CN110639446A

CN110639446A - Metal organic framework-based micro-membrane reactor, preparation method and application

Info

Publication number: CN110639446A
Application number: CN201910274090.6A
Authority: CN
Inventors: 杨经伦; 何凯琳; 韩伟
Original assignee: Shenzhen Research Institute HKUST
Current assignee: Shenzhen Research Institute HKUST
Priority date: 2018-04-11
Filing date: 2019-04-04
Publication date: 2020-01-03

Abstract

The invention discloses a preparation method of a metal organic framework-based micro-membrane reactor, which comprises the following steps: preparing a fiber membrane substrate; growing a metal organic framework film on the fiber film; the fiber membrane with the metal organic framework is assembled into a micro-membrane reactor. Compared with a plane substrate, the invention provides larger surface area by the fiber substrate, so that the surface area can be increased by limiting or growing the metal organic framework nano particles on the fiber substrate, thereby increasing the catalytic active sites; in addition, the rough surface and porous internal space of the fiber membrane can be regarded as micro flow channels, promoting mass and heat transfer processes of catalytic reactions.

Description

Metal organic framework-based micro-membrane reactor, preparation method and application

Technical Field

The invention relates to a metal organic framework based catalytic membrane reactor, which comprises the preparation of a metal organic framework membrane, the design and the assembly of a microreactor and the application in catalytic reaction.

Background

Metal organic frameworks and noble metal doped metal organic frameworks are potential catalysts in organic reactions. Large areas of metal organic framework nanoparticles provide sufficient catalytically active sites. However, in the tank reaction, the nanoparticle catalyst is difficult to separate and reuse; in fixed bed reactions, they also bring about a high pressure drop. The catalytic membrane reactor integrating reaction and separation can increase reaction conversion rate, improve selectivity, simplify product separation and promote the process of continuous reaction. However, low loading and small active surface area are major weaknesses of catalytic membrane materials.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a metal organic framework based micro-membrane reactor and its application in catalytic reaction to promote the mixing of reactants and catalyst, obtain high yield in a short time, and do not need to separate catalyst.

The technical scheme adopted by the invention for solving the technical problems is as follows: the preparation method for constructing the metal organic framework-based micro-membrane reactor comprises the following steps:

preparing a fiber membrane substrate;

growing a metal organic framework film on the fiber film; and

the metal organic framework membrane is assembled into a micro-membrane reactor.

In the preparation method of the metal organic framework-based micro-membrane reactor provided by the invention, the fiber matrix is selected from glass fiber base materials, carbon cloth, carbon paper and cellulose paper.

In the preparation method of the metal organic framework-based micro-membrane reactor provided by the invention, the metal organic framework is selected from ZIF-8, FeBDC, CuBDC, HKUST-1 and UiO-66.

In the preparation method of the metal organic framework-based micro-membrane reactor provided by the invention, the metal organic framework membrane is prepared by an in-situ method, a secondary growth method and an improved secondary growth method.

In the preparation method of the metal organic framework-based micro-membrane reactor provided by the invention, the assembled micro-membrane reactor is a square plate type or a tubular type, and the assembly of the tubular type micro-membrane reactor comprises a coiling method and a stacking method.

Correspondingly, the invention also provides the metal organic framework-based micro-membrane reactor prepared by the preparation method.

Correspondingly, the invention also provides the application of the metal organic framework-based micro-membrane reactor prepared by the preparation method in catalytic reactions, wherein the catalytic reactions comprise condensation reaction, reduction reaction and acetalization reaction.

In the application provided by the invention, the condensation reaction is Knoevenagel condensation reaction between benzaldehyde and ethyl cyanoacetate.

In the application provided by the invention, the reduction reaction is a 4-nitrophenol reduction reaction.

In the application provided by the invention, the acetalization reaction is an acetalization reaction between benzaldehyde and methanol.

