Fluorination catalyst and method for preparing 2-chloro-3, 3, 3-trifluoropropene

Abstract

The invention relates to a fluorination catalyst and a method for preparing 2-chloro-3, 3, 3-trifluoropropene. The fluorination catalyst is prepared by the following steps: 1) loading a water-soluble trivalent chromium salt on aluminum oxide according to a molar ratio of Cr to Al of 1: (5-20) by an impregnation method to obtain aluminum oxide loaded with the water-soluble trivalent chromium salt; 2) drying the aluminum oxide loaded with the water-soluble trivalent chromium salt, and roasting at 200-300 DEG C for 2-8 hours to obtain a catalyst precursor; and 3) fluorinating the catalyst precursor with hydrogen fluoride to prepare the fluorination catalyst. The catalyst disclosed by the invention is high in stability, and can be used for preparing 2-chloro-3, 3, 3-trifluoropropene with a simple process and high conversion rate and selectivity.

Description

Technical Field

[0001] The present invention belongs to the field of chemical synthesis. Specifically, the present invention relates to a fluorination catalyst and a method for preparing 2-chloro-3,3,3-trifluoropropene. Background Art

[0002] Second-generation refrigerants such as pentafluoroethane (HFC-125) and 1,1,1,2-tetrafluoroethane (HFC-134a) are potent global warming substances, which have caused concerns among countries about the possible global warming impact caused by their spread.

[0003] The fourth-generation refrigerant 2,3,3,3-tetrafluoropropene is considered an ideal substitute for HFC-134a because its ozone depletion potential (ODP) is 0, its global warming potential (GWP) is 4, and its refrigeration performance is similar to that of HFC-134a. It has become a research hotspot in the fluorine-containing chemical industry around the world. 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is an important intermediate for preparing HFO-1234yf.

[0004] U.S. Patent US 9902671B2 discloses a method for gas-phase preparation of HCFO-1233xf by reacting a chlorine-containing hydrocarbon selected from 1,1,2,3-tetrachloropropene, 1,1,1,2,3-pentachloropropane (HCC-240db), and 2,3,3,3-tetrachloropropene or a mixture thereof with hydrogen fluoride in the presence of a fluorination catalyst and at least one stabilizer, wherein the catalyst is Cr2O3 and the stabilizer is diisopropylamine. The addition of the stabilizer in this method will affect the subsequent separation of the product.

[0005] Chinese Patent Application CN 1028690637A discloses a method for catalytic fluorination of 1,1,1,2,3-pentachloropropane and / or 1,1,2,2,3-pentachloropropane into HCFO-1233xf in the liquid phase, but this method introduces a stabilizer and has a high reaction pressure, which is not conducive to subsequent separation and scale-up production.

[0006] Chinese Patent Application CN 111 559954A discloses a method that first uses 3,3,3-trifluoropropene as a raw material to carry out a photochlorination reaction with chlorine to prepare 2,3-dichloro-1,1,1-trifluoropropane, and then uses 2,3-dichloro-1,1,1-trifluoropropane as a raw material to carry out a gas-phase catalytic dehydrochlorination reaction with oxygen-deficient nitrogen to obtain 2-chloro-3,3,3-trifluoropropene. This method has two reaction steps, and the efficiency is limited by the efficiency of each individual step, and the intermediate product also needs to be rectified and purified, increasing the processing cost.

[0007] Accordingly, there is a need in the art for a method for preparing 2-chloro-3,3,3-trifluoropropene with simple process, high conversion rate and selectivity. SUMMARY OF THE INVENTION

[0008] One object of the present application is to provide a method for preparing 2-chloro-3,3,3-trifluoropropene with simple process, high conversion rate and selectivity.

[0009] The inventors of the present application have found that: by preparing a specific catalyst and adopting a certain preparation process, the advantages of simple process, high conversion rate and selectivity can be achieved.

[0010] Therefore, according to the first aspect, the present invention provides a fluorination catalyst, which is characterized by being prepared by the following steps:

[0011] 1) A water-soluble trivalent chromium salt is loaded on alumina by an impregnation method according to a molar ratio of Cr:A of 1:5-20 to obtain alumina loaded with the water-soluble trivalent chromium salt;

[0012] 2) The alumina loaded with the water-soluble trivalent chromium salt is first dried and then calcined at 200-300 °C for 2-8 hours to obtain a catalyst precursor; and

[0013] 3) The catalyst precursor is fluorinated with hydrogen fluoride to obtain a fluorination catalyst.

