CN112023939A

CN112023939A - Magnetic core-shell type hydrogenation catalyst and method for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol

Info

Publication number: CN112023939A
Application number: CN202010755096.8A
Authority: CN
Inventors: 杨磊; 成有为; 时强; 邱敏茜; 易磊; 张新平; 王韩
Original assignee: Zhejiang University ZJU; Zhejiang Henglan Technology Co Ltd
Current assignee: Zhejiang University ZJU; Zhejiang Henglan Technology Co Ltd
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2020-12-04
Anticipated expiration: 2040-07-30
Also published as: CN112023939B

Abstract

The invention relates to the field of catalyst preparation, and discloses a magnetic core-shell type hydrogenation catalyst and a method for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol, wherein the catalyst is expressed as Fe₃O₄@ S/M; wherein, Fe₃O₄The composite material is a nuclear layer, S is a shell layer carrier, and M is a main active metal and/or an auxiliary metal loaded on the shell layer carrier; the active metal is one or more of Ru, Ni, Ir, Pd and PtThe loading amount is 1-50 wt% of the catalyst; the auxiliary metal is one or more of Cu, Fe, Co, Zn and Sn, and the molar ratio of the auxiliary metal to the main active metal is 0.1-10: 1. The catalyst of the invention has the following advantages: the hydrogenation speed is high; secondly, the conversion rate of the raw materials is high, and the selectivity of the target product is high; and thirdly, the magnetic separator has strong magnetism, can realize rapid magnetic separation, and does not need filtration and separation.

Description

Magnetic core-shell type hydrogenation catalyst and method for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol

Technical Field

The invention relates to the field of catalyst preparation, in particular to a magnetic core-shell type hydrogenation catalyst and a method for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol.

Background

2,2,4, 4-tetramethyl-1, 3-Cyclobutanediol (CBDO) is an important aliphatic diol polyester monomer, and is mainly used for producing a high-performance copolyester product with high glass transition temperature, high transparency and strong impact resistance to replace the traditional Polycarbonate (PC). The PC material needs to be added with toxic bisphenol A in order to improve the performance of the polyester, and obviously does not meet the requirements of future green and environment-friendly products. The high-performance polyester copolymerized by CBDO, terephthalic acid and 1, 4-cyclohexanedimethanol not only improves the temperature resistance, flexibility, transparency and other properties of the polyester material, but also does not need to add toxic substances, is green and environment-friendly, and has wide application prospect.

The CBDO production process mainly comprises a thermal cracking process taking isobutyric acid or isobutyric anhydride as a raw material and a dehalogenation synthesis process taking isobutyryl chloride as a raw material. The dechlorination process using isobutyryl chloride as a raw material has the problems of more synthesis byproducts, large solvent consumption, low yield and the like, and does not have the advantages of industrial production. Currently, the thermal cracking process of isobutyric acid or isobutyric anhydride is used in industry to produce CBDO. First, thermally cracking isobutyric acid or isobutyric anhydride to form Dimethylketene (DMK); secondly, DMK dimerizes to obtain 2,2,4, 4-tetramethyl-1, 3-Cyclobutanedione (CBDK); finally, CBDO is obtained through a CBDK hydrogenation process. Among these, CBDK hydrogenation is the key to this process.

The CBDK hydrogenation reaction mostly adopts a slurry bed hydrogenation reaction kettle, and has the advantages of stirring and enhancing mass transfer and heat transfer, but the catalyst particles and the reaction solution also have the problem of difficult separation. U.S. Pat. Nos. 9206950 and 20080132738A1 report that a Ni-based catalyst is adopted in a slurry bed hydrogenation reaction kettle to carry out hydrogenation reaction on CBDK, the CBDO and the catalyst are subjected to heat filtration treatment, and the yield of the CBDO product is 60-95%. CN110124674A reports a magnetically stabilized bed hydrogenation reactor, which uses Fe or Ni or Co catalyst to perform hydrogenation reaction of CBDK, the CBDO and the catalyst are separated by a solid-liquid cyclone first, and then the crude CBDO product is obtained by a filtering device. Therefore, the catalyst in the slurry bed hydrogenation reactor is usually in powder form, and the catalyst and the hydrogenated CBDO need to be separated in a filtration mode subsequently. However, the melting point of CBDO is 126-129 ℃, CBDO is very easy to crystallize at normal temperature, a hot filtration mode is required, the operation of the process is complex, the economic cost is high, and CBDO loss and catalyst waste are inevitably caused. If larger particle catalysts or shaped catalysts are used, the hydrogenation activity of the CBDK will necessarily be greatly reduced and the selectivity of the CBDO will be reduced. Therefore, a slurry bed hydrogenation reaction device needs to be developed, which not only meets the requirements of high activity and selectivity of CBDK hydrogenation, but also meets the requirement of rapid and efficient separation of a catalyst and CBDO, and realizes efficient production of CBDO prepared by slurry bed reactor hydrogenation.

Disclosure of Invention

In order to solve the technical problems, the invention provides a magnetic core-shell type hydrogenation catalyst and a method for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol. The catalyst of the invention has the following advantages: the hydrogenation speed of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is high; secondly, the conversion rate of the raw materials is high, and the selectivity of the target product is high; and thirdly, the magnetic separator has strong magnetism, can realize rapid magnetic separation, and does not need filtration and separation.

The specific technical scheme of the invention is as follows:

in a first aspect, the present invention provides a magnetic core-shell type hydrogenation catalyst for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol, said catalyst being expressed as Fe₃O₄@ S/M; wherein, Fe₃O₄The composite material is a nuclear layer, S is a shell layer carrier, and M is a main active metal and/or an auxiliary metal loaded on the shell layer carrier; the active metal is one or more of Ru, Ni, Ir, Pd and Pt, and the load is 1-50 wt% of the catalyst; the auxiliary metal is one or more of Cu, Fe, Co, Zn and Sn, and the molar ratio of the auxiliary metal to the main active metal is 0.1-10: 1.

Fe₃O₄The ferromagnetic particles are used as the nucleus, and on the one hand, when an external magnetic field is provided, the catalyst can be quickly and efficiently separated. On the other hand, the catalyst can provide a magnetic field by itself, and the hydrogenation activity and selectivity are improved through the interaction of the magnetic field and the active metal particles. The shell layer carrier material with a certain thickness can prevent Fe₃O₄Agglomeration of the particles without weakening the magnetic field strength. On the other hand, the catalyst can provide high specific surface area, is beneficial to improving the dispersion degree of active metals and improving hydrogenation activity and selectivity.

Preferably, the shell carrier is one or more of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, diatomite, carbon nanotubes, activated carbon, molecular sieves, rare earth oxides, silicon carbide, organic metal frameworks and organic porous polymers.

Preferably, the main active metal is Ru, and the loading amount is 1-20 wt% of the catalyst.

Preferably, the auxiliary metal is one or more of Cu, Sn and Zn.

Preferably, the molar ratio of the active metal to the promoter metal is 0.5 to 5.

As a further preferred, the shell layer support is one or more of silica, alumina, titania and an organometallic framework.

More preferably, the main active metal is Ru, and the loading amount is 1-10 wt% of the catalyst.

Preferably, the size of the nuclear layer of the catalyst is 100-400 nm; the thickness of the shell layer is 50-200 nm; the particle size of the main active metal is 1-10 nm; the specific surface area of the catalyst is 50-600 m²(ii)/g; the particle diameter of the catalyst is 300-600 nm; the average pore diameter is 1.2-15 nm; the pore volume is 0.05-1.5 m³/g。

In a second aspect, the present invention provides a method for preparing the above catalyst, comprising the steps of:

a)Fe₃O₄preparation of nanoparticles

Under the protection of nitrogen, dissolving an iron-containing precursor compound into ethylene glycol to obtain a transparent iron-containing solution; adding sodium acetate, polyethylene glycol and sodium citrate, heating to 100-200 ℃, and stirring for 1-3 hours; crystallizing the uniformly mixed solution at 100-200 ℃ for 8-16 h; washing the crystallized black solution with ethanol, and vacuum-drying at 60-80 ℃ for 10-20 h to obtain Fe₃O₄Nanoparticles;

b)Fe₃O₄preparation of @ S

Mixing Fe₃O₄Placing the nano particles in a dilute hydrochloric acid solution for ultrasonic treatment for 10-60 min, performing surface acid treatment, and magnetically separating Fe₃O₄Washing the nano particles with ethanol; mixing Fe₃O₄Re-dispersing the nanoparticles in a mixed solution of alcohol water or alcohol acetonitrile, and stirring for 1-3 h under the assistance of ultrasonic waves; slowly adding ammonia water, and adjusting the pH value of the solution to 9-12; dissolving a shell layer carrier or/and a precursor compound thereof in a mixed solution of absolute ethyl alcohol and absolute acetonitrile; slowly injecting the obtained solution into a solution containing Fe₃O₄Stirring the mixed solution for 1 to 3 hours at the temperature of between 30 and 80 ℃ under the assistance of ultrasonic waves; crystallizing the obtained mixture at 100-200 ℃ for 10-20 h; washing the crystallized black solution with ethanol, performing magnetic separation, and vacuum drying at 60-80 deg.CDrying for 10-20 h to obtain Fe₃O₄@S；

c)Fe₃O₄Preparation of @ S/M

Dissolving a precursor compound containing active metal or/and auxiliary metal in an anhydrous alcohol solvent, and stirring to obtain a transparent uniform solution; mixing Fe₃O₄@ S is dispersed in the uniform solution under ultrasonic-assisted stirring; adding an alkaline solution, adjusting the pH value to 10-12, and continuously performing ultrasonic-assisted stirring for 10-20 hours; magnetically separating the solid, washing the solid with absolute ethyl alcohol, and drying the solid in vacuum at the temperature of between 60 and 80 ℃ for 10 to 20 hours; calcining the obtained powder for 2-6 h at 200-300 ℃ in air atmosphere at the heating rate of 2-5 ℃/min to obtain Fe₃O₄@S/M。

