阅读说明：本技术 一种亚纳米AlF3催化剂及其制备方法和应用 (Sub-nanometer AlF3Catalyst, preparation method and application thereof ) 是由 韩文锋 贾忠盛 吴森 王传钊 余厚霖 刘兵 韦小丽 唐浩东 李瑛� 于 2021-01-22 设计创作，主要内容包括：本发明公开了一种亚纳米AlF-3催化剂及其制备方法和应用,所述制备方法为以MIL-53-Al为前驱体制备亚纳米AlF-3催化剂,具体制备过程为：将适量的Al(NO-3)-3·9H-2O和有机配体放入聚四氟乙烯内衬中搅拌30min,搅拌均匀然后放入水热釜中,160～220℃下水热反应0.5d～3d,自然冷却至室温。再用DMF、乙醇分别在60～80℃下水浴洗涤2h～4.5h,在60～120℃下烘干10～24h,得到白色粉末MIL-53-Al,待用。在氟源的作用下,将白色粉末(MIL-53-Al)氟化,得到所述亚纳米AlF-3催化剂。本发明方法制备出的催化剂在含氟烷烃气相脱HF制备含氟烯烃的反应中显示了极高的活性和稳定性。本发明提供的催化剂具有制备简单、转化率高、选择性好、稳定性高和不易积碳的特点。(The invention discloses a sub-nano AlF 3 The preparation method is to prepare the sub-nanometer AlF by taking MIL-53-Al as a precursor 3 The catalyst is prepared by the following specific steps: adding proper amount of Al (NO) 3 ) 3 ·9H 2 And (3) placing the O and the organic ligand into a polytetrafluoroethylene lining, stirring for 30min, uniformly stirring, then placing into a hydrothermal kettle, carrying out hydrothermal reaction at 160-220 ℃ for 0.5-3 d, and naturally cooling to room temperature. Reuse DAnd respectively washing the MF and the ethanol in a water bath at the temperature of 60-80 ℃ for 2-4.5 h, and drying at the temperature of 60-120 ℃ for 10-24 h to obtain white powder MIL-53-Al for later use. Fluorinating white powder (MIL-53-Al) under the action of a fluorine source to obtain the sub-nano AlF 3 A catalyst. The catalyst prepared by the method shows extremely high activity and stability in the reaction of preparing fluorine-containing olefin by removing HF from the gas phase of fluorine-containing alkane. The catalyst provided by the invention has the characteristics of simple preparation, high conversion rate, good selectivity, high stability and difficult carbon deposition.)

1. Sub-nanometer AlF₃The preparation method of the catalyst is characterized by comprising the following steps:

1) mixing Al (NO)₃)₃·9H₂Placing the O and the organic ligand into a polytetrafluoroethylene lining, uniformly stirring, then placing into a hydrothermal kettle, carrying out hydrothermal reaction at 160-220 ℃ for 0.5-3 d, and naturally cooling to room temperature after the hydrothermal reaction is finished to obtain white mixed solution for later use;

2) centrifuging the white mixed solution obtained in the step 1) to remove unreacted nitrate and organic ligand, washing the white mixed solution with DMF (dimethyl formamide) and ethanol in a water bath at the temperature of 60-80 ℃ for 2-4.5 hours respectively, and drying the white mixed solution at the temperature of 60-120 ℃ for 10-24 hours to obtain white powder MIL-53-Al for later use;

3) fluorinating the MIL-53-Al obtained in the step 2) under the action of a fluorine source, screening and collecting a product with the particle size of 20-40 meshes, namely the sub-nano AlF₃The catalyst has a particle size of 20-40 meshes, the fluorine source is at least one of a gas-phase fluorine source, a liquid-phase fluorine source and a solid-phase fluorine source, and the solid-phase fluorine source is one of a fluorine-containing compound and a fluorine-containing polymer.

2. The sub-nano AlF according to claim 1₃The preparation method of the catalyst is characterized in that when the fluorine source in the step 3) is a gas-phase fluorine source, the specific process of MIL-53-Al fluorination is as follows: putting MIL-53-Al into an atmosphere tube furnace, introducing a gas-phase fluorine source, roasting for 1-4 h at 250-400 ℃, and switching N after roasting is finished₂Naturally cooling to room temperature in the atmosphere to obtain sub-nanometerAlF₃The catalyst is calcined preferably at 300 ℃ for 2 hours; the gas-phase fluorine source is CHFCl₂Or CHClF₂Preferably CHClF₂。

3. The sub-nano AlF according to claim 1₃The preparation method of the catalyst is characterized in that when the fluorine source in the step 3) is a liquid-phase fluorine source, the specific process of MIL-53-Al fluorination is as follows: adding MIL-53-Al into a liquid-phase fluorine source, stirring and reacting for 6-12 h at the temperature of 30-60 ℃ in a water bath, centrifugally washing after the reaction is finished, and drying at the temperature of 55-65 ℃ to obtain sub-nano AlF₃The temperature of the water bath is preferably 45 ℃, the stirring time is preferably 8h, and the liquid phase fluorine source is 40wt% HF solution.

