Process for the production of 2,3,3,3-tetrafluoropropene

Abstract

The present invention relates to a process for the production of 2,3,3,3-tetrafluoropropene comprising the steps of: i) contacting 2-chloro-3,3,3-trifluoropropene with gaseous hydrofluoric acid in the presence of a catalyst in a first reactor to produce a stream A comprising 2,3,3,3-tetrafluoropropene, HF and unreacted 2-chloro-3,3,3-trifluoropropene; and ii) contacting hydrofluoric acid with at least one chlorinated compound selected from 1,1,1,2,3-pentachloropropane, 2,3-dichloro-1,1,1-trifluoropropane and 1,1,2,3-tetrachloropropene in the gas phase and optionally in the presence of a catalyst in a second reactor to produce a stream B comprising 2-chloro-3,3,3-trifluoropropene; characterized in that the stream A obtained in step i) is fed to the second reactor for step ii); and the temperature at which step i) is carried out is not more than the temperature at which step ii) is carried out.

Description

Technical Field

[0001] This invention relates to a method for producing fluorinated olefins. In particular, this invention relates to a method for producing 2,3,3,3-tetrafluoropropylene. Background Technology

[0002] Halogenated hydrocarbons, particularly fluorinated hydrocarbons such as hydrofluoroolefins, are compounds having structures that allow them to be used as monomers or starting materials for functional polymers. Hydrofluoroolefins, such as 2,3,3,3-tetrafluoropropylene (HFO-1234yf), have attracted attention due to their promising performance as refrigerants with low global warming potential.

[0003] Methods for producing fluorinated olefins are typically carried out in the presence of starting materials such as chlorinated alkanes or chlorinated olefins, and in the presence of a fluorinating agent such as hydrogen fluoride. These methods can be carried out in the gas phase or in the liquid phase, in the absence of a catalyst or without a catalyst. For example, US 2009 / 0240090 discloses a gas-phase method for preparing 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) from 1,1,1,2,3-pentachloropropane (HCC-240db). The resulting HCFO-1233xf is then converted in the liquid phase to 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), which is then converted to 2,3,3,3-tetrafluoropropene.

[0004] WO 2013 / 088195 also discloses a method for preparing 2,3,3,3-tetrafluoropropene from 1,1,1,2,3-pentachloropropane and / or 1,1,2,2,3-pentachloropropane, comprising the following stages: (a) a catalytic reaction of 1,1,1,2,3-pentachloropropane and / or 1,1,2,2,3-pentachloropropane with HF to give a reaction mixture comprising HCl, 2-chloro-3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, unreacted HF and optionally 1,1,1,2,2-pentafluoropropane; (b) reacting the reaction mixture with HF to obtain a reaction mixture comprising HCl, 2-chloro-3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, unreacted HF and optionally 1,1,1,2,2-pentafluoropropane; (c) Separation into a first stream containing HCl and 2,3,3,3-tetrafluoropropene and a second stream containing HF, 2-chloro-3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane; and (d) catalytic reaction of the second stream to give a reaction mixture containing 2,3,3,3-tetrafluoropropene, HCl, unreacted 2-chloro-3,3,3-trifluoropropene, unreacted HF and optionally 1,1,1,2,2-pentafluoropropane; and (d) supplying the reaction mixture obtained in stage c) directly to stage a without separation.

[0005] More efficient methods for producing 2,3,3,3-tetrafluoropropylene are still needed. Summary of the Invention

[0006] This invention relates to a method for producing 2,3,3,3-tetrafluoropropylene, comprising the following stages:

[0007] i) In a first reactor, 2-chloro-3,3,3-trifluoropropene is contacted with hydrofluoric acid in the gas phase in the presence of a catalyst to produce stream A, which comprises 2,3,3,3-tetrafluoropropene, HF, and unreacted 2-chloro-3,3,3-trifluoropropene; and

[0008] ii) In a second reactor, with or without a catalyst, hydrofluoric acid is contacted in the gas phase with at least one chlorinated compound selected from 1,1,1,2,3-pentachloropropane, 2,3-dichloro-1,1,1-trifluoropropane, and 1,1,2,3-tetrachloropropene to produce stream B containing 2-chloro-3,3,3-trifluoropropene.

[0009] The feature is that the stream A obtained in stage i) is fed into the second reactor for stage ii); and the temperature implemented in stage i) is lower than or equal to the temperature implemented in stage ii).

[0010] According to a preferred embodiment, the temperature at which stage i) is implemented is lower than the temperature at which stage ii) is implemented; and the difference between the temperature at which stage i) is implemented and the temperature at which stage ii) is implemented is greater than 0.2°C, advantageously greater than 0.5°C, preferably greater than 1°C, more preferably greater than 5°C, and particularly greater than 10°C. The temperature difference is expressed in absolute value.

[0011] According to the present invention, the temperature at which stage i) is carried out is lower than or equal to, preferably lower than, the temperature at which stage ii) is carried out, thereby reducing coke formation and maintaining the activity of the catalyst used in stage i). This also reduces the formation rate of side reactions, particularly the formation of compounds HCFO-1233zdE / Z, HFO-1234zeE / Z, or HFC-245fa. Furthermore, the temperature at which stage ii) is carried out is higher than that at stage i, thereby achieving very good selectivity for HCFO-1233xf (i.e., 2-chloro-3,3,3-trifluoropropene); and also maintaining the 1232xf content at a very low level. Therefore, the present invention allows for a significant improvement in the stability of the catalyst used in stage i), while simultaneously increasing the overall productivity of the process.