Preferably, in step a): the precursor compound containing iron is ferric chloride, ferric sulfate or ferric acetate; further preferably, the precursor compound containing iron is ferric chloride; wherein the mass ratio of ferric chloride to sodium acetate to polyethylene glycol to sodium citrate is 1: 3-5: 0.3-0.5; the mass ratio of the ferric chloride to the ethylene glycol is 60-80: 1.

Preferably, in step b):

in the alcohol water or the alcohol acetonitrile, the mass ratio of the ethanol to the water or the ethanol to the acetonitrile is 3: 1-6: 1;

the precursor compound of the shell carrier is one or more of tetraethyl orthosilicate, tetrabutyl silicate, aluminum isopropoxide, aluminum chloride, tetrabutyl titanate, ethyl titanate, 2-methylimidazole and zinc nitrate hexahydrate; further preferably, the precursor compound of the shell layer support is tetraethyl orthosilicate, aluminum isopropoxide, or tetrabutyl titanate.

Fe₃O₄The mass ratio of the carrier to the shell layer carrier and/or the precursor compound thereof is 0.3-1: 1.

And the shell materials of different substances are added simultaneously or step by step; further preferably, the precursor compound of silicon is added to prepare a silicon dioxide shell, and then other shell materials are coated step by step.

Preferably, in step c):

the precursor compound of the main active metal is selected from one or a mixture of more of ruthenium trichloride, ruthenium acetate and ruthenium acetylacetonate.

The precursor compound of the auxiliary metal is one or more of chloride, nitrate, sulfate, acetate and oxalate containing the auxiliary metal.

The alcohol is methanol, ethanol or propanol. More preferably, the alcohol is methanol.

The alkaline solution is sodium hydroxide solution, potassium hydroxide solution, ammonia water or urea solution. Further preferably, the alkaline solution is a sodium hydroxide solution.

In a third aspect, the invention provides a magnetic separation hydrogenation device for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol, which comprises a nitrogen/hydrogen supply pipe, a raw material and catalyst preparation kettle, a slurry bed hydrogenation reaction kettle and a magnetic separation device, wherein the raw material and catalyst preparation kettle, the slurry bed hydrogenation reaction kettle and the magnetic separation device are sequentially communicated through pipelines; the nitrogen/hydrogen supply pipe is communicated with a bottom air inlet of the slurry bed hydrogenation reaction kettle; a gas return pipeline is arranged between the gas outlet of the slurry bed hydrogenation reaction kettle and the nitrogen/hydrogen supply pipe, and an aerogel condensing device is arranged on the gas return pipeline; the magnetic separation device is of a conical structure and is provided with an external magnetic field device; the lower end feed inlet of the conical structure is communicated with the slurry bed hydrogenation reaction kettle, and the lower end discharge outlet is connected with the raw material and the catalyst preparation kettle.

Preferably, a heating and stirring mechanism is arranged in the raw material and catalyst preparation kettle.

Preferably, the slurry bed hydrogenation reaction kettle is provided with a gas distributor, a jacket, a stirring mechanism, a pressure gauge, a safety valve and a pressure sensor. Wherein the gas distributor can be a perforated plate, a membrane distribution plate, a ring distributor, an arm distributor or a perforated pipe, and is preferably a membrane distribution plate or a perforated plate.

In a third aspect, the present invention provides a process for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol comprising the steps of:

1) before the reaction, the catalyst is reduced by using hydrogen/nitrogen mixed gas to obtain the reduced metal supported catalyst.

2) Mixing 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione, solvent and catalyst in a raw material and catalyst preparation kettle to obtain a catalyst-containing 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione solution, and injecting the catalyst-containing 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione solution into a slurry bed hydrogenation reaction kettle.

3) By using N₂The pressure of the reaction system is backed to a set value, the temperature is set as the set value, and H is continuously introduced when the temperature and the pressure of the system are stable₂Replacement, H₂Adjusting the flow to a set value; after the hydrogen flows out and passes through the gas condensing device, the gas is mixed with fresh hydrogen and is introduced into the slurry bed hydrogenation reaction kettle again.

4) The materials are stirred and reacted in a slurry bed hydrogenation reaction kettle, and the obtained hydrogenation reaction liquid is input into a magnetic separation device after the reaction.

5) And opening the magnetic field to magnetically separate the catalyst.

6) And conveying the obtained reaction liquid to a crystallization refining unit to obtain the 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol.

7) And closing the magnetic field, so that the catalyst falls into the raw material, is mixed with the catalyst preparation kettle and the fresh catalyst, and is conveyed to the slurry bed hydrogenation reaction kettle for continuous circulating reaction.

Preferably, in the step 1), the hydrogen content in the hydrogen/nitrogen mixed gas is 10-50%, and the hydrogen is reduced for 2-4 hours at the temperature of 200-600 ℃; further preferably, the reduction temperature is 300-500 ℃, and when the shell carrier is a metal organic framework, the reduction temperature is not more than 400 ℃.

Preferably, in step 2), the solvent is selected from one or a mixture of more of ethyl acetate, butyl acetate, isobutyl isobutyrate, dimethyl 1, 4-cyclohexanedicarboxylate, dimethyl adipate, methanol, ethanol, propanol, isopropanol, hexane, heptane, cyclohexane, branched alkane, isoalkane, and hydrocarbons containing at least 6 carbon atoms (hydrocarbons with lower carbon atoms have a generally low boiling point and are gaseous at normal temperature and normal pressure, and cannot be used as a solvent).

In the step 2), based on the total weight of the solution, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is not more than 20 wt%, and the content of the catalyst is 1-50 wt%; more preferably, the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 5-20 wt% and the catalyst is 2-10 wt%.

In the step 4), the hydrogenation reaction temperature is 60-140 ℃, the hydrogen pressure is 1-6 MPa, and the stirring speed is not lower than 1000 rpm.

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

(1) the hydrogenation speed of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is high;

(2) the conversion rate to raw materials is high, and the selectivity to target products is high;

(3) the magnetic separator has strong magnetism, can realize rapid magnetic separation, and does not need filtration and separation.

Drawings

FIG. 1 is a process flow diagram of the preparation of 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol in a slurry bed reactor by using the catalyst prepared in example 1;

FIG. 2 catalyst preparation example 1 magnetic core-shell catalyst Fe₃O₄@ ZIF-8/Ru-Zn Transmission Electron microscopy (Black part is magnetic core Fe)₃O₄And the light color part is shell material ZIF-8).

Reference numerals: a nitrogen/hydrogen supply pipe 1, a raw material and catalyst preparation kettle 2, a slurry bed hydrogenation reaction kettle 3, a magnetic separation device 4, a gas return pipeline 5, a gas condensation and condensation device 6 and an external magnetic field device 7.

Detailed Description

The present invention will be further described with reference to the following examples.

General examples

In a first aspect, the present invention provides a magnetic core-shell type hydrogenation catalyst for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol, said catalyst being expressed as Fe₃O₄@ S/M; wherein, Fe₃O₄The composite material is a nuclear layer, S is a shell layer carrier, and M is a main active metal and/or an auxiliary metal loaded on the shell layer carrier; the active metal is one or more of Ru, Ni, Ir, Pd and Pt, and the load is 1-50 wt% of the catalyst; the assistant metal is Cu, Fe,One or more of Co, Zn and Sn, wherein the molar ratio of the auxiliary metal to the main active metal is 0.1-10: 1.

Preferably, the main active metal is Ru, and the loading amount is 1-20 wt% of the catalyst. The auxiliary metal is one or more of Cu, Sn and Zn. The molar ratio of the active metal to the auxiliary metal is 0.5-5.