The metal organic framework-based micro-membrane reactor, the preparation method and the application have the following beneficial effects: compared with a plane substrate, the invention provides larger surface area by the fiber substrate, so that the surface area can be increased by limiting or growing the metal organic framework nano particles on the fiber substrate, thereby increasing the catalytic active sites; in addition, the rough surface and porous internal space of the fiber membrane can be regarded as micro flow channels, promoting mass and heat transfer processes of catalytic reactions.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts:

FIGS. 1A, 1B and 1C are schematic views illustrating a process for preparing a metal-organic framework film, wherein FIG. 1A shows an in-situ growth method; FIG. 1B is a secondary growth method; FIG. 1C is a modified overgrowth process for noble metal doping;

FIGS. 2A and 2B are schematic representations of a method of assembling a microreactor, wherein FIG. 2A shows a microreactor cross-sectional configuration and FIG. 2B shows a different reactor design, including a square-shaped flat-plate and a tubular microreactor; the tubular reactor comprises a metal organic framework fiber membrane wound inside or stacked layer by layer;

FIGS. 3A and 3B show a catalytic activity test apparatus, wherein FIG. 3A is an aldolization reaction and a Knoevenagel condensation reaction; FIG. 3B is a reduction of p-nitrophenol;

FIGS. 4A-K are scanning electron microscope images and energy dispersive X-ray spectral element distribution images, wherein FIG. 4A is a FeBDC film surface; FIG. 4B is a UiO-66 film (solution 1) prepared by in situ growth; FIG. 4C a UiO-66 film (solution 2) prepared using an in situ growth method; FIG. 4D is a HKUST-1 membrane; FIG. 4E is a ZIF-8 membrane grown without ethanol wetting; FIGS. 4F, 4G and 4H are ZIF-8 membranes prepared by wetting with ethanol; FIGS. 4J and 4K are energy dispersive X-ray spectroscopy elemental distribution images of the ZIF-8 film of FIG. 4I;

FIGS. 5A and 5B are the surface and interior of ZIF-8 membranes (not wetted with ethanol) after 4 hours of flow reaction;

FIGS. 6A-D are scanning electron microscope images and energy dispersive X-ray spectroscopy elemental distribution images of Pd/ZIF-8 with a Pd loading of 3.1 mol%;

FIGS. 7A, 7B and 7C are X-ray diffraction (XRD) patterns of FeBDC, ZIF-8 and Pd/ZIF-8 films, respectively;

FIGS. 8A and 8B compare ZIF-8 loading of ZIF-8 glass fiber membranes obtained from different manufacturing methods, including whether the hydrophobic glass fiber membranes were ethanol soaked and whether the glass fiber membranes were hydrophobic;

FIGS. 9A, 9B and 9C are Fourier Transform Infrared (FTIR) spectra of FeBDC, ZIF-8 and CuBTC films;

FIGS. 10A-C show benzaldehyde conversion in a tank reactor and a microreactor, wherein FIG. 10A shows benzaldehyde conversion of different MOF membranes in a tank reactor; fig. 10B is the catalytic results of a microreactor and a tank reactor for a febec c membrane; fig. 10C shows benzaldehyde conversion of zrbc and CuBTC membranes in a flow microreactor;

FIGS. 11A-C are the results of Knoevenagel reactions with ZIF-8 membranes grown on hydrophobic glass fiber substrates; FIG. 11A is the catalytic results for a ZIF-8 membrane reactor in three runs (15 wt% ZIF-8 loading, reaction at 60 ℃ C., 1 hour residence time); FIG. 11B is the catalytic results for a ZIF-8 membrane reactor (7 wt% ZIF-8 loading, reaction at 60 ℃ C., 1 hour residence time); FIG. 11C is the catalytic results for a ZIF-8 membrane reactor (15 wt% ZIF-8 loading, reaction at 22 ℃ C. with 1 hour residence time);

FIG. 12 is the 4-nitrophenol reduction of a Pd/ZIF-8MOF membrane microreactor, where FIG. 12A is the catalytic results of a Pd/ZIF-8 membrane reactor prepared using a 0.6 mol% Pd suspension; FIG. 12B is the catalytic results of a Pd/ZIF-8 membrane reactor prepared using a 3 mol% Pd suspension.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Exemplary embodiments of the invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth 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.

In order to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to the drawings and the specific embodiments in the specification, and it should be understood that the embodiments and the specific features in the embodiments of the present invention are detailed descriptions of the technical solution of the present application, and are not limited to the technical solution of the present application, and the technical features in the embodiments and the examples of the present invention may be combined with each other without conflict.

The invention provides a preparation method of a metal organic framework-based micro-membrane reactor, which comprises the following steps: preparing a fiber membrane substrate; growing a metal organic framework film on the fiber film; and assembling the metal-organic framework membrane into a micro-membrane reactor.

