Synthesis method of 1, 1, 1, 2, 3-pentafluoropropane and 2, 3, 3, 3-tetrafluoropropene

Abstract

The invention belongs to the field of refrigerants, the field of fire fighting, the field of fluorine chemical engineering new materials, the field of foaming agents and the field of chemical synthesis, and particularly relates to a synthesis method of 1, 1, 1, 2, 3-pentafluoropropane and 2, 3, 3, 3-tetrafluoropropene. The synthesis method of the 1, 1, 1, 2, 3-pentafluoropropane comprises the following steps: carrying out a first reaction on 3, 3, 3-trifluoropropene, a first catalyst, an HF source and a selective fluorine reagent in a first solvent to obtain the 1, 1, 1, 2, 3-pentafluoropropane. The synthetic method of the 2, 3, 3, 3-tetrafluoropropene comprises the following step: carrying out a second reaction on the obtained 1, 1, 1, 2, 3-pentafluoropropane in the presence of a second catalyst to obtain the 2, 3, 3, 3-tetrafluoropropene. The synthesis method of 1, 1, 1, 2, 3-pentafluoropropane provided by the invention has the advantages of simplicity in operation, short time consumption, mild reaction, simple reagents required by reaction, high substrate conversion rate, high target product selectivity and the like, and is beneficial to industrial production. The preparation method of 2, 3, 3, 3-tetrafluoropropene provided by the invention has the advantages of safety, environmental protection, simplicity in operation, mild reaction, high yield, high target product selectivity, high reaction speed and the like, and is beneficial to industrial production.

Description

Technical Field

[0001] This invention relates to the fields of refrigerants, fire protection, new fluorochemical materials, foaming agents, and chemical synthesis, specifically to methods for synthesizing 1,1,1,2,3-pentafluoropropane and 2,3,3,3-tetrafluoropropylene. Background Technology

[0002] 2,3,3,3-Tetrafluoropropylene, chemically known as 2,3,3,3-tetrafluoro-1-propene, and traded as HFO-1234yf or R-1234yf, is a hydrofluoroolefin (HFO) compound. Due to its excellent environmental characteristics (ODP=0, GWP=4, and an atmospheric lifetime of only 11 days), and its thermodynamic properties being highly similar to HFC-134a, 2,3,3,3-tetrafluoropropylene can be directly used in existing R134a systems without significant modifications, and is widely recognized as an ideal alternative in fields such as automotive air conditioning.

[0003] Chinese patent application CN105367378A discloses a process for preparing 2,3,3,3-tetrafluoropropylene. However, this process has problems such as the need to use fluorine gas, alkaline solution, expensive solvent, ultra-low temperature, and special treatment of reaction vessels. Among these, fluorine gas is dangerous and highly toxic, requiring safety protection during use and making the operation complex; the use of alkaline solution results in high costs due to waste, and the expensive solvent, ultra-low temperature, and special treatment of reaction vessels lead to complex operation and high cost.

[0004] Chinese patent application CN101979364B discloses a preparation process for 2,3,3,3-tetrafluoropropylene and its intermediates. However, the preparation process has problems such as long steps, complex operation, ultra-low temperature, ultraviolet light irradiation and use of chlorine. Among them, the long process steps, ultra-low temperature and ultraviolet light irradiation lead to high cost and complex operation. The use of chlorine is dangerous and highly toxic, and safety protection is required when using it.

[0005] 1,1,1,2,3-Pentafluoropropane, commonly known as HFC-245eb, belongs to the class of hydrofluorocarbons (HFCs) and is an environmentally friendly fluorinated solvent / foaming agent / refrigerant with low ozone depletion potential and low global warming potential. It is also an important intermediate in the synthesis of fluorinated fine chemicals and is widely used in fine chemical synthesis, electronic cleaning, foaming materials, cryogenic refrigeration and other fields.

[0006] Chinese patent application CN101921169A discloses a method for preparing 1,1,1,2,3-pentafluoropropane, but this method has problems such as requiring a catalyst containing noble metals, high reaction temperature, and low selectivity of the target product.

[0007] Therefore, there is still an urgent need for a safe, environmentally friendly, simple, mild, and high-yield method for preparing 2,3,3,3-tetrafluoropropene, and a simple, time-efficient, mild, and readily available method for synthesizing 1,1,1,2,3-pentafluoropropane with high substrate conversion and high selectivity. Summary of the Invention

[0008] To address the aforementioned technical problems, the present invention provides the following technical solutions.

[0009] In a first aspect, the present invention provides a method for synthesizing 1,1,1,2,3-pentafluoropropane.

[0010] A method for synthesizing 1,1,1,2,3-pentafluoropropane, comprising: , 3,3,3-trifluoropropene, a first catalyst, an HF source, and a selective fluorine reagent undergo a first reaction in a first solvent to give 1,1,1,2,3-pentafluoropropane; The selective fluorine reagent includes 1-chloromethyl-4-fluoro-1,4-diazotized bicyclo[2.2.2]octanedi(tetrafluoroborate).

[0011] In some embodiments, the HF source includes at least one of Et3N·xHF and Pyr·yHF, wherein x and y are each independently selected from integers from 1 to 10.

[0012] In some embodiments, x and y are each independently selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0013] In some embodiments, the HF source includes at least one of Et3N·3HF and Pyr·HF, which is beneficial for improving substrate conversion and selectivity for the target product 1,1,1,2,3-pentafluoropropane. In some preferred embodiments, the HF source is a mixture of Et3N·3HF and Pyr·HF, which is beneficial for improving substrate conversion and selectivity for the target product 1,1,1,2,3-pentafluoropropane.

[0014] In some embodiments, the molar ratio of Et3N·3HF to Pyr·HF in the mixture is 1:1 to 1:10. In some embodiments, the molar ratio of Et3N·3HF to Pyr·HF in the mixture is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, or any value within the range of any two values ​​therein. In some preferred embodiments, the molar ratio of Et3N·3HF to Pyr·HF in the mixture is 1:1 to 1:8, which is beneficial for improving the substrate conversion and the selectivity of the target product 1,1,1,2,3-pentafluoropropane. In some preferred embodiments, the molar ratio of Et3N·3HF to Pyr·HF in the mixture is 1:4, which is more conducive to improving the conversion rate of the substrate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane.