As a further preferred, the shell layer support is one or more of silica, alumina, titania and an organometallic framework. The main active metal is Ru, and the loading amount is 1-10 wt% of the catalyst.

Preferably, the size of the nuclear layer of the catalyst is 100-400 nm; the thickness of the shell layer is 50-200 nm; the particle size of the main active metal is 1-10 nm; the specific surface area of the catalyst is 50-600 m²(ii)/g; the particle diameter of the catalyst is 300-600 nm; the average pore diameter is 1.2-15 nm; the pore volume is 0.05-1.5 m³(ii) in terms of/g. The particle size of the main active metal and the particle size of the catalyst particles are obtained by observing a high-resolution transmission electron microscope (JEOL, JEM-2100), and the number of the counted particles is at least 100. The specific surface area, pore diameter, pore volume and the like of the catalyst are represented by N₂An adsorption-desorption curve (Micrometrics ASAP 2010 degassed at 150 ℃ and 1 mmHg for 6 hours, then nitrogen adsorption-desorption data acquisition in liquid nitrogen at-196 ℃) was determined.

a)Fe₃O₄preparation of nanoparticles

Under the protection of nitrogen, dissolving an iron-containing precursor compound into ethylene glycol to obtain a transparent iron-containing solution; adding sodium acetate, polyethylene glycol and sodium citrate, heating to 100-200 ℃, and stirring for 1-3 hours; crystallizing the uniformly mixed solution at 100-200 ℃ for 8-16 h; washing the crystallized black solution with ethanolWashing, and drying in vacuum at 60-80 ℃ for 10-20 h to obtain Fe₃O₄Nanoparticles;

b)Fe₃O₄preparation of @ S

Mixing Fe₃O₄Placing the nano particles in a dilute hydrochloric acid solution for ultrasonic treatment for 10-60 min, performing surface acid treatment, and magnetically separating Fe₃O₄Washing the nano particles with ethanol; mixing Fe₃O₄Re-dispersing the nanoparticles in a mixed solution of alcohol water or alcohol acetonitrile, and stirring for 1-3 h under the assistance of ultrasonic waves; slowly adding ammonia water, and adjusting the pH value of the solution to 9-12; dissolving a shell layer carrier or/and a precursor compound thereof in a mixed solution of absolute ethyl alcohol and absolute acetonitrile; slowly injecting the obtained solution into a solution containing Fe₃O₄Stirring the mixed solution for 1 to 3 hours at the temperature of between 30 and 80 ℃ under the assistance of ultrasonic waves; crystallizing the obtained mixture at 100-200 ℃ for 10-20 h; washing the crystallized black solution with ethanol, performing magnetic separation, and performing vacuum drying at 60-80 ℃ for 10-20 h to obtain Fe₃O₄@S；

c)Fe₃O₄Preparation of @ S/M

Preferably, in step b):

Preferably, in step c):

In a third aspect, as shown in fig. 1, the present invention provides a magnetic separation hydrogenation apparatus for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol, comprising a nitrogen/hydrogen supply pipe 1, and a raw material and catalyst preparation kettle 2, a slurry bed hydrogenation reaction kettle 3, and a magnetic separation apparatus 4, which are sequentially communicated through a pipeline; the nitrogen/hydrogen supply pipe is communicated with a bottom air inlet of the slurry bed hydrogenation reaction kettle; a gas return pipeline 5 is arranged between the gas outlet of the slurry bed hydrogenation reaction kettle and the nitrogen/hydrogen supply pipe, and an aerogel condensing device 6 is arranged on the gas return pipeline; the magnetic separation device is of a conical structure and is provided with an external magnetic field device 7; the lower end feed inlet of the conical structure is communicated with the slurry bed hydrogenation reaction kettle, and the lower end discharge outlet is connected with the raw material and the catalyst preparation kettle.

Preferably, a heating and stirring mechanism is arranged in the raw material and catalyst preparation kettle. The slurry bed hydrogenation reaction kettle is provided with a gas distributor, a jacket, a stirring mechanism, a pressure gauge, a safety valve and a pressure sensor. Wherein the gas distributor can be a perforated plate, a membrane distribution plate, a ring distributor, an arm distributor or a perforated pipe, and is preferably a membrane distribution plate or a perforated plate.

Preferably, the stirring mechanism can be an electric stirrer, the rotating speed of the stirrer can be adjusted, and the setting of the specific rotating speed is determined according to production needs. According to the specific embodiment of the invention, the speed can be adjusted to 200rpm/min, 300rpm/min, 500rpm/min and the like.

Preferably, the raw material and catalyst preparation kettle, the magnetic separation device and the pipeline have a heat preservation function, and the 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol crystals are prevented from blocking the pipeline. Preferably, the temperature of the raw materials, the catalyst preparation kettle and the magnetic separation device is maintained to be not lower than 40 ℃ by adopting constant-temperature circulating water bath; the system pipeline adopts a heating belt for heat preservation, is provided with a plurality of temperature measuring points, and maintains the temperature not lower than 40 ℃.

3) By using N₂The pressure of the reaction system is backed to a set value, the temperature is set as the set value, and H is continuously introduced when the temperature and the pressure of the system are stable₂Replacement, H₂Adjusting the flow to a set value; hydrogen gas flows out and passes through the gasAfter the condensing device, the gas is mixed with fresh hydrogen and is re-introduced into the slurry bed hydrogenation reaction kettle.

5) And opening the magnetic field to magnetically separate the catalyst.

Preferably, in step 2), the solvent is selected from one or a mixture of several of ethyl acetate, butyl acetate, isobutyl isobutyrate, dimethyl 1, 4-cyclohexanedicarboxylate, dimethyl adipate, methanol, ethanol, propanol, isopropanol, hexane, heptane, cyclohexane, branched alkane, isoalkane, and hydrocarbon containing at least 6 carbon atoms and more.

The CBDK hydrogenation reaction data referred to in the examples of the invention are processed according to the following formula:

the present invention will be described in detail below with reference to examples

Catalyst preparation example 1

First, 2.70g of FeCl were sequentially weighed by an electronic balance₃·6H₂O, 7.67g of sodium acetate, 2.10g of polyethylene glycol and 0.80g of sodium citrate are dissolved in 150mL of ethylene glycol and mixed uniformly; heating the mixed solution to 170 ℃, and mechanically stirring for 1 hour to obtain a uniform black solution; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; cooling the crystallization kettle to room temperature, and separating Fe by using a magnet₃O₄Washing the nano particles with ethanol for several times, transferring the nano particles into a vacuum drying oven, and drying the nano particles for 12 hours at the temperature of 60 ℃;

then, the Fe obtained above is mixed with₃O₄Dispersing nano particles (0.5g) in a dilute hydrochloric acid (0.1mol/L) solution, performing ultrasonic treatment for 30min, washing with ethanol for 3 times, performing magnetic separation, dispersing again in absolute methanol containing 420mL, and stirring for 30min under the assistance of ultrasonic treatment; 2.25g of zinc nitrate hexahydrate and 1.35g of dimethylimidazole were added and stirred for 1 hour with the aid of ultrasound at 70 ℃; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; the resulting product was magnetically separated, washed several times with ethanol and deionized water, respectively, and vacuum dried at 60 ℃ for 12 hours.

Finally, the ruthenium chloride solution is measured in turn(5mL, 29.5mmol/L), zinc nitrate solution (4mL, 22, 1mmol/L) and anhydrous methanol (100mL), pouring into a 250mL three-neck flask, and stirring vigorously for 20min until the mixture is mixed uniformly; the magnetic core-shell carrier Fe prepared by the method₃O₄@ ZIF-8(0.5g) was added to the above mixture and stirred for 1 hour with the aid of ultrasound; slowly dripping sodium hydroxide solution (1.0mol/L) into the solution, adjusting the pH value to 12, and continuing stirring for 20 hours; magnetically separating the catalyst, washing with anhydrous methanol for several times; vacuum drying the prepared sample at 60 ℃ for 10 hours to obtain the magnetic core-shell catalyst A, Fe₃O₄@ZIF-8/Ru-Zn_0.6. The loading of the primary active metal Ru was 3 wt% and the loading of the secondary metal Zn was 1.9 wt% by ICP analysis.

FIG. 1 catalyst preparation example 1 magnetic core-shell catalyst Fe₃O₄@ ZIF-8/Ru-Zn Transmission Electron microscopy (Black part is magnetic core Fe)₃O₄And the light color part is shell material ZIF-8).