The metal organic framework film is prepared by an in-situ growth method and a secondary growth method, or a modified secondary growth method is used for doping noble metal into the metal organic framework film. A tightly packaged metal-organic framework-based micro-membrane reactor is prepared through superposing a cover plate with inlet and outlet on a metal-organic framework membrane, and packaging with polydimethyl siloxane. The rough surface and porous structure of the fibrous substrate can be considered as micro flow channels for organic reactions. The fibrous substrate may simultaneously confine the metal-organic framework particles therein and support the growth of the metal-organic framework layer on the fiber surface to provide sufficient catalyst loading for the catalytic membrane reactor. The microreactor further promotes mass transfer and heat transfer, so that the microreactor has higher reaction efficiency.

FIGS. 1A-C show several methods for preparing metal organic framework fiberglass membranes. FIG. 1A shows an in situ growth method. FIG. 1B is a secondary growth method comprising: (1) pretreatment of the fiber membrane (whether ethanol soaking is adopted or not); (2) growing and washing seed crystals; (3) growing and washing. FIG. 1C shows a modified overgrowth process for noble metal doping, comprising: (1) pretreatment of fiber membranes (ethanol soaking); (2) growing and washing seed crystals; (3) doping with ethanol suspension of palladium, and evaporating the ethanol solution; (4) and (5) growing and washing.

Example 1: preparation of ZIF-8 Metal organic framework Membrane on hydrophilic or hydrophobic glass fiber Membrane (Secondary growth method)

The glass fiber membrane substrate soaked in ethanol is placed in 10ml of seed crystal solution for 30 minutes at the temperature of 30 ℃. The molar ratio of the seed solution is 1Zn (NO)₃)₂·6H₂70-802-methylimidazole O and 5000-6000 water. The seeded substrate was then washed 3 times with water and added to 10ml of fresh growth solution for 24 hours at a temperature of 30 ℃. In a molar ratio of 1Zn (NO)₃)₂·6H₂70-802-methylimidazole O and 5000-6000 water. The dried glass fiber membrane, without ethanol soaking, was also treated by the above steps. The glass fiber membranes were weighed before and after loading with ZIF-8 to calculate the amount of ZIF-8 loaded. FIG. 8A shows the loading of ZIF-8 on a hydrophobic glass fiber membrane; FIG. 8B is the ZIF-8 loading on a hydrophilic glass fiber membrane. The ethanol soaking can improve the loading capacity of ZIF-8, and the hydrophilic glass fiber can load more ZIF-8.

FIG. 4E is a ZIF-8 membrane on hydrophobic glass fibers (without ethanol soak); FIGS. 4F-G are ZIF-8 membranes on hydrophobic glass fibers (ethanol soak pretreatment). FIG. 4H is the internal structure of a ZIF-8 membrane on hydrophobic glass fibers (ethanol soak). All scanning electron microscope images showed that the ZIF-8 layer on the fiber surface was uniformly grown. FIGS. 4J and 4K are energy dispersive X-ray spectroscopy elemental distribution images of the area shown in FIG. 4I, confirming the presence of ZIF-8.

FIG. 5A is the surface morphology of ZIF-8MOF membranes after 4 hours of flow catalysis with a flux of 5 μ L/min. ZIF-8 adheres tightly to the fiber surface. FIG. 11A is the benzaldehyde conversion for 3 Knoevenagel reactions using a 15 wt% ZIF-8 loaded metal organic framework membrane microreactor. The reaction temperature is 60 ℃, the flow rate of reactants is 5 mu L/min, and the conversion rate is stable. FIG. 11B is the conversion of a metal organic framework membrane microreactor loaded with 7 wt% ZIF-8. FIG. 11C is the conversion, temperature 22 ℃ using a 15 wt% ZIF-8 loaded metal organic framework membrane microreactor. It can be seen that the conversion at low temperature is lower. Temperature will affect conversion, but lower loadings such as 7 wt% will have little effect on conversion.

Example 2: growing ZIF-8 metal-organic framework film on carbon cloth (secondary growth method)

The carbon cloth soaked in the ethanol is placed in 10ml of seed crystal solution for 30 minutes at the temperature of 30 ℃. The molar ratio of the seed solution is 1Zn (NO)₃)₂·6H₂70-802-methylimidazole O and 5000-6000 water. The seeded substrate was then washed 3 times with water and added to 10ml of fresh growth solution for 24 hours at a temperature of 30 ℃. In a molar ratio of 1Zn (NO)₃)₂·6H₂70-802-methylimidazole O and 5000-6000 water. The carbon cloth was finally washed with methanol to remove the deposits.