[0015] In some preferred embodiments, the first catalyst comprises at least one of 4-iodotoluene, 1-iodo-4-methoxybenzene, ethyl 4-iodobenzoate, 2-iodo-1,3-dimethoxybenzene, 2-(2-iodophenyl)-2-propanol, or 2-iodobenzoic acid, which is beneficial for improving the conversion of the substrate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane. In some more preferred embodiments, the first catalyst comprises at least one of 4-iodotoluene, 1-iodo-4-methoxybenzene, or 2-iodo-1,3-dimethoxybenzene, which is even more beneficial for improving the conversion of the substrate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane. In some most preferred embodiments, the first catalyst comprises at least one of 4-iodotoluene and 1-iodo-4-methoxybenzene, which is most beneficial for improving the conversion of the substrate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane.

[0016] In some embodiments, the reaction temperature of the first reaction is 20°C to 50°C. In some embodiments, the reaction temperature of the first reaction is 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, or any value within the range of any two of these values. In some preferred embodiments, the reaction temperature of the first reaction is selected from 20°C to 40°C, which is beneficial for improving the conversion rate of the substrate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane. In some more preferred embodiments, the reaction temperature of the first reaction is 30°C, which is even more beneficial for improving the conversion rate of the substrate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane.

[0017] In some embodiments, the reaction time of the first reaction is 14 hours or more. In some embodiments, the reaction time of the first reaction is 14 to 50 hours. In some embodiments, the reaction time of the first reaction is any value within the range of 14 hours, 14.5 hours, 15 hours, 15.5 hours, 16 hours, 16.5 hours, 17 hours, 17.5 hours, 18 hours, 18.5 hours, 19 hours, 19.5 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, 45 hours, 50 hours, or any two of these values. In some embodiments, the reaction time of the first reaction is 14 to 20 hours.

[0018] In some preferred embodiments, the first solvent includes at least one selected from acetonitrile, dichloromethane, chloroform, carbon tetrachloride, and 1,1-dichloroethane, which is beneficial for improving the conversion rate of the substrate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane. In some more preferred embodiments, the first solvent is 1,1-dichloroethane, which is even more beneficial for improving the conversion rate of the substrate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane.

[0019] In some embodiments, the molar ratio of 3,3,3-trifluoropropylene to the first catalyst is 1:1 to 10:1. In some embodiments, the molar ratio of 3,3,3-trifluoropropylene to the first catalyst is 1:1, 2:1, 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, or any value within a range of any two of these values. In some embodiments, the molar ratio of 3,3,3-trifluoropropylene to the first catalyst is 1:1 to 5:1. In some embodiments, the molar ratio of 3,3,3-trifluoropropylene to the first catalyst is 3:1 to 5:1.

[0020] In some embodiments, the molar ratio of 3,3,3-trifluoropropylene to the selective fluorine reagent is 1:1 to 10:1. In some embodiments, the molar ratio of 3,3,3-trifluoropropylene to the selective fluorine reagent is 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 7.1:1, 7.2:1, 7.3:1, 7.4:1, 7.5:1, 7.6:1, 7.7:1, 8:1, 9:1, 10:1, or any value within a range of any two values ​​therein. In some embodiments, the molar ratio of 3,3,3-trifluoropropylene to the selective fluorine reagent is 7:1 to 8:1.

[0021] In some embodiments, the molar ratio of F element in the 3,3,3-trifluoropropylene and HF source is 1:2 or less. In some embodiments, the molar ratio of F element in the 3,3,3-trifluoropropylene and HF source is 1:2 to 1:10. In some embodiments, the molar ratio of F element in the 3,3,3-trifluoropropylene and HF source is 1:2, 1:3, 1:4, 1:5, 1:6, 1:6.5, 1:6.9, 1:7, 1:8, 1:9, 1:10, or any value within the range of any two of these values.

[0022] In some embodiments, 0.1 mol to 10 mol of the 3,3,3-trifluoropropylene is added per 1 L of the first solvent. In some embodiments, 0.1 mol, 0.5 mol, 1 mol, 2 mol, 3 mol, 3.5 mol, 3.9 mol, 3.96 mol, 4 mol, 5 mol, 6 mol, 7 mol, 8 mol, 9 mol, 10 mol of the 3,3,3-trifluoropropylene, or any value within any two of these values, are added per 1 L of the first solvent.

[0023] In some preferred embodiments, the first reaction occurs under a nitrogen atmosphere or an inert gas atmosphere. In some preferred embodiments, the first reaction occurs in a closed reaction vessel under a nitrogen atmosphere or an inert gas atmosphere.

[0024] In some embodiments, the inert gas in the first reaction includes at least one of helium, neon, argon, krypton, and xenon.

[0025] Secondly, the present invention provides a method for synthesizing 2,3,3,3-tetrafluoropropylene.

[0026] A method for synthesizing 2,3,3,3-tetrafluoropropylene, comprising: , 1,1,1,2,3-pentafluoropropane is synthesized according to the synthetic method described in the first aspect, and then the obtained 1,1,1,2,3-pentafluoropropane is subjected to a second reaction in the presence of a second catalyst to give 2,3,3,3-tetrafluoropropene.

[0027] In some embodiments, the reaction temperature of the second reaction is 200°C to 400°C. In some embodiments, the reaction temperature of the second reaction is 200°C, 250°C, 300°C, 350°C, 400°C, or any value within the range of any two of these values.

[0028] In some embodiments, the second reaction is carried out in a continuous reactor filled with the second catalyst.

[0029] In some embodiments, the 1,1,1,2,3-pentafluoropropane is mixed with a carrier gas and then introduced into a continuous reactor for reaction.