Catalyst preparation example 2

First, 2.70g of FeCl were sequentially weighed by an electronic balance₃·6H₂O, 7.67g of sodium acetate, 2.10g of polyethylene glycol and 0.80g of sodium citrate are dissolved in 150mL of ethylene glycol and mixed uniformly; heating the mixed solution to 170 ℃, and mechanically stirring for 1 hour to obtain a uniform black solution; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; cooling the crystallization kettle to room temperature, and separating Fe by using a magnet₃O₄Washing the nano particles with ethanol for several times, transferring the nano particles into a vacuum drying oven, and drying the nano particles for 12 hours at the temperature of 60 ℃; then, the Fe obtained above is mixed with₃O₄Dispersing nano particles (0.5g) in a dilute hydrochloric acid (0.1mol/L) solution, performing ultrasonic treatment for 30min, washing with ethanol for 3 times, performing magnetic separation, dispersing again in a mixed solution containing 360mL of ethanol and 90mL of water, and stirring for 30min with the assistance of ultrasonic treatment; slowly dripping 12mL of ammonia water into the mixed solution by using an injection pump until the pH value is 10, and continuing ultrasonic-assisted stirring for 30 min; adding 0.5mL of tetraethoxysilane, stirring for 2 hours under the assistance of ultrasound, and carrying out hydrolysis-condensation reaction on the tetraethoxysilane; dissolving the above materials in waterFilling the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; the prepared product is magnetically separated, washed with ethanol and deionized water for several times respectively, and dried under vacuum at 60 ℃ for 12 hours.

Finally, measuring a ruthenium chloride solution (5mL, 29.5mmol/L) and anhydrous methanol (100mL) in turn, pouring the solution into a 250mL three-neck flask, and stirring vigorously for 20min until the solution is mixed uniformly; the magnetic core-shell carrier Fe prepared by the method₃O₄@SiO₂(0.5g) adding the mixed solution, and continuing stirring for 1 hour under the assistance of ultrasound; slowly dripping sodium hydroxide solution (1.0mol/L) into the solution, adjusting the pH value to 12, and continuing stirring for 20 hours; magnetically separating the catalyst, washing with anhydrous methanol for several times; vacuum drying the prepared sample at 60 ℃ for 10 hours to obtain the magnetic core-shell catalyst B, Fe₃O₄@SiO₂Ru. The active metal loading was 3 wt% by ICP analysis.

Catalyst preparation example 3

First, 2.70g of FeCl were sequentially weighed by an electronic balance₃·6H₂O, 7.67g of sodium acetate, 2.10g of polyethylene glycol and 0.80g of sodium citrate are dissolved in 150mL of ethylene glycol and mixed uniformly; heating the mixed solution to 170 ℃, and mechanically stirring for 1 hour to obtain a uniform black solution; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; cooling the crystallization kettle to room temperature, and separating Fe by using a magnet₃O₄Washing the nano particles with ethanol for several times, transferring the nano particles into a vacuum drying oven, and drying the nano particles for 12 hours at the temperature of 60 ℃; then, the Fe obtained above is mixed with₃O₄Dispersing nano particles (0.5g) in a dilute hydrochloric acid (0.1mol/L) solution, performing ultrasonic treatment for 30min, washing with ethanol for 3 times, performing magnetic separation, dispersing again in a mixed solution containing 360mL of ethanol and 90mL of water, and stirring for 30min with the assistance of ultrasonic treatment; slowly dripping 12mL of ammonia water into the mixed solution by using an injection pump until the pH value is 10, and continuing ultrasonic-assisted stirring for 30 min; adding 0.5g of aluminum isopropoxide, stirring for 2 hours under the assistance of ultrasound, and carrying out alcoholysis-condensation reaction on the aluminum isopropoxide; dissolving the above materials in waterFilling the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; the prepared product is magnetically separated, washed with ethanol and deionized water for several times respectively, and dried in vacuum at 60 ℃ for 12 hours.

Finally, measuring a ruthenium chloride solution (5mL, 29.5mmol/L) and anhydrous methanol (100mL) in turn, pouring the solution into a 250mL three-neck flask, and stirring vigorously for 20min until the solution is mixed uniformly; the magnetic core-shell carrier Fe prepared by the method₃O₄@Al₂O₃(0.5g) adding the mixed solution, and continuing stirring for 1 hour under the assistance of ultrasound; slowly dripping sodium hydroxide solution (1.0mol/L) into the solution, adjusting the pH value to 12, and continuing stirring for 20 hours; magnetically separating the catalyst, washing with anhydrous methanol for several times; vacuum drying the prepared sample at 60 ℃ for 10 hours to obtain the magnetic core-shell catalyst C, Fe₃O₄@Al₂O₃Ru. The active metal loading was 3 wt% by ICP analysis.

Catalyst preparation example 4

First, 2.70g of FeCl were sequentially weighed by an electronic balance₃·6H₂O, 7.67g of sodium acetate, 2.10g of polyethylene glycol and 0.80g of sodium citrate are dissolved in 150mL of ethylene glycol and mixed uniformly; heating the mixed solution to 170 ℃, and mechanically stirring for 1 hour to obtain a uniform black solution; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; cooling the crystallization kettle to room temperature, and separating Fe by using a magnet₃O₄Washing the nano particles with ethanol for several times, transferring the nano particles into a vacuum drying oven, and drying the nano particles for 12 hours at the temperature of 60 ℃; then, the Fe obtained above is mixed with₃O₄Dispersing nano particles (0.5g) in a dilute hydrochloric acid (0.1mol/L) solution, performing ultrasonic treatment for 30min, washing with ethanol for 3 times, performing magnetic separation, dispersing again in a mixed solution containing 360mL of ethanol and 90mL of acetonitrile, and stirring for 30min with the assistance of ultrasonic treatment; slowly dripping 12mL of ammonia water into the mixed solution by using an injection pump until the pH value is 10, and continuing ultrasonic-assisted stirring for 30 min; 0.5g of tetrabutyl titanate is added and stirred for 2 hours with the aid of ultrasound to carry out the alcohol of aluminum isopropoxidePerforming a decomposition-condensation reaction; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; the prepared product is magnetically separated, washed with ethanol and deionized water for several times respectively, and dried under vacuum at 60 ℃ for 12 hours.

Finally, sequentially measuring a ruthenium chloride solution (2mL, 24.5mmol/L) and anhydrous methanol (100mL), pouring into a 250mL three-neck flask, and stirring vigorously for 20min until the ruthenium chloride solution and the anhydrous methanol are mixed uniformly; the magnetic core-shell carrier Fe prepared by the method₃O₄@TiO₂(0.5g) adding the mixed solution, and continuing stirring for 1 hour under the assistance of ultrasound; slowly dripping sodium hydroxide solution (1.0mol/L) into the solution, adjusting the pH value to 12, and continuing stirring for 20 hours; magnetically separating the catalyst, washing with anhydrous methanol for several times; vacuum drying the prepared sample at 60 ℃ for 10 hours to obtain the magnetic core-shell catalyst D, Fe₃O₄@TiO₂Ru. The active metal loading was 1 wt% by ICP analysis.

Catalyst preparation example 5

First, 2.70g of FeCl were sequentially weighed by an electronic balance₃·6H₂O, 7.67g of sodium acetate, 2.10g of polyethylene glycol and 0.80g of sodium citrate are dissolved in 150mL of ethylene glycol and mixed uniformly; heating the mixed solution to 170 ℃, and mechanically stirring for 1 hour to obtain a uniform black solution; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; cooling the crystallization kettle to room temperature, and separating Fe by using a magnet₃O₄Washing the nano particles with ethanol for several times, transferring the nano particles into a vacuum drying oven, and drying the nano particles for 12 hours at the temperature of 60 ℃; then, the Fe obtained above is mixed with₃O₄Dispersing nano particles (0.5g) in a dilute hydrochloric acid (0.1mol/L) solution, performing ultrasonic treatment for 30min, washing with ethanol for 3 times, performing magnetic separation, dispersing again in absolute methanol containing 420mL, and stirring for 30min under the assistance of ultrasonic treatment; 2.25g of zinc nitrate hexahydrate and 1.35g of dimethylimidazole were added and stirred for 1 hour with the aid of ultrasound at 70 ℃; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, and moving the crystallization kettle to a drumAir drying, crystallizing at 200 deg.C for 16 hr; the resulting product was magnetically separated, washed several times with ethanol and deionized water, respectively, and vacuum dried at 60 ℃ for 12 hours.

Finally, measuring a ruthenium chloride solution (5mL, 29.5mmol/L) and anhydrous methanol (100mL) in turn, pouring the solution into a 250mL three-neck flask, and stirring vigorously for 20min until the solution is mixed uniformly; the magnetic core-shell carrier Fe prepared by the method₃O₄@ ZIF-8(0.5g) was added to the above mixture and stirred for 1 hour with the aid of ultrasound; slowly dripping sodium hydroxide solution (1.0mol/L) into the solution, adjusting the pH value to 12, and continuing stirring for 20 hours; magnetically separating the catalyst, washing with anhydrous methanol for several times; vacuum drying the prepared sample at 60 ℃ for 10 hours to obtain the magnetic core-shell catalyst E, Fe₃O₄@ ZIF-8/Ru. The active metal loading was 3 wt% by ICP analysis.

