Preparation method of 2, 3, 3, 3-tetrafluoropropene
By optimizing the four-step reaction route of tetrachloropropene and trifluoropropene, the problems of long synthesis route and high raw material cost of 2,3,3,3-tetrafluoropropene were solved, and efficient and low-cost industrial production was achieved.
Patent Information
- Application Number
- CN202511646411.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-11
- Publication Date
- 2026-02-06
AI Technical Summary
Existing methods for synthesizing 2,3,3,3-tetrafluoropropylene suffer from problems such as long preparation routes, difficulty in obtaining raw materials, high costs, complex processes, and unsuitability for industrial production.
By leveraging the technical advantages of the tetrachloropropene and trifluoropropene methods, a four-step reaction optimization synthesis route is adopted. Using 1,1,1,3-tetrachloropropane as a raw material, 3,3,3-trifluoropropene is prepared under the action of a gas-phase fluorination catalyst. Then, 2,3,3,3-tetrafluoropropene is finally obtained through photochlorination, saponification and thermal decomposition reactions.
It improves reaction efficiency, reduces energy consumption and production costs, and enables efficient preparation for industrial production, increasing production capacity to 10,000 tons, giving it strong industry competitiveness.
Smart Images
Figure SMS_1 
Figure SMS_2 
Figure SMS_3
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of fluorine-containing organic chemical synthesis, and particularly relates to a preparation method of 2,3,3,3-tetrafluoropropene. BACKGROUND
[0002] In recent years, with the aggravation of global warming and the promotion of environmental protection regulations, the fourth generation refrigerant 2,3,3,3-tetrafluoropropene (HFO-1234yf) gradually emerges. As a substitute for 1,1,1,2-tetrafluoroethane (HFC-134a), HFO-1234yf has excellent environmental parameters, zero ozone depletion potential and low global warming potential, and the climate performance in the life cycle is also significantly lower than that of HFC-134a. In addition to meeting the refrigeration demand, it can also reduce the impact on the environment. It is a low-carbon refrigerant product that is promoted by the state. It can not only be used in automobile air conditioning, but also be widely used in refrigerator refrigeration, heat transfer medium, foaming agent and other fields, showing its wide application prospect.
[0003] At present, the synthesis methods of 2,3,3,3-tetrafluoropropene include hexafluoropropene method, tetrachloropropene method and trifluoropropene method. The hexafluoropropene method is to use 1,1,2,3,3,3-hexafluoropropene (HFP) as a starting material, and to synthesize HFO-1234yf through hydrogenation, dehydrofluorination, hydrogenation and dehydrofluorination. The preparation route is long, the reaction raw material is not easy to obtain, the cost is high, and hydrogen needs to be introduced. The conditions are harsh, the safety is low, and it is not conducive to industrial production. The 1,1,2,3-tetrachloropropene method is to synthesize HFC-245eb from 1,1,2,3-tetrachloropropene in liquid phase, and then to generate HFO-1234yf by removing HF. This method has fewer reaction steps, but it needs to remove HF under strong alkaline conditions, and the process is complex. The trifluoropropene method uses 3,3,3-trifluoropropene as a raw material, and 2,3,3,3-tetrafluoropropene is prepared through four steps of photochlorination, liquid phase fluorination and liquid phase de-HCl. However, the cost of raw materials is high, and it is not suitable for industrial production. SUMMARY
[0004] To solve the above technical problems, the present application provides a preparation method of 2,3,3,3-tetrafluoropropene, which optimizes the synthesis route and process conditions to improve the reaction efficiency. The process is simple, the energy consumption is low, the raw materials are easy to obtain and the cost is low. The industrial synthesis route has strong industry competitiveness.
