2,3,3,3-tetrafluoropropylene and synthesis method and synthesis device thereof

Abstract

The invention belongs to the technical field of fluorine chemical industry, and is particularly related to 2,3,3,3-tetrafluoropropylene and its synthesis method and synthesis device. The synthesis method of 2,3,3,3-tetrafluoropropylene of the present invention: first, triphenylmethylphosphonium halide is reacted with sodium hydride or sodium metal in a solvent environment to prepare a methylene triphenylphosphine solution, and then the treated methylene triphenylphosphine solution is reacted with trifluoroacetyl fluoride to generate a crude product of 2,3,3,3-tetrafluoropropylene, and finally the crude product of 2,3,3,3-tetrafluoropropylene is treated to obtain 2,3,3,3-tetrafluoropropylene. The present invention also provides its synthesis device. The present invention provides a synthesis method of 2,3,3,3-tetrafluoropropylene, simple process, low energy consumption, high reaction conversion rate, high purity and high yield of the synthesized 2,3,3,3-tetrafluoropropylene, and the 2,3,3,3-tetrafluoropropylene synthesis device adopted is simple to operate.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorine chemical industry, and specifically relates to 2,3,3,3-tetrafluoropropylene and a synthesis method and a synthesis device thereof. Background Art

[0002] 2,3,3,3-tetrafluoropropene (HFO-1234yf), molecular formula: CF3CF=CH2, boiling point -28.3℃, CAS No. 754-12-1, as a single refrigerant, has excellent environmental parameters, global warming potential (GWP) = 4, ODP = 0, life cycle climate performance (LCCP) is lower than HFC-134a, atmospheric decomposition products are the same as HFC-134a, and its system performance is better than HFC-134a, becoming an excellent substitute for fluorine refrigerants. 2,3,3,3-tetrafluoropropene can be used in refrigerator refrigerants, fire extinguishing agents, heat transfer media, propellants, foaming agents, foaming agents, gas media, sterilant carriers, polymer monomers, particle removal fluids, carrier gas fluids, grinding and polishing agents, replacement desiccants, electric cycle working fluids and other fields.

[0003] At present, the main synthetic routes of 2,3,3,3-tetrafluoropropene are: tetrachloropropane method, tetrafluoroethylene method, trifluoropropyne method, trifluoropropylene method, tetrafluoropropanol method, hexafluoropropylene method (HFP), tetrachloropropylene method, HCFC-242 method, difluorochloromethane method, tetrafluoromonochloropropane, 2,3-dichloro-1,1,1-trifluoropropane method. Among them, the hexafluoropropylene method is one of the most studied routes. For example, US20070179324A, CN102026947A, etc. disclose that hexafluoropropylene is used as the starting material, and 2,3,3,3-tetrafluoropropene is obtained through four steps of hydrogenation, dehydrofluorination, rehydrogenation, dehydrofluorination, etc. The synthetic methods provided above generally have the disadvantages of many process steps, complicated operation, large safety hazards in the hydrogenation process, large equipment investment, and high separation and purification costs.

[0004] CN115403442A discloses a five-step catalytic synthesis of 2,3,3,3-tetrafluoropropene using 1,1,1,3-tetrachloropropane as a starting material. Although the catalyst is fully utilized and the reaction conditions are optimized, the reaction process involved is relatively complicated and the process route is long, which increases the difficulty of industrial production.

[0005] CN103073386A discloses a method for synthesizing 1,2-dichloro-3,3,3-trifluoropropane from hydrogen fluoride and 1,1,2,3-tetrachloropropene under the action of a catalyst, then reacting hydrogen fluoride with 1,2-dichloro-3,3,3-trifluoropropane under the action of a catalyst, separating impurities to obtain 1,1,1,2,3-pentafluoropropane, and finally dehydrofluorinating 1,1,1,2,3-pentafluoropropane under the action of a catalyst to separate impurities to obtain 2,3,3,3-tetrafluoropropene. The operation temperature of the synthesis process is too high, the equipment cost is high, and there are also problems such as complex process flow and high difficulty in operating the process of introducing catalysts multiple times.

[0006] Therefore, the existing synthesis method of 2,3,3,3-tetrafluoropropene has the problems of long process synthesis route, complicated operation, high technical level required of operators, increased risk of dangerous processes, many types of catalysts involved in the synthesis route, and great difficulty in subsequent recovery and treatment. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for synthesizing 2,3,3,3-tetrafluoropropene. The method has simple process, low energy consumption, high reaction conversion rate, and the synthesized 2,3,3,3-tetrafluoropropene has high purity and high yield. The adopted 2,3,3,3-tetrafluoropropene synthesis device is simple to operate.