[0030] In some embodiments, the volume hourly space velocity (VHSV) of the 1,1,1,2,3-pentafluoropropane and the carrier gas in the second reaction is 100 h⁻¹. -1 ~1000h -1 In some embodiments, the volume hourly space velocity (VHSV) of the 1,1,1,2,3-pentafluoropropane and the carrier gas in the second reaction is 100 h⁻¹. -1 150h -1 200h -1 250h -1 300h -1 350h -1 400h -1 450h -1 500h -1 550h -1 600h -1 650h -1 700h -1 750h -1 800h -1 850h -1 900h -1 950h -1 1000h -1 Or any value within the range between any two of these values.

[0031] In some embodiments, the carrier gas includes an inert gas and / or nitrogen.

[0032] In some embodiments, the inert gas in the carrier gas during the second reaction includes at least one of helium, neon, argon, krypton, and xenon.

[0033] In some embodiments, the molar ratio of 1,1,1,2,3-pentafluoropropane to carrier gas is 1:5 to 1:20. In some embodiments, the molar ratio of 1,1,1,2,3-pentafluoropropane to carrier gas is 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, or any value within a range of any two of these values. In some embodiments, the molar ratio of 1,1,1,2,3-pentafluoropropane to carrier gas is 1:10.

[0034] In some embodiments, the second catalyst is activated before use.

[0035] In some embodiments, activation of the second catalyst includes heating the second catalyst in a nitrogen or inert gas atmosphere.

[0036] In some embodiments, the heating temperature during the activation of the second catalyst includes 200°C to 600°C. In some embodiments, the heating temperature during the activation of the second catalyst includes 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, or any value within a range of any two of these values. In some embodiments, the heating temperature during the activation of the second catalyst includes 350°C to 500°C.

[0037] In some embodiments, the heating time for activation of the second catalyst is 5 hours or more. In some embodiments, the heating time for activation of the second catalyst is 5 to 30 hours. In some embodiments, the heating time for activation of the second catalyst is 15 hours or more. In some embodiments, the heating time for activation of the second catalyst is 15 to 30 hours. In some embodiments, the heating time for activation of the second catalyst is 5 hours, 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, or any value within a range of any two of these values.

[0038] In some embodiments, the inert gas used in the activation of the second catalyst includes at least one of helium, neon, argon, krypton, and xenon.

[0039] In some embodiments, the second catalyst comprises any one of (1) to (4): (1) Main catalyst, or (2) Main catalyst and co-catalyst, or (3) Main catalyst, co-catalyst and molding aid; or (4) Main catalyst and molding aid.

[0040] In some embodiments, the main catalysts in groups (1) to (4) each independently comprise an oxide of a first metal element.

[0041] In some embodiments, the first metal element in the oxides of the first metal element in groups (1) to (4) independently includes at least one of Cr, Mn, Fe, Zn, Ni, Cu, Co, Al, Mg, Ga, In, Y, Zr, Ti, and Nb. In some preferred embodiments, the first metal element in the oxides of the first metal element in groups (1) to (4) is independently selected from at least one of Cr, Al, Fe, and Mg. In some more preferred embodiments, the first metal element in the oxides of the first metal element in groups (1) to (4) is independently selected from at least one of Cr, Al, and Fe.

[0042] In some embodiments, the cocatalysts in groups (2) to (3) each independently comprise an oxide of a second metal element.

[0043] In some embodiments, the second metal element in the oxide of the second metal element in groups (2) to (3) independently includes at least one of rare earth elements, main group metal elements, and transition metal elements.

[0044] In some embodiments, the rare earth elements in groups (2) to (3) each independently include at least one of lanthanum and yttrium.

[0045] In some embodiments, the main group metal elements in groups (2) to (3) each independently include at least one of aluminum and magnesium.

[0046] In some embodiments, the transition metal elements in groups (2) to (3) each independently include at least one of zinc and nickel.

[0047] In some preferred embodiments, in the (2) or (3) group, the co-catalyst independently includes at least one of Cr2O3, Al2O3, and Fe2O3.

[0048] In some preferred embodiments, in groups (2) to (3), the main catalyst independently includes at least one of Cr2O3 and Al2O3, and the co-catalyst independently includes at least one of lanthanum oxide, yttrium oxide and zinc oxide.

[0049] In some embodiments, the preparation method of the catalyst in group (2) includes method 1 or method 2; Method 1: Mix the main catalyst and the co-catalyst to obtain the second catalyst; Method 2: Mix the salt of the first metal element or its hydrate with the salt of the second metal element or its hydrate in water, add alkali to mix, form a precipitate, filter, dry the precipitate obtained by filtration, calcine in a nitrogen or inert gas atmosphere, and pulverize to obtain the second catalyst.

[0050] In some embodiments, the preparation method of the catalyst of the third group includes method 3 or method 4; Method 3: Mix the main catalyst, co-catalyst, and molding aid, and compress the mixture into tablets to obtain the second catalyst; Method 4: Mix the salt of the first metal element or its salt hydrate with the salt of the second metal element or its salt hydrate in water, add alkali to mix, form a precipitate, filter, dry the precipitate obtained by filtration, calcine in a nitrogen or inert gas atmosphere, pulverize, and obtain a mixture of main catalyst and co-catalyst. Mix the obtained mixture with a molding aid, compress into tablets, and obtain the second catalyst.

[0051] In some embodiments, the inert gas in methods 2 and 4 independently includes at least one of helium, neon, argon, krypton, and xenon.

[0052] In some embodiments, during the mixing in water as described in methods 2 and 4, each 1g of the salt of the first metal element or a hydrate of its salt is mixed with 10mL to 50mL of water. In some embodiments, during the mixing in water as described in methods 2 and 4, each 1g of the salt of the first metal element or a hydrate of its salt is mixed with 15mL to 25mL of water. In some embodiments, during the mixing in water as described in methods 2 and 4, each 1g of the salt of the first metal element or a hydrate of its salt is mixed with 10mL, 15mL, 16mL, 17mL, 18mL, 19mL, 19.1mL, 19.2mL, 20mL, 21mL, 22mL, 25mL, 30mL, 35mL, 40mL, 45mL, 50mL of water, or any value within a range of any two of these values.