Catalyst preparation example 6

First, 2.70g of FeCl were sequentially weighed by an electronic balance₃·6H₂O, 7.67g of sodium acetate, 2.10g of polyethylene glycol and 0.80g of sodium citrate are dissolved in 150mL of ethylene glycol and mixed uniformly; heating the mixed solution to 170 ℃, and mechanically stirring for 1 hour to obtain a uniform black solution; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; cooling the crystallization kettle to room temperature, and separating Fe by using a magnet₃O₄Washing the nano particles with ethanol for several times, transferring the nano particles into a vacuum drying oven, and drying the nano particles for 12 hours at the temperature of 60 ℃; then, the Fe obtained above is mixed with₃O₄Dispersing nano particles (0.5g) in a dilute hydrochloric acid (0.1mol/L) solution, performing ultrasonic treatment for 30min, washing with ethanol for 3 times, performing magnetic separation, dispersing again in a mixed solution containing 360mL of ethanol and 90mL of water, and stirring for 30min with the assistance of ultrasonic treatment; slowly dripping 12mL of ammonia water into the mixed solution by using an injection pump until the pH value is 10, and continuing ultrasonic-assisted stirring for 30 min; adding 0.5mL of tetraethoxysilane, stirring for 2 hours under the assistance of ultrasound, and carrying out hydrolysis-condensation reaction on the tetraethoxysilane; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, and moving the crystallization kettle to a blast air drying deviceCrystallizing at 200 deg.C for 16 hr; the prepared product is magnetically separated, washed with ethanol and deionized water for several times respectively, and dried under vacuum at 60 ℃ for 12 hours.

Then, the magnetic core Fe obtained above is added₃O₄@SiO₂Dispersing particles (0.5g) in a dilute hydrochloric acid (0.1mol/L) solution for 30min by ultrasonic treatment, washing with ethanol for 3 times, performing magnetic separation, dispersing again in a mixed solution containing 360mL of ethanol and 90mL of water, and stirring for 30min with the assistance of ultrasonic treatment; slowly dripping 12mL of ammonia water into the mixed solution by using an injection pump until the pH value is 10, and continuing ultrasonic-assisted stirring for 30 min; adding 0.5g of aluminum isopropoxide, stirring for 2 hours under the assistance of ultrasound, and carrying out alcoholysis-condensation reaction on the aluminum isopropoxide; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; the prepared product is magnetically separated, washed with ethanol and deionized water for several times respectively, and dried under vacuum at 60 ℃ for 12 hours.

Finally, measuring a ruthenium chloride solution (17mL, 29.5mmol/L) and anhydrous methanol (100mL) in turn, pouring the solution into a 250mL three-neck flask, and stirring vigorously for 20min until the solution is mixed uniformly; the magnetic core-shell carrier Fe prepared by the method₃O₄@SiO₂@Al₂O₃(0.5g) adding the mixed solution, and continuing stirring for 1 hour under the assistance of ultrasound; slowly dripping sodium hydroxide solution (1.0mol/L) into the solution, adjusting the pH value to 12, and continuing stirring for 20 hours; magnetically separating the catalyst, washing with anhydrous methanol for several times; vacuum drying the prepared sample at 60 ℃ for 10 hours to obtain the magnetic core-shell catalyst F, Fe₃O₄@SiO₂@Al₂O₃Ru. The active metal loading was 10 wt% by ICP analysis.

Catalyst preparation example 7

First, 2.70g of FeCl were sequentially weighed by an electronic balance₃·6H₂O, 7.67g of sodium acetate, 2.10g of polyethylene glycol and 0.80g of sodium citrate are dissolved in 150mL of ethylene glycol and mixed uniformly; heating the mixed solution to 170 ℃, and mechanically stirring for 1 hour to obtain a uniform black solution; the solution was filled into 200 mL-volume polytetrafluoroethylenePutting the mixture into a liner, sealing the liner in a crystallization kettle, moving the liner to a blast oven, and crystallizing the liner for 16 hours at 200 ℃; cooling the crystallization kettle to room temperature, and separating Fe by using a magnet₃O₄Washing the nano particles with ethanol for several times, transferring the nano particles into a vacuum drying oven, and drying the nano particles for 12 hours at the temperature of 60 ℃; then, the Fe obtained above is mixed with₃O₄Dispersing nano particles (0.5g) in a dilute hydrochloric acid (0.1mol/L) solution, performing ultrasonic treatment for 30min, washing with ethanol for 3 times, performing magnetic separation, dispersing again in absolute methanol containing 420mL, and stirring for 30min under the assistance of ultrasonic treatment; 2.25g of zinc nitrate hexahydrate and 1.35g of dimethylimidazole were added and stirred for 1 hour with the aid of ultrasound at 70 ℃; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; the resulting product was magnetically separated, washed several times with ethanol and deionized water, respectively, and vacuum dried at 60 ℃ for 12 hours.

Finally, measuring a ruthenium chloride solution (5mL, 29.5mmol/L), a stannous chloride solution (4mL, 19, 3mmol/L) and anhydrous methanol (100mL) in turn, pouring into a 250mL three-neck flask, and stirring vigorously for 20min until the mixture is uniformly mixed; the magnetic core-shell carrier Fe prepared by the method₃O₄@ ZIF-8(0.5g) was added to the above mixture and stirred for 1 hour with the aid of ultrasound; slowly dripping sodium hydroxide solution (1.0mol/L) into the solution, adjusting the pH value to 12, and continuing stirring for 20 hours; magnetically separating the catalyst, washing with anhydrous methanol for several times; vacuum drying the prepared sample at 60 ℃ for 10 hours to obtain the magnetic core-shell catalyst G, Fe₃O₄@ZIF-8/Ru-Cu_0.6. The loading of the main active metal Ru was 3 wt% and the loading of the co-metal Cu was 1.67 wt% by ICP analysis.

Catalyst preparation example 8

First, 2.70g of FeCl were sequentially weighed by an electronic balance₃·6H₂O, 7.67g of sodium acetate, 2.10g of polyethylene glycol and 0.80g of sodium citrate are dissolved in 150mL of ethylene glycol and mixed uniformly; heating the mixed solution to 170 ℃, and mechanically stirring for 1 hour to obtain a uniform black solution; the solution is put into a polytetrafluoroethylene inner container with the volume of 200mL, put into a crystallization kettle and sealed,moving to a blast oven, and crystallizing for 16 hours at 200 ℃; cooling the crystallization kettle to room temperature, and separating Fe by using a magnet₃O₄Washing the nano particles with ethanol for several times, transferring the nano particles into a vacuum drying oven, and drying the nano particles for 12 hours at the temperature of 60 ℃; then, the Fe obtained above is mixed with₃O₄Dispersing nano particles (0.5g) in a dilute hydrochloric acid (0.1mol/L) solution, performing ultrasonic treatment for 30min, washing with ethanol for 3 times, performing magnetic separation, dispersing again in absolute methanol containing 420mL, and stirring for 30min under the assistance of ultrasonic treatment; 2.25g of zinc nitrate hexahydrate and 1.35g of dimethylimidazole were added and stirred for 1 hour with the aid of ultrasound at 70 ℃; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; the resulting product was magnetically separated, washed several times with ethanol and deionized water, respectively, and vacuum dried at 60 ℃ for 12 hours.

Finally, measuring a ruthenium chloride solution (5mL, 29.5mmol/L), a stannous chloride solution (4mL, 40.67mmol/L) and anhydrous methanol (100mL) in turn, pouring into a 250mL three-neck flask, and stirring vigorously for 20min until the mixture is uniformly mixed; the magnetic core-shell carrier Fe prepared by the method₃O₄@ ZIF-8(0.5g) was added to the above mixture and stirred for 1 hour with the aid of ultrasound; slowly dripping sodium hydroxide solution (1.0mol/L) into the solution, adjusting the pH value to 12, and continuing stirring for 20 hours; magnetically separating the catalyst, washing with anhydrous methanol for several times; vacuum drying the prepared sample at 60 ℃ for 10 hours to obtain the magnetic core-shell catalyst H, Fe₃O₄@ZIF-8/Ru-Sn_0.6. The loading of the primary active metal Ru was 3 wt% and the loading of the secondary metal Sn was 3.5 wt% by ICP analysis.