4. The sub-nano AlF according to claim 1₃The preparation method of the catalyst is characterized in that when a fluorine source is a solid-phase fluorine source fluorine-containing compound, the specific process of MIL-53-Al fluorination is as follows: ball-milling the fluorine-containing compound and MIL-53-Al, wherein the ball-milling rotation speed is 150-400 r/min, the ball-milling time is 2-6 h, and after the ball-milling is finished, putting the ball-milling product into an atmosphere tube furnace₂Roasting in atmosphere, cooling to room temperature to obtain sub-nanometer AlF₃A catalyst.

5. The sub-nano AlF according to claim 4₃The preparation method of the catalyst is characterized in that the ball milling speed is 250r/min, and the ball milling time is 4 h; the roasting temperature is 250-400 ℃, preferably 350 ℃, and the roasting time is 2-10 hours, preferably 6 hours; the fluorine-containing compound is ammonium fluoride NH₄F or ammonium bifluoride NH₄HF₄The molar ratio of the fluorine-containing compound to the MIL-53-Al is 1: 1-6, preferably 1: 3; the fluorine-containing polymer is one of PVDF, PTFE and PVF, and ammonium fluoride is preferred.

6. The sub-nano AlF according to claim 1₃The preparation method of the catalyst is characterized in that when a fluorine source is a fluorine-containing polymer, the specific process of MIL-53-Al fluorination is as follows: dissolving fluorine-containing polymer in proper amount of organic solventObtaining a solution in the agent, uniformly dispersing MIL-53-Al in the solution, drying and burning the organic solvent at 60-120 ℃, then placing the organic solvent in a muffle furnace for roasting at 250-400 ℃ for 1-15 h, and then cooling to room temperature to obtain the sub-nano AlF₃A catalyst.

7. The sub-nano AlF according to claim 6₃The preparation method of the catalyst is characterized in that the fluorine-containing polymer is one of PVDF, PTFE and PVF, the organic solvent is N, N-dimethylformamide andor butanone, the drying temperature is 80 ℃, the roasting temperature is 350 ℃, and the roasting time is 10 hours.

8. Sub-nano AlF prepared by the method of any one of claims 1 to 7₃A catalyst.

9. The sub-nano AlF of claim 8₃The catalyst is applied to the reaction of preparing fluorine-containing olefin by removing HF from fluorine-containing alkane.

10. The application of claim 9, wherein the fluorine-containing alkane is 1, 1-difluoroethane or 1,1,1,3, 3-pentafluoropropane, the reaction temperature for removing HF from the fluorine-containing alkane to prepare the fluorine-containing alkene is 300-450 ℃, the reaction pressure is normal pressure, and the prepared fluorine-containing alkene is vinyl fluoride or 1,1,1, 3-tetrafluoropropene.

Technical Field

The invention belongs to the technical field of chemical catalysts, and particularly relates to sub-nano AlF₃A catalyst, a preparation method and application thereof.

Background

Fluorine-containing alkanes (HFCs) are indispensable functional chemicals in modern society and are widely used in refrigerants, foaming agents, mold release agents, cleaning agents and the like. However, the fluorine-containing alkane belongs to greenhouse gases, has high greenhouse effect potential value (GWP), causes harm to the environment when being used in large quantity, and is a gas which is controlled to be discharged in the Kyoto protocol. Therefore, in order to cope with climate change, the resource conversion of fluorine-containing alkane into fluorine-containing alkene is in the trend. Fluoroolefins (HFOs) have less environmental impact and are considered to be the most desirable alternative to HFCs. The fluorine-containing alkane is widely applied to fluorine-containing rubber, fluorine-containing resin, fluorine-containing paint, fluorine-containing polymer hollow fiber and the like, wherein the fluoroethylene obtained by cracking 1, 1-difluoroethane is widely applied to sound insulation materials of expensive automobiles.