[0053] In some embodiments, the alkali in methods 2 and 4 independently comprises concentrated ammonia or an aqueous ammonia solution.

[0054] In some embodiments, the concentration of NH3 in the concentrated ammonia solution in methods 2 and 4 is independently selected from 25wt% to 28wt%. In some embodiments, the concentration of NH3 in the concentrated ammonia solution in methods 2 and 4 is independently selected from 25wt%, 26wt%, 27wt%, 28wt%, or any value within the range of any two of these values.

[0055] In some embodiments, the concentration of NH3 in the ammonia solution in methods 2 and 4 is independently selected from 1 wt% to 10 wt%. In some embodiments, the concentration of NH3 in the ammonia solution in methods 2 and 4 is independently selected from 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.1 wt%, 5.5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, or any value within any two of these ranges. In some embodiments, the concentration of NH3 in the ammonia solution in methods 2 and 4 is independently selected from 4.5 wt% to 5.1 wt%.

[0056] In some embodiments, the molar ratio of NH3 in the alkali of methods 2 and 4 to the first metal element in the salt or hydrate of the first metal element is independently selected from 1:3 to 1:10. In some embodiments, the molar ratio of NH3 in the alkali of methods 2 and 4 to the first metal element in the salt or hydrate of the first metal element is independently selected from 1:3 to 1:6.5. In some embodiments, the molar ratio of NH3 in the alkali of methods 2 and 4 to the first metal element in the salt or hydrate of the first metal element is independently selected from 1:5 to 1:6.5. In some embodiments, the molar ratio of NH3 in the alkali of method 2 and method 4 to the first metal element in the salt of the first metal element or the hydrate of the salt thereof is independently selected from 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:5.7, 1:6, 1:6.1, 1:6.2, 1:6.3, 1:6.5, 1:7, 1:8, 1:9, 1:10 or any value within a range of any two values ​​therein.

[0057] In some embodiments, the calcination of method 2 or method 4 independently includes calcination in a nitrogen or inert gas atmosphere at 200°C to 300°C (e.g., 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, or any value within any two of these values) or at 250°C for 5 hours to 10 hours (e.g., 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, or any value within these values). (any value within the range between two values), and then calcined in a nitrogen or inert gas atmosphere at 300℃~400℃ (e.g., 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃ or any value within the range between any two values) or 350℃ for 5 hours~10 hours (e.g., 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours or any value within the range between any two values).

[0058] In some embodiments, the salt of the first metal element in method 2 or method 4 independently includes chromium chloride.

[0059] In some embodiments, the hydrate of the salt of the first metal element in method 2 or method 4 independently comprises chromium chloride hexahydrate.

[0060] In some embodiments, the salt of the second metal element in method 2 or method 4 independently includes either a nitrate of the second metal element or a chloride of the second metal element.

[0061] In some embodiments, the hydrates of the second metal element salts in method 2 or method 4 independently include hydrates of the second metal element nitrates or hydrates of the second metal element chlorides.

[0062] In some embodiments, the preparation method of the catalyst of the group (4) includes method 5: mixing the main catalyst with a molding aid, compressing and molding to obtain the second catalyst.

[0063] In some embodiments, in method 1, both the main catalyst and the co-catalyst are pulverized before mixing.

[0064] In some embodiments, in method 3, the main catalyst, co-catalyst, and molding aid are all pulverized before mixing.

[0065] In some embodiments, in method 5, both the main catalyst and the co-catalyst are pulverized before mixing.

[0066] In some embodiments, the molding aids in groups (2) to (3) each independently include graphite.

[0067] In some embodiments, the molar ratio of the first metal element and the second metal element in group (2) or (3) is independently selected from 1:0.01 to 1:0.1. In some embodiments, the molar ratio of the first metal element and the second metal element in group (2) or (3) is independently selected from 1:0.01, 1:0.05, 1:0.1 or any value within the range of any two of these values.

[0068] In some embodiments, the ratio of the total mass of the main catalyst and co-catalyst in group (3) to the mass of the molding aid is 100:0.1 to 100:10. In some embodiments, the ratio of the total mass of the main catalyst and co-catalyst in group (3) to the mass of the molding aid is 100:0.1, 100:0.5, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5, 100:5, 100:5.5, 100:6, 100:6.5, 100:7, 100:7.5, 100:8, 100:8.5, 100:9, 100:9.5, 100:10, or any value within the range of any two of these values. In some embodiments, the ratio of the total mass of the main catalyst and co-catalyst in the third group to the mass of the molding aid is 100:5.

[0069] In some embodiments, the mass ratio of the main catalyst to the molding aid in group (4) is 100:0.1 to 100:10. In some embodiments, the mass ratio of the main catalyst to the molding aid in group (4) is 100:0.1, 100:0.5, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5, 100:5, 100:5.5, 100:6, 100:6.5, 100:7, 100:7.5, 100:8, 100:8.5, 100:9, 100:9.5, 100:10, or any value within a range of any two of these values. In some embodiments, the mass ratio of the main catalyst to the molding aid in group (4) is 100:5.

[0070] Thirdly, the present invention provides a catalyst.

[0071] A catalyst comprising the second catalyst of group (2) or group (3) as described in the synthesis method of the second aspect.

[0072] Fourthly, the present invention provides an application of the catalyst described in the third aspect.

[0073] The use of the catalyst described in the third aspect in the reaction of 1,1,1,2,3-pentafluoropropane to prepare 2,3,3,3-tetrafluoropropene.

[0074] Beneficial effects Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects: (1) Compared with not adding the first catalyst, the present invention preferably adds at least one of 4-iodotoluene, 1-iodo-4-methoxybenzene, ethyl 4-iodobenzoate, 2-iodo-1,3-dimethoxybenzene, 2-(2-iodophenyl)-2-propanol or 2-iodobenzoic acid, which is beneficial to significantly improve the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects.