Catalyst comparative preparation example 1

2.70g of FeCl were weighed in turn with an electronic balance₃·6H₂O, 7.67g of sodium acetate, 2.10g of polyethylene glycol and 0.80g of sodium citrate are dissolved in 150mL of ethylene glycol and mixed uniformly; heating the mixed solution to 170 ℃, and mechanically stirring for 1 hour to obtain a uniform black solution; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle at the temperature of 200 ℃ for 16 hours; cooling the crystallization kettle to room temperature, and separating Fe by using a magnet₃O₄Washing the nano particles with ethanol for several times, transferring the nano particles into a vacuum drying oven, and drying the nano particles for 12 hours at the temperature of 60 ℃;

sequentially measuring a ruthenium chloride solution (5mL, 29.5mmol/L) and anhydrous methanol (100mL), pouring into a 250mL three-neck flask, and stirring vigorously for 20min until the ruthenium chloride solution and the anhydrous methanol are mixed uniformly; the Fe prepared above is added₃O₄Adding nano particles (0.5g) into the mixed solution, and continuously stirring for 1 hour under the assistance of ultrasonic waves; slowly dripping sodium hydroxide solution (1.0mol/L) into the solution, adjusting the pH value to 12, and continuing stirring for 20 hours; magnetically separating the catalyst, washing with anhydrous methanol for several times; vacuum drying the prepared sample at 60 ℃ for 10 hours to obtain the magnetic catalyst I, Fe₃O₄Ru. The primary active metal Ru loading was 3 wt% by ICP analysis.

Catalyst comparative preparation example 2

Sequentially weighing 360mL of ethanol and 90mL of water, and slowly dripping 12mL of ammonia water into the mixed solution by using an injection pump until the pH value is 10; adding 0.5mL of tetraethoxysilane into the mixed solution, stirring for 2 hours under the assistance of ultrasound, and carrying out hydrolysis-condensation reaction on the tetraethoxysilane; putting the solution into a polytetrafluoroethylene inner container with the volume of 200mL, putting the polytetrafluoroethylene inner container into a crystallization kettle, sealing the crystallization kettle, moving the crystallization kettle to a blast oven, and crystallizing the crystallization kettle for 16 hours at the temperature of 200 ℃; the obtained product is filtered and separated, washed with ethanol and deionized water for several times respectively, and dried under vacuum at 60 ℃ for 12 hours.

Sequentially measuring a ruthenium chloride solution (5mL, 29.5mmol/L) and anhydrous methanol (100mL), pouring into a 250mL three-neck flask, and stirring vigorously for 20min until the ruthenium chloride solution and the anhydrous methanol are mixed uniformly; SiO prepared by the method₂Adding a carrier (0.5g) into the mixed solution, and continuously stirring for 1 hour under the assistance of ultrasonic waves; slowly dripping sodium hydroxide solution (1.0mol/L) into the solution, adjusting the pH value to 12, and continuing stirring for 20 hours; filtering and separating the catalyst, and washing the catalyst for a plurality of times by using anhydrous methanol; vacuum drying the prepared sample at 60 ℃ for 10 hours to obtain the catalysts J and SiO₂Ru. The active metal loading was 3 wt% by ICP analysis.

Comparative example 1

5g of catalystPlacing the reagent I in a quartz tube reactor, and reacting with 50% H at 300 deg.C (temperature rising rate: 5 deg.C/min)₂/N₂Reducing the mixed gas for 2 hours. N for reduced catalyst₂Protecting, adding a catalyst preparation kettle, stirring with 2,2,4, 4-tetramethyl-1, 3-cyclobutane ketone and isobutyl isobutyrate solvent in the kettle at 40 ℃ and 500rpm/min to obtain a solution containing the magnetic catalyst. Wherein, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 10 weight percent, the content of the catalyst is 5 weight percent, and the total mass of the solution is calculated; the high-pressure advection pump is adopted to pump the mixture into a slurry bed hydrogenation reaction kettle at one time.

By using N₂The pressure backpressure of the reaction system is 3MPa, the temperature is set to 130 ℃, and H is continuously introduced when the temperature and the pressure of the system are stable₂System N₂Replacement, H₂The flow is regulated to be 100 mL/min; starting a slurry bed reactor to stir at the rotating speed of 1200 rpm/min.

After the reaction lasts for 2 hours, inputting reaction liquid in the slurry bed hydrogenation reaction kettle into a magnetic separation device through a pump, turning on an external magnetic field switch, and quickly separating the magnetic core-shell catalyst from the hydrogenation reactor; pumping the separated liquid into a crystallization refining unit through a pump to obtain a 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol product. Closing the external magnetic switch, enabling the catalyst to fall into the catalyst preparation kettle to be mixed with the fresh catalyst, sequentially adding the solvent and the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione, and pumping the mixture into a slurry bed reactor to perform hydrogenation reaction. The separated reaction solution was taken for gas chromatography analysis, and the yield of CBDO and the catalyst loss rate after ten cycles of hydrogenation were calculated, and the results are shown in table 1.

Comparative example 2

5g of catalyst J were placed in a quartz tube reactor at 300 ℃ and 50% H at a rate of 5 ℃/min₂/N₂Reducing the mixed gas for 2 hours. N for reduced catalyst₂Protecting, adding a catalyst preparation kettle, stirring the catalyst preparation kettle, 2,4, 4-tetramethyl-1, 3-cyclobutane ketone and a solvent isobutyl isobutyrate in the kettle, controlling the temperature to be 40 ℃ and the rotating speed to be 500rpm/min, and obtaining a solution containing the catalyst. Wherein, 2,2,4, 4-tetramethyl-the content of 1, 3-cyclobutanedione is 10% by weight and the content of catalyst is 5% by weight, based on the total mass of the solution; the high-pressure advection pump is adopted to pump the mixture into a slurry bed hydrogenation reaction kettle at one time.

After the reaction lasts for 2 hours, separating the reaction liquid in the slurry bed hydrogenation reaction kettle by a pump through a thermal filtering device, and pumping the separated reaction liquid into a crystallization refining unit to obtain a 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol product. Adding the separated catalyst into a catalyst preparation kettle, mixing with a fresh catalyst, sequentially adding a solvent and 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione, and pumping into a slurry bed reactor for hydrogenation reaction. The separated reaction solution was taken for gas chromatography analysis, and the yield of CBDO and the catalyst loss rate after ten cycles of hydrogenation were calculated, and the results are shown in table 1.

Example 1

5g of catalyst A were placed in a quartz tube reactor with 50% H at 300 ℃ C (rate of temperature rise: 5 ℃/min)₂/N₂Reducing the mixed gas for 2 hours. N for reduced catalyst₂Protecting, adding a catalyst preparation kettle, stirring with 2,2,4, 4-tetramethyl-1, 3-cyclobutane ketone and isobutyl isobutyrate solvent in the kettle at 40 ℃ and 500rpm/min to obtain a solution containing the magnetic catalyst. Wherein, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 10 weight percent, the content of the catalyst is 5 weight percent, and the total mass of the solution is calculated; the high-pressure advection pump is adopted to pump the mixture into a slurry bed hydrogenation reaction kettle at one time.

By using N₂The pressure backpressure of the reaction system is 3MPa, the temperature is set to 130 ℃, and H is continuously introduced when the temperature and the pressure of the system are stable₂System N₂Replacement, H₂The flow is regulated to be 100 mL/min; starting a slurry bed reactor to stir at the rotating speed of 1200 rpm/min. After flowing out, the hydrogen is cooled by gasAfter the separation device is condensed, the gas is mixed with fresh hydrogen and is re-introduced into the slurry bed hydrogenation reaction kettle.

Example 2

5g of catalyst B were placed in a quartz tube reactor with 50% H at 300 ℃ C (rate of temperature rise: 5 ℃/min)₂/N₂Reducing the mixed gas for 2 hours. N for reduced catalyst₂Protecting, adding a catalyst preparation kettle, stirring with 2,2,4, 4-tetramethyl-1, 3-cyclobutane ketone and isobutyl isobutyrate solvent in the kettle at 40 ℃ and 500rpm/min to obtain a solution containing the magnetic catalyst. Wherein, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 10 weight percent, the content of the catalyst is 5 weight percent, and the total mass of the solution is calculated; the high-pressure advection pump is adopted to pump the mixture into a slurry bed hydrogenation reaction kettle at one time.

By using N₂The pressure backpressure of the reaction system is 3MPa, the temperature is set to 130 ℃, and H is continuously introduced when the temperature and the pressure of the system are stable₂System N₂Replacement, H₂The flow is regulated to be 100 mL/min; starting a slurry bed reactor to stir at the rotating speed of 1200 rpm/min. After the hydrogen flows out and passes through the gas condensation separation device, the gas and the fresh hydrogen are mixed and are introduced into the slurry bed hydrogenation reaction kettle again.