Example 3: preparation of ZIF-8 Metal organic framework films on cellulose paper (Secondary growth method)

The cellulose paper soaked in ethanol is placed in 10ml of seed crystal solution for 30 minutes at 30 ℃. The molar ratio of the seed solution is 1Zn (NO)₃)₂·6H₂70-802-methylimidazole O and 5000-6000 water. The seeded substrate was then washed 3 times with water and added to 10ml of fresh growth solution for 24 hours at a temperature of 30 ℃. In a molar ratio of 1Zn (NO)₃)₂·6H₂70-802-methylimidazole O and 5000-6000 water. The carbon cloth was finally washed with methanol to remove the deposits.

Example 4: preparation of Pd/ZIF-8 Metal organic framework film on glass fiber film (improved secondary growth method)

The molar ratio of the reaction solution of palladium is 1PdCl₂13KBr 1.8 vitamin C3182 water containing 1 wt% of polyvinylpyrrolidone. The reaction solution of palladium was stirred at 100 ℃ for 3 hours, and then washed several times with acetone and chloroform, and the obtained palladium nanoparticles were dispersed in ethanol (molar ratio 1Pd:893 ethanol).

The cellulose paper soaked in ethanol is placed in 10ml of seed crystal solution for 30 minutes at 30 ℃. The molar ratio of the seed solution is 1Zn (NO)₃)₂·6H₂70-802-methylimidazole O and 5000-6000 water. This substrate with the seed was then washed 3 times with water. 200 μ L to 1ml of the Pd suspension was dropped onto 3cm by 3cm of a glass fiber membrane with ZIF-8 seed crystals, then the excess solvent was allowed to evaporate naturally at 22 ℃ and placed in 10ml of fresh growth solution for 24 hours at 30 ℃. In a molar ratio of 1Zn (NO)₃)₂·6H₂70-802-methylimidazole O and 5000-6000 water. The carbon cloth was finally washed with methanol to remove the deposits.

FIG. 6A is a scanning electron microscope image of a Pd/ZIF-8 metal organic framework film with a hydrophobic glass fiber film as a substrate, and FIGS. 6B-D are energy dispersive X-ray spectroscopy elemental distribution images of the region shown in FIG. 6A. The atomic percentage of Pd was 3.1%. FIG. 12A shows the reduction of nitrophenol with a Pd/ZIF-8 metal organic framework membrane with 0.6 mol% Pd. FIG. 12B shows the results of reduction using a Pd/ZIF-8MOF glass fiber membrane, which was prepared using 1ml of Pd suspension. The latter has higher conversion rate and better stability.

Example 5: preparation of FeBDC metal organic framework film on glass fiber substrate (in-situ growth method)

The molar ratio of the reaction solution is 1 terephthalic acid to 1FeCl₃294N, N-dimethylformamide 15 acetic acid. The glass fiber substrate was placed in 45ml of the reaction solution. The reaction solution and the membrane are placed in a clean glass reactor for reaction at the temperature of 110 ℃ for 24 hours. And putting the reacted glass fiber membrane into methanol to replace the solvent for one day, and repeating the methanol replacement step once. The glass fiber membranes should be weighed before and after the reaction to determine the loading of the febc catalyst. The average FeBDC loading was about 20 wt%. Fig. 4A is a surface of a febc metal organic framework film. Fig. 10A is the conversion of benzaldehyde in a tank reactor and fig. 10B is the conversion of benzaldehyde for the aldolisation reaction with the FeBDC/glass fibre membrane, including microreactor flow catalysis and tank reactor catalysis. Compared with the traditional fixed bed reactor, the micro-reactor enables the reaction speed to be faster, and mass transfer is promoted probably due to micro-channels.

Example 6: preparation of HKUST-1 Metal organic framework film on glass fiber film (in-situ growth method)

The molar ratio of the reaction solution was 1Cu (NO)₃)₂·3H₂O0.55 trimesic acid 12N, N-dimethylformamide, and the reactants were mixed for 10 minutes, and 2ml of the mixture was dropped on a glass fiber membrane (average pore diameter 0.22 μm, membrane diameter 50mm), followed by placing in a 180 ℃ oven for 15 minutes (dry reaction). After natural cooling, the film was left in methanol for one day to displace the solvent, and then dried. FIG. 4D is a scanning electron microscope image of the HKUST-1 metal organic framework film, and it can be seen that HKUST-1 grows on the surface of the glass fiber film.