[0012] According to a preferred embodiment, as these stages are implemented, the temperature of stage i) and / or the temperature of stage ii) are increased.

[0013] According to a preferred embodiment, the temperature during stage ii) remains constant, and the temperature during stage i) increases as stage i) is implemented.

[0014] According to a preferred embodiment, the temperature during stage i) remains constant, and the temperature during stage ii) increases as stage ii) is implemented.

[0015] According to a preferred embodiment, the temperature of stage i) and / or stage ii) is increased incrementally by 0.5°C to 20°C, advantageously by 0.5°C to 15°C, preferably by 0.5°C to 10°C, more preferably by 1°C to 10°C, particularly by 1°C to 8°C, and even more particularly by 3°C to 8°C.

[0016] According to a preferred embodiment, stage i) is carried out at a temperature between 330°C and 360°C; and the temperature of stage i) is increased incrementally by 0.5°C to 20°C, provided that the temperature does not exceed 360°C and remains below or equal to the temperature of stage ii).

[0017] According to a preferred embodiment, stage ii) is carried out at a temperature of 340°C to 380°C, and the temperature of stage ii) is increased incrementally by 0.5°C to 20°C, provided that the temperature does not exceed 380°C.

[0018] According to one embodiment, stage ii) is carried out in the presence of a catalyst at a temperature of 340°C to 380°C, and the temperature of stage ii) is increased incrementally by 0.5°C to 20°C.

[0019] According to a preferred embodiment, as these stages are implemented, the temperature during stage i) and the temperature during stage ii) remain constant.

[0020] According to a preferred embodiment, stages i) and ii) are carried out in the presence of a catalyst, preferably a chromium-based catalyst; in particular, the catalyst is chromium oxyfluoride, chromium oxide, or chromium fluoride.

[0021] According to a preferred embodiment, the chromium-based catalyst further includes a co-catalyst selected from Ni, Zn, Co, Mn and Mg; preferably, the content of the co-catalyst is between 0.01% and 10% based on the total weight of the catalyst.

[0022] According to a preferred embodiment, the weight content of 2,3-dichloro-3,3-difluoropropylene (HCFO-1232xf) in logistics B is less than 1%, based on the total weight of said logistics B. Detailed Implementation

[0023] This invention relates to a method for producing 2,3,3,3-tetrafluoropropylene, comprising the following stages:

[0024] i) In a first reactor, 2-chloro-3,3,3-trifluoropropene is contacted with hydrofluoric acid in the gas phase in the presence of a catalyst to produce stream A, which comprises 2,3,3,3-tetrafluoropropene, HF, and unreacted 2-chloro-3,3,3-trifluoropropene; and

[0025] ii) In a second reactor, hydrofluoric acid is contacted in the gas phase with at least one chlorinated compound selected from 1,1,1,2,3-pentachloropropane, 2,3-dichloro-1,1,1-trifluoropropane, and 1,1,2,3-tetrachloropropene, with or without a catalyst, to produce stream B containing 2-chloro-3,3,3-trifluoropropene.

[0026] Preferably, stream A may further contain 1,1,1,2,2-pentafluoropropane. Stream A may contain other compounds, such as (E / Z)-1,3,3,3-tetrafluoropropene (HFO-1234ze), 1,1,1,3,3-pentafluoropropane (HFC-245fa), or (E / Z)-1233zd (1-chloro-3,3,3-trifluoropropene). The method according to the invention is carried out under conditions that effectively minimize the content of HFO-1234ze, HFC-245fa, and HCFO-1233zd in stream A. For example, if it is contained, the content of (E / Z)-1,3,3,3-tetrafluoropropene (HFO-1234ze) may be less than 5% by weight, advantageously less than 4.5% by weight, preferably less than 4% by weight, more preferably less than 3.5% by weight, particularly less than 3% by weight, and even more particularly less than 2% by weight, based on the total weight of stream A. If it is contained, the content of 1,1,1,3,3-pentafluoropropane may be less than 8 wt%, advantageously less than 7 wt%, preferably less than 6 wt%, more preferably less than 5 wt%, particularly less than 4 wt%, and even more particularly less than 3 wt%, based on the total weight of said stream A. If it is contained, the content of HCFO-1233zd(E / Z) may be less than 4 wt%, advantageously less than 3 wt%, preferably less than 2 wt%, more preferably less than 1 wt%, particularly less than 0.8 wt%, and even more particularly less than 0.5 wt%, based on the total weight of said stream A.

[0027] Preferably, the method according to the invention can be carried out under conditions that effectively minimize the content of 2,3-dichloro-3,3-difluoropropene (HCFO-1232xf) in stream B. Therefore, stream B may also contain less than 1% by weight of 2,3-dichloro-3,3-difluoropropene, advantageously less than 0.5% by weight, preferably less than 0.1% by weight, more preferably less than 0.05% by weight, and particularly less than or equal to 0.01% by weight, based on the total weight of stream B.