[0075] (2) Compared with other catalysts (such as ethyl 4-iodobenzoate, 2-(2-iodophenyl)-2-propanol or 2-iodobenzoic acid), using at least one of 4-iodotoluene, 1-iodo-4-methoxybenzene, and 2-iodo-1,3-dimethoxybenzene is more conducive to significantly improving the substrate conversion and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, with unexpected technical effects; the preferred choice is to use at least one of 4-iodotoluene and 1-iodo-4-methoxybenzene, which is most conducive to significantly improving the substrate conversion and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, with unexpected technical effects.

[0076] (3) In the synthesis method of 1,1,1,2,3-pentafluoropropane provided by the present invention, compared with other solvents (such as N,N-dimethylformamide, ethanol, dimethyl sulfoxide or toluene), the present invention preferably uses at least one of acetonitrile, dichloromethane, chloroform, carbon tetrachloride and 1,1-dichloroethane, which is more conducive to significantly improving the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects.

[0077] (4) In the method for synthesizing 1,1,1,2,3-pentafluoropropane provided by the present invention, the present invention uses at least one of Et3N·3HF and Pyr·HF as HF source, which is more conducive to improving substrate conversion rate and selectivity of target product 1,1,1,2,3-pentafluoropropane, and has excellent technical effect.

[0078] (5) In the method for synthesizing 1,1,1,2,3-pentafluoropropane provided by the present invention, the present invention preferably uses a mixture of Et3N·3HF and Pyr·HF with a molar ratio of 1:1 to 1:8 as the HF source, which is beneficial to improving the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects; more preferably, a mixture of Et3N·3HF and Pyr·HF with a molar ratio of 1:4 is used as the HF source, which is even more beneficial to improving the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects.

[0079] (6) In the synthesis method of 1,1,1,2,3-pentafluoropropane provided by the present invention, the synthesis method of 1,1,1,2,3-pentafluoropropane provided by the present invention uses 20~40℃ as the reaction temperature, which is more conducive to improving the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has excellent technical effects.

[0080] (7) The method for synthesizing 1,1,1,2,3-pentafluoropropane provided by the present invention preferably adopts a reaction temperature of 30°C, which is more conducive to improving the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects.

[0081] (8) In the synthesis method of 2,3,3,3-tetrafluoropropylene provided by the present invention, the second catalyst provided by the present invention is used to catalyze the preparation of 2,3,3,3-tetrafluoropropylene. The substrate conversion rate is high and the target product 2,3,3,3-tetrafluoropropylene has high selectivity, which has excellent technical effect.

[0082] (9) In the method for synthesizing 2,3,3,3-tetrafluoropropylene provided by the present invention, the present invention preferably uses a second catalyst containing an oxide of at least one first metal element selected from Cr and Al and an oxide of at least one second metal element selected from La, Y and Zn. This is more conducive to improving the selectivity of the obtained second catalyst for 2,3,3,3-tetrafluoropropylene in the reaction of catalyzing the synthesis of 2,3,3,3-tetrafluoropropylene from 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects.

[0083] (10) The preparation method of 2,3,3,3-tetrafluoropropylene provided by the present invention has the advantages of being safe, environmentally friendly, simple to operate, mild reaction, high yield, high selectivity of target product, and fast reaction speed, which is conducive to industrial production.

[0084] (11) The method for synthesizing 1,1,1,2,3-pentafluoropropane provided by the present invention has the advantages of simple operation, short time consumption, mild reaction, simple reagents required for the reaction, high substrate conversion rate and high selectivity of target product, which is conducive to industrial production.

[0085] Terminology Explanation In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0086] The term “room temperature” refers to ambient temperature, which is between approximately 10°C and approximately 30°C, or approximately 20°C and approximately 30°C, or approximately 25°C.

[0087] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0088] The group "Me" represents methyl. The group "Et" represents ethyl. "Et3N" represents triethylamine. "Pyr" represents pyridine.

[0089] In the following content, all numbers disclosed herein, whether or not they are expressed using words such as "approximately" or "about," are approximate values. The value of each number may vary by 1%, 2%, 5%, 7%, 8%, 10%, 15%, or 20%, etc. Whenever a number with a value of N is disclosed, any number having a value of N+ / -1%, N+ / -2%, N+ / -3%, N+ / -5%, N+ / -7%, N+ / -8%, N+ / -10%, N+ / -15%, or N+ / -20% will be explicitly disclosed, where "+ / -" indicates addition or subtraction. Detailed Implementation

[0090] To enable those skilled in the art to better understand the technical solutions of the present invention, some non-limiting embodiments are further disclosed below to provide a more detailed description of the present invention.

[0091] I. Reagents The reagents or consumables used in this invention can be purchased from the market or prepared by the methods described in this invention.

[0092] Selectfluor®: 1-Chloromethyl-4-fluoro-1,4-diazotized bicyclo[2.2.2]octane di(tetrafluoroborate).

[0093] Et3N·3HF: Triethylamine trihydrofluoride, its CAS number is 73602-61-6; Pyr·HF: Pyridine hydrogen fluoride, its CAS number is 32001-55-1.

[0094] Examples 1-7: Synthesis of 1,1,1,2,3-pentafluoropropane - Catalyst Investigation

[0095] In a closed reactor under a nitrogen atmosphere, the first catalyst (6.21 mol, specific selections are shown in Table 1) and the first solvent (5 L, specific selections are shown in Table 1) were mixed. 3,3,3-trifluoropropene (19.8 mol) was then introduced into the mixture. HF source (45.8 mol, specific selections are shown in Table 1) and Selectfluor® (2.75 mol) were added while stirring to carry out the reaction (reaction temperature is shown in Table 1). 1,1,1,2,3-pentafluoropropane was obtained. After the reaction was completed (14 hours), the product (the reaction product has a low boiling point and is gaseous at room temperature) was blown into a low-temperature collector using nitrogen for product collection. The conversion rate and selectivity were detected by gas chromatography, and the results are shown in Table 1.