Metal-organic framework Materials (MOFs) are coordination polymers which develop rapidly in the last decade, have three-dimensional pore structures, generally take metal ions as connecting points, and organic ligands support and form space 3D extension, are another important novel porous material besides zeolite and carbon nanotubes, and are widely applied to catalysis, energy storage and separation. Currently, MOFs have become an important research direction for many chemical branches of inorganic chemistry, organic chemistry, and the like. Metal-organic frameworks (Metal-organic frameworks) refer to crystalline porous materials with periodic network structures formed by self-assembly of transition Metal ions and organic ligands. The method has the advantages of high porosity, low density, large specific surface area, regular pore channels, adjustable pore diameter, diversity and tailorability of topological structures and the like.

The most commonly used catalyst for HF removal by cracking of fluorine-containing alkanes is aluminum fluoride (AlF)₃) However, aluminum fluoride (AlF) has been conventionally used₃) The catalyst is easy to generate carbon deposition and sintering phenomena in the catalytic reaction process, so that the catalyst is inactivated. Low specific surface area inherent in metal fluoride and poor catalyst stability.

Disclosure of Invention

Aiming at the problem of catalyst deactivation caused by the carbon deposition and sintering phenomena in the existing catalyst, the invention aims to provide a method for preparing sub-nanometer AlF by using MIL-53-Al as a precursor₃Methods and uses of the catalyst. The method has the characteristics of short preparation period, high yield, high conversion rate and simple operation, and belongs to an environment-friendly material. The catalyst synthesized by the method has high catalytic activity and stability in the reaction of preparing fluorine-containing olefin by removing HF from fluorine-containing alkane.

The sub-nano AlF₃The preparation method of the catalyst is characterized by comprising the following steps:

1) mixing Al (NO)₃)₃·9H₂Placing the O and the organic ligand into a polytetrafluoroethylene lining, uniformly stirring, then placing into a hydrothermal kettle, carrying out hydrothermal reaction at 160-220 ℃ for 0.5-3 d, and naturally cooling to room temperature after the hydrothermal reaction is finished to obtain white mixed solution for later use;

2) centrifuging the white mixed solution obtained in the step 1) to remove unreacted nitrate and organic ligand, washing the white mixed solution with DMF (dimethyl formamide) and ethanol in a water bath at the temperature of 60-80 ℃ for 2-4.5 hours respectively, and drying the white mixed solution at the temperature of 60-120 ℃ for 10-24 hours to obtain white powder MIL-53-Al for later use;

3) under the action of a fluorine source, step 2)The obtained MIL-53-Al is fluorinated to prepare the sub-nano AlF₃The catalyst comprises a fluorine source, a catalyst and a catalyst, wherein the fluorine source is at least one of a gas-phase fluorine source, a liquid-phase fluorine source and a solid-phase fluorine source, and the solid-phase fluorine source is one of a fluorine-containing compound and a fluorine-containing polymer.

The sub-nano AlF₃The preparation method of the catalyst is characterized in that when the fluorine source in the step 3) is a gas-phase fluorine source, the specific process of MIL-53-Al fluorination is as follows: putting MIL-53-Al into an atmosphere tube furnace, introducing a gas-phase fluorine source, roasting for 1-4 h at 250-400 ℃, and switching N after roasting is finished₂Naturally cooling to room temperature in the atmosphere to prepare the sub-nano AlF₃The catalyst is calcined preferably at 300 ℃ for 2 hours; the gas-phase fluorine source is CHFCl₂Or CHClF₂Preferably CHClF₂。

The sub-nano AlF₃The preparation method of the catalyst is characterized in that when the fluorine source in the step 3) is a liquid-phase fluorine source, the specific process of MIL-53-Al fluorination is as follows: adding MIL-53-Al into a liquid-phase fluorine source, stirring and reacting for 6-12 h at the temperature of 30-60 ℃ in a water bath, centrifugally washing after the reaction is finished, and drying at the temperature of 55-65 ℃ to obtain sub-nano AlF₃The temperature of the water bath is preferably 45 ℃, the stirring time is preferably 8h, and the liquid phase fluorine source is 40wt% HF solution.

The sub-nano AlF₃The preparation method of the catalyst is characterized in that when a fluorine source is a solid-phase fluorine source fluorine-containing compound, the specific process of MIL-53-Al fluorination is as follows: ball-milling the fluorine-containing compound and MIL-53-Al, wherein the ball-milling rotation speed is 150-400 r/min, the ball-milling time is 2-6 h, and after the ball-milling is finished, putting the ball-milling product into an atmosphere tube furnace₂Roasting in atmosphere, cooling to room temperature to obtain sub-nanometer AlF₃A catalyst.