[0028] The logistics B may also contain 2,3,3,3-tetrafluoropropylene and 1,1,1,2,2-pentafluoropropane.

[0029] Preferably, the stream A obtained in stage i) is fed into the second reactor for stage ii).

[0030] Preferably, the temperature at which stage i) is implemented is lower than or equal to the temperature at which stage ii) is implemented. As mentioned above, the temperature at which stage i) is implemented is lower than or equal to, preferably lower than, the temperature at which stage ii) is implemented, so as to reduce the formation of coke and maintain the activity of the catalyst used in stage i), while minimizing the formation of side reactions.

[0031] According to the first preferred embodiment, the temperature at which stage i) is carried out is the same as the temperature at which stage ii) is carried out. Preferably, stages i) and ii) are carried out at a temperature between 310°C and 420°C, advantageously between 310°C and 400°C, more preferably between 310°C and 375°C, more preferably between 310°C and 360°C, and particularly between 330°C and 360°C. Preferably, during the implementation of these stages, the temperature at which stages i) and ii) are carried out is increased. For example, the temperature can be increased when the catalyst used in stage i) is partially deactivated, that is, when a significant decrease in conversion is observed. In this case, the temperature of stages i) and ii) can be increased incrementally. The temperature in each of stages i) and ii) can be increased incrementally by 0.5℃, 0.6℃, 0.7℃, 0.8℃, 0.9℃, 1.0℃, 1.1℃, 1.2℃, 1.3℃, 1.4℃, 1.5℃, 1.6℃, 1.7℃, 1.8℃, 1.9℃, 2.0℃, 2.1℃, 2.2℃, 2.3℃, 2.4℃, 2.5℃, 2.6℃, 2.7℃, 2.8℃, 2.9℃, 3.0℃, 3.1℃, 3.2℃, 3.3℃, ​​3.4℃, 3.5℃, 3.6℃, ​​3.7℃, and 3.8℃ respectively. ℃, 3.9℃, 4.0℃, 4.1℃, 4.2℃, 4.3℃, 4.4℃, 4.5℃, 4.6℃, 4.7℃, 4.8℃, 4.9℃, 5.0℃, 5.1℃, 5.2℃, 5.3℃, 5.4℃, 5.5℃, 5.6℃, 5.7℃, 5.8℃, 5.9℃, 6.0℃, 6.1℃, 6.2℃, 6.3℃, 6.4℃, 6.5℃, 6.6℃, 6.7℃, 6.8℃, 6.9℃, 7.0℃, 7.1℃, 7.2℃, 7.3℃, 7.4℃, 7.5℃, 7.6℃ 7.7℃, 7.8℃, 7.9℃, 8.0℃, 8.1℃, 8.2℃, 8.3℃, 8.4℃, 8.5℃, 8.6℃, 8.7℃, 8.8℃, 8.9℃, 9.0℃, 9.1℃, 9.2℃, 9.3℃, 9.4℃, 9.5℃, 9.6℃, 9.7℃, 9.8℃, 9.9℃, 10.0℃, 10.1℃, 10.2℃, 10.3℃, 10.4℃, 10.5℃, 10.6℃, 10.7℃, 10.8℃, 10.9℃, 11.0℃, 11.1℃, 11. 2℃, 11.3℃, 11.4℃, 11.5℃, 11.6℃, 11.7℃, 11.8℃, 11.9℃, 12.0℃, 12.1℃, 12.2℃, 12.3℃, 12.4℃, 12.5℃, 12.6℃, 12.7℃, 12.8℃, 12.9℃, 13.0℃, 13.1℃, 13.2℃, 13.3℃, ​​13.4℃, 13.5℃, 13.6℃, ​​13.7℃, 13.8℃, 13.9℃, 14.0℃, 14.1℃, 14.2℃, 14.3℃, 14.4℃, 14.5℃, 14.6℃, 14.7℃, 14.8℃, 14.9℃, 15.0℃, 15.1℃, 15.2℃, 15.3℃, 15.4℃, 15.5℃, 15.6℃, 15.7℃, 15.8℃, 15.9℃, 16.0℃, 16.1℃, 16.2℃, 16.3℃, 16.4℃, 16.5℃, 16.6℃, 16.7℃, 16.8℃, 16.9℃, 17.0℃, 17.1℃, 17.2℃ Temperatures of 17.3℃, 17.4℃, 17.5℃, 17.6℃, 17.7℃, 17.8℃, 17.9℃, 18.0℃, 18.1℃, 18.2℃, 18.3℃, 18.4℃, 18.5℃, 18.6℃, 18.7℃, 18.8℃, 18.9℃, 19.0℃, 19.1℃, 19.2℃, 19.3℃, 19.4℃, 19.5℃, 19.6℃, 19.7℃, 19.8℃, 19.9℃, or 20.0℃.

[0032] The temperature can be maintained at a certain temperature for a period of time from 1 hour to 5000 hours, and then gradually increased again.

