the above separation and washing process was repeated to obtain a PEI / Au bilayer magnetic microspher...

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Abstract

The invention relates to a magnetically-separable noble metal catalyst and a preparation method thereof. The catalyst consists of a magnetic carrier and noble metal nanoparticles, wherein the magnetic carrier is a microsphere with a core-shell structure; the core is made of ferroferric oxide and the shell is made of silicon dioxide; and the noble metal nanoparticles are aurum nanoparticles. The aurum nanoparticles are loaded on the magnetic microsphere by a layer-by-layer self-assembling method, so that the catalyst can be effectively separated out from a solution obtained after reaction through an external magnetic field and can be reused, and the problem that the metal nanoparticles in the conventional noble metal catalytic reaction system are difficult to separate is solved.

Description

technical field [0001] The invention belongs to the technical field of noble metal nano-catalysts, and in particular relates to a magnetically separable gold catalyst, its preparation method and its application in organic and inorganic reduction reactions. Background technique [0002] Noble metal nanoparticles are widely used as catalysts due to their small size and high surface activity. Noble metal nanoparticles can catalyze the breaking of H-H, C-H, C-C and C-O bonds under appropriate conditions. Because the particle has no pores, it can avoid some side reactions caused by the slow diffusion of reactants to the inner pores, so its activity and selectivity are higher than similar traditional catalysts. However, two disadvantages of noble metal nanoparticles limit their application in the field of catalysis. First of all, due to the small size and high dispersion of noble metal nanoparticles in the reaction system, it is difficult to completely separate them from the sys...

Claims

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Application Information

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IPC IPC(8): B01J31/26B01J31/40B01J35/08C07C215/76C07C213/02C01C3/14
CPCY02P20/584
Inventor 李红芳曹荣
Owner FUJIAN INST OF RES ON THE STRUCTURE OF MATTER CHINESE ACAD OF SCI
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