The sub-nano AlF₃The preparation method of the catalyst is characterized in that the ball milling speed is 250r/min, and the ball milling time is 4 h; the roasting temperature is 250-400 ℃, preferably 350 ℃, and the roasting time is 2-10 hours, preferably 6 hours; the fluorine-containing compound is ammonium fluoride NH₄F or ammonium bifluoride NH₄HF₄The molar ratio of the fluorine-containing compound to the MIL-53-Al is 1: 1 to 6, preferably 1: 3; the fluorine-containing compound being NH₄F or ammonium bifluoride NH₄HF₄Preferably, it is ammonium fluoride.

The sub-nano AlF₃The preparation method of the catalyst is characterized in that when a fluorine source is a fluorine-containing polymer, the specific process of MIL-53-Al fluorination is as follows: dissolving a fluorine-containing polymer in a proper amount of organic solvent to obtain a solution, uniformly dispersing MIL-53-Al in the solution, drying and baking the organic solvent at 60-120 ℃, then placing the dried organic solvent in a muffle furnace to bake for 1-15 h at 250-400 ℃, and then cooling to room temperature to obtain the sub-nano AlF₃A catalyst.

The sub-nano AlF₃The preparation method of the catalyst is characterized in that the fluorine-containing polymer is one of PVDF, PTFE and PVF, the organic solvent is N, N-dimethylformamide andor butanone, the drying temperature is 80 ℃, the roasting temperature is 350 ℃, and the roasting time is 10 hours.

The sub-nanometer AlF prepared by the method of the invention₃A catalyst.

The sub-nano AlF₃The application of the catalyst in the reaction of preparing fluorine-containing olefin by removing HF from fluorine-containing alkane is characterized in that the fluorine-containing alkane is 1, 1-difluoroethane or 1,1,1,3, 3-pentafluoropropane, the reaction temperature for preparing fluorine-containing olefin by removing HF from fluorine-containing alkane is 300-450 ℃, the reaction pressure is normal pressure, and the prepared fluorine-containing olefin is vinyl fluoride or 1,1,1, 3-tetrafluoropropene.

By adopting the technology, compared with the prior art, the invention has the following beneficial effects:

the sub-nano AlF of the invention₃The catalyst is prepared by taking MIL-53-Al as a precursor through fluorination, roasting and screening, and the method has the advantages of short preparation period, high yield and conversion rate, simple operation and easy industrialization; the obtained sub-nano AlF₃The catalyst has higher catalytic activity and stability in the reaction of preparing the fluorine-containing olefin by removing HF from the gas phase of the fluorine-containing alkane, the service life is prolonged, and the catalyst is not easy to deposit carbon and deactivate in the reaction.

Detailed Description

The present invention is further illustrated by the following examples, which should not be construed as limiting the scope of the invention.

Example 1

6.698g of Al (NO)₃)₃·9H₂And O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermally treated for 0.5d at 160 ℃. Washing with DMF and ethanol at 60 deg.C for 2 hr, respectively, and oven drying at 60 deg.C for 10 hr to obtain white powder MIL-53-Al. MIL-53-Al is put into an atmosphere tube furnace, and a gas phase fluorine source CHClF is introduced at 300 DEG C₂Fluorinating for 1h at the flow rate of the gas-phase fluorine source of 20ml/min, and then, after the gas-phase fluorination is finished, fluorinating for 1 h; the atmosphere in the tube furnace is switched to N₂Until naturally cooled to room temperature, the stable sub-nanometer AlF is obtained₃A catalyst. And screening the obtained catalyst sample by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing 1, 1-difluoroethane (HFC-152 a) to crack to prepare vinyl fluoride, and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂And HFC-152a, N₂The flow rate is 10mL/min, the HFC-152a flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HCFC-152a is 1200/h, and the reaction temperature is 300 ℃. Reaction for 3h, sampling and analyzing, and obtaining the following results: the conversion of the reactant 1, 1-difluoroethane (HFC-152 a) was 86% and the selectivity to the product vinyl fluoride was 100%, and the catalyst analyzed after 15h for a sample of conversion of 85.8% and a selectivity of 100% (i.e. the conversion of the reactant and the selectivity to the target product were essentially unchanged).