[0005] The specific technical scheme is as follows: A preparation method of 2,3,3,3-tetrafluoropropene, comprising the following steps: (1) Using 1,1,1,3-tetrachloropropane (TCP) and AHF as raw materials, the reaction temperature is 200-240℃ and the reaction pressure is 0.3-0.5MPa(G). A continuous gas-phase catalytic fluorination reaction is carried out in the presence of a gas-phase fluorination catalyst. The reaction product is washed with water and alkali, compressed and removed from light and heavy components, and then separated by distillation to obtain 1,1,1-trifluoropropylene (TFP) product, which is sent to the next step of the reaction. (2) 1,1,1-trifluoropropylene (TFP) and chlorine are metered and added to a photochlorination reactor. The reaction is carried out at a temperature of 20-80℃ and a pressure of 60-80kPa to generate 2,2-chloro-1,1,1-trifluoropropylene (HCFC-243db). Then, the reaction is carried out in the presence of 30% sodium hydroxide and at a temperature of 45-90℃ for 1.5-3h. The gaseous product is separated by distillation to obtain 2-chloro-3,3,3-trifluoropropylene (HCFO-1233xf), which is then sent to the next step of the reaction. (3) 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), HF and catalyst are metered and added to the reactor. The reaction is carried out at 20-80℃ for 4-5 hours. The reaction product is purified by distillation to obtain 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), which is then sent to the next step of the reaction. The catalyst is TiCl4 or SbCl5. (4) 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and dilution gas are preheated to 600-750℃ and then put into the reactor for thermal cracking reaction for 4-6 hours. The product is obtained by distillation to remove light and heavy components and drying. The dilution gas is HF, N2 or water vapor.
[0006] Preferably, in step (1), the molar ratio of 1,1,1,3-tetrachloropropane (TCP) to AHF is 30-50:1.
[0007] Preferably, in step (1), the gas-phase fluorination catalyst is chromium trioxide.
[0008] Preferably, in step (2), the molar ratio of chlorine to 1,1,1-trifluoropropylene (TFP) is 1-5:1.
[0009] Preferably, in step (2), the molar ratio of NaOH to 2,2-chloro-1,1,1-trifluoropropene (HCFC-243db) is 1-3:1.
[0010] Preferably, in step (3), the molar ratio of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) to HF is 1:8-15, and the molar ratio of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) to the catalyst is 1:0.2-0.4.
[0011] Preferably, in step (3), the catalyst is SbCl5.
[0012] More preferably, in step (4), the molar ratio of the dilution gas to 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) is 10-30:1.
[0013] This invention combines the technical advantages of the tetrachloropropylene and trifluoropropylene methods, and optimizes the reaction route to prepare HFO-1234yf through a four-step reaction. The reaction principle is as follows: (1) Using 1,1,1,3-tetrachloropropane (TCP) as a raw material, 3,3,3-trifluoropropene (TFP) is synthesized by gas-phase fluorination under the catalysis of a gas-phase fluorination catalyst. The chemical reaction equation is as follows:
[0014] (2) This step adopts a two-step cascade method: using TFP as raw material, 2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db) is synthesized by photochlorination. Using HCFC-243db as raw material, 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is synthesized by saponification and removal of hydrogen chloride under the action of 30% sodium hydroxide. The chemical reaction equation is as follows:
[0015] (3) Under the catalytic action of a catalyst, HCFO-1233xf is fluorinated in the liquid phase to synthesize HCFC-244bb. The chemical reaction equation is as follows:
[0016] (4) 2,3,3,3-Tetrafluoropropene (HFO-1234yf) is synthesized by deHClation of HCFO-244bb. The chemical reaction equation is as follows:
[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses tetrachloropropane (HCC-250fb) as raw material and combines the technical advantages of tetrachloropropene and trifluoropropene methods. By optimizing the synthesis route and process conditions, the reaction efficiency is improved. The process is simple and energy consumption is low. Furthermore, the low price of tetrachloropropane (HCC-250fb) further reduces production costs. The production capacity is scaled up and innovated within the industry, achieving a capacity increase to 10,000 tons. The industrial synthesis route has extremely strong industry competitiveness. Detailed Implementation
[0018] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
[0019] The method for preparing 2,3,3,3-tetrafluoropropylene of the present invention includes the following steps: (1) Using 1,1,1,3-tetrachloropropane (TCP) and AHF as raw materials, the reaction temperature is 200-240℃ and the reaction pressure is 0.3-0.5MPa(G). A continuous gas-phase catalytic fluorination reaction is carried out in the presence of a gas-phase fluorination catalyst. The reaction product is washed with water and alkali, compressed and removed from light and heavy components, and then separated by distillation to obtain 1,1,1-trifluoropropylene (TFP) product, which is sent to the next step of the reaction. (2) 1,1,1-trifluoropropylene (TFP) and chlorine are metered and added to a photochlorination reactor. The reaction is carried out at a temperature of 20-80℃ and a pressure of 60-80kPa to generate 2,2-chloro-1,1,1-trifluoropropylene (HCFC-243db). Then, the reaction is carried out in the presence of 30% sodium hydroxide and at a temperature of 45-90℃ for 1.5-3h. The gaseous product is separated by distillation to obtain 2-chloro-3,3,3-trifluoropropylene (HCFO-1233xf), which is then sent to the next step of the reaction. (3) 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), HF and catalyst are metered and added to the reactor. The reaction is carried out at 20-80℃ for 4-5 hours. The reaction product is purified by distillation to obtain 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), which is then sent to the next step of the reaction. The catalyst is TiCl4 or SbCl5. (4) 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and dilution gas are preheated to 600-750℃ and then put into the reactor for thermal cracking reaction for 4-6 hours. The product is obtained by distillation to remove light and heavy components and drying. The dilution gas is HF, N2 or water vapor.