Example 7: preparation of UiO-66 Metal organic framework film on glass fiber film (in situ growth method, solution 1)

The molar ratio of the reaction solution is 1ZrCl₄1.38 terephthalic acid 363N, N-dimethylformamide 18.87 hydrochloric acid. After mixing the reactants, stirring until completely dissolved. The glass fiber membrane is placed in the reaction solution to react for 15 hours at the temperature of 80 ℃. The film after the reaction was immersed in methanol for one day for solvent replacement. FIG. 4C is a scanning electron microscope image of the UiO-66 metal organic framework film obtained from solution 1.

Example 8: preparation of UiO-66 Metal organic framework film on glass fiber film (in situ growth method, solution 2)

The molar ratio of the reaction solution is 1ZrCl ₄1 terephthalic acid, 1 water: 26N, N-dimethylformamide. The glass fiber membrane was placed therein and reacted at 120 ℃ for 3 days. The resulting glass fiber membrane was immersed in methanol for one day for solution displacement. FIG. 4B is a scanning electron microscope image of the UiO-66 metal organic framework film obtained from solution 2.

Characterization of Metal organic framework films

X-ray diffraction Spectroscopy (XRD)

XRD was used to determine the MOF types grown on the fibrous matrix. XRD patterns of the glass fiber membranes and MOF glass fiber membranes were collected using a PANalytic X' pert Pro X-ray diffractometer and CuK α X-rays with a scanning step of 0.05 °.

Fourier Transform Infrared (FTIR) Spectroscopy

FTIR was also used to determine MOFs formed on the glass fiber membranes. FTIR spectra of the thin film samples were characterized by a Perkin-Elmer FTIR microscope system equipped with a liquid nitrogen cooled Mercury Cadmium Telluride (MCT) detector. The MOF membrane samples were placed horizontally and the examination area was randomly selected. The scanning range is 4000 to 400/cm.

Scanning Electron Microscope (SEM) and energy dispersive X-ray Spectroscopy (EDX)

SEM and EDX images were obtained by JEOL JSM-6390SEM with an EDX detector and JEOL JSM-6700SEM with an EDX detector.

Design and assembly of membrane reactors

Fig. 2A and 2B are schematic views of a manufacturing process. The assembly is assembled as shown in fig. 2A and sealed as shown in fig. 2B. The reactor shape includes a square plate shape and a cylindrical shape. The 2D squares can minimize reactor height to microns by directly utilizing fiberglass film thickness as reactor height. The cylindrical shape involves placing a roll of MOF/fiberglass film within the cylinder, or stacking it layer by layer. The boundary effect of the cylindrical shape is smaller than that of a square reactor because it is centrosymmetric. But rolling or stack-filling strategies may affect micro-mixing efficiency.

Example 9: square plate type

And sequentially stacking the upper glass cover, the metal organic framework glass fiber membrane and the lower glass cover, fixing by using a clamp, and sealing by using PDMS at 100 ℃ to assemble the microreactor. The glass cover and the film are both square with the side length of 2-5 cm. The volume of the micro-reactor is about 100-900 muL. PEEK mini-connectors were bonded to the inlet and outlet holes by applying epoxy glue (Araldite 2000plus, Huntsman), which could be used to connect 1.6mm outer diameter tubes.

Example 10: tube-coiling method

And rolling up the MOF film and putting the MOF film into a tubular reactor, wherein the inner diameter of the tube is 6-8 mm, and the length of the tube is 5-30 mm. PEEK mini-connectors were bonded to the inlet and outlet holes by applying epoxy glue (Araldite 2000plus, Huntsman), which could be used to connect 1.6mm outer diameter tubes.

Example 11: tubular-to-laminated method

And stacking the MOF films and putting the MOF films into a tubular reactor layer by layer, wherein the inner diameter of the tube is 6-8 mm, and the length of the tube is 5-30 mm. PEEK mini-connectors were bonded to the inlet and outlet holes by applying epoxy glue (Araldite 2000plus, Huntsman), which could be used to connect 1.6mm outer diameter tubes.

Test for catalytic reaction

Fig. 3A and 3B are devices for catalytic activity testing. FIG. 3A is for Knoevenagel condensation and aldolization reactions; FIG. 3B shows the reduction of p-nitrophenol.

