Catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene and its application

Abstract

The invention discloses a catalyst and its application for gas phase synthesis of 2,3,3,3 tetrafluoropropylene, the catalyst is with silicon-modified aluminum fluoride as carrier, load Pd and auxiliary agent, auxiliary agent is any one or more of In, Zn, Mg, Sb;With the mass of carrier as 100%, the load of Pd is 0.5%~2.5%, and the load of auxiliary agent is 0.1%~5%;Its preparation method is first silicon-modified and low-temperature treated to aluminum fluoride with silanol, then impregnated with a precursor solution containing active Pd component and auxiliary agent component, then sequentially through desolvation, drying and roasting. Catalyst preparation method of the present invention is simple to operate, and raw material is easy to obtain, and gained catalyst is used for the reaction of 2 chloro-3,3,3 trifluoropropylene gas phase synthesis 2,3,3,3 tetrafluoropropylene, effectively solves the problem that the heat resistance and high temperature stability of aluminum-based catalyst are poor, with good catalytic performance, and easily realizes the advantage of gas phase continuous large-scale production, with industrial value.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst preparation, and particularly relates to a catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropylene. Background Art

[0002] Currently, third-generation hydrofluorocarbon (HFC) refrigerants, represented by 1,1,1,2-tetrafluoroethane (HFC-134a), are widely used in mobile air conditioning systems. Although their ozone depletion potential (ODP) is zero, their long atmospheric residence time and high global warming potential (GWP) contribute to global warming. The EU's Mobile Air Conditioning Directive and F-Gas Directive prohibit the use of refrigerants with a GWP exceeding 150 in all vehicles starting in 2017. The replacement of high-GWP HFC refrigerants with fourth-generation, low-GWP refrigerants is inevitable.

[0003] 2,3,3,3-Tetrafluoropropene (HFO-1234yf) has a GWP of 4, an ODP of zero, and an atmospheric lifetime of only 11 days. It is an economical "drop-in replacement" for HFC-134a and has become a fourth-generation refrigerant. HFO-1234yf offers similar cooling performance to HFC-134a and has been accepted by automobile manufacturers in Western Europe. Globally, automotive air conditioning accounts for nearly 98.38% of total HFO-1234yf consumption. HFO-1234yf consumption is projected to reach 33,966 tons in 2023.

[0004] While liquid-phase fluorine-chlorine exchange synthesis of HFO-1234yf offers mild reaction conditions, the yield is low. Furthermore, the process is a batch process, making catalyst recovery and reuse difficult and unsuitable for large-scale continuous production. Therefore, vapor-phase synthesis of HFO-1234yf holds great promise. Currently, commonly used catalysts for vapor-phase catalytic synthesis of HFO-1234yf can be categorized as chromium-, aluminum-, and magnesium-based. Chromium-based catalysts suffer from rapid loss of active species during high-temperature reactions, leading to rapid catalyst deactivation. Aluminum-based catalysts are prone to forming large amounts of carbon deposits, which can deactivate the catalyst. Magnesium-based catalysts, on the other hand, suffer from low catalytic activity. Therefore, finding highly active and stable catalysts is a key challenge that needs to be addressed in the synthesis of HFO-1234yf.

[0005] Patent CN102295522A uses a palladium-on-carbon catalyst with pentafluorochloropropane and hydrogen as the raw materials to form a 1,1,1,2,2-pentafluoropropane intermediate product stream. HF is then removed over an HF removal catalyst to produce HFO-1234yf. Patent CN103896725A uses Zn / Al / Cr to catalyze the reaction of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) with hydrogen fluoride (molar ratio of 1:12). The reaction temperature is 350°C, and the contact time is 24 seconds. At this time, the HCFO-1233xf conversion rate is 32.36%, and the HFO-1234yf selectivity is 98.89%. Patent US20110319674A1 describes the dehydrogenation of 1,1,1,2-tetrafluoropropane (HFC-254eb) in a hydrogen atmosphere using a 0.5% Pt / AlO0.75F1.50 catalyst at 600°C for a contact time of 30 seconds. The HFC-254eb conversion is 31%, and the HFO-1234yf selectivity is 94%. The catalyst in this patent suffers from low single-pass conversion and a short catalyst life. Furthermore, the catalytic synthesis of HFO-1234yf requires a long process route and high reaction temperatures, placing high demands on equipment and consuming high energy, making it unsuitable for industrial production. Therefore, the development of a high-performance catalyst for the vapor-phase synthesis of HFO-1234yf is a pressing matter. Summary of the Invention

[0006] The object of the present invention is to provide a catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene and its application in view of the above-mentioned deficiencies in the prior art.