Example 2

6.698g of Al (NO)₃)₃·9H₂O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermal for 3d at 220 ℃. Washing with DMF and ethanol at 80 deg.C for 4.5 hr, respectively, oven drying at 120 deg.C for 24 hr to obtain white powder MIL-53-Al. Putting MIL-53-Al into 20ml of 40wt% HF solution, water-bathing for 8h at 60 ℃ with stirring, centrifugally washing, drying at 60 ℃ to obtain the catalyst, and drying at 400 ℃ to obtain the catalyst₂Roasting for 3h in the atmosphere, and naturally cooling to room temperature to obtain the stable sub-nano AlF₃And screening the catalyst and the obtained catalyst sample by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing the cracking of 1,1,1,3, 3-pentafluoropropane (HFC-245fa) to prepare 1,3,3, 3-tetrafluoropropene (HFO-1234 ze), and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂Mixed gas of HFC-245fa, N₂The flow rate is 10mL/min, the HFC-245fa flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HFC-152a is 1200/h, and the reaction temperature is 350 ℃. A sample is taken for analysis after 8h of reaction, and the result is as follows: reactant 1,1,1,3, 3-pentafluoropropane conversion was 79.6%, product cis-trans 1,3,3, 3-tetrafluoropropene (HFO-1234 ze) selectivity was 99.8%, and the catalyst analyzed after 18h sampling for conversion of 79.4% and selectivity of 99.5% (i.e., reactant conversion and selectivity to target product were essentially unchanged).

Example 3

6.698g of Al (NO)₃)₃·9H₂O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermal for 3d at 220 ℃. Washing with DMF and ethanol at 80 deg.C for 4.5 hr, and oven drying at 120 deg.C for 24 hr to obtain white powder MIL-53-Al. 5.366g of MIL-53-Al and 13.686g of ammonium hydrogen fluoride (NH)₄HF₄) Putting the mixture into a ball milling tank, and putting the ball milling tank into a ball mill for fixing. The ball mill program is set to 400r/min, ball milling is carried out for 3h, and suspension is carried out for 30min every hour until the program is finished. Putting the ball milling tank and the ball milled sample into an oven for drying for 6h at 80 ℃, taking out the sample, and putting the sample into a tube furnace for N₂Baking at 400 ℃ in an atmosphereAnd (5) burning for 3 hours. And (5) obtaining a catalyst sample, and screening by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing the cracking of 1,1,1,3, 3-pentafluoropropane (HFC-245fa) to prepare 1,3,3, 3-tetrafluoropropene (HFO-1234 ze), and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂Mixed gas of HFC-245fa, N₂The flow rate is 10mL/min, the HFC-245fa flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HFC-245fa is 1200/h, and the reaction temperature is 300 ℃. Reaction for 3h, sampling and analyzing, and obtaining the following results: reactant 1,1,1,3, 3-pentafluoropropane conversion was 86.5%, product cis-trans 1,3,3, 3-tetrafluoropropene (HFO-1234 ze) selectivity was 88.6%, and the catalyst analyzed after 10h sampling for conversion of 86.9% and selectivity of 89.0% (i.e., reactant conversion and selectivity to target product were essentially unchanged).

Example 4

6.698g of Al (NO)₃)₃·9H₂O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermal for 3d at 220 ℃. Washing with DMF and ethanol at 80 deg.C for 4.5 hr, drying at 120 deg.C for 24 hr to obtain white powder MIL-53-Al, adding 5.366g MIL-53-Al and 13.712g PVDF into 120ml MDF, and stirring for 1 hr. After stirring, the mixture is put into an oven at 120 ℃ until DMF is dried, and the dried sample is roasted in a muffle furnace at 390 ℃ for 10 h. And (5) obtaining a catalyst sample, and screening by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing 1, 1-difluoroethane (HFC-152 a) to crack to prepare vinyl fluoride, and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂And HFC-152a, N₂The flow rate is 10mL/min, the HFC-152a flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HCFC-152a is 1200/h, and the reaction temperature is 320 ℃. A sample is taken for 4h of reaction and analyzed, and the result is as follows: the conversion of the reactant HFC-152a was 85% and the selectivity to the product Vinyl Fluoride (VF) was 100%, and the catalyst sampled after 16h for analysis to have a conversion of 85.2% and a selectivity of 100% (i.e., the conversion of the reactant and the selectivity to the target product were essentially unchanged).

Example 5

6.698g of Al (NO)₃)₃·9H₂And O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermally treated for 0.5d at 160 ℃. Washing with DMF and ethanol at 60 deg.C for 2 hr, respectively, and oven drying at 60 deg.C for 10 hr to obtain white powder MIL-53-Al. 5.366g of MIL-53-Al and 6.895g of ammonium fluoride (NH)₄F) Putting the mixture into a ball milling tank, and putting the ball milling tank into a ball mill for fixing. The ball mill program is set to 400r/min, ball milling is carried out for 3h, and suspension is carried out for 30min every hour until the program is finished. Putting the ball milling tank and the ball milled sample into an oven for drying for 6h at 80 ℃, taking out the sample, and putting the sample into a tube furnace for N₂Roasting for 3 hours at 350 ℃ in the atmosphere. And (5) obtaining a catalyst sample, and screening by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing 1, 1-difluoroethane (HFC-152 a) to crack to prepare vinyl fluoride, and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂And HFC-152a, N₂The flow rate is 10mL/min, the HFC-152a flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HCFC-152a is 1200/h, and the reaction temperature is 300 ℃. Reaction 2h sampling analysis, the result is: reaction product ofThe conversion rate of the product HFC-152a is 88.6 percent, and the selectivity of the product Vinyl Fluoride (VF) is 98.5 percent. And after 18h a sample was taken for analysis of 88.8% conversion and 98.9% selectivity (i.e. reactant conversion and target product selectivity were essentially unchanged).