[0096] Table 1: Results of Catalyst Investigation

[0097] Remark: 1. In Table 1, "None" means that no catalyst was added.

[0098] 2. The following are the structures of the catalysts in Table 1 and their corresponding codes:

[0099] Conclusion: As shown in Table 1, (1) Compared with not adding the first catalyst, the present invention preferably adds at least one of the following first catalysts: first catalyst A (4-iodotoluene), first catalyst B (1-iodo-4-methoxybenzene), first catalyst C (ethyl 4-iodobenzoate), first catalyst D (2-iodo-1,3-dimethoxybenzene), first catalyst E (2-(2-iodophenyl)-2-propanol), or first catalyst F (2-iodobenzoic acid), which is beneficial to significantly improve the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects.

[0100] (2) Compared with other catalysts (such as first catalyst C (ethyl 4-iodobenzoate), first catalyst E (2-(2-iodophenyl)-2-propanol) or first catalyst F (2-iodobenzoic acid)), using at least one of first catalyst A (4-iodotoluene), first catalyst B (1-iodo-4-methoxybenzene), and first catalyst D (2-iodo-1,3-dimethoxybenzene) is more conducive to significantly improving the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, with unexpected technical effects; the most preferred option is to use at least one of first catalyst A (4-iodotoluene) and first catalyst B (1-iodo-4-methoxybenzene), which is most conducive to significantly improving the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, with unexpected technical effects.

[0101] Examples 8-15: Synthesis of 1,1,1,2,3-pentafluoropropane - Investigation of the first solvent The method of Example 2 was used for investigation, except that the first solvent was selected differently (see Table 2 for details). The other conditions were the same as in Example 2, and the results are shown in Table 2.

[0102] Table 2: Results of the solvent investigation

[0103] Conclusion: As shown in Tables 1 and 2, compared with other solvents (such as N,N-dimethylformamide, ethanol, dimethyl sulfoxide, or toluene), the present invention preferably uses at least one of acetonitrile, dichloromethane, chloroform, carbon tetrachloride, and 1,1-dichloroethane as the first solvent, which is beneficial to significantly improve the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects; more preferably, 1,1-dichloroethane is used, which is even more beneficial to significantly improve the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane.

[0104] Examples 16-20: Synthesis of 1,1,1,2,3-pentafluoropropane - Investigation of HF source The method of Example 15 was examined, except that the HF source was selected differently (see Table 3 for details). The other conditions were the same as in Example 15, and the results are shown in Table 3.

[0105] Table 3: Results of the investigation of HF sources

[0106] in conclusion: (1) As can be seen from the results in Tables 1, 2 and 3, the present invention uses at least one of Et3N·3HF and Pyr·HF as the HF source, which is more conducive to providing substrate conversion and selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has excellent technical effects.

[0107] (2) As can be seen from the results in Table 3, the present invention preferably uses a mixture of Et3N·3HF and Pyr·HF with a molar ratio of 1:1 to 1:8 as the HF source, which is beneficial to improving the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects; more preferably, a mixture of Et3N·3HF and Pyr·HF with a molar ratio of 1:4 is used as the HF source, which is even more beneficial to improving the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects.

[0108] Examples 21-22: Synthesis of 1,1,1,2,3-pentafluoropropane - Investigation of reaction temperature The method of Example 19 was investigated, except that the reaction temperature was different (see Table 4 for details). The other conditions were the same as in Example 19, and the results are shown in Table 4.

[0109] Table 4: Results of the investigation on reaction temperature

[0110] in conclusion: (1) As can be seen from the results in Tables 1 to 4, the synthesis method of 1,1,1,2,3-pentafluoropropane provided by the present invention uses a reaction temperature of 20 to 40 °C, which is more conducive to improving the substrate conversion rate and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has excellent technical effects.

[0111] (2) As can be seen from the results of Example 19 in Table 3 and Table 4, the synthesis method of 1,1,1,2,3-pentafluoropropane provided by the present invention is more preferably a reaction temperature of 30°C, which is more conducive to improving the yield of the obtained product 1,1,1,2,3-pentafluoropropane and the selectivity of the target product 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects.

[0112] Example 23: Preparation of the second catalyst (oxide without a second metal element) 250g of chromium chloride hexahydrate was added to 4.79L of deionized water and stirred to dissolve, yielding solution 1. 365g of concentrated ammonia (containing 25wt%~28wt% NH3) was added to 1.65L of water to prepare an ammonia solution. The ammonia solution was then added to solution 1 to form a precipitate. The precipitate was filtered and dried at 120℃ for 12 hours, calcined at 250℃ under nitrogen for 5 hours, and then calcined at 350℃ under nitrogen for 5 hours. The solid was then pulverized to obtain catalyst powder, which was then mixed with graphite (graphite:catalyst powder = 2:100 (mass ratio)), pressed into tablets, and granulated to obtain the second catalyst (composed of Cr2O3 and graphite).

[0113] Examples 24-32: Preparation of the Second Catalyst 250g of chromium chloride hexahydrate and a salt of the second metal element (specific selection and molar ratio are shown in Table 5) were added to 4.79L of deionized water and stirred to dissolve, obtaining solution 1. 365g of concentrated ammonia water (containing 25wt%~28wt% NH3) was added to 1.65L of water to prepare an ammonia solution. The ammonia solution was then added to solution 1 to form a precipitate. The precipitate was filtered and dried at 120℃ for 12 hours, calcined at 250℃ under nitrogen for 5 hours, and then calcined at 350℃ under nitrogen for 5 hours. The solid was then pulverized to obtain catalyst powder, which was then mixed with graphite (graphite:catalyst powder = 2:100 (mass ratio)), pressed into tablets and granulated to obtain the second catalyst (composed of Cr2O3, oxide of the second metal element and graphite).

[0114] Table 5: Types of salts of the second metallic element, molar ratio of chromium to the second metallic element.