[0033] Preferably, the temperatures of stages i) and ii) can be increased incrementally by 0.5°C to 20°C, 0.5°C to 19°C, 0.5°C to 18°C, 0.5°C to 17°C, 0.5°C to 16°C, or 0.5°C to 15°C. Advantageously, the temperatures of stages i) and ii) can be increased incrementally by 0.5°C to 14°C, 0.5°C to 13°C, 0.5°C to 12°C, 0.5°C to 11°C, or 0.5°C to 10°C. Preferably, the temperatures of stages i) and ii) can be increased incrementally by 0.6°C to 10°C, 0.7°C to 10°C, 0.8°C to 10°C, 0.9°C to 10°C, or 1°C to 10°C. More preferably, the temperatures of stages i) and ii) can be increased incrementally by 1°C to 9°C or 1°C to 8°C. Specifically, the temperatures of stages i) and ii) can be increased incrementally by 2°C to 8°C or by 3°C to 8°C.

[0034] As described above, the temperatures of stages i) and ii) are increased while keeping them the same.

[0035] In an alternative implementation, the temperature of stage ii) may rise faster than the temperature of stage i). Then, the temperature of stage i) becomes lower than the temperature of stage ii). This alternative implementation then corresponds to the second preferred implementation described above.

[0036] According to the second preferred implementation scheme, the temperature during stage i) is lower than the temperature during stage ii).

[0037] Preferably, the temperature difference between stage i) and stage ii) is greater than 0.2°C, advantageously greater than 0.5°C, preferably greater than 1°C, more preferably greater than 5°C, and particularly greater than 10°C. Preferably, the temperature difference between stage i) and stage ii) is less than 60°C, advantageously less than 55°C, preferably less than 50°C, more preferably less than 45°C, particularly less than 40°C, even more particularly less than 35°C, advantageously less than 30°C, preferably advantageously less than 25°C, and particularly advantageously less than 20°C. In a particular embodiment, the temperature difference between stage i) and stage ii) is between 5°C and 20°C.

[0038] According to a preferred embodiment, as these stages are implemented, the temperature of stage i) and / or the temperature of stage ii) are increased.

[0039] According to a preferred embodiment, stage i) is carried out at a temperature between 310°C and 420°C, advantageously between 310°C and 400°C, preferably between 310°C and 375°C, more preferably between 310°C and 360°C, and particularly between 330°C and 360°C.

[0040] According to a preferred embodiment, the temperature during stage i) is no more than 420°C, advantageously no more than 400°C, preferably no more than 375°C, and more preferably no more than 360°C.

[0041] Preferably, when the catalyst is partially deactivated, the temperature of stage i) can be increased incrementally, as explained in the first embodiment.

[0042] According to a preferred embodiment, the temperature of stage i) is increased incrementally by 0.5℃, 0.6℃, 0.7℃, 0.8℃, 0.9℃, 1.0℃, 1.1℃, 1.2℃, 1.3℃, 1.4℃, 1.5℃, 1.6℃, 1.7℃, 1.8℃, 1.9℃, 2.0℃, 2.1℃, 2.2℃, 2.3℃, 2.4℃, 2.5℃, 2.6℃, 2.7℃, 2.8℃, 2.9℃, 3.0℃, 3.1℃, 3.2℃, 3.3℃, ​​3.4℃, 3.5℃, 3.6℃, ​​3.7℃, 3.8℃, 3.9℃, 4.0℃, 4.1℃, 4.2℃, 4.3℃, 4.4℃, 4.5℃, 4.6℃, 4.7℃, 4.8℃, and 4.9℃. 5.0℃, 5.1℃, 5.2℃, 5.3℃, 5.4℃, 5.5℃, 5.6℃, 5.7℃, 5.8℃, 5.9℃, 6.0℃, 6.1℃, 6.2℃, 6.3℃, 6.4℃, 6.5℃, 6.6℃, 6.7℃, 6.8℃, 6.9℃, 7.0℃, 7.1℃, 7.2℃, 7.3℃, 7.4℃ 7.5℃, 7.6℃, 7.7℃, 7.8℃, 7.9℃, 8.0℃, 8.1℃, 8.2℃, 8.3℃, 8.4℃, 8.5℃, 8.6℃, 8.7℃, 8.8℃, 8.9℃, 9.0℃, 9.1℃, 9.2℃, 9.3℃, 9.4℃, 9.5℃, 9.6℃, 9.7℃, 9.8℃, 9.9℃ 10.0℃, 10.1℃, 10.2℃, 10.3℃, 10.4℃, 10.5℃, 10.6℃, 10.7℃, 10.8℃, 10.9℃, 11.0℃, 11.1℃, 11.2℃, 11.3℃, 11.4℃, 11.5℃, 11.6℃, 11.7℃, 11.8℃, 11.9℃, 12.0℃ 12.1℃, 12.2℃, 12.3℃, 12.4℃, 12.5℃, 12.6℃, 12.7℃, 12.8℃, 12.9℃, 13.0℃, 13.1℃, 13.2℃, 13.3℃, ​​13.4℃, 13.5℃, 13.6℃, ​​13.7℃, 13.8℃, 13.9℃, 14.0℃, 14.1℃ ℃, 14.2℃, 14.3℃, 14.4℃, 14.5℃, 14.6℃, 14.7℃, 14.8℃, 14.9℃, 15.0℃, 15.1℃, 15.2℃, 15.3℃, 15.4℃, 15.5℃, 15.6℃, 15.7℃, 15.8℃, 15.9℃, 16.0℃, 16.1℃, 16. 2℃, 16.3℃, 16.4℃, 16.5℃, 16.6℃, 16.7℃, 16.8℃, 16.9℃, 17.0℃, 17.1℃, 17.2℃, 17.3℃, 17.4℃, 17.5℃, 17.6℃, 17.7℃, 17.8℃, 17.9℃, 18.0℃, 18.1℃, 18.2℃, 18.3℃, 18.4℃, 18.5℃, 18.6℃, 18.7℃, 18.8℃, 18.9℃, 19.0℃, 19.1℃, 19.2℃, 19.3℃, 19.4℃, 19.5℃, 19.6℃, 19.7℃, 19.8℃, 19.9℃, or 20.0℃.