Example 6

6.698g of Al (NO)₃)₃·9H₂And O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermally treated for 0.5d at 160 ℃. Washing with DMF and ethanol at 80 deg.C for 3 hr, and oven drying at 120 deg.C for 10 hr to obtain white powder MIL-53-Al. 5.366g of MIL-53-A and 18.712g of PVDF were placed in 120ml of MDF and stirred for 1 h. After stirring, the mixture is put into an oven at 120 ℃ until DMF is dried, and the dried sample is roasted for 10 hours at 400 ℃ in a muffle furnace. And (5) obtaining a catalyst sample, and screening by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing the cracking of 1,1,1,3, 3-pentafluoropropane (HFC-245fa) to prepare 1,3,3, 3-tetrafluoropropene (HFO-1234 ze), and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂Mixed gas of HFC-245fa, N₂The flow rate is 10mL/min, the HFC-245fa flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HCFC-245fa is 1200/h, and the reaction temperature is 300 ℃. Reaction for 3h, sampling and analyzing, and obtaining the following results: reactant 1,1,1,3, 3-pentafluoropropane conversion was 89.5%, product cis-trans 1,3,3, 3-tetrafluoropropene (HFO-1234 ze) selectivity was 85.6%, and the catalyst analyzed after 15h for conversion by sampling at 89.8% and selectivity at 85.9% (i.e., reactant conversion and target product selectivity were essentially unchanged).

Example 7

6.698g of Al (NO)₃)₃·9H₂O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into the polytetrafluoroethylene lining to be stirred evenlyHydrothermal reaction in a hydrothermal kettle at 160 deg.c for 0.5 hr. Washing with DMF and ethanol at 70 deg.C in water bath for 2 hr, and oven drying at 80 deg.C for 12 hr to obtain white powder MIL-53-Al. 5.366g of MIL-53-Al and 19.686g of ammonium hydrogen fluoride (NH)₄HF₄) Putting the mixture into a ball milling tank, and putting the ball milling tank into a ball mill for fixing. The ball mill program is set to 400r/min, ball milling is carried out for 3h, and suspension is carried out for 30min every hour until the program is finished. Putting the ball milling tank and the ball milled sample into an oven for drying for 6h at 80 ℃, taking out the sample, and putting the sample into a tube furnace for N₂Roasting for 6h at 400 ℃ in the atmosphere. And (5) obtaining a catalyst sample, and screening by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing 1, 1-difluoroethane (HFC-152 a) to crack to prepare vinyl fluoride, and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂And HFC-152a, N₂The flow rate is 10mL/min, the HFC-152a flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HFC-152a is 1200/h, and the reaction temperature is 350 ℃. Reaction 2h sampling analysis, the result is: the conversion of reactant HFC-152a was 89.5% and the selectivity of product Vinyl Fluoride (VF) was 98.6%. And a sample taken after 10 hours of reaction was analyzed for a conversion of 89.6% and a selectivity of 98.8% (i.e., reactant conversion and selectivity to the desired product were essentially unchanged).

Example 8

6.698g of Al (NO)₃)₃·9H₂And O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermally treated for 0.5d at 160 ℃. Washing with DMF and ethanol at 70 deg.C in water bath for 2 hr, and oven drying at 80 deg.C for 12 hr to obtain white powder MIL-53-Al. MIL-53-Al is put into an atmosphere tube furnace, and a gas phase fluorine source CHClF is introduced at 400 DEG C₂The flow rate of a gas phase fluorine source is 20ml/min, the fluorination is carried out for 4 hours, and then the tube furnace is placed in the furnace after the gas phase fluorination is finishedIs switched to N₂Until naturally cooled to room temperature, the stable sub-nanometer AlF is obtained₃A catalyst. And screening the obtained catalyst sample by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing 1, 1-difluoroethane (HFC-152 a) to crack to prepare vinyl fluoride, and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂And HFC-152a, N₂The flow rate is 10mL/min, the HFC-152a flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HFC-152a is 1200/h, and the reaction temperature is 350 ℃. Reaction 2h sampling analysis, the result is: the conversion of reactant HFC-152a was 86.3% and the selectivity of product Vinyl Fluoride (VF) was 97.6%. And after 10h of reaction, a sample was taken for analysis of 85.6% conversion and 97.4% selectivity (i.e., reactant conversion and selectivity to the desired product were essentially unchanged).