[0007] To achieve the above object, the catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropylene provided by the present invention uses silicon-modified aluminum fluoride as a carrier, loads an active component Pd and an auxiliary agent, and the auxiliary agent is any one or more of In, Zn, Mg, and Sb; based on the mass of the carrier as 100%, the loading amount of the active component is 0.5% to 2.5%, and the loading amount of the auxiliary agent is 0.1% to 5%.

[0008] In the above catalyst, the auxiliary agent is preferably any one or more of In and Sb; based on the mass of the carrier as 100%, the loading amount of the active component is preferably 0.5% to 1%, and the loading amount of the auxiliary agent is preferably 0.5% to 1%.

[0009] The BET specific surface area of ​​the above catalyst is 180 to 240 m 2 / g, and the pore size is between 13 and 16 nm.

[0010] The preparation method of the catalyst of the present invention consists of the following steps:

[0011] Step 1: mixing aluminum fluoride with a solvent, stirring at 60-80°C for 6-24 hours to fully disperse the aluminum fluoride, then adding silanol and continuing to stir until the silanol fully covers the surface of the aluminum fluoride, standing at 5-10°C for 5-8 hours, and then rotary evaporating to remove the solvent. The resulting solid is dried under vacuum conditions, and finally calcined at 300-500°C for 2-8 hours to obtain silicon-modified aluminum fluoride; the silanol is any one or more of trimethylsilanol, triethylsilanol, triisopropylsilanol, and dimethylsilanediol, and the amount of the silanol added is 2% to 20% of the mass of the aluminum fluoride;

[0012] Step 2: Add the precursor of the active component and the precursor of the auxiliary component to deionized water in sequence, mix them evenly, add silicon-modified aluminum fluoride for impregnation, then remove the deionized water by rotary evaporation, dry to constant weight under vacuum conditions, and finally calcine at 300-550°C for 4-10 hours to obtain a catalyst.

[0013] In the above step 1, the silanol is preferably any one of trimethylsilanol and triisopropylsilanol; and the added amount of the silanol is preferably 5% to 10% of the mass of aluminum fluoride.

[0014] In the above step 1, the solvent is preferably any one or more of cyclohexane, toluene, and dimethylformamide.

[0015] In the above step 1, the calcination treatment is preferably performed at 400° C. for 3 to 6 hours.

[0016] In the above step 2, the precursor of the active component is any one of chloropalladic acid, palladium nitrate, and dinitrosodichloropalladium, and the precursor of the auxiliary component is the nitrate of the corresponding auxiliary.

[0017] In the above step 2, the immersion temperature is preferably 25 to 40° C. and the immersion time is preferably 10 to 24 hours.

[0018] In the above step 2, the calcination treatment is preferably performed at 450-500° C. for 6-8 hours.

[0019] The catalyst of the present invention can be used for gas-phase synthesis of 2,3,3,3-tetrafluoropropene. The specific method is as follows: 2-chloro-3,3,3-trifluoropropene and hydrogen fluoride are gasified and then introduced into a fixed-bed reactor filled with the catalyst, and chlorine or oxygen is introduced into the reactor to carry out the reaction at 280-420° C. with a contact time of 16-34 seconds; the flow rate of the 2-chloro-3,3,3-trifluoropropene is 5-20 mL / min, the flow rate of HF is 50-100 mL / min, and the flow rate of the chlorine or oxygen is 5%-10% of the flow rate of the 2-chloro-3,3,3-trifluoropropene.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention uses aluminum fluoride as a catalyst carrier, which is more environmentally friendly than chromium-based catalysts. Since aluminum fluoride has problems such as surface defects and lattice defects that reduce its activity and stability as a catalyst carrier, its specific surface area and pore size can be increased by silanol modification and low-temperature treatment, making the specific surface area of ​​the modified carrier exceed 220m 2 / g, improving the diffusion rate of reactants and the availability of active sites, while obtaining a carrier with better thermal stability and water resistance, and reducing the formation of carbon deposits.