[0043] According to a preferred embodiment, the temperature of stage i) is increased incrementally by 0.5°C to 20°C, 0.5°C to 19°C, 0.5°C to 18°C, 0.5°C to 17°C, 0.5°C to 16°C, or 0.5°C to 15°C. Advantageously, the temperature of stage i) is increased incrementally by 0.5°C to 14°C, 0.5°C to 13°C, 0.5°C to 12°C, 0.5°C to 11°C, or 0.5°C to 10°C. Preferably, the temperature of stage i) is increased incrementally by 0.6°C to 10°C, 0.7°C to 10°C, 0.8°C to 10°C, 0.9°C to 10°C, or 1°C to 10°C. More preferably, the temperature of stage i) is increased incrementally by 1°C to 9°C or 1°C to 8°C. Specifically, the temperature of stage i) is increased by 2°C to 8°C or by 3°C to 8°C.

[0044] In this second preferred embodiment, even if the temperature of stage i) is increased, it remains lower than the temperature of stage ii).

[0045] According to a preferred embodiment, stage ii) is carried out at a temperature between 320°C and 440°C, advantageously between 320°C and 420°C, preferably between 330°C and 400°C, more preferably between 330°C and 390°C, and particularly between 340°C and 380°C.

[0046] According to a preferred embodiment, the temperature during stage ii) is no more than 440°C, advantageously no more than 420°C, preferably no more than 400°C, more preferably no more than 390°C, and particularly no more than 380°C.

[0047] Preferably, the temperature of stage ii) is increased incrementally.

[0048] According to a preferred embodiment, the temperature of stage ii) is increased incrementally by 0.5℃, 0.6℃, 0.7℃, 0.8℃, 0.9℃, 1.0℃, 1.1℃, 1.2℃, 1.3℃, 1.4℃, 1.5℃, 1.6℃, 1.7℃, 1.8℃, 1.9℃, 2.0℃, 2.1℃, 2.2℃, 2.3℃, 2.4℃, 2.5℃, 2.6℃, 2.7℃, 2.8℃, 2.9℃, 3.0℃, 3.1℃, 3.2℃, 3.3℃, ​​3.4℃, 3.5℃, 3.6℃, ​​3.7℃, 3.8℃, 3.9℃, 4.0℃, 4.1℃, 4.2℃, 4.3℃, 4.4℃, 4.5℃, 4.6℃, 4.7℃, 4.8℃, and 4.9℃. ℃, 5.0℃, 5.1℃, 5.2℃, 5.3℃, 5.4℃, 5.5℃, 5.6℃, 5.7℃, 5.8℃, 5.9℃, 6.0℃, 6.1℃, 6.2℃, 6.3℃, 6.4℃, 6.5℃, 6.6℃, 6.7℃, 6.8℃, 6.9℃, 7.0℃, 7.1℃, 7.2℃, 7.3℃, 7. 4℃, 7.5℃, 7.6℃, 7.7℃, 7.8℃, 7.9℃, 8.0℃, 8.1℃, 8.2℃, 8.3℃, 8.4℃, 8.5℃, 8.6℃, 8.7℃, 8.8℃, 8.9℃, 9.0℃, 9.1℃, 9.2℃, 9.3℃, 9.4℃, 9.5℃, 9.6℃, 9.7℃, 9.8℃, 9. 9℃, 10.0℃, 10.1℃, 10.2℃, 10.3℃, 10.4℃, 10.5℃, 10.6℃, 10.7℃, 10.8℃, 10.9℃, 11.0℃, 11.1℃, 11.2℃, 11.3℃, 11.4℃, 11.5℃, 11.6℃, 11.7℃, 11.8℃, 11.9℃, 1 2.0℃, 12.1℃, 12.2℃, 12.3℃, 12.4℃, 12.5℃, 12.6℃, 12.7℃, 12.8℃, 12.9℃, 13.0℃, 13.1℃, 13.2℃, 13.3℃, ​​13.4℃, 13.5℃, 13.6℃, ​​13.7℃, 13.8℃, 13.9℃, 14.0℃ 14.1℃, 14.2℃, 14.3℃, 14.4℃, 14.5℃, 14.6℃, 14.7℃, 14.8℃, 14.9℃, 15.0℃, 15.1℃, 15.2℃, 15.3℃, 15.4℃, 15.5℃, 15.6℃, 15.7℃, 15.8℃, 15.9℃, 16.0℃, 16.1℃ ℃, 16.2℃, 16.3℃, 16.4℃, 16.5℃, 16.6℃, 16.7℃, 16.8℃, 16.9℃, 17.0℃, 17.1℃, 17.2℃, 17.3℃, 17.4℃, 17.5℃, 17.6℃, 17.7℃, 17.8℃, 17.9℃, 18.0℃, 18.1℃, 18.2℃, 18.3℃, 18.4℃, 18.5℃, 18.6℃, 18.7℃, 18.8℃, 18.9℃, 19.0℃, 19.1℃, 19.2℃, 19.3℃, 19.4℃, 19.5℃, 19.6℃, 19.7℃, 19.8℃, 19.9℃, or 20.0℃.