Example 9

6.698g of Al (NO)₃)₃·9H₂And O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermally treated for 0.5d at 160 ℃. Washing with DMF and ethanol at 70 deg.C in water bath for 2 hr, and oven drying at 80 deg.C for 12 hr to obtain white powder MIL-53-Al. MIL-53-Al is put into an atmosphere tube furnace, and a gas phase fluorine source CHFCl is introduced at 250 DEG C₂The flow rate of a gas-phase fluorine source is 20ml/min, the fluorination is carried out for 1h, and then the atmosphere in the tube furnace is switched to N after the gas-phase fluorination is finished₂Until naturally cooled to room temperature, the stable sub-nanometer AlF is obtained₃A catalyst. And screening the obtained catalyst sample by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing the cracking of 1,1,1,3, 3-pentafluoropropane (HFC-245fa) to prepare 1,3,3, 3-tetrafluoropropene (HFO-1234 ze), and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂Mixed gas of HFC-245fa, N₂The flow rate is 10mL/min, the HFC-245fa flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HCFC-245fa is 1200/h, and the reaction temperature is 300 ℃. Reaction for 3h, sampling and analyzing, and obtaining the following results: reactant 1,1,1,3, 3-pentafluoropropane conversion was 82.5%, product cis-trans 1,3,3, 3-tetrafluoropropene (HFO-1234 ze) selectivity was 88.8%, and the catalyst analyzed after 15h for conversion by sampling at 82.1% and selectivity at 88.5% (i.e., reactant conversion and target product selectivity were essentially unchanged).

Example 10

6.698g of Al (NO)₃)₃·9H₂And O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermally treated for 0.5d at 160 ℃. Washing with DMF and ethanol at 60 deg.C for 3 hr, respectively, oven drying at 120 deg.C for 12 hr to obtain white powder MIL-53-Al., adding MIL-53-Al into 20ml of 40wt% HF solution, water-washing at 120 deg.C for 12 hr while stirring, centrifuging, washing at 60 deg.C to obtain catalyst, and drying at 400 deg.C to obtain catalyst₂Roasting for 3h in the atmosphere, and naturally cooling to room temperature to obtain the stable sub-nano AlF₃And screening the catalyst and the obtained catalyst sample by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing 1, 1-difluoroethane (HFC-152 a) to crack to prepare vinyl fluoride, and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂And HFC-152a, N₂The flow rate is 10mL/min, the HFC-152a flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HFC-152a is 1200/h, and the reaction temperature is 350 ℃. Reaction 2h sampling analysis, the result is: the conversion of reactant HFC-152a was 88.6%, and the selectivity of product Vinyl Fluoride (VF) was 97.3%. And a sample taken after 10 hours of reaction was analyzed for conversion of 88.2% and selectivity of 96.5% (i.e., reactant conversion and selectivity to the desired product were essentially unchanged).

Example 11

6.698g of Al (NO)₃)₃·9H₂O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermal for 3d at 220 ℃. Washing with DMF and ethanol at 80 deg.C for 4.5 hr, and oven drying at 120 deg.C for 24 hr to obtain white powder MIL-53-Al. 5.366g of MIL-53-Al and 13.686g of ammonium hydrogen fluoride (NH)₄HF₄) Putting the mixture into a ball milling tank, and putting the ball milling tank into a ball mill for fixing. The ball mill program is set to 250r/min, ball milling is carried out for 3h, and suspension is carried out for 30min every hour until the program is finished. Putting the ball milling tank and the ball milled sample into an oven for drying for 6h at 80 ℃, taking out the sample, and putting the sample into a tube furnace for N₂Roasting for 2 hours at 250 ℃ in the atmosphere. And (5) obtaining a catalyst sample, and screening by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing 1, 1-difluoroethane (HFC-152 a) to crack to prepare vinyl fluoride, and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂And HFC-152a, N₂The flow rate is 10mL/min, the HFC-152a flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HCFC-152a is 1200/h, and the reaction temperature is 320 ℃. A sample is taken for 4h of reaction and analyzed, and the result is as follows: the conversion rate of the reactant HFC-152a is 85 percent, the selectivity of the product Vinyl Fluoride (VF) is 100 percent, and the sampling analysis of the catalyst after 16 hours shows that the conversion rate is 85.2 percent, and the selectivity is 100 percent (namely the conversion rate of the reactant and the selective group of the target product)Originally unchanged).