[0022] 2. In the catalyst preparation process of the present invention, the impregnation of the auxiliary metal can weaken the strong interaction between the active component Pd and the carrier, and improve the dispersibility of Pd on the carrier surface; the addition of the auxiliary metal and Pd not only enhances the activity and selectivity of the catalyst, but also weakens the acidity of the overall catalyst and reduces the formation of carbon deposits; by loading the active metal Pd and the auxiliary agent, the reaction activity and service life of the catalyst can be improved; and the catalyst can contain a smaller amount of the main active component (i.e., the precious metal palladium), which can effectively reduce the cost of the catalyst.

[0023] 3. The catalyst of the present invention is used for gas-phase synthesis of 2,3,3,3-tetrafluoropropene using 2-chloro-3,3,3-trifluoropropene as a raw material. The synthesis route is short and the yield is higher than that of liquid-phase synthesis. There is no obvious deactivation after operation for more than 72 hours. The conversion rate of 2-chloro-3,3,3-trifluoropropene is always greater than 40%, and the selectivity of 2,3,3,3-tetrafluoropropene is always maintained at more than 96%. The catalyst is easy to recycle and reuse, which is conducive to large-scale continuous production. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the embodiments, but the protection scope of the present invention is not limited to these embodiments.

[0025] Example 1

[0026] The catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene in this embodiment includes a carrier, and an active component Pd and an auxiliary agent In supported on the carrier. The carrier is aluminum fluoride modified with silanol and treated at low temperature. The loading amounts of Pd and In are 1% and 1% respectively, based on the mass percentage of aluminum fluoride. The catalyst is prepared as follows:

[0027] Step 1: Mix 100 g of aluminum fluoride with 100 g of toluene, stir at 60°C to fully disperse the aluminum fluoride, then add 10 g of trimethylsilanol, continue stirring for 12 hours, so that the trimethylsilanol fully covers the surface of the aluminum fluoride, and then place the resulting solution in an 8°C incubator for 6 hours, then rotary evaporate to remove the toluene, and dry the resulting solid sample at 80°C under vacuum conditions. Finally, calcinate it at 400°C in a muffle furnace for 5 hours to obtain silicon-modified aluminum fluoride, abbreviated as SAF-1.

[0028] Step 2: 1.67g of chloropalladic acid and 1.74g of indium nitrate were added to 100mL of deionized water in sequence and mixed well to obtain an impregnation solution; 100g of silicon-modified aluminum fluoride was poured into the impregnation solution and impregnated at room temperature for 12 hours; then the deionized water was removed by rotary evaporation, and the mixture was dried at 80°C under vacuum conditions to constant weight. Finally, the mixture was calcined in a muffle furnace at 480°C for 7 hours to obtain a catalyst, which was designated as 1% Pd-1% In / SAF-1. The BET specific surface area of ​​the catalyst was 232m 2 / g, pore size is 14.7nm. The method for gas phase synthesis of 2,3,3,3-tetrafluoropropene by the present embodiment catalyst is: 10mL catalyst is loaded in the reaction tube of fixed bed reactor, 2-chloro-3,3,3-trifluoropropene after gasification is passed through, and hydrogen fluoride gas and chlorine are passed through to react, reaction temperature is 350 DEG C, 2-chloro-3,3,3-trifluoropropene flow rate is 10mL / minute, hydrogen fluoride gas flow rate is 60mL / minute, and chlorine flow rate is 0.5mL / minute. The reacted material is sampled after washing with 0.5mol / L sodium hydroxide aqueous solution and deionized water, and reactants and products are analyzed online by gas chromatography (Shimadzu GC-2014, Japan) equipped with a hydrogen flame ionization detector (FID detector) and a chromatographic column GS-GASPRO (30m × 0.32mm). The results are shown in Table 1.

[0029] Example 2

[0030] The catalyst composition of this embodiment is the same as that of embodiment 1, except that in step 1 of the catalyst preparation, 10 g of triisopropylsilanol is used to replace trimethylsilanol. The other preparation processes are the same as those of embodiment 1 to obtain a catalyst, which is designated as 1% Pd-1% In / SAF-2. The BET specific surface area of ​​the catalyst is 224 m 2 / g, and the pore size is 13.6nm.