[0014] According to the second aspect, the present invention provides a method for preparing 2-chloro-3,3,3-trifluoropropene, which is characterized by comprising the following steps:

[0015] i) Preheating a pentachloropropane selected from 1,1,1,2,3-pentachloropropane and 1,1,2,2,3-pentachloropropane to a temperature of 60-240 °C; and

[0016] ii) Reacting hydrogen fluoride with the preheated pentachloropropane in the presence of the above-mentioned fluorination catalyst and a carrier gas to obtain 2-chloro-3,3,3-trifluoropropene,

[0017] wherein in step ii), the carrier gas is nitrogen and / or argon, the molar ratio of pentachloropropane to hydrogen fluoride is 1:5-30, the reaction temperature is 200-400 °C, and the space velocity is 500-2000 h -1 .

[0018] The inventors have found that: compared with the prior art, the present invention has the following beneficial effects:

[0019] 1) The catalyst of the present invention has high stability;

[0020] 2) The method for preparing 2-chloro-3,3,3-trifluoropropene according to the present invention can achieve a high conversion rate, at least 90%, and a high selectivity for 2-chloro-3,3,3-trifluoropropene, at least 90%.

[0021] 3) The raw materials used in the present invention have low costs, and the process is simple and easy to industrialize. Specific Embodiments

[0022] Some specific embodiments of the present invention will now be described for illustrative purposes and not for limitation.

[0023] Fluorination catalyst

[0024] According to the first aspect, the present invention provides a fluorination catalyst, which is characterized in that it is prepared by the following steps:

[0025] 1) A water-soluble trivalent chromium salt is loaded on alumina by an impregnation method according to a Cr:Al molar ratio of 1:5 - 20 to obtain alumina loaded with the water-soluble trivalent chromium salt.

[0026] 2) The alumina loaded with the water-soluble trivalent chromium salt is first dried and then calcined at 200 - 300 °C for 2 - 8 hours to obtain a catalyst precursor; and

[0027] 3) The catalyst precursor is fluorinated with hydrogen fluoride to obtain a fluorination catalyst.

[0028] Preferably, before impregnation, the alumina is pressed into a mold, crushed and sieved to obtain porous alumina particles.

[0029] Preferably, the specific surface area of the porous alumina particles is 200 - 400 m 2 / g.

[0030] The specific surface area described herein can be measured by the gas adsorption method (BET method) according to ISO 9277:2010.

[0031] The water-soluble trivalent chromium salt described herein refers to a trivalent chromium salt with a solubility in water of not less than 10 g / 100 ml of water.

[0032] Preferably, the water-soluble trivalent chromium salt is selected from chromium nitrate, chromium chloride, chromium sulfate, and chromium acetate.

[0033] More preferably, the water-soluble trivalent chromium salt is chromium nitrate.

[0034] Preferably, the water-soluble trivalent chromium salt is in the form of a hydrate.

[0035] Preferably, in step 1), the Cr:Al molar ratio is 1:6 - 15. More preferably, in step 1), the Cr:Al molar ratio is 1:8 - 10.

[0036] In step 2), the drying can be carried out in a suitable manner.

[0037] Preferably, in step 2), the drying is carried out by maintaining at 80 - 110 °C for 1 - 4 hours.

[0038] The drying can be carried out in suitable equipment, such as in an oven.

[0039] The calcination can be carried out in suitable equipment, such as in a muffle furnace.

[0040] Preferably, it is calcined at 220 - 280 °C for 3 - 6 hours.

[0041] More preferably, it is calcined at 230 - 260 °C for 4 - 5 hours

[0042] The fluorination can be carried out in suitable equipment, such as in a fixed - bed reactor or a stirred - tank reactor.

[0043] Preferably, the fluorination is carried out in a fixed - bed tubular reactor.

[0044] Preferably, the fluorination is carried out at 150 - 300 °C for 8 - 24 hours. The catalyst of the present invention has high stability.

[0045] Method for preparing 2-chloro-3,3,3-trifluoropropene

[0046] According to a second aspect, the present invention provides a method for preparing 2 - chloro - 3,3,3 - trifluoropropene, characterized by comprising the following steps:

[0047] i) Preheating a pentachloropropane selected from 1,1,1,2,3 - pentachloropropane and 1,1,2,2,3 - pentachloropropane to a temperature of 60 - 240 °C; and

[0048] ii) Reacting hydrogen fluoride and the preheated pentachloropropane in the presence of the above - mentioned fluorination catalyst and a carrier gas to obtain 2 - chloro - 3,3,3 - trifluoropropene,

[0049] wherein in step ii), the carrier gas is nitrogen and / or argon, the molar ratio of pentachloropropane to hydrogen fluoride is 1:5 - 30, the reaction temperature is 200 - 400 °C, and the space velocity is 500 - 2000 h -1 .