[0020] Examples 1-4 2,3,3,3-Tetrafluoropropylene is prepared according to the following method. (1) Using 1,1,1,3-tetrachloropropane (TCP) and AHF as raw materials, a continuous gas-phase catalytic fluorination reaction was carried out in the presence of chromium trioxide as a gas-phase fluorination catalyst. The reaction product was washed with water and alkali, compressed and removed from light and heavy components, and then separated by distillation to obtain 1,1,1-trifluoropropylene (TFP) product, which was sent to the next step of the reaction. In Examples 1-4, the process parameters for step (1) are shown in Table 1.
[0021] Table 1 Process parameters for step (1) Item Reaction temperature / °C Reaction pressure / MPa (G) Molar ratio of TCP to AHF Example 1 200 0.4 35:1 Example 2 220 0.3 40:1 Example 3 240 0.5 30:1 Example 4 220 0.4 50:1 The TCP conversion rate and TFP selectivity were calculated, and the results are shown in Table 2.
[0022] Table 2 Selective Evaluation Results of TCP Conversion Rate and TFP Item TCP conversion / % TFP selectivity / % Example 1 100 88.58 Example 2 100 86.64 Example 3 100 85.50 Example 4 100 89.38 As shown in Table 2, in step (1), the TCP conversion rate can reach 100%, and the TFP selectivity is greater than 90%.
[0023] (2) 1,1,1-trifluoropropene (TFP) and chlorine are metered and added to a photochlorination reactor. The reaction is carried out at a certain temperature and pressure to generate 2,2-chloro-1,1,1-trifluoropropene (HCFC-243db). Then, the reaction is carried out in the presence of 30% sodium hydroxide. The gaseous product is separated by distillation to obtain 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), which is then sent to the next step of the reaction. In Examples 1-4, the process parameters for step (2) are shown in Table 3.
[0024]
[0025] The conversion rate of TFP, the selectivity of HCFC-243db and HCFO-1233x were calculated, and the results are shown in Table 4.
[0026] Table 4. Results of TFP conversion rate, HCFC-243db and HCFO-1233x selectivity
[0027] As shown in Table 4, in this step, the conversion rate of HCFC-243db is ≥99%, and the selectivity of HCFC-1233xfde is ≥95%. (3) 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), HF and catalyst are metered and added to the reactor for reaction. The reaction product is distilled to remove light and heavy components to obtain 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), which is then sent to the next reaction step. In Examples 1-4, the process parameters for step (3) are shown in Table 5.
[0028] Table 5 Process parameters for step (3)
[0029] The conversion rate of HCFC-1233xf and the selectivity of HCFC-244bb were analyzed by gas chromatography, and the results are shown in Table 6.
[0030] Table 6. Conversion rate of HCFC-1233xf and selectivity of HCFC-244bb
[0031] As shown in Table 6, the conversion rate of HCFC-1233xf is ≥98%, and the selectivity of HCFC-244bb is ≥92%.