[0031] The method for using the catalyst of this example to synthesize 2,3,3,3-tetrafluoropropene in the gas phase is the same as that in Example 1. The results are shown in Table 1.

[0032] Example 3

[0033] The catalyst composition of this embodiment is the same as that of embodiment 1, except that in step 1 of the catalyst preparation, 5 g of dimethylsilanediol is used to replace trimethylsilanol. The other preparation processes are the same as those of embodiment 1 to obtain a catalyst, which is designated as 1% Pd-1% In / SAF-3. The BET specific surface area of ​​the catalyst is 231 m 2 / g, and a pore size of 13.5nm. The method for using the catalyst of this example to synthesize 2,3,3,3-tetrafluoropropene in gas phase is the same as that of Example 1. The results are shown in Table 1.

[0034] Example 4

[0035] In the catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene in this embodiment, the loading amounts of Pd and In are respectively Pd 0.5% and In 1%, and the rest of the composition is the same as in Example 1. The difference between the preparation method of the catalyst and that of Example 1 is that 0.84 g of chloropalladic acid is weighed in step 2. The rest of the preparation process is the same as in Example 1 to obtain a catalyst, designated as 0.5% Pd-1% In / SAF-1. The BET specific surface area of ​​the catalyst is 229 m 2 / g, and the pore size is 13.8nm.

[0036] The method for using the catalyst of this example to synthesize 2,3,3,3-tetrafluoropropene in the gas phase is the same as that in Example 1. The results are shown in Table 1.

[0037] Example 5

[0038] In the catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene in this embodiment, the loading amounts of Pd and In are respectively Pd 2% and In 0.5%, and the rest of the composition is the same as in Example 1. The difference between the preparation method of the catalyst and that of Example 1 is that in step 2, the amount of chloropalladic acid added is 3.34 g and the amount of indium nitrate added is 0.87 g. The rest of the preparation process is the same as in Example 1, and the catalyst is obtained, which is designated as 2% Pd-0.5% In / SAF-1. The BET specific surface area of ​​the catalyst is 233 m 2 / g, and the pore size is 14.3nm.

[0039] The method for using the catalyst of this example to synthesize 2,3,3,3-tetrafluoropropene in the gas phase is the same as that in Example 1. The results are shown in Table 1.

[0040] Example 6

[0041] The catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropylene in this embodiment includes a carrier, and an active component Pd and an auxiliary agent Zn supported on the carrier. The carrier is aluminum fluoride modified with silanol and treated at low temperature. The loading amounts of Pd and Zn are 1% Pd and 1% In, respectively, based on the mass percentage of aluminum fluoride. The difference between the preparation method of the catalyst and that of Example 1 is that the indium nitrate in step 2 is replaced with 4.55g zinc nitrate hexahydrate. The other preparation processes are the same as those of Example 1, and the catalyst is obtained, which is recorded as 1% Pd-1% Zn / SAF-1. The BET specific surface area of ​​the catalyst is 224m 2 / g, and the pore size is 13.9nm.

[0042] The method for using the catalyst of this example to synthesize 2,3,3,3-tetrafluoropropene in the gas phase is the same as that in Example 1. The results are shown in Table 1.

[0043] Example 7

[0044] The catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene in this embodiment includes a carrier, and an active component Pd and an auxiliary agent Sb supported on the carrier. The carrier is aluminum fluoride modified with silanol and treated at low temperature. The loading amounts of Pd and Sb are 1% Pd and 1% In, respectively, based on the mass percentage of aluminum fluoride. The difference between the preparation method of the catalyst and that of Example 1 is that the indium nitrate in step 2 is replaced with 2.53g antimony nitrate. The other preparation processes are the same as those of Example 1, and the catalyst is obtained, which is recorded as 1% Pd-1% Sb / SAF-1. The BET specific surface area of ​​the catalyst is 234m 2 / g, and the pore size is 14.6nm.

[0045] The method for using the catalyst of this example to synthesize 2,3,3,3-tetrafluoropropene in the gas phase is the same as that in Example 1. The results are shown in Table 1.

[0046] Example 8

[0047] The composition and preparation method of the catalyst in this example are the same as those in Example 1. The difference between the method for using the catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene and Example 1 is that the chlorine gas introduced in the reaction is replaced with oxygen at an oxygen flow rate of 0.5 mL / min. The other steps are the same as those in Example 1. The results are shown in Table 1.