[0050] Preferably, in step i), the pentachloropropane is preheated to a temperature of 120 - 180 °C.

[0051] Preferably, in step ii), the molar ratio of pentachloropropane to hydrogen fluoride (HF) is 1:10 - 20.

[0052] More preferably, in step ii), the molar ratio of pentachloropropane to hydrogen fluoride is 1:10.

[0053] In the method of the present invention, nitrogen and / or argon is used as the carrier gas, which can play a role in anti-coking of the catalyst.

[0054] Preferably, the molar ratio of the carrier gas to hydrogen fluoride is 1:5 - 20. More preferably, the molar ratio of the carrier gas to hydrogen fluoride is 1:5 - 10.

[0055] Preferably, the reaction in step ii) is carried out in a fixed-bed tubular reactor.

[0056] Preferably, in step ii), the reaction temperature is 250 - 350 °C. More preferably, in step ii), the reaction temperature is 280 - 320 °C.

[0057] Preferably, the reaction space velocity is 500 - 1000 h -1 .

[0058] In some embodiments, step ii) is carried out under atmospheric pressure or pressurized conditions.

[0059] The method for preparing 2-chloro-3,3,3-trifluoropropene of the present invention can achieve a high conversion rate, even up to 100%, and has a relatively high selectivity for 2-chloro-3,3,3-trifluoropropene, even exceeding 97%.

[0060] As used in this application, "comprising" and "including" cover the cases that also contain or include other elements not explicitly mentioned and the cases consisting of the mentioned elements.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. When the definition of a term in this specification conflicts with the meaning commonly understood by those skilled in the art to which the present invention pertains, the definition in this specification shall prevail.

[0062] Unless otherwise specified, all numerical values expressing amounts of ingredients, temperatures, etc. used in the specification and claims are understood to be modified by the term "about". Therefore, unless there is a contrary indication, the numerical parameters set forth herein are approximate values that can vary as required to obtain the desired performance.

[0063] Examples

[0064] The concept of the present invention and the resulting technical effects will be further described below in conjunction with embodiments, so that those skilled in the art can fully understand the purpose, features, and effects of the present invention. It is not difficult for those skilled in the art to understand that the embodiments here are only for illustrative purposes, and the scope of the present invention is not limited thereto. If not specified explicitly, the raw materials used in the embodiments are those commonly used in the art.

[0065] Example 1

[0066] Prepare a fluorination catalyst as described below.

[0067] Weigh 13.08 g of Cr(NO3)3·9H2O and 8.34 g of Al2O3 porous particles (specific surface area is 200 m 2 / g) according to the molar ratio of Cr to Al of 1:5. Dissolve Cr(NO3)3·9H2O in 10 ml of water, and then load it onto the surface of Al2O3 by the impregnation method to obtain 20 ml of alumina particles loaded with Cr(NO3)3.

[0068] First, place the prepared alumina particles loaded with Cr(NO3)3 in an oven for drying (maintain at 100 °C for 2 hours), then calcine them in a muffle furnace at 240 °C for 4 hours. Then, take 10 ml of the calcined alumina particles loaded with Cr(NO3)3 and put them into a fixed-bed tubular reactor with an inner diameter of 15 mm. Heat up to 200 °C and introduce hydrogen fluoride gas for 8 hours to prepare the fluorination catalyst.

[0069] Prepare 2-chloro-3,3,3-trifluoropropene as described below.

[0070] Introduce nitrogen, HF, and 1,1,1,2,3-pentachloropropane (HCC-240db) into the above fixed-bed tubular reactor to carry out the reaction, controlling the molar ratio as N2:HF:HCC-240db = 10:100:10, and the space velocity as 500 h -1 , and the reaction temperature is 300 °C.

[0071] After the reaction product is washed with water and alkali to remove acidic gases, analyze the conversion rate of HCC-240db by gas chromatography as 100%, and the selectivity of HCFO-1233xf as 92.1%.

[0072] Example 2

[0073] This example is carried out with reference to Example 1, the difference being that the molar ratio of Cr to Al is 1:10.