Example 12

6.698g of Al (NO)₃)₃·9H₂O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermal for 3d at 220 ℃. Washing with DMF and ethanol at 80 deg.C for 4.5 hr, drying at 120 deg.C for 24 hr to obtain white powder MIL-53-Al, adding 5.366g MIL-53-Al and 19.264g PVE into 120ml MDF, and stirring for 1 hr. After stirring, the mixture is put into an oven at 120 ℃ until DMF is dried, and the dried sample is roasted in a muffle furnace at 390 ℃ for 10 h. And (5) obtaining a catalyst sample, and screening by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing the cracking of 1,1,1,3, 3-pentafluoropropane (HFC-245fa) to prepare 1,3,3, 3-tetrafluoropropene (HFO-1234 ze), and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂Mixed gas of HFC-245fa, N₂The flow rate is 10mL/min, the HFC-245fa flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HCFC-245fa is 1200/h, and the reaction temperature is 300 ℃. Reaction for 3h, sampling and analyzing, and obtaining the following results: reactant 1,1,1,3, 3-pentafluoropropane conversion was 81.7%, product cis-trans 1,3,3, 3-tetrafluoropropene (HFO-1234 ze) selectivity was 80.6%, and the catalyst analyzed after 15h for conversion by sampling at 80.9% and selectivity at 80.3% (i.e., reactant conversion and target product selectivity were essentially unchanged).

Example 13

6.698g of Al (NO)₃)₃·9H₂O and 2.586g of organic ligand are put into a polytetrafluoroethylene lining to be stirred for 30min, and then the mixture is put into a hydrothermal kettle to be hydrothermal for 3d at 220 ℃. Washing with DMF and ethanol at 80 deg.C for 4.5 hr, respectively, oven drying at 120 deg.C for 24 hr to obtain white powder MIL-53-Al, adding 5.366g MIL-53-Al and 16.685g P TFE, and standingInto 120ml of MDF, and stirred for 1 hour. After stirring, putting the mixture into a drying oven at 120 ℃ until DMF is dried, and putting the dried sample into a tube furnace N₂Roasting for 10 hours at 390 ℃ in the atmosphere. And (5) obtaining a catalyst sample, and screening by using a sample separating sieve of 20-40 meshes.

Sub-nanometer AlF prepared by the method₃The catalyst is used for catalyzing the cracking of 1,1,1,3, 3-pentafluoropropane (HFC-245fa) to prepare 1,3,3, 3-tetrafluoropropene (HFO-1234 ze), and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂Mixed gas of HFC-245fa, N₂The flow rate is 10mL/min, the HFC-245fa flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HCFC-245fa is 1200/h, and the reaction temperature is 300 ℃. Reaction for 3h, sampling and analyzing, and obtaining the following results: reactant 1,1,1,3, 3-pentafluoropropane conversion was 82.6%, product cis-trans 1,3,3, 3-tetrafluoropropene (HFO-1234 ze) selectivity was 81.9%, and the catalyst analyzed after 15h for conversion by sampling at 82.8% and selectivity at 81.8% (i.e., reactant conversion and target product selectivity were essentially unchanged).

Example 14

In conventional AlF₃As a catalyst, conventional AlF was used₃After a particle sample with the size of 20-40 meshes is screened by the catalyst, the particle sample is used for catalyzing 1,1,1,3, 3-pentafluoropropane (HFC-245fa) to crack to prepare 1,3,3, 3-tetrafluoropropene (HFO-1234 ze), and the reaction formula is as follows:

the reaction conditions are as follows: the catalyst is filled into a fixed bed reactor, the filling amount of the catalyst is 1mL, and N is introduced₂Mixed gas of HFC-245fa, N₂The flow rate is 10mL/min, the HFC-245fa flow rate is 10mL/min, N₂The total space velocity of the mixed gas of HCFC-245fa is 1200/h, and the reaction temperature is 300 ℃. Taking out after reacting for 3 hoursThe sample is analyzed, and the result is: the conversion of the reactant 1,1,1,3, 3-pentafluoropropane was 36.4%, the selectivity of the product cis-trans 1,3,3, 3-tetrafluoropropene (HFO-1234 ze) was 60.8%, and the conversion decreased to 12.4% and the selectivity decreased to 25.6% after 5 hours of continuous use of the catalyst (i.e., the conversion of the reactant and the selectivity of the target product decreased substantially).

The statements in this specification merely set forth a list of implementations of the inventive concept and the scope of the present invention should not be construed as limited to the particular forms set forth in the examples.