Strong magnetic core-shell structural nano copper-based hydrotalcite catalyst and preparation method thereof

A core-shell structure and magnetic nanotechnology, applied in chemical instruments and methods, preparation of organic compounds, physical/chemical process catalysts, etc., can solve the problems of long synthesis cycle, many influencing factors, complex synthesis process, etc., and achieve strong magnetic properties , the effect of controllable particle size

Inactive Publication Date: 2010-12-29
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Molecular sieve catalysts have good selectivity, but the synthesis process is complicated and the cost is high
Heteropolyacids are suitable for homogeneous reactions. Although they have high conversion rates, they have poor selectivity, severely corrode equipment, are difficult to separate and recover, and cause great pollution to the environment.
Although the preparation process of metal oxides is simple, there are many influencing factors and the catalytic performance varies greatly.
Although hydrotalcite-like catalysts have the advantages of simple preparation process, low cost, suitable for heterogeneous catalytic reactions, reusable and high selectivity, they also have the problem of difficult separation and recovery.
[0003] In 2009, Shi Fengwei et al. (CuMgAl-like hydrotalcite loaded VO 3 - , MoO 4 2- and WO 4 2- Microwave Synthesis of Catalyst and

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Preparation of magnetic substances

[0023] Weigh 10.73g (0.04mol) ferric chloride hexahydrate (FeCl 3 ·6H 2 O) and 28.82g (0.21mol) sodium acetate trihydrate (CH 3 COONa·3H 2 O) Dissolved in 320mL ethylene glycol, transferred to a 500mL reaction kettle, crystallized at 200°C for 8 hours, cooled to room temperature naturally, washed 2-3 times with ethanol and deionized water, and dried at 60°C for 24 hours , to obtain a black powder, denoted as Fe 3 o 4 .

[0024] (2) Preparation of magnetic catalyst

[0025] Weigh 0.3g Fe 3 o 4 The solid was dispersed in 80ml of methanol, ultrasonically dispersed for 0.5 hours, then transferred to a round bottom flask, and stirred at room temperature.

[0026] Prepare 100ml of NaOH alkali solution with a molar concentration of 1.6mol / L, which is recorded as A solution.

[0027] Press (Cu 2+ +Mg 2+ ) / Al 3+ Molar ratio 3, Cu 2+ / Mg 2+ Molar ratio is 0.2, weigh 0.73g Cu(NO 3 ) 2 ·3H 2 O, 3.81g Mg(NO 3 ) 2 ·6H 2 O ...

Embodiment 2

[0031] (1) Preparation of magnetic substances

[0032] Weigh 10.73g (0.04mol) ferric chloride hexahydrate (FeCl 3 ·6H 2 O) and 28.82g (0.21mol) sodium acetate trihydrate (CH 3 COONa·3H 2 O) Dissolved in 320mL ethylene glycol, transferred to a 500mL reaction kettle, crystallized at 200°C for 8 hours, cooled to room temperature naturally, washed 2-3 times with ethanol and deionized water, and dried at 60°C for 24 hours , to obtain a black powder, denoted as Fe 3 o 4 .

[0033] (2) Preparation of magnetic catalyst

[0034] Weigh 0.3g Fe 3 o 4 The solid was dispersed in 80ml of methanol, ultrasonically dispersed for 0.5 hours, then transferred to a round bottom flask, and stirred at room temperature.

[0035] Prepare 100ml of NaOH alkali solution with a molar concentration of 1.6mol / L, which is recorded as A solution.

[0036] Press (Cu 2+ +Mg 2+ ) / Al 3+ Molar ratio 3, Cu 2+ / Mg 2+ Molar ratio is 0.2, weigh 0.73g Cu(NO 3 ) 2 ·3H 2 O, 3.81g Mg(NO 3 ) 2 ·6H 2 O ...

Embodiment 3

[0040] (1) Preparation of magnetic substances

[0041] Weigh 10.73g (0.04mol) ferric chloride hexahydrate (FeCl 3 ·6H 2 O) and 28.82g (0.21mol) sodium acetate trihydrate (CH 3 COONa·3H 2 O) Dissolved in 320mL ethylene glycol, transferred to a 500mL reaction kettle, crystallized at 200°C for 8 hours, cooled to room temperature naturally, washed 2-3 times with ethanol and deionized water, and dried at 60°C for 24 hours , to obtain a black powder, denoted as Fe 3 o 4 .

[0042] (2) Preparation of magnetic catalyst

[0043] Weigh 0.3g Fe 3 o 4 The solid was dispersed in 80ml of methanol, ultrasonically dispersed for 0.5 hours, then transferred to a round bottom flask, and stirred at room temperature.

[0044] Prepare 100ml of NaOH alkali solution with a molar concentration of 1.6mol / L, which is recorded as A solution.

[0045] Press (Cu 2+ +Mg 2+ ) / Al 3+ Molar ratio 3, Cu 2+ / Mg 2+ Molar ratio is 0.2, weigh 0.73g Cu(NO 3 ) 2 ·3H 2 O, 3.81g Mg(NO 3 ) 2 ·6H 2 O ...

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Abstract

The invention discloses a strong magnetic core-shell structural nano copper-based hydrotalcite catalyst and a preparation method thereof, and belongs to the technical field of nano catalysts. The catalyst consists of a strong magnetic core-shell structural nano copper-based hydrotalcite catalyst CuM2+Al hydrotalcite shell and a Fe3O4 magnetic nano particle core; the strong magnetic core-shell structural nano copper-based hydrotalcite catalyst is expressed as Fe3O4@CuM2+Al-LDH and consists of 60 to 80 percent of Fe3O4 magnetic nano particles and 20 to 40 percent of CuM2+Al-LDH hydrotalcite in percentage by mass; the particle size of the core-shell structural magnetic nano catalyst is 500 to 540 nanometers; the specific saturation magnetization intensity sigma s is 40.2 to 60.7emu/g; and the phenolic conversion rate is 38.28 to 55.47 percent. The preparation method has the advantages of simple catalyst preparation process, low cost, suitability for phenolic hydroxylation reaction and phenol-containing wastewater treatment, and convenient enrichment, reclamation and reutilization through an additional magnetic field after the reaction is finished.

Description

technical field [0001] The invention belongs to the technical field of nano-catalysts, in particular to a nano-copper-based hydrotalcite catalyst with a strong magnetic core-shell structure and a preparation method thereof. technical background [0002] The products of phenol hydroxylation reaction are catechol and hydroquinone, which are important fine chemical products. Currently, the catalysts used for the hydroxylation of phenol include molecular sieves, heteropolyacids, metal oxides, and hydrotalcites. Molecular sieve catalysts have good selectivity, but the synthesis process is complicated and the cost is high. Heteropolyacids are suitable for homogeneous reactions. Although they have high conversion rates, they have poor selectivity, severely corrode equipment, are difficult to separate and recover, and cause great pollution to the environment. Although the preparation process of metal oxides is simple, there are many influencing factors and the catalytic performanc...

Claims

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Application Information

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IPC IPC(8): B01J23/745B01J35/02C07C39/08C07C37/00
Inventor 张慧张国彦杨科段雪
Owner BEIJING UNIV OF CHEM TECH
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