Example 12: knoevenagel condensation reaction

10mmol benzaldehyde, 10mmol ethyl cyanoacetate and 50mmol dimethyl sulfoxide were mixed and charged to a 5ml Hamilton glass syringe. The sealed reactor was wrapped with a heating tape and the temperature was controlled at 60 ℃. The pumping rate is 5-10 mu L/min, and the retention time is 1 hour. Liquid samples were taken at intervals for GC analysis. 2ml of toluene were added to 20ml of acetone as an internal standard solution. 800. mu.L of acetone, 20. mu.L of the internal standard solution and 20. mu.L of the product liquid were mixed and filtered through a 0.2 μm pore size PTFE filter and subjected to GC-FID analysis. The chromatographic column was HP-5, 30m in length, 320 μm in diameter, and the stationary phase membrane thickness was 5 μm. The test temperature program was: the furnace temperature was maintained at 70 degrees for 4 minutes, then ramped up to 240 degrees at a ramp rate of 10 degrees/minute and maintained at 240 degrees for 2 minutes. GC-MS (Agilent 7890A GC-5975C Masslictive Detector) was used for the determination of the product structure.

Example 13: reduction of p-nitrophenol

0.2mM of 4-nitrophenol in water and 40mM of NaBH₄The ethanol solution is respectively sucked into two injectors, the injectors are connected with a T-shaped tee joint by a pipe, and the outlet ends of the injectors are connected with a microreactor. The flow rate per syringe was 10. mu.L/min and the temperature was 22 ℃. The retention time was 15 minutes. The pumped liquid was collected at intervals and subjected to UV-Vis spectroscopy using a Perkin Elmer UV/VIS spectrophotometer to determine conversion. The scan range is 500 to 250 nm. A 1:1 volume ratio mixture of ethanol and water was used as a blank sample.

Example 14: and (4) carrying out an acetalization reaction.

1mmol of benzaldehyde was added to 74.25mmol of methanol as a reactant solution. In the tank reactor, the catalyst amount was 0.1g of a glass fiber membrane loaded with 23 wt% FeBDC, and no stirring was applied during the reaction to ensure that the membrane was not damaged. The temperature is about 22 degrees. For the membrane microreactor experiments, the flow rate was 10. mu.L/min and the retention time was measured to be 30 minutes. The reaction temperature was 22 ℃. mu.L of product was removed and added to a mixture of 800. mu.L of methanol and 60. mu.L of internal standard solution (0.01g naphthalene in 9ml methanol). Then filtered with a 0.2 μm PTFE filter and analyzed by GC-FID (Agilent 6890). The chromatographic column was HP-5, 30m in length, 320 μm in diameter, and the stationary phase membrane thickness was 5 μm. The test temperature program was: the furnace temperature was maintained at 70 degrees for 4 minutes, then ramped up to 240 degrees at a ramp rate of 10 degrees/minute and maintained at 240 degrees for 2 minutes.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A preparation method of a metal organic framework-based micro-membrane reactor is characterized by comprising the following steps:

preparing a fiber membrane substrate;

growing a metal organic framework film on the fiber film; and

2. The method of claim 1 wherein the fiber matrix is selected from the group consisting of glass fiber substrate, carbon cloth, carbon paper, and cellulose paper.

3. The method of claim 1 wherein the metal organic framework-based micro membrane reactor is selected from the group consisting of ZIF-8, FeBDC, CuBDC, HKUST-1 and uo-66.

4. The method of preparing a metal-organic framework-based micro-membrane reactor of claim 1, wherein the metal-organic framework membrane is prepared by an in-situ growth method, a secondary growth method and a modified secondary growth method.

5. The method of preparing a metal-organic framework-based micro-membrane reactor of claim 1, wherein the micro-membrane reactor is assembled in a square plate type or a tube type, and the assembly of the tube type micro-membrane reactor includes a roll-to-roll method and a stack method.

6. A metal-organic framework-based micro-membrane reactor, characterized by being prepared by the process of claims 1-5.

7. Use of a metal organic framework based micro-membrane reactor prepared according to the method of claims 1-5 in catalytic reactions, wherein the catalytic reactions comprise condensation, reduction and acetalization reactions.

8. Use according to claim 7, wherein the condensation reaction is a Knoevenagel condensation reaction between benzaldehyde and ethyl cyanoacetate.

9. Use according to claim 7, wherein the reduction is a 4-nitrophenol reduction.

10. Use according to claim 7, characterized in that the acetalisation reaction is an acetalisation reaction between benzaldehyde and methanol.