[0074] Weigh 6.54 g of Cr(NO3)3·9H2O and 8.34 g of Al2O3 porous particles (specific surface area is 200 m 2 / g). Dissolve Cr(NO3)3·9H2O in 10 ml of water, and then load it onto the surface of Al2O3 by the impregnation method to obtain 20 ml of alumina particles loaded with Cr(NO3)3.

[0075] The prepared alumina particles loaded with Cr(NO3)3 were first dried in an oven (kept at 100 °C for 2 hours) and then calcined in a muffle furnace at 240 °C for 4 hours. Then, 10 ml of the calcined alumina particles loaded with Cr(NO3)3 were placed into a fixed-bed tubular reactor with an inner diameter of 15 mm, heated to 200 °C, and hydrogen fluoride gas was introduced for 8 hours to obtain the fluorination catalyst.

[0076] Nitrogen, HF, and 1,1,1,2,3-pentachloropropane (HCC-240db) were introduced into the above fixed-bed tubular reactor for reaction, controlling the molar ratio as N2:HF:HCC-240db = 10:100:10, and the space velocity was 500 h -1 , and the reaction temperature was 300 °C.

[0077] After the reaction products were washed with water and alkali to remove acidic gases, the conversion rate of HCC-240db was analyzed by a gas chromatograph to be 100%, and the selectivity of HCFO-1233xf was 97.2%.

[0078] The reaction products were continuously analyzed. After 500.87 hours of continuous operation, the conversion rate of HCC-240db was still 100%, and the selectivity of HCFO-1233xf was at least 92.03%.

[0079] Example 3

[0080] This example was carried out with reference to Example 1, the difference being that the molar ratio of Cr to Al was 1:20.

[0081] Weigh 3.27 g of Cr(NO3)3·9H2O and 8.34 g of Al2O3 (specific surface area of 200 m 2 / g) according to the molar ratio of Cr to Al of 1:20. Dissolve Cr(NO3)3·9H2O in 10 ml of water, and then load it onto the surface of Al2O3 by the impregnation method to obtain 20 ml of alumina particles loaded with Cr(NO3)3.

[0082] The prepared alumina particles loaded with Cr(NO3)3 were first dried in an oven (kept at 100 °C for 2 hours) and then calcined in a muffle furnace at 240 °C for 4 hours. Then, 10 ml of the calcined alumina particles loaded with Cr(NO3)3 were placed into a fixed-bed tubular reactor with an inner diameter of 15 mm, heated to 200 °C, and hydrogen fluoride gas was introduced for 8 hours to obtain the fluorination catalyst.

[0083] 2-Chloro-3,3,3-trifluoropropene was prepared as described below.

[0084] Nitrogen, HF, and 1,1,1,2,3-pentachloropropane (HCC-240db) were introduced into the above fixed-bed tubular reactor for reaction, controlling the molar ratio as N2:HF:HCC-240db = 10:100:10, and the space velocity was 500 h -1 , and the reaction temperature was 300 °C.

[0085] After the reaction product was washed with water and alkali to remove acidic gases, the conversion rate of HCC-240db was analyzed by gas chromatography to be 98.0%, and the selectivity of HCFO-1233xf was 95.2%.

[0086] Example 4

[0087] This example was carried out with reference to Example 2, the difference being that the reaction temperature of HCC-240db and hydrogen fluoride was 250 °C.

[0088] 6.54 g of Cr(NO3)3·9H2O and 8.34 g of Al2O3 (specific surface area 200 m 2 / g) were weighed according to the molar ratio of Cr and Al of 1:10. Cr(NO3)3·9H2O was dissolved in 10 ml of water, and then impregnated on the surface of Al2O3 to obtain 20 ml of alumina particles loaded with Cr(NO3)3.

[0089] The prepared alumina particles loaded with Cr(NO3)3 were first dried in an oven (kept at 100 °C for 2 hours) and then calcined in a muffle furnace at 240 °C for 4 hours. Then, 10 ml of the calcined alumina particles loaded with Cr(NO3)3 were placed into a fixed-bed tubular reactor with an inner diameter of 15 mm, heated to 200 °C, and hydrogen fluoride gas was introduced for 8 hours to prepare a fluorination catalyst.

[0090] 2-Chloro-3,3,3-trifluoropropene was prepared as described below.

[0091] Nitrogen, HF, and 1,1,1,2,3-pentachloropropane (HCC-240db) were introduced into the above fixed-bed tubular reactor for reaction, controlling the molar ratio as N2:HF:HCC-240db = 10:100:10, and the space velocity was 500 h -1 , and the reaction temperature was 250 °C.

