Quasi homogeneous magnetic nano-particle supported palladium catalyst and preparation method

A technology of magnetic nanoparticles and magnetic nanocarriers, which is applied in the field of palladium catalysts supported by ferroferric oxide magnetic nanoparticles wrapped in silica gel and its preparation, to achieve the effects of rapid separation and recovery, basically unchanged activity and high yield

Inactive Publication Date: 2015-07-22
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the huge specific surface area of ​​the nano-size effect, the influence of mass transfer resistance can be greatly reduced, and the activity is well maintained. However, because the nano-carrier is too small, it is still difficult to separate the supported catalyst from the reaction system.

Method used

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  • Quasi homogeneous magnetic nano-particle supported palladium catalyst and preparation method
  • Quasi homogeneous magnetic nano-particle supported palladium catalyst and preparation method
  • Quasi homogeneous magnetic nano-particle supported palladium catalyst and preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The preparation method of magnetic nanoparticle supported palladium catalyst is as follows:

[0036] (1) Preparation of nano-ferric oxide magnetic particles coated with silica gel: Take 11.0g of ferric chloride and 4.0g of ferrous chloride and dissolve them in 250mL of deionized water under nitrogen atmosphere at 85°C with vigorous stirring, and then adjust them with concentrated ammonia water When the pH value reaches 9, the stirring is continued for 4 hours, and the precipitate is washed with deionized water to neutrality to obtain black ferric oxide particles (8-12nm). Take 2.0g of the above iron ferric oxide particles and ultrasonicate at room temperature for 30min, disperse in 400mL ethanol, then add 12mL concentrated ammonia water and 4.0mL tetraethyl orthosilicate, stir and react for 24h, the black precipitate is magnetically separated and washed with ethanol several times After vacuum drying, the silica gel-wrapped ferroferric oxide magnetic nanoparticles (20-30...

Embodiment 2

[0044] Only the method of loading nano-palladium on magnetic nanoparticles in Step 5 of Example 1 is changed as follows, and other steps are consistent with Example 1.

[0045] Get 34mg palladium chloride and 13mg sodium chloride in 2mL methanol room temperature reaction 24h and make brown red sodium chloropalladate (Na 2 PD 2 Cl 6 ) in methanol. Add 0.5 g of the magnetic particles prepared in step 4 and 18 mL of methanol, and then react at 60° C. for 24 h. After that, 110 mg of sodium acetate was added and stirred at room temperature for 90 min. After the reaction is completed, the palladium catalyst is obtained by magnetic separation, washed with methanol, water and acetone in sequence, and vacuum-dried for use as Pd Cat.2. Palladium content: Pd 2.16% (ICP-AES).

Embodiment 3

[0047] Only the method of loading nano-palladium on magnetic nanoparticles in Step 5 of Example 1 is changed as follows, and other steps are consistent with Example 1.

[0048] Get 17mg palladium chloride and 6mg sodium chloride in 1mL methanol room temperature reaction 24h and make brown red sodium chloropalladate (Na 2 PD 2 Cl 6 ) in methanol. Add 1.0 g of magnetic particles prepared in step 4 and 9 mL of methanol, and then react at 60° C. for 24 h. After that, 56 mg of sodium acetate was added and stirred at room temperature for 1 h. After the reaction is completed, the palladium catalyst is obtained by magnetic separation, washed with methanol, water and acetone in sequence, and vacuum-dried for use as Pd Cat.3. Palladium content: Pd 0.67% (ICP-AES).

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Abstract

The invention relates to a magnetic nano-particle supported palladium catalyst and a preparation method thereof. The catalyst carrier selects silica gel-wrapped ferriferrous oxide magnetic nanoparticles with core shell structure, and has a high specific surface area, and excellent dispersibility and mechanical properties. The catalyst has superparamagnetism at room temperature, and is easy to be magnetized under applied magnetic field action, and magnetism is disappeared when the magnetic field is removed, so it is easy to implement purposes of rapid separation recovery and cycling usage of the palladium catalyst. The surface of the nano carrier covalently grafts a schiff base ligand by 'click chemistry' strategy to firmly and effectively support an organic ligand, and an intermediately longer carbon chain makes the schiff base ligand far from constraint of the carrier, and makes the schiff base ligand to be better coordinated with metal, thereby reaching homogeneous catalysis effect. The catalyst is suitable for Suzuki reaction of halogeno-benzene and aryl boric acid. Under mild reaction conditions, high yield can be obtained, and the catalyst can be repeatedly used almost without activity change.

Description

technical field [0001] The invention relates to a palladium catalyst supported by magnetic nanoparticles and a preparation method thereof, in particular to a palladium catalyst supported by ferric iron tetroxide magnetic nanoparticles coated with silica gel surface-modified by "click chemistry" and a preparation method thereof. Background technique [0002] Palladium-catalyzed C-C coupling reactions such as Suzuki, Heck, and Sonogashira reactions are important methods for forming C-C bonds in pharmaceutical synthetic chemistry. Homogeneous catalysts such as palladium chloride or palladium acetate can effectively catalyze the above C-C coupling reaction, but these homogeneous palladium catalysts are difficult to separate and recover from the reaction system. In addition, palladium black is easily formed during the reaction process, which not only significantly reduces the activity of the catalyst, but also contaminates the reaction product, which limits its practical applicat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J31/28B01J35/02B01J35/10C07C15/14C07C1/32
Inventor 罗军张强苏红
Owner NANJING UNIV OF SCI & TECH
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