阅读说明：本技术 Cu掺杂MOF-5型催化剂及其制备方法和应用 (Cu-doped MOF-5 type catalyst and preparation method and application thereof ) 是由 向柏霖 欧阳跃军 陈桂 陈雅 王飘 于 2019-12-06 设计创作，主要内容包括：本发明涉及一种Cu掺杂MOF-5型催化剂及其制备方法和应用。该制备方法包括如下步骤：将锌盐、铜盐、溶剂、对苯二甲酸和催化剂混合,反应得到MOF-5(Cu)；再对MOF-5(Cu)进行煅烧处理,得到Cu掺杂MOF-5型催化剂。通过把铜掺杂到MOF-5的结构中,将催化活性位与MOF-5牢固地结合在一起,可得到稳定性非常好的Cu掺杂MOF-5型催化剂。该制备方法工艺简单,利于工业化生产。(The invention relates to a Cu-doped MOF-5 type catalyst, and a preparation method and application thereof. The preparation method comprises the following steps: mixing zinc salt, copper salt, solvent, terephthalic acid and catalyst, and reacting to obtain MOF-5 (Cu); and then calcining MOF-5(Cu) to obtain the Cu-doped MOF-5 type catalyst. By doping copper into the structure of the MOF-5, catalytic active sites and the MOF-5 are firmly combined together, and the Cu-doped MOF-5 type catalyst with excellent stability can be obtained. The preparation method has simple process and is beneficial to industrial production.)

1. A preparation method of a Cu-doped MOF-5 type catalyst is characterized by comprising the following steps:

mixing zinc salt, copper salt, solvent, terephthalic acid and catalyst, and reacting to obtain MOF-5 (Cu);

and carrying out calcination treatment on the MOF-5 (Cu).

2. The method according to claim 1, wherein the molar ratio of the zinc salt to the copper salt is 1:0.01 to 1: 0.5.

3. The method according to claim 1, wherein the molar ratio of the zinc salt to the copper salt is 1:0.02 to 1: 0.08.

4. The preparation method according to claim 1, wherein the molar ratio of the terephthalic acid to the zinc salt is 1:0.8 to 1: 1.5.

5. The preparation method according to claim 1, characterized in that the specific steps of the calcination treatment are: raising the temperature to 400-900 ℃ at the heating rate of 4-10 ℃/min, and carrying out constant-temperature calcination treatment on the MOF-5(Cu) for 1-4 h.

6. The method according to any one of claims 1 to 5, wherein the ratio of the sum of the mass of the zinc salt and the copper salt to the mass of the solvent is 1:30 to 1: 50.

7. The method according to any one of claims 1 to 5, wherein the zinc salt is selected from one or more of zinc chloride, zinc sulfate, zinc nitrate and zinc acetate; the copper salt is selected from one or more of copper chloride, copper sulfate, copper nitrate and copper acetate.

8. The production method according to any one of claims 1 to 5, wherein the solvent is one or more selected from the group consisting of ethanol, methanol, N-dimethylformamide, and dimethylsulfoxide.

9. A Cu doped MOF-5 type catalyst obtained by the process of any one of claims 1 to 8.

10. Use of a Cu doped MOF-5 type catalyst according to claim 9 as a catalyst for phenol hydroxylation reactions.

Technical Field

The invention relates to the field of composite materials, in particular to a Cu-doped MOF-5 type catalyst and a preparation method and application thereof.

Background

The benzenediol mainly comprises pyrocatechol and hydroquinone, is an important organic intermediate, is used for synthesizing carbofuran, propoxur, berberine, epinephrine, vanillin, piperonal and the like, and can also be used for dyes, photosensitive materials, electroplating materials, special inks, auxiliaries and the like. The process for directly oxidizing phenol to generate benzenediol by using hydrogen peroxide is simple, the reaction condition is mild, the oxidation by-product is water, and the process is environment-friendly. The key of phenol hydrogen peroxide hydroxylation is to select a proper catalyst to improve the catalytic activity, and the current catalysts for catalyzing phenol hydroxylation comprise modified molecular sieves, composite metal oxides, organic metal complexes and the like.

Metal-Organic Frameworks (MOFs) are novel nanoporous framework materials with periodic network structures formed by self-assembly of Organic ligands containing nitrogen or oxygen elements and transition Metal ions through complexation. The MOFs material has controllable pore size and ordered pore size, so that the MOFs material has shape-selective effect in specific catalytic reaction, and is favorable for improving the selectivity of the reaction. Whereas MOF-5 is a typical representation of a family of metal-organic framework complexes, formed by 4 Zn and one O [ Zn ]₄O]The inorganic group is connected with p-xylylene to form a three-dimensional, high specific surface and regular pore structure, the specific surface and the pore volume are much higher than that of active carbon, zeolite molecular sieve and silicon dioxide, but the existing catalyst containing the MOF-5 structure has poor stability, is easy to decompose in the reaction process and has poor recycling performance.

Disclosure of Invention

Based on this, the invention aims to provide a preparation method capable of obtaining a Cu-doped MOF-5 type catalyst with good stability.

In addition, the invention also provides a Cu-doped MOF-5 type catalyst and application thereof as a phenol hydroxylation reaction catalyst.

A preparation method of a Cu-doped MOF-5 type catalyst comprises the following steps:

mixing zinc salt, copper salt, solvent, terephthalic acid and catalyst, and reacting to obtain MOF-5 (Cu);

and carrying out calcination treatment on the MOF-5 (Cu).