[0115] Examples 33-36: Preparation of the Second Catalyst Example 33: Solid Al2O3 was pulverized to obtain catalyst powder, which was then mixed with graphite (graphite:catalyst powder = 2:100 (mass ratio)), pressed into tablets and granulated to obtain a second catalyst (composed of Al2O3 and graphite).

[0116] Example 34: Solid Al2O3 and solid ZnO were pulverized and mixed at a molar ratio of Al to Zn of 1:0.02 to obtain catalyst powder. Then, it was mixed with graphite (graphite:catalyst powder = 2:100 (mass ratio)), pressed into tablets and granulated to obtain a second catalyst (composed of Al2O3, ZnO and graphite).

[0117] Example 35: Fe2O3 solid was pulverized to obtain catalyst powder, which was then mixed with graphite (graphite:catalyst powder = 2:100 (mass ratio)), pressed into tablets and granulated to obtain a second catalyst (composed of Fe2O3 and graphite).

[0118] Example 36: MgO solid was crushed to obtain catalyst powder, which was then mixed with graphite (graphite:catalyst powder = 2:100 (mass ratio)), pressed into tablets and granulated to obtain a second catalyst (composed of MgO and graphite).

[0119] Example 37: Synthesis of 2,3,3,3-Tetrafluoropropylene

[0120] 100 ml of a second catalyst (specific selection shown in Table 6) was packed into a tubular reactor, and N2 was introduced at a flow rate of 2.5 L / min. Activation was carried out for 15 h at a pressure of 0.1 MPa and a temperature of 400 °C. Then, 1,1,1,2,3-pentafluoropropane and N2 were mixed at a molar ratio of 1:10 and introduced into the tubular reactor for reaction to obtain 2,3,3,3-tetrafluoropropene. The specific reaction temperature was selected as shown in Table 6, and the volume hourly space velocity (calculated based on the total volume of 1,1,1,2,3-pentafluoropropane and N2) was 500 h⁻¹. -1 The conversion rate of 1,1,1,2,3-pentafluoropropane and the selectivity of 2,3,3,3-tetrafluoropropene were detected within 24 hours of reaction, and the results are shown in Table 6.

[0121] Table 6: Conversion Rate and Selectivity Results

[0122] in conclusion: (1) As shown in Table 6, the second catalyst provided by the present invention can be used to catalyze the preparation of 2,3,3,3-tetrafluoropropylene with high substrate conversion and high selectivity of target product, which has excellent technical effect.

[0123] (2) As can be seen from the results in Table 6, the present invention preferably uses a second catalyst containing an oxide of at least one first metal element selected from Cr and Al and an oxide of at least one second metal element selected from La, Y and Zn. This is more conducive to improving the selectivity of the obtained second catalyst for 2,3,3,3-tetrafluoropropylene in the reaction of catalyzing the synthesis of 2,3,3,3-tetrafluoropropylene from 1,1,1,2,3-pentafluoropropane, and has unexpected technical effects.

[0124] The method of this invention has been described through preferred embodiments. Those skilled in the art will readily be able to modify or appropriately alter and combine the methods and applications described herein within the scope, spirit, and context of this invention to implement and apply the technology of this invention. Those skilled in the art can refer to the content herein to appropriately improve process parameters. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the scope of this invention.

Claims

1. A method for synthesizing 1,1,1,2,3-pentafluoropropane, characterized in that, include: ， 3,3,3-trifluoropropene, a first catalyst, an HF source, and a selective fluorine reagent undergo a first reaction in a first solvent to give 1,1,1,2,3-pentafluoropropane; The selective fluorine reagent includes 1-chloromethyl-4-fluoro-1,4-diazotized bicyclo[2.2.2]octanedi(tetrafluoroborate).

2. The synthesis method according to claim 1, wherein the HF source comprises at least one of Et3N·xHF and Pyr·yHF, wherein, x and y are each independently selected from integers from 1 to 10; and / or The HF source includes at least one of Et3N·3HF and Pyr·HF, preferably a mixture of Et3N·3HF and Pyr·HF; Optionally, the molar ratio of Et3N·3HF to Pyr·HF in the mixture is 1:1 to 1:10, preferably 1:1 to 1:8, and more preferably 1:4; Preferably, the first catalyst comprises at least one of 4-iodotoluene, 1-iodo-4-methoxybenzene, ethyl 4-iodobenzoate, 2-iodo-1,3-dimethoxybenzene, 2-(2-iodophenyl)-2-propanol, or 2-iodobenzoic acid; more preferably, the first catalyst comprises at least one of 4-iodotoluene, 1-iodo-4-methoxybenzene, or 2-iodo-1,3-dimethoxybenzene; most preferably, the first catalyst comprises at least one of 4-iodotoluene and 1-iodo-4-methoxybenzene.

3. The synthesis method according to any one of claims 1 to 2, wherein the reaction temperature of the first reaction is 20°C to 50°C, preferably selected from 20°C to 40°C, more preferably 30°C; and / or The reaction time of the first reaction is 14 hours or more; and / or The first solvent includes at least one selected from acetonitrile, dichloromethane, chloroform, carbon tetrachloride, and 1,1-dichloroethane, preferably 1,1-dichloroethane; and / or The molar ratio of 3,3,3-trifluoropropylene to the first catalyst is 1:1 to 10:1, or 3:1 to 5:1; and / or The molar ratio of the 3,3,3-trifluoropropylene to the selective fluorine reagent is 1:1 to 10:1, or 7:1 to 8:1; and / or The molar ratio of F in the 3,3,3-trifluoropropylene and HF source is 1:2 or less, preferably 1:2 to 1:10; and / or Optionally, 0.1 mol to 10 mol of the 3,3,3-trifluoropropylene is added to each 1 L of the first solvent; and / or Preferably, the first reaction is carried out under nitrogen atmosphere or inert gas atmosphere conditions; Optionally, the inert gas in the first reaction includes at least one of helium, neon, argon, krypton, and xenon.