[0092] After the final reaction product was washed with water and alkali to remove acidic gases, the conversion rate of HCC-240db was analyzed by gas chromatography to be 97.8%, and the selectivity of HCFO-1233xf was 95.3%.

[0093] Example 5

[0094] This example is carried out with reference to Example 2, the difference being that the reaction temperature of HCC-240db and hydrogen fluoride is 350 °C.

[0095] Weigh 6.54 g of Cr(NO3)3·9H2O and 8.34 g of Al2O3 (specific surface area is 200 m 2 / g) according to the molar ratio of Cr to Al of 1:10. Dissolve Cr(NO3)3·9H2O in 10 ml of water, and then load it on the surface of Al2O3 by the impregnation method to obtain 20 ml of alumina particles loaded with Cr(NO3)3.

[0096] The prepared alumina particles loaded with Cr(NO3)3 are first dried in an oven (kept at 100 °C for 2 hours) and then calcined in a muffle furnace at 240 °C for 4 hours. Then, take 10 ml of the calcined alumina particles loaded with Cr(NO3)3 and put them into a fixed-bed tubular reactor with an inner diameter of 15 mm. Heat up to 200 °C and introduce hydrogen fluoride gas for 8 hours to prepare a fluorination catalyst.

[0097] Introduce nitrogen, HF and 1,1,1,2,3-pentachloropropane (HCC-240db) to carry out the reaction, control the molar ratio as N2:HF:HCC-240db = 10:100:10, and the space velocity is 500 h -1 , and the reaction temperature is 350 °C.

[0098] After the reaction products are washed with water and alkali to remove acidic gases, the conversion rate of HCC-240db is analyzed by gas chromatography to be 100%, and the selectivity of HCFO-1233xf is 90.2%.

[0099] Example 6

[0100] This example is carried out with reference to Example 2, the difference being that the molar ratio of N2:HF:HCC-240db is 10:50:10.

[0101] Weigh 6.54 g of Cr(NO3)3·9H2O and 8.34 g of Al2O3 (specific surface area is 200 m 2 / g) according to the molar ratio of Cr to Al of 1:10. Dissolve Cr(NO3)3·9H2O in 10 m; of water, and then load it on the surface of Al2O3 by the impregnation method to obtain 20 ml of alumina particles loaded with Cr(NO3)3.

[0102] The prepared alumina particles loaded with Cr(NO3)3 were first dried in an oven (kept at 100 °C for 2 hours) and then calcined in a muffle furnace at 240 °C for 4 hours. Then, 10 ml of the calcined alumina particles loaded with Cr(NO3)3 were placed into a fixed-bed tubular reactor with an inner diameter of 15 mm, heated to 200 °C, and hydrogen fluoride gas was introduced for 8 hours to obtain a fluorination catalyst.

[0103] Nitrogen, HF, and 1,1,1,2,3-pentachloropropane (HCC-240db) were introduced for reaction, controlling the molar ratio as N2:HF:HCC-240db = 10:50:10, and the space velocity was 500 h -1 , and the reaction temperature was 300 °C.

[0104] After the reaction products were washed with water and alkali to remove acidic gases, the conversion rate of HCC-240db was analyzed to be 91.7% and the selectivity of HCFO-1233xf was 96.2% by gas chromatography.

[0105] Example 7

[0106] This example was carried out with reference to Example 2, the difference being that the molar ratio of N2:HF:HCC-240db was 10:200:10.

[0107] According to the molar ratio of Cr and Al being 1:10, 6.54 g of Cr(NO3)3·9H2O and 8.34 g of Al2O3 (specific surface area of 200 m 2 / g) were weighed. Cr(NO3)3·9H2O was dissolved in 10 ml of water and then loaded onto the surface of Al2O3 by the impregnation method to obtain 20 ml of alumina particles loaded with Cr(NO3)3.

[0108] The prepared alumina particles loaded with Cr(NO3)3 were first dried in an oven (kept at 100 °C for 2 hours) and then calcined in a muffle furnace at 240 °C for 4 hours. Then, 10 ml of the calcined alumina particles loaded with Cr(NO3)3 were placed into a fixed-bed tubular reactor with an inner diameter of 15 mm, heated to 200 °C, and hydrogen fluoride gas was introduced for 8 hours to obtain a fluorination catalyst.

