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

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...

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 Its Catalytic Hydroxylation Activity of Phenol. Acta Catalytica Sinica, 2009, 30, 201-206) The ternary CuMgAl hydrotalcite-like compound precursor was synthesized by microwave crystallization method, and further prepared by co-precipitation microwave crystallization method Load VO 3 - 、MoO 4 2- and WO 4 2- The hydrotalcite-like catalyst, the article discusses the phenol hydroxylation reaction activity of the catalyst, but does not mention the recovery and reuse of the catalyst

Although the double-shell solid acid catalyst has both magnetic properties and high acid catalytic activity, its preparation steps are cumbersome, the synthesis cycle is long, and the cost is high.

[0004] So far, there has been no report on the preparation of a phenol hydroxylation catalyst that has catalytic activity and can be recycled and reused by a simple synthesis method.