[0049] According to a preferred embodiment, the temperature of stage ii) is increased incrementally by 0.5°C to 20°C, 0.5°C to 19°C, 0.5°C to 18°C, 0.5°C to 17°C, 0.5°C to 16°C, or 0.5°C to 15°C. Advantageously, the temperature of stage ii) is increased incrementally by 0.5°C to 14°C, 0.5°C to 13°C, 0.5°C to 12°C, 0.5°C to 11°C, or 0.5°C to 10°C. Preferably, the temperature of stage ii) is increased incrementally by 0.6°C to 10°C, 0.7°C to 10°C, 0.8°C to 10°C, 0.9°C to 10°C, or 1°C to 10°C. More preferably, the temperature of stage ii) is increased incrementally by 1°C to 9°C or 1°C to 8°C. Specifically, the temperature of stage ii) is increased by 2°C to 8°C or by 3°C to 8°C.

[0050] Specifically, stage ii) is carried out in the presence of a catalyst. More specifically, when stage ii) is carried out in the presence of a catalyst and when the catalyst is partially deactivated, the temperature of stage ii) is increased incrementally as described above. Even in the absence of a catalyst, the temperature can be increased incrementally, for example, to promote the selectivity of the reaction or to increase the conversion rate of the latter.

[0051] Several configurations are possible when the temperature of stage i) is lower than that of stage ii).

[0052] According to the first configuration, as stages i) and ii) are implemented, the temperatures of stage i) and stage ii) remain constant. Therefore, the first and second reactors operate with a fixed temperature difference.

[0053] According to the second configuration, the temperature of stage i) increases as it is implemented, for example to compensate for the loss of catalyst activity, while the temperature of stage ii) remains constant as it is implemented. Therefore, with the implementation of stages i) and ii), the temperature difference between the first and second reactors decreases. However, the temperature of stage i) remains lower than that of stage ii).

[0054] According to the third configuration, the temperatures of stage i) and stage ii) increase as the stages are implemented, for example, incrementally as described above. Therefore, as stages i) and ii) are implemented, the temperature difference between the first and second reactors decreases, increases, or remains constant.

[0055] According to the fourth configuration, the temperature of stage ii) increases as it is implemented, while the temperature of stage i) remains constant as it is implemented. Therefore, with the implementation of stages i) and ii), the temperature difference between the first and second reactors increases.

[0056] According to a preferred embodiment, stages i) and ii) are carried out in the presence of a catalyst, preferably a chromium-based catalyst. Preferably, the chromium-based catalyst may be chromium oxide (e.g., CrO2, CrO3, or Cr2O3), chromium oxyfluoride, or chromium fluoride (e.g., CrF3), or mixtures thereof. The chromium oxyfluoride may contain fluorine content between 1% and 60% by weight, advantageously between 5% and 55% by weight, preferably between 10% and 52% by weight, more preferably between 15% and 52% by weight, particularly between 20% and 50% by weight, even more particularly between 25% and 45% by weight, advantageously between 30% and 45% by weight, and even more advantageously between 35% and 45% by weight, based on the total weight of the chromium oxyfluoride. The catalyst may also include a co-catalyst selected from: Ni, Co, Zn, Mg, Mn, Fe, Zn, Ti, V, Zr, Mo, Ge, Sn, Pb, and Sb; preferably Ni, Co, Zn, Mg, and Mn; particularly Ni, Co, and Zn. The weight content of the co-catalyst is between 1% and 10% by weight, based on the total weight of the catalyst. The catalyst may be supported or unsupported. Supports may be used, such as alumina, for example in its α-form, activated alumina, aluminum halides (e.g., AlF3), aluminum oxyhalides, activated carbon, magnesium fluoride, or graphite.

[0057] Preferably, the specific surface area of ​​the catalyst can be between 1 and 100 m². 2 Between / g, preferably between 5 and 80m 2 Between / g, more preferably between 5 and 70m 2 Between / g, ideally between 5 and 50m 2 Between / g, especially at 10 and 50m 2 Between / g, and more specifically between 15 and 45m 2 Between / g.