Example 3

5g of catalyst C were placed in a quartz tube reactor with 50% H at 300 ℃ C (rate of temperature rise: 5 ℃/min)₂/N₂Reducing the mixed gas for 2 hours. N for reduced catalyst₂Protecting, adding a catalyst preparation kettle, stirring with 2,2,4, 4-tetramethyl-1, 3-cyclobutane ketone and isobutyl isobutyrate solvent in the kettle at 40 ℃ and 500rpm/min to obtain a solution containing the magnetic catalyst. Wherein, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 10 weight percent, the content of the catalyst is 5 weight percent, and the total mass of the solution is calculated; the high-pressure advection pump is adopted to pump the mixture into a slurry bed hydrogenation reaction kettle at one time.

Example 4

5g of catalyst D were placed in a quartz tube reactor with 50% H at 300 ℃ C (rate of temperature rise: 5 ℃/min)₂/N₂Reducing the mixed gas for 2 hours. N for reduced catalyst₂Protecting, adding a catalyst preparation kettle, stirring with 2,2,4, 4-tetramethyl-1, 3-cyclobutane ketone and isobutyl isobutyrate solvent in the kettle at 40 ℃ and 500rpm/min to obtain a solution containing the magnetic catalyst. Wherein, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 10 weight percent, the content of the catalyst is 5 weight percent, and the total mass of the solution is calculated; the high-pressure advection pump is adopted to pump the mixture into a slurry bed hydrogenation reaction kettle at one time.

Example 5

5g of catalystE is placed in a quartz tube reactor and is heated with 50% H at 300 ℃ (heating rate: 5 ℃/min)₂/N₂Reducing the mixed gas for 2 hours. N for reduced catalyst₂Protecting, adding a catalyst preparation kettle, stirring with 2,2,4, 4-tetramethyl-1, 3-cyclobutane ketone and isobutyl isobutyrate solvent in the kettle at 40 ℃ and 500rpm/min to obtain a solution containing the magnetic catalyst. Wherein, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 10 weight percent, the content of the catalyst is 5 weight percent, and the total mass of the solution is calculated; the high-pressure advection pump is adopted to pump the mixture into a slurry bed hydrogenation reaction kettle at one time.

Example 6

5g of catalyst F were placed in a quartz tube reactor with 50% H at 300 ℃ C (rate of temperature rise: 5 ℃/min)₂/N₂Reducing the mixed gas for 2 hours. N for reduced catalyst₂Protecting, adding catalyst preparing kettle, stirring with 2,2,4, 4-tetramethyl-1, 3-cyclobutane ketone and isobutyl isobutyrate as solvent in the kettleControlling the temperature at 40 ℃ and the rotating speed at 500rPm/min to obtain the solution containing the magnetic catalyst. Wherein, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 10 weight percent, the content of the catalyst is 5 weight percent, and the total mass of the solution is calculated; the high-pressure advection pump is adopted to pump the mixture into a slurry bed hydrogenation reaction kettle at one time.

Example 7

5G of catalyst G were placed in a quartz tube reactor with 50% H at 300 ℃ C (rate of temperature rise: 5 ℃/min)₂/N₂Reducing the mixed gas for 2 hours. N for reduced catalyst₂Protecting, adding a catalyst preparation kettle, stirring with 2,2,4, 4-tetramethyl-1, 3-cyclobutane ketone and isobutyl isobutyrate solvent in the kettle at 40 ℃ and 500rpm/min to obtain a solution containing the magnetic catalyst. Wherein, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 10 weight percent, the content of the catalyst is 5 weight percent, and the total mass of the solution is calculated; the high-pressure constant-flow pump is adopted to pump the slurry into a slurry bed for hydrogenation reaction at one timeAnd (4) reaction in a kettle.

Example 8

5g of catalyst H were placed in a quartz tube reactor with 50% H at 300 ℃ C (rate of temperature rise: 5 ℃/min)₂/N₂Reducing the mixed gas for 2 hours. N for reduced catalyst₂Protecting, adding a catalyst preparation kettle, stirring with 2,2,4, 4-tetramethyl-1, 3-cyclobutane ketone and isobutyl isobutyrate solvent in the kettle at 40 ℃ and 500rpm/min to obtain a solution containing the magnetic catalyst. Wherein, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 10 weight percent, the content of the catalyst is 5 weight percent, and the total mass of the solution is calculated; the high-pressure advection pump is adopted to pump the mixture into a slurry bed hydrogenation reaction kettle at one time.

By using N₂The pressure backpressure of the reaction system is 3MPa, the temperature is set to 130 ℃, and H is continuously introduced when the temperature and the pressure of the system are stable₂System N₂Replacement, H₂The flow is regulated to be 100 mL/min; starting the slurry bed reactor to stir,the rotation speed is 1200 rpm/min. After the hydrogen flows out and passes through the gas condensation separation device, the gas and the fresh hydrogen are mixed and are introduced into the slurry bed hydrogenation reaction kettle again.

Example 9

5g of catalyst A were placed in a quartz tube reactor with 50% H at 300 ℃ C (rate of temperature rise: 5 ℃/min)₂/N₂Reducing the mixed gas for 2 hours. N for reduced catalyst₂Protecting, adding a catalyst preparation kettle, stirring the catalyst preparation kettle, 2,4, 4-tetramethyl-1, 3-cyclobutane ketone and solvent butyl acetate in the kettle at the temperature of 40 ℃ and the rotating speed of 500rpm/min to obtain a solution containing the magnetic catalyst. Wherein, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 5 weight percent, the content of the catalyst is 10 weight percent, and the total mass of the solution is calculated; the high-pressure advection pump is adopted to pump the mixture into a slurry bed hydrogenation reaction kettle at one time.

By using N₂The pressure backpressure of the reaction system is 4MPa, the temperature is set to 120 ℃, and H is continuously introduced when the temperature and the pressure of the system are stable₂System N₂Replacement, H₂The flow is adjusted to be 50 mL/min; starting a slurry bed reactor to stir at the rotating speed of 1200 rpm/min. After the hydrogen flows out and passes through the gas condensation separation device, the gas and the fresh hydrogen are mixed and are introduced into the slurry bed hydrogenation reaction kettle again.

TABLE 1 catalyst composition and reaction results

[a] Average value after ten times of circulating hydrogenation reaction

By analysis of comparative example and example, the catalyst of comparative example 1 has only magnetic nuclei Fe₃O₄Although the catalyst loss after ten cycles was 0, the average conversion of CBDK was only 85.79% with selectivity only 83.88%, significantly lower than the example level; catalyst of comparative example 2, in the presence of only shell support material SiO₂Although the hydrogenation activity is high, the conversion rate of CBDK can reach 99.96%, but the loss rate of the catalyst after filtration and separation is as high as 3.58%, which causes the waste of the catalyst and the reduction of the selectivity of CBDO.

Through the experimental results of comparative example 2 and comparative example 2, Fe₃O₄Not only can the catalyst be separated quickly and efficiently, and the loss of the catalyst is reduced, but also the hydrogenation activity and selectivity can be improved through the interaction of the magnetic field and active metal Ru particles, and the CBDO selectivity 91.82% is improved to 96.73%.

It can be seen from comparative examples 2 to 6 that the coating with different shell materials does not affect Fe₃O₄The loss rate of the catalyst is 0.02-0.04%, and the loss rate of the catalyst in example 6 is slightly higher than 0.18%, which is probably caused by that two shell materials are sequentially coated with a thick shell layer, and the thickness of the thick shell layer is thicker. In addition, different shell materials do not affect the CBDThe hydrogenation activity of K, but the selectivity to CBDO, e.g. as SiO₂When the shell material is adopted, the selectivity of the CBDO is 96.73%, and when the shell material is adopted as ZIF-8, the selectivity of the CBDO is 98.91%.

By comparing example 5 with examples 1, 7-9, the addition of the second metal promoter is beneficial in increasing the selectivity to CBDO, both of which are greater than 99%.

The raw materials and equipment used in the invention are common raw materials and equipment in the field if not specified; the methods used in the present invention are conventional in the art unless otherwise specified.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, alterations and equivalents of the above embodiments according to the technical spirit of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A magnetic core-shell hydrogenation catalyst for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol is characterized in that: the catalyst is expressed as Fe₃O₄@ S/M; wherein, Fe₃O₄The composite material is a nuclear layer, S is a shell layer carrier, and M is a main active metal and/or an auxiliary metal loaded on the shell layer carrier; the active metal is one or more of Ru, Ni, Ir, Pd and Pt, and the load is 1-50 wt% of the catalyst; the auxiliary metal is one or more of Cu, Fe, Co, Zn and Sn, and the molar ratio of the auxiliary metal to the main active metal is 0.1-10: 1.

2. The catalyst of claim 1, wherein:

the shell carrier is one or more of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, diatomite, carbon nano tubes, active carbon, molecular sieves, rare earth oxides, silicon carbide, organic metal frameworks and organic porous polymers; and/or

The main active metal is Ru, and the loading amount is 1-20 wt% of the catalyst; and/or

The auxiliary metal is one or more of Cu, Sn and Zn; and/or

The molar ratio of the active metal to the auxiliary metal is 0.5-5.