4. A method for synthesizing 2,3,3,3-tetrafluoropropylene, characterized in that, include: ， 1,1,1,2,3-pentafluoropropane is synthesized by the synthetic method according to any one of claims 1 to 3, and then the obtained 1,1,1,2,3-pentafluoropropane is subjected to a second reaction in the presence of a second catalyst to obtain 2,3,3,3-tetrafluoropropene.

5. The synthesis method according to claim 4, wherein the reaction temperature of the second reaction is 200℃~400℃; Optionally, the second reaction is carried out in a continuous reactor packed with the second catalyst.

6. The synthesis method according to any one of claims 4 to 6, The 1,1,1,2,3-pentafluoropropane is mixed with a carrier gas and then introduced into a continuous reactor for reaction; and / or In the second reaction, the volume hourly space velocity (VHSV) of the 1,1,1,2,3-pentafluoropropane and the carrier gas is 100 h⁻¹. -1 ~1000h -1 ; and / or The carrier gas includes an inert gas and / or nitrogen; and / or The inert gas in the carrier gas of the second reaction includes at least one of helium, neon, argon, krypton, and xenon; and / or The molar ratio of 1,1,1,2,3-pentafluoropropane to carrier gas is 1:5 to 1:20, or 1:

10.

7. The synthesis method according to any one of claims 4 to 6, wherein the second catalyst comprises any group of (1) to (4): (1) Main catalyst, or (2) Main catalyst and co-catalyst, or (3) Main catalyst, co-catalyst and molding aid; or (4) Main catalyst and molding aid; Optionally, the main catalyst in groups (1) to (4) each independently comprises an oxide of a first metal element; and / or Optionally, the first metal element in the oxides of the first metal element in groups (1) to (4) each independently includes: At least one of Cr, Mn, Fe, Zn, Ni, Cu, Co, Al, Mg, Ga, In, Y, Zr, Ti, and Nb, preferably selected independently from at least one of Cr, Al, Fe, and Mg, and more preferably selected independently from at least one of Cr, Al, and Fe; Optionally, the cocatalysts in groups (2) to (3) each independently comprise an oxide of a second metal element; Optionally, the second metal element in the oxide of the second metal element in groups (2) to (3) may independently include at least one of rare earth elements, main group metal elements, and transition metal elements; Optionally, the rare earth elements in groups (2) to (3) each independently include at least one of lanthanum and yttrium; Optionally, the main group metal elements in groups (2) to (3) each independently include at least one of aluminum and magnesium; Optionally, the transition metal elements in groups (2) to (3) each independently include at least one of zinc and nickel; Preferably, in group (2) or (3), the co-catalyst independently includes at least one of Cr2O3, Al2O3, and Fe2O3; Preferably, in groups (2) to (3), the main catalyst independently includes at least one of Cr2O3 and Al2O3, and the co-catalyst independently includes at least one of lanthanum oxide, yttrium oxide and zinc oxide.

8. The synthesis method according to claim 7, wherein the preparation method of the catalyst in group (2) includes method 1 or method 2; Method 1: Mix the main catalyst and the co-catalyst to obtain the second catalyst; Method 2: Mix the salt of the first metal element or its salt hydrate with the salt of the second metal element or its salt hydrate in water, add alkali to mix, form a precipitate, filter, dry the precipitate obtained by filtration, calcine in a nitrogen or inert gas atmosphere, pulverize, and obtain the second catalyst; The preparation method of the catalyst in group (3) includes method 3 or method 4; Method 3: Mix the main catalyst, co-catalyst, and molding aid, and compress the mixture into tablets to obtain the second catalyst; Method 4: Mix the salt of the first metal element or its salt hydrate with the salt of the second metal element or its salt hydrate in water, add alkali to mix, form a precipitate, filter, dry the precipitate obtained by filtration, calcine in a nitrogen or inert gas atmosphere, pulverize, and obtain a mixture of main catalyst and co-catalyst. Mix the obtained mixture with a molding aid, compress into tablets, and obtain the second catalyst. Optionally, the calcination of method 2 or method 4 independently includes calcination at 200°C to 300°C or 250°C for 5 to 10 hours in a nitrogen or inert gas atmosphere, and then calcination at 300°C to 400°C or 350°C for 5 to 10 hours in a nitrogen or inert gas atmosphere. Optionally, the salt of the first metallic element in method 2 or method 4 each independently includes chromium chloride; Optionally, the hydrates of the salts of the first metallic element in method 2 or method 4 each independently comprise chromium chloride hexahydrate; Optionally, the salt of the second metal element in method 2 or method 4 independently includes either a nitrate of the second metal element or a chloride of the second metal element. Optionally, the inert gas in methods 2 and 4 may independently include at least one of helium, neon, argon, krypton, and xenon. Optionally, the hydrates of the second metal element salts in method 2 or method 4 independently include hydrates of the second metal element nitrates or hydrates of the second metal element chlorides. Optionally, the preparation method of the catalyst in the group (4) includes method 5: mixing the main catalyst with a molding aid, compressing it into tablets, and obtaining the second catalyst; Optionally, in method 1, both the main catalyst and the co-catalyst are pulverized before mixing; Optionally, in method 3, the main catalyst, co-catalyst, and molding aid are all pulverized before mixing; Optionally, in method 5, both the main catalyst and the co-catalyst are pulverized before mixing; Optionally, the molding aids in groups (2) to (3) each independently include graphite; Optionally, the molar ratio of the first metal element and the second metal element in the (2) or (3) group is independently selected from 1:0.01 to 1:0.1; Optionally, the ratio of the total mass of the main catalyst and the co-catalyst in the third group to the mass of the molding aid is 100:0.1 to 100:10, or 100:5; Optionally, the mass ratio of the main catalyst to the molding aid in the group (4) is 100:0.1 to 100:10, or 100:

5.

9. A catalyst, characterized in that, It includes the second catalyst from group (2) or group (3) as described in any one of claims 7 to 8.

10. Use of the catalyst of claim 9 in the reaction of catalyzing 1,1,1,2,3-pentafluoropropane to prepare 2,3,3,3-tetrafluoropropene.

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