[0058] According to a preferred embodiment, stage i) is carried out at atmospheric pressure or at a pressure greater than atmospheric pressure, advantageously at a pressure greater than 1.5 bara, preferably at a pressure greater than 2.0 bara, particularly at a pressure greater than 2.5 bara, and even more particularly at a pressure greater than 3.0 bara. Preferably, stage i) is carried out at a pressure between atmospheric pressure and 20 bara, preferably between 2 and 18 bara, and more preferably between 3 and 15 bara. Preferably, stage i) of this method is carried out with a contact time between 1 and 100 s, preferably between 2 and 75 s, and particularly between 3 and 50 s. Preferably, the molar ratio of HF / 1233xf can vary between 1:1 and 150:1, preferably between 2:1 and 125:1, and more preferably between 3:1 and 100:1. An oxidant, such as oxygen or chlorine, may be added during stage i). The molar ratio of the oxidant to the hydrocarbon compound can be between 0.005 and 2, preferably between 0.01 and 1.5. The oxidant can be pure oxygen, air, or a mixture of oxygen and nitrogen.

[0059] According to a preferred embodiment, stage ii) is carried out at atmospheric pressure or at a pressure greater than atmospheric pressure, advantageously at a pressure greater than 1.5 bara, preferably at a pressure greater than 2.0 bara, particularly at a pressure greater than 2.5 bara, and even more particularly at a pressure greater than 3.0 bara. Preferably, stage ii) is carried out at a pressure between atmospheric pressure and 20 bara, preferably between 2 and 18 bara, and more preferably between 3 and 15 bara. Preferably, stage ii) of this method is carried out with a contact time between 1 and 100 s, preferably between 2 and 75 s, and particularly between 3 and 50 s. Preferably, the molar ratio of HF / chlorinated compound can vary between 1:1 and 150:1, preferably between 2:1 and 125:1, and more preferably between 3:1 and 100:1. An oxidant, such as oxygen or chlorine, can be added during stage ii). The molar ratio of oxidant to hydrocarbon compound can be between 0.005 and 2, preferably between 0.01 and 1.5. The oxidant can be pure oxygen, air, or a mixture of oxygen and nitrogen.

[0060] Preferably, stream A obtained from stage i) is fed into the second reactor without purification before being injected into the second reactor. Preferably, a stream of hydrofluoric acid and 1,1,1,2,3-pentachloropropane or 2,3-dichloro-1,1,1-trifluoropropane or 1,1,2,3-tetrachloropropene is also fed into the second reactor.

[0061] Preferably, the method further includes a stage iii) for separating the stream B obtained from stage ii). Stage iii) enables the separation of different components of stream B. For example, stage iii) enables the separation of 2-chloro-3,3,3-trifluoropropene from 2,3,3,3-tetrafluoropropene and 1,1,1,2,2-pentafluoropropane.

[0062] Example

[0063] Example 1

[0064] Fluorination of HCFO-1233xf at a certain conversion rate is carried out in a first multi-tube reactor to yield HFO-1234yf (2,3,3,3-tetrafluoropropene) and optionally 1,1,1,2,2-pentafluoropropane. The product stream from this fluorination is fed to a second reactor. Hydrofluoric acid and a stream of 1,1,1,2,3-pentachloropropane are also fed to the second reactor. Fluorination of HCC-240db at a certain conversion rate is carried out in the second multi-tube reactor to yield HCFO-1233xf (2-chloro-3,3,3-trifluoropropene). A recirculation loop (with a controlled flow rate) allows some of the product to be returned to the first reactor. Both the first and second reactors contain a chromium oxide-based bulk catalyst. The catalyst is activated through a series of stages, including drying, fluorination, air treatment, and recirculation fluorination. This multi-stage treatment allows for both activity and selectivity of the catalytic solid.

[0065] In the first reactor, the fluorination process is carried out under the following operating conditions:

[0066] The absolute pressure in the fluorination reactor is 6 bar.

[0067] The molar ratio of HF to the total organic material fed through the recycling loop is between 1:1 and 1:3.

[0068] - Contact time is between 18 and 20 seconds.

[0069] - The constant temperature in the reactor is 350℃.

[0070] In the second reactor, the fluorination process is carried out under the following operating conditions:

[0071] The absolute pressure in the fluorination reactor is 6 bar.

[0072] The molar ratio of HF to the total organic material fed through the recycling loop is between 1:1 and 1:3.

[0073] - Contact time is between 11 and 13 seconds.

[0074] - The constant temperature in the reactor is 350℃.

[0075] After running for 530 hours, a final conversion rate of 48% was achieved.

[0076] Example 2

[0077] The method according to the invention was carried out in the same manner as in Example 1. The operating conditions in the second reactor were the same as in Example 1. The operating conditions in the first reactor were the same as in Example 1, except for the temperature:

[0078] - The initial temperature in the first reactor is 330°C, and then it is increased incrementally by 5°C:

[0079] At time t = 150 h, the reactor temperature was set to 335 °C.

[0080] At time t = 320 h, the reactor temperature was set to 340 °C.

[0081] At time t = 450h, the reactor temperature was set to 345℃.

[0082] After running for 600 hours (i.e., a 13% increase), a final conversion rate of 48% was achieved.

[0083] Example 3

[0084] The method according to the invention was carried out in the same manner as in Example 1. The operating conditions in the first reactor were the same as in Example 1, except that the temperature in the first reactor was set to 340°C. After running for 650 hours (i.e., a 20% increase), a final conversion rate of 48% was achieved.