[0048] Example 9

[0049] The catalyst composition of this embodiment is the same as that of Example 1, except that 100 g of cyclohexane is used to replace toluene in step 1 of the catalyst preparation. The other preparation processes are the same as those of Example 1 to obtain a catalyst, which is designated as 1% Pd-1% In / SAF-4. The BET specific surface area of ​​the catalyst is 224 m 2 / g, and the pore size is 14.2nm.

[0050] The method for using the catalyst of this example to synthesize 2,3,3,3-tetrafluoropropene in the gas phase is the same as that in Example 1. The results are shown in Table 1.

[0051] Comparative Example 1

[0052] The catalyst of this comparative example differs from that of Example 1 in that the catalyst does not contain the auxiliary agent In. The other compositions and catalyst preparation methods are the same as those of Example 1. The obtained catalyst is designated as 1% Pd / SAF-1. The BET specific surface area of ​​the catalyst is 172 m 2 The catalyst was used for gas phase synthesis of 2,3,3,3-tetrafluoropropene in the same manner as in Example 1. The results are shown in Table 1.

[0053] Comparative Example 2

[0054] The composition and preparation method of the catalyst in this comparative example are the same as those in Example 1. The difference between the method of using the catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene and Example 1 is that chlorine gas is not introduced. The other steps are the same as those in Example 1. The results are shown in Table 1.

[0055] Comparative Example 3

[0056] The difference between the catalyst of this comparative example and that of Example 1 is that the aluminum fluoride is not modified with trimethylsilanol, that is, trimethylsilanol is not added in step 1 of the catalyst preparation method. The other compositions and preparation methods are the same as those of Example 1. The obtained catalyst is recorded as 1% Pd-1% In / AlF3-1, and the BET specific surface area of ​​the catalyst is 171 m 2 The catalyst was used for gas phase synthesis of 2,3,3,3-tetrafluoropropene in the same manner as in Example 1. The results are shown in Table 1.

[0057] Comparative Example 4

[0058] The catalyst composition of this comparative example is the same as that of Example 7, except that in the catalyst preparation step 1, the process of placing the obtained solution in an 8°C incubator for 6 hours is omitted. The other preparation processes are the same as those of Example 7. The obtained catalyst is recorded as 1% Pd-1% Sb / SAF-5. The BET specific surface area of ​​the catalyst is 182 m 2 The catalyst was used for gas phase synthesis of 2,3,3,3-tetrafluoropropene in the same manner as in Example 8. The results are shown in Table 1.

[0059] Comparative Example 5

[0060] The catalyst composition of this comparative example is the same as that of Example 6, except that the carrier is conventional commercially available aluminum fluoride, and the silicon modification and low-temperature treatment process of step 1 are not performed. The active component Pd and the auxiliary agent Zn are directly loaded according to the method of step 2. The obtained catalyst is recorded as 1% Pd-1% Zn / AlF3, and the BET specific surface area of ​​the catalyst is 168m 2 The catalyst was used for gas-phase synthesis of 2,3,3,3-tetrafluoropropene in the same manner as in Example 8. The results are shown in Table 1.

[0061] Table 1

[0062]

[0063]

[0064] As can be seen from Table 1, the catalyst prepared by the method provided by the present invention is used for the gas-phase synthesis of 2,3,3,3-tetrafluoropropene from 2-chloro-3,3,3-trifluoropropene as a raw material. There is no obvious deactivation after operation for more than 72 hours, the conversion rate of 2-chloro-3,3,3-trifluoropropene is always greater than 40%, and the selectivity of 2,3,3,3-tetrafluoropropene is always maintained at more than 96%.

[0065] The catalyst prepared by the present invention has a stronger interaction between the active metal Pd and the additive, making the Pd more evenly dispersed than the catalyst prepared by using the traditional aluminum fluoride carrier. In the application of gas phase synthesis of 2,3,3,3-tetrafluoropropene using 2-chloro-3,3,3-trifluoropropene as raw material, the catalytic activity of the catalyst is effectively improved. The present invention modifies the aluminum fluoride carrier by using silanol and performs low temperature treatment on the modified carrier, so that the specific surface area of ​​the modified carrier exceeds 220m 2 / g, which improves the diffusion rate of reactants and the availability of active sites, thereby achieving higher thermal stability and reducing the formation of carbon deposits.