Compared with the prior art, the invention has the following beneficial effects:

mixing zinc salt, copper salt, a solvent, terephthalic acid and a catalyst, and reacting to obtain MOF-5 (Cu); and then calcining the MOF-5(Cu) to obtain the Cu-doped MOF-5 type catalyst. By doping copper into the structure of the MOF-5, catalytic active sites and the MOF-5 are firmly combined together, and the Cu-doped MOF-5 type catalyst with excellent stability can be obtained. The preparation method has simple process and is beneficial to industrial production.

Drawings

FIG. 1 is an XRD spectrum of MOF-5(Cu) and common MOF-5 obtained in examples 1-4;

FIG. 2 is an XRD spectrum of MOF-5(Cu) -D obtained in examples 1-4.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

A preparation method of a Cu-doped MOF-5 type catalyst comprises the following steps:

mixing zinc salt, copper salt, solvent, terephthalic acid and catalyst, and reacting to obtain MOF-5 (Cu);

and carrying out calcination treatment on the MOF-5 (Cu).

Mixing zinc salt, copper salt, a solvent, terephthalic acid and a catalyst, and reacting to obtain MOF-5 (Cu); and then calcining the MOF-5(Cu) to obtain the Cu-doped MOF-5 type catalyst. By doping copper into the structure of the MOF-5, catalytic active sites and the MOF-5 are firmly combined together, and the Cu-doped MOF-5 type catalyst with excellent stability can be obtained. The preparation method has simple process and is beneficial to industrial production.

Preferably, the preparation method of the Cu doped MOF-5 type catalyst comprises the following steps:

(1) under the condition of room temperature, mixing zinc salt, copper salt, a solvent 1 and terephthalic acid, continuously stirring, adding a catalyst into a system after the solid is completely dissolved, continuously stirring, reacting for 1-3 h to obtain a white solid, filtering, washing a filter cake for 3-4 times by using a solvent 2, removing unreacted inorganic salt and organic acid in a product, and finally drying the filter cake for 3-12 h at the temperature of 40-65 ℃ to obtain MOF-5 (Cu);

wherein the molar ratio of the zinc salt to the copper salt is 1: 0.01-1: 0.5; the molar ratio of the terephthalic acid to the zinc salt is 1: 0.8-1: 1.5; the mass ratio of the sum of the mass of the zinc salt and the copper salt to the mass of the solvent 1 is 1: 30-1: 50;

(2) and raising the temperature to 400-900 ℃ at the heating rate of 4-10 ℃/min, and calcining the MOF-5(Cu) at constant temperature for 1-4 h to obtain the Cu-doped MOF-5 type catalyst.

In some preferred embodiments, the molar ratio of the zinc salt and the copper salt in step (1) is 1:0.02 to 1: 0.04.

In some preferred embodiments, the molar ratio of the terephthalic acid to the zinc salt in step (1) is 1:1.0 to 1: 1.4.

In a preferred embodiment, the zinc salt of step (1) is selected from one or more of zinc chloride, zinc sulfate, zinc nitrate and zinc acetate; the copper salt is one or more of copper chloride, copper sulfate, copper nitrate and copper acetate.

In a preferred embodiment, the catalyst of step (1) is selected from triethylamine or triethanolamine.

In a preferred embodiment, the solvent 1 in step (1) is one or more selected from ethanol, methanol, N-dimethylformamide and dimethylsulfoxide.

In a preferred embodiment, the solvent 2 is selected from one or more of ethanol, methanol, N-dimethylformamide and dimethylsulfoxide.

In some preferred embodiments, the temperature rise rate in the step (2) is 6 ℃/min to 10 ℃/min, the constant-temperature calcination temperature is 600 ℃ to 800 ℃, and the constant-temperature calcination time is 2h to 3 h; in a more preferred embodiment, the temperature rise rate is 10 ℃/min, the temperature of the constant-temperature calcination is 600 ℃, and the time of the constant-temperature calcination is 2 h.

The invention also provides a Cu-doped MOF-5 type catalyst obtained by the preparation method, which is abbreviated as MOF-5(Cu) -D, and an application of the Cu-doped MOF-5 type catalyst as a phenol hydroxylation reaction catalyst.

The Cu-doped MOF-5 type catalyst is applied to a phenol hydroxylation reaction and comprises the following steps:

mixing an MOF-5(Cu) -D catalyst, phenol, hydrogen peroxide (30%) and deionized water, stirring and reacting for 1-3 h at 70-90 ℃, filtering after the reaction is finished, extracting the filtrate for three times by using ethyl acetate, and analyzing the content of phenol and benzenediol in the extract by using a gas chromatograph-mass spectrometer;

the mass ratio of the MOF-5(Cu) -D catalyst to phenol is 1: 5-1: 15, the volume ratio of phenol to hydrogen peroxide is 1: 15-1: 25, and the volume ratio of phenol to deionized water is 1: 30-1: 50; the solvent for extraction is at least one selected from ethyl acetate, chloroform and carbon tetrachloride.

And repeating the step of applying the Cu-doped MOF-5 type catalyst to the phenol hydroxylation reaction for 2 times, and detecting the catalytic activity of the Cu-doped MOF-5 type catalyst after recycling.

The present invention will be described in further detail with reference to specific examples.

If no special description is provided, the raw materials used in the invention are all commercially available raw materials, and the model of the gas chromatograph-mass spectrometer used in the invention is Shimadzu GCMS 2010-plus.