[0085] The contents of 1233zdE / Z, 1234zeE / Z, and 245fa in stream A after 200 hours of reaction in the above embodiments are described in detail in Table 1 below. Additionally, the weight contents of HCFO-1232xf in stream B of the above three embodiments are 0.008 wt%, 0.01 wt%, and 0.01 wt%, respectively.

[0086] Table 1

[0087]

Claims

1. A method for producing 2,3,3,3-tetrafluoropropylene, wherein... Includes the following stages: i) In a first reactor, 2-chloro-3,3,3-trifluoropropene is contacted with hydrofluoric acid in the gas phase in the presence of a catalyst to produce stream A, which comprises 2,3,3,3-tetrafluoropropene, HF, and unreacted 2-chloro-3,3,3-trifluoropropene; and ii) In a second reactor, with or without a catalyst, hydrofluoric acid is contacted in the gas phase with at least one chlorinated compound selected from 1,1,1,2,3-pentachloropropane, 2,3-dichloro-1,1,1-trifluoropropane, and 1,1,2,3-tetrachloropropene to produce stream B containing 2-chloro-3,3,3-trifluoropropene. The characteristic is that the stream A obtained in stage i) is fed into the second reactor for stage ii); and the temperature implemented in stage i) is lower than or equal to the temperature implemented in stage ii). Phase i) is carried out at a temperature between 330°C and 360°C, and phase ii) is carried out at a temperature between 340°C and 380°C; Phases i) and ii) are carried out in the presence of a chromium-based catalyst.

2. The method as described in the preceding claims, characterized in that... The temperature implemented in stage i) is lower than the temperature implemented in stage ii); and the difference between the temperature implemented in stage i) and the temperature implemented in stage ii) is greater than 0.2℃.

3. The method as described in claim 2, characterized in that... The temperature implemented in stage i) is lower than the temperature implemented in stage ii); and the difference between the temperature implemented in stage i) and the temperature implemented in stage ii) is greater than 0.5°C.

4. The method as described in claim 2, characterized in that... The temperature implemented in stage i) is lower than the temperature implemented in stage ii); and the difference between the temperature implemented in stage i) and the temperature implemented in stage ii) is greater than 1°C.

5. The method as described in claim 2, characterized in that... The temperature at which phase i) is implemented is lower than the temperature at which phase ii) is implemented; and the difference between the temperature at which phase i) is implemented and the temperature at which phase ii) is implemented is greater than 5°C.

6. The method as described in claim 2, characterized in that... The temperature implemented in stage i) is lower than the temperature implemented in stage ii); and the difference between the temperature implemented in stage i) and the temperature implemented in stage ii) is greater than 10°C.

7. The method according to any one of claims 1 to 6, characterized in that... As these phases are implemented, the temperature of phase i) and / or phase ii) increases.

8. The method according to any one of claims 1 to 6, characterized in that The temperature during phase ii) remains constant, and the temperature during phase i) increases as phase i) is implemented.

9. The method according to any one of claims 1 to 6, characterized in that The temperature during phase i) remains constant, and the temperature during phase ii) increases as phase ii) is implemented.

10. The method according to any one of claims 1 to 6, characterized in that... Increase the temperature of stage i) and / or stage ii) incrementally by 0.5°C to 20°C.

11. The method as described in claim 10, characterized in that... Increase the temperature of stage i) and / or stage ii) incrementally by 0.5°C to 15°C.

12. The method as described in claim 10, characterized in that... Increase the temperature of stage i) and / or stage ii) incrementally by 0.5°C to 10°C.

13. The method as described in claim 10, characterized in that... Increase the temperature of stage i) and / or stage ii) incrementally by 1°C to 10°C.

14. The method as described in claim 10, characterized in that... Increase the temperature of stage i) and / or stage ii) incrementally by 1°C to 8°C.

15. The method as described in claim 10, characterized in that... Increase the temperature of stage i) and / or stage ii) incrementally by 3°C to 8°C.

16. The method according to any one of claims 1 to 6, characterized in that Increase the temperature of stage i) incrementally by 0.5°C to 20°C, provided that the temperature does not exceed 360°C and remains below or equal to the temperature of stage ii).

17. The method according to any one of claims 1 to 6, characterized in that Increase the temperature of stage ii) incrementally by 0.5°C to 20°C, provided that the temperature does not exceed 380°C.

18. The method according to any one of claims 1 to 6, characterized in that Stage ii) is carried out in the presence of a catalyst at a temperature of 340°C to 380°C, and the temperature of stage ii) is increased incrementally by 0.5°C to 20°C.

19. The method according to any one of claims 1 to 6, characterized in that As these phases are implemented, the temperature during phase i) and phase ii) remains constant.

20. The method according to any one of claims 1 to 6, characterized in that The catalyst is chromium oxyfluoride, chromium oxide, or chromium fluoride.

21. The method as described in claim 20, characterized in that... Chromium-based catalysts also include co-catalysts selected from Ni, Zn, Co, Mn, and Mg.

22. The method as described in claim 21, characterized in that The content of the co-catalyst is between 0.01% and 10%, based on the total weight of the catalyst.

23. The method according to any one of claims 1 to 6, characterized in that The weight content of 2,3-dichloro-3,3-difluoropropene (HCFO-1232xf) in Item B is less than 1%, based on the total weight of Item B.

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