[0066] Comparative Example 1 demonstrates that, during the catalyst preparation process, the addition of promoter metals not only enhances the activity and selectivity of the catalyst, but also weakens the acidity of the overall catalyst, reduces the formation of carbon deposits, and meets the requirements of specific reactions.

[0067] Comparative Example 2 demonstrates that introducing a certain amount of chlorine or oxygen into the reaction of gas-phase synthesis of 2,3,3,3-tetrafluoropropene using 2-chloro-3,3,3-trifluoropropene as a raw material can effectively act as a catalyst degradation inhibitor and effectively improve the selectivity of the target product.

[0068] Comparative Examples 3 to 5 demonstrate that the aluminum fluoride support needs to be subjected to silanol modification and low-temperature treatment in sequence in order to effectively and synergistically improve the catalytic performance of the catalyst.

Claims

1. A catalyst for gas phase synthesis of 2,3,3,3-tetrafluoropropene, characterized in that: The catalyst uses silicon-modified aluminum fluoride as a carrier, loaded with an active component Pd and an auxiliary agent, wherein the auxiliary agent is any one or more of In, Zn, Mg, and Sb; based on the mass of the carrier as 100%, the loading amount of the active component is 0.5% to 2.5%, and the loading amount of the auxiliary agent is 0.1% to 5%; The catalyst is prepared by the following method: Step 1: mixing aluminum fluoride with a solvent, stirring at 60-80° C. for 6-24 hours to fully disperse the aluminum fluoride, then adding silanol and continuing to stir until the silanol fully covers the surface of the aluminum fluoride, standing at 5-10° C. for 5-8 hours, and then rotary evaporating to remove the solvent. The resulting solid is dried under vacuum conditions, and finally calcined at 300-500° C. for 2-8 hours to obtain silicon-modified aluminum fluoride; the silanol is any one or more of trimethylsilanol, triethylsilanol, triisopropylsilanol, and dimethylsilanediol, and the amount of the silanol added is 2% to 20% of the mass of the aluminum fluoride; Step 2: Add the precursor of the active component and the precursor of the auxiliary component to deionized water in sequence, mix them evenly, add silicon-modified aluminum fluoride for impregnation, then remove the deionized water by rotary evaporation, dry to constant weight under vacuum conditions, and finally calcine at 300-550°C for 4-10 hours to obtain a catalyst.

2. The catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that The auxiliary agent is any one or more of In and Sb; based on the mass of the carrier being 100%, the loading amount of the active component is 0.5% to 1%, and the loading amount of the auxiliary agent is 0.5% to 1%.

3. The catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that In step 1, the silanol is any one of trimethylsilanol and triisopropylsilanol; the amount of the silanol added is 5% to 10% of the mass of aluminum fluoride.

4. The catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that In step 1, the solvent is any one or more of cyclohexane, toluene, and dimethylformamide.

5. The catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that In step 1, the sintering process is carried out at 400° C. for 3 to 6 hours.

6. The catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that In step 2, the precursor of the active component is any one of chloropalladic acid, palladium nitrate, and dinitrosodichloropalladium, and the precursor of the auxiliary component is the nitrate of the corresponding auxiliary.

7. The catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that In step 2, the immersion temperature is 25 to 40° C. and the immersion time is 10 to 24 hours.

8. The catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that In step 2, the sintering process is carried out at 450-500° C. for 6-8 hours.

9. The catalyst for gas-phase synthesis of 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that: The BET specific surface area of ​​the catalyst is 180 to 240 m 2 / g, and the pore size is between 13 and 16 nm.

10. Use of the catalyst according to any one of claims 1 to 9 for gas-phase synthesis of 2,3,3,3-tetrafluoropropene, characterized in that: Hydrogen fluoride gas and gasified 2-chloro-3,3,3-trifluoropropene are introduced into a fixed-bed reactor loaded with a catalyst, and chlorine or oxygen is introduced into the reactor to react at 280-420° C. with a contact time of 16-34 seconds. The flow rate of the 2-chloro-3,3,3-trifluoropropene is 5-20 mL / min, the flow rate of HF is 50-100 mL / min, and the flow rate of the chlorine or oxygen is 5%-10% of the flow rate of the 2-chloro-3,3,3-trifluoropropene.

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