3. The catalyst of claim 2, wherein:

the shell layer carrier is one or more of silicon oxide, aluminum oxide, titanium oxide and organic metal framework; and/or

The main active metal is Ru, and the loading amount is 1-10 wt% of the catalyst.

4. The catalyst of claim 1, wherein: the size of the nuclear layer of the catalyst is 100-400 nm; the thickness of the shell layer is 50-200 nm; the particle size of the main active metal is 1-10 nm; the specific surface area of the catalyst is 50-600 m²(ii)/g; the particle size of the catalyst is 300-600 nm; the average pore diameter is 1.2-15 nm; the pore volume is 0.05-1.5 m³/g。

5. A process for preparing a catalyst as claimed in any one of claims 1 to 4, characterized by the steps of:

a）Fe₃O₄preparation of nanoparticles

Under the protection of nitrogen, dissolving an iron-containing precursor compound into ethylene glycol to obtain a transparent iron-containing solution; adding sodium acetate, polyethylene glycol and sodium citrate, and heating to 100-200%^oC, stirring for 1-3 h; uniformly mixing the solution at 100-200^oC, crystallizing for 8-16 h; washing the crystallized black solution with ethanol at 60-80%^oVacuum drying for 10-20 h under C to obtain Fe₃O₄Nanoparticles;

b）Fe₃O₄preparation of @ S

Mixing Fe₃O₄Placing the nano particles in dilute hydrochloric acid solution for ultrasonic treatment for 10-60 min, performing surface acid treatment, and magnetically separating Fe₃O₄Washing the nano particles with ethanol; mixing Fe₃O₄The nano particles are re-dispersed in the mixed solution of alcohol water or alcohol acetonitrile and assisted by ultrasoundStirring for 1-3 h; slowly adding ammonia water, and adjusting the pH value of the solution to 9-12; dissolving a shell layer carrier or/and a precursor compound thereof in a mixed solution of absolute ethyl alcohol and absolute acetonitrile; slowly injecting the obtained solution into a solution containing Fe₃O₄In the mixed solution of (1), under the assistance of ultrasonic wave, 30-80^oC, stirring for 1-3 h; mixing the obtained mixture in 100-200^oC, crystallizing for 10-20 hours; washing the crystallized black solution with ethanol, and magnetically separating at 60-80%^oVacuum drying for 10-20 h under C to obtain Fe₃O₄@S；

c）Fe₃O₄Preparation of @ S/M

Dissolving a precursor compound containing active metal or/and auxiliary metal in an anhydrous alcohol solvent, and stirring to obtain a transparent uniform solution; mixing Fe₃O₄@ S is dispersed in the uniform solution under ultrasonic-assisted stirring; adding an alkaline solution, adjusting the pH value to 10-12, and continuously performing ultrasonic-assisted stirring for 10-20 hours; magnetically separating the solid, washing with absolute ethanol, and purifying at 60-80 deg.C^oC, vacuum drying for 10-20 h; subjecting the obtained powder to 200-300% atmosphere^oCalcining for 2-6 h under C, wherein the heating rate is 2-5^oC/min to obtain Fe₃O₄@S/M。

6. The method of claim 5, wherein:

in the step a), the precursor compound containing iron is ferric chloride, ferric sulfate or ferric acetate;

in the step b), the step (c),

in the alcohol water or the alcohol acetonitrile, the ratio of ethanol: water or ethanol: the mass ratio of the acetonitrile is 3: 1-6: 1;

the precursor compound of the shell carrier is one or more of tetraethyl orthosilicate, tetrabutyl silicate, aluminum isopropoxide, aluminum chloride, tetrabutyl titanate, ethyl titanate, 2-methylimidazole and zinc nitrate hexahydrate;

Fe₃O₄the mass ratio of the carrier to the shell carrier and/or precursor compound thereof is 0.3-1: 1;

and the shell materials of different substances are added simultaneously or step by step;

in the step c), the step (c),

the precursor compound of the main active metal is selected from one or a mixture of more of ruthenium trichloride, ruthenium acetate and ruthenium acetylacetonate;

the precursor compound of the assistant metal is one or more of chloride, nitrate, sulfate, acetate and oxalate containing the assistant metal;

the alcohol is methanol, ethanol or propanol;

the alkaline solution is sodium hydroxide solution, potassium hydroxide solution, ammonia water or urea solution.

7. The method of claim 6, wherein:

in the step a), the precursor compound containing iron is ferric chloride; wherein, ferric chloride: sodium acetate: polyethylene glycol: the mass ratio of the sodium citrate is 1: 3-5: 0.3-0.5: 0.3 to 0.5; iron chloride: the mass ratio of the ethylene glycol is 60-80: 1;

in the step b), the precursor compound of the shell layer carrier is tetraethyl orthosilicate, aluminum isopropoxide or tetrabutyl titanate;

firstly, adding a precursor compound of silicon to prepare a silicon dioxide shell, and then coating other shell materials step by step;

in step c), the alcohol is methanol; the alkaline solution is a sodium hydroxide solution.

8. A magnetic separation hydrogenation device for preparing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol is characterized in that: comprises a nitrogen/hydrogen supply pipe, a raw material and catalyst preparation kettle, a slurry bed hydrogenation reaction kettle and a magnetic separation device which are sequentially communicated through pipelines; the nitrogen/hydrogen supply pipe is communicated with a bottom air inlet of the slurry bed hydrogenation reaction kettle; a gas return pipeline is arranged between the gas outlet of the slurry bed hydrogenation reaction kettle and the nitrogen/hydrogen supply pipe, and an aerogel condensing device is arranged on the gas return pipeline; the magnetic separation device is of a conical structure and is provided with an external magnetic field device; a feed port at the lower end of the conical structure is communicated with a slurry bed hydrogenation reaction kettle, and a discharge port at the lower end is connected with a raw material and a catalyst preparation kettle;

a heating and stirring mechanism is arranged in the raw material and catalyst preparation kettle;

the slurry bed hydrogenation reaction kettle is provided with a gas distributor, a jacket, a stirring mechanism, a pressure gauge, a safety valve and a pressure sensor.

9. A process for producing 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol using the catalyst of any one of claims 1 to 4 or the catalyst obtained by the production process of any one of claims 5 to 7 and the apparatus of claim 8, wherein: the method comprises the following steps:

1) before the catalyst is reacted, reducing the catalyst by using hydrogen/nitrogen mixed gas to obtain a reduced metal supported catalyst;

2) mixing 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione, solvent and catalyst in a raw material and catalyst preparation kettle to obtain a catalyst-containing 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione solution, and injecting the catalyst-containing 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione solution into a slurry bed hydrogenation reaction kettle;

3) by using N₂The pressure of the reaction system is backed to a set value, the temperature is set as the set value, and H is continuously introduced when the temperature and the pressure of the system are stable₂Replacement, H₂Adjusting the flow to a set value; after the hydrogen flows out and passes through the gas condensing device, the gas is mixed with fresh hydrogen and is introduced into the slurry bed hydrogenation reaction kettle again;

4) stirring the materials in a slurry bed hydrogenation reaction kettle for reaction, and inputting the obtained hydrogenation reaction liquid into a magnetic separation device after the reaction;

5) opening a magnetic field to magnetically separate the catalyst;

6) conveying the obtained reaction liquid to a crystallization refining unit to obtain 2,2,4, 4-tetramethyl-1, 3-cyclobutanediol;

10. The method of claim 9, wherein:

in the step 1), the content of hydrogen in the hydrogen/nitrogen mixed gas is 10-50% and is 200-600%^oReducing for 2-4 h under C;

in step 2), the solvent is selected from one or a mixture of more of ethyl acetate, butyl acetate, isobutyl isobutyrate, dimethyl 1, 4-cyclohexanedicarboxylate, dimethyl adipate, methanol, ethanol, propanol, isopropanol, hexane, heptane, cyclohexane, branched alkane, isoalkane and hydrocarbon at least containing 6 carbon atoms and more;

in the step 2), based on the total weight of the solution, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is not more than 20 wt%, and the content of the catalyst is 1-50 wt%;

in the step 4), the hydrogenation reaction temperature is 60-140 DEG^oC, hydrogen pressure is 1-6 MPa, and stirring speed is not lower than 1000 rpm.

11. The method of claim 10, wherein:

in the step 1), the reduction temperature is 300-500 DEG C^oC, when the shell carrier is a metal organic framework, the reduction temperature does not exceed 400 DEG^oC；

In the step 2), based on the total weight of the solution, the content of the 2,2,4, 4-tetramethyl-1, 3-cyclobutanedione is 5-20 wt%, and the content of the catalyst is 2-10 wt%.