[0032] (4) 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and dilution gas are preheated and then fed into the reactor for thermal cracking reaction. The product is then dried after distillation to remove light and heavy components, and 2,3,3,3-tetrafluoropropene (HFO-1234yf) is obtained. In Examples 1-4, the process parameters for step (4) are shown in Table 7.
[0033] Table 7 Process parameters for step (4)
[0034] The obtained reaction products were analyzed by gas chromatography to determine the conversion rate of HCFC-244bb and the selectivity of HFO-1234yf. The results are shown in Table 8.
[0035] Table 8. Evaluation results of HCFC-244bb conversion rate and TFPHFO-1234yf selectivity.
[0036] As shown in Table 8, the conversion rate of HCFC-244bb is ≥95%, and the selectivity of HFO-1234yf is ≥90%.
[0037] In summary, this invention uses tetrachloropropane (HCC-250fb) as a raw material to prepare HFO-1234yf through a four-step reaction. Each step exhibits high conversion rates of the raw materials, good product selectivity, and high route efficiency.
Claims
1. A method for preparing 2,3,3,3-tetrafluoropropylene, characterized in that, Includes the following steps: (1) Using 1,1,1,3-tetrachloropropane and AHF as raw materials, the reaction temperature is 200-240℃ and the reaction pressure is 0.3-0.5MPa(G). A continuous gas-phase catalytic fluorination reaction is carried out in the presence of a gas-phase fluorination catalyst. The reaction product is washed with water and alkali, compressed and removed from light and heavy components, and then separated by distillation to obtain 1,1,1-trifluoropropylene product, which is then sent to the next reaction step. (2) After metering 1,1,1-trifluoropropylene and chlorine, add them to the photochlorination reactor and react at a temperature of 20-80℃ and a pressure of 60-80kPa to generate 2,2-chloro-1,1,1-trifluoropropylene. Then, saponify the product under the action of 30% sodium hydroxide for 1.5-3h at 45-90℃. After distillation to remove light and heavy phases, 2-chloro-3,3,3-trifluoropropylene is obtained and sent to the next step of the reaction. (3) 2-chloro-3,3,3-trifluoropropene, HF and catalyst are added to the reactor after metering and reacted at 20-80℃ for 4-5h. The reaction product is then distilled to remove light and heavy components to obtain 2-chloro-1,1,1,2-tetrafluoropropane, which is then sent to the next step of the reaction. The catalyst is TiCl4 or SbCl5. (4) 2-chloro-1,1,1,2-tetrafluoropropane and dilution gas are preheated to 600-750°C and then put into the reactor for thermal cracking reaction for 4-6 hours. The product is obtained by distillation to remove light and heavy components and drying. The dilution gas is HF, N2 or water vapor.
2. The method for preparing 2,3,3,3-tetrafluoropropylene according to claim 1, characterized in that: In step (1), the molar ratio of 1,1,1,3-tetrachloropropane and AHF is 30-50:
1.
3. The method for preparing 2,3,3,3-tetrafluoropropylene according to claim 1 or 2, characterized in that: In step (1), the gas-phase fluorination catalyst is chromium trioxide.
4. The method for preparing 2,3,3,3-tetrafluoropropylene according to claim 1, characterized in that: In step (2), the molar ratio of chlorine and 1,1,1-trifluoropropylene is 1-5:
1.
5. The method for preparing 2,3,3,3-tetrafluoropropylene according to claim 1 or 4, characterized in that: In step (2), the molar ratio of NaOH to 2,2-chloro-1,1,1-trifluoropropylene is 1-3:
1.
6. The method for preparing 2,3,3,3-tetrafluoropropylene according to claim 1, characterized in that: In step (3), the molar ratio of 2-chloro-3,3,3-trifluoropropene to HF is 1:8-15, and the molar ratio of 2-chloro-3,3,3-trifluoropropene to catalyst is 1:0.2-0.
4.
7. The method for preparing 2,3,3,3-tetrafluoropropylene according to claim 1 or 6, characterized in that: In step (3), the catalyst is SbCl5.
8. The method for preparing 2,3,3,3-tetrafluoropropylene according to claim 1, characterized in that: In step (4), the molar ratio of the dilution gas to 2-chloro-1,1,1,2-tetrafluoropropane is 10-30:1.