[0109] Nitrogen, HF, and 1,1,1,2,3-pentachloropropane (HCC-240db) were introduced for reaction, controlling the molar ratio as N2:HF:HCC-240db = 10:200:10, and the space velocity was 500 h -1 , and the reaction temperature was 300 °C.

[0110] After the reaction products were washed with water and alkali to remove acidic gases, the conversion rate of HCC-240db was analyzed to be 100% and the selectivity of HCFO-1233xf was 93.2% by gas chromatography.

[0111] Comparative Example 1

[0112] In this comparative example, the liquid-phase catalytic fluorination method was adopted, and the catalyst was a combined ionic liquid of ethylmethylimidazolium chloride and antimony pentachloride.

[0113] 0.5 moles of 1,1,1,2,3-pentachloropropane (HCC-240db) and 0.2 moles of the catalyst (a combination of 0.2 moles of ethylmethylimidazolium chloride and 0.4 moles of antimony pentachloride, providing 0.2 moles of the fluorination complex catalyst EMIm + Sb2F 11 - EMImCl) were introduced into the reaction kettle. 151 g of 1,1,2-trichloro-2,2-difluoroethane was added to the reaction kettle as a solvent. Then HF was continuously added at a constant flow rate of 1 mol / h within 5 hours. The temperature was 133 °C and the absolute pressure was 9 bar. The set point of the regulator of the condenser was 90 °C. HCl was passed through the reaction kettle to improve mixing and assist in stripping the product. The molar ratio of HCl:240db was close to 2:1.

[0114] The conversion rate of HCC-240db was 99.7%, and the selectivity of HCFO-1233xf was 54.2%.

[0115] Although some aspects of the present invention have been shown and discussed, those skilled in the art should realize that the above aspects can be changed without departing from the principles and spirit of the present invention. Therefore, the scope of the present invention will be defined by the claims and their equivalents.

Claims

1. A fluorination catalyst, characterized in that, Prepared by the following steps: 1) A water-soluble trivalent chromium salt is loaded onto alumina by an impregnation method at a Cr:Al molar ratio of 1:5 - 20 to obtain alumina loaded with the water-soluble trivalent chromium salt; 2) The alumina loaded with the water-soluble trivalent chromium salt is first dried and then calcined at 200 - 300 °C for 2 - 8 hours to obtain a catalyst precursor; and 3) The catalyst precursor is fluorinated with hydrogen fluoride to obtain a fluorinated catalyst.

2. The fluorination catalyst according to claim 1, wherein The water-soluble trivalent chromium salt is selected from chromium nitrate, chromium chloride, chromium sulfate, and chromium acetate.

3. The fluorination catalyst according to claim 1 or 2, characterized in that, In step 1), the Cr:Al molar ratio is 1:5 - 20, preferably, the Cr:Al molar ratio is 1:8 - 10.

4. The fluorination catalyst according to any one of claims 1 to 3, characterized in that, In step 3), the fluorination is carried out at 150 - 300 °C for 8 - 24 hours.

5. A method for preparing 2-chloro-3,3,3-trifluoropropene, characterized in that, Comprising the following steps: i) Preheating a pentachloropropane selected from 1,1,1,2,3 - pentachloropropane and 1,1,2,2,3 - pentachloropropane to a temperature of 60 - 240 °C; and ii) Reacting hydrogen fluoride with the preheated pentachloropropane in the presence of the fluorinated catalyst according to any one of claims 1 to 4 and a carrier gas to obtain 2 - chloro - 3,3,3 - trifluoropropene, Among them, in step ii), the carrier gas is nitrogen and / or argon, the molar ratio of pentachloropropane to hydrogen fluoride is 1:5 - 30, the reaction temperature is 200 - 400 °C, and the space velocity is 500 - 2000 h -1 .

6. The method according to claim 5, wherein In step i), the pentachloropropane is preheated to a temperature of 120 - 180 °C.

7. The method according to claim 5 or 6, characterized in that, In step ii), the molar ratio of pentachloropropane to hydrogen fluoride is 1:10 - 20.

8. The method according to any one of claims 5 to 7, characterized in that, The molar ratio of the carrier gas to hydrogen fluoride is 1:5 - 20.

9. The method according to any one of claims 5 to 8, characterized in that The molar ratio of the carrier gas to hydrogen fluoride is 1:5 - 10.

10. The method according to any one of claims 5 to 9, characterized in that, In step ii), the reaction temperature is 250 - 350 °C, preferably, the reaction temperature is 280 - 320 °C.