[0008] The method for synthesizing 2,3,3,3-tetrafluoropropene of the present invention comprises the following steps: firstly, triphenylmethylphosphonium halide is reacted with sodium hydride or metallic sodium in a solvent environment to prepare a methylenetriphenylphosphine solution; then, the treated methylenetriphenylphosphine solution is reacted with trifluoroacetyl fluoride to generate a crude 2,3,3,3-tetrafluoropropene product and triphenylphosphine oxide; and finally, the crude 2,3,3,3-tetrafluoropropene product is treated to obtain 2,3,3,3-tetrafluoropropene.

[0009] The solvent is one of ether, toluene, tetrahydrofuran and propyl ether. The triphenylmethyl phosphonium halide is triphenylmethyl phosphonium chloride, triphenylmethyl phosphonium bromide or triphenylmethyl phosphonium iodide.

[0010] The molar ratio of the sodium hydride or metallic sodium to the triphenylmethyl phosphonium halide is (1.01-1.06):1; the molar ratio of the trifluoroacetyl fluoride to the triphenylmethyl phosphonium halide is (1.02-1.07):1.

[0011] The reaction temperature for preparing the methylenetriphenylphosphine solution is -10-0°C, and the reaction time is 30-60 minutes.

[0012] The prepared methylenetriphenylphosphine solution is filtered to remove salt, and the filtering temperature is -10-(-5)°C.

[0013] The reaction temperature of the treated methylenetriphenylphosphine solution and trifluoroacetyl fluoride is 0-5°C.

[0014] The treatment process of the crude 2,3,3,3-tetrafluoropropene product includes condensation, acid removal and drying to obtain 2,3,3,3-tetrafluoropropene. The condensation, acid removal and drying can be performed multiple times according to actual conditions.

[0015] 2,3,3,3-tetrafluoropropene is synthesized by the synthesis method of 2,3,3,3-tetrafluoropropene.

[0016] The synthesis device of 2,3,3,3-tetrafluoropropylene comprises a dispersing and dissolving kettle, a No. 1 reactor, a filtering and washing kettle, and a No. 2 reactor. The dispersing and dissolving kettle is connected to the No. 1 reactor, the No. 1 reactor is connected to the filtering and washing kettle, the filtering and washing kettle is connected to the No. 2 reactor, the No. 2 reactor is connected to the No. 2 condenser, the No. 2 condenser is connected to the No. 3 condenser, the No. 3 condenser is connected to the alkali washing tower, and the alkali washing tower is provided with an alkali washing pump.

[0017] The No. 1 reactor is provided with a No. 1 condenser, which is connected to a hydrogen processing device.

[0018] The bottom and top of the filtering and washing kettle are connected with a circulation pipeline, and a circulation pump is arranged on the circulation pipeline.

[0019] The bottom of the 2# reactor is connected with a trifluoroacetyl fluoride tank, and the top of the 2# reactor is connected with the 2# condenser through a condensation pump.

[0020] The circulation pipeline of the alkali washing tower is provided with an alkali washing pump.

[0021] A 1# inlet pump is arranged between the dispersion and dissolution kettle and the 1# reaction kettle.

[0022] A 2# inlet pump is arranged between the 1# reaction kettle and the filtering and washing kettle.

[0023] The filtering and washing kettle is provided with a solvent adding tube.

[0024] Specifically, the method for synthesizing 2,3,3,3-tetrafluoropropene using the synthesis device comprises the following steps:

[0025] (1) Add the solvent to the dispersing and dissolving kettle and stir, and add triphenylmethylphosphonium halide to disperse and dissolve; add the solvent to the 1# reactor and stir, and add sodium hydride to disperse and dissolve; set the condensation temperature in the 1# condenser to -5-0°C, and continuously inject the ether solution of triphenylmethylphosphonium halide in the dispersing and dissolving kettle into the 1# reactor, control the temperature of the 1# reactor to -10-0°C, and stir and react for 30-60 minutes after injection. The reaction formula is:

[0026] .

[0027] (2) After the reaction in reactor #1 is completed, the reaction liquid is introduced into the filter-washing reactor and desalinated by a circulating pump until the reaction liquid is free of salt crystals. The temperature of the filtration process is controlled at -10-(-5)°C. The filtrate is introduced into reactor #2 and the solvent is added to the filter-washing reactor through the solvent addition tube for circulated washing, flushing and settling. The washing liquid is also introduced into reactor #2.

[0028] (3) Open the 2# condenser and 3# condenser and set the temperature to 0-5°C and -10-(-15°C) respectively. The temperature in the 2# reactor is controlled at 0-5°C. Trifluoroacetyl fluoride is continuously added to the 2# reactor. The obtained reaction liquid is pumped into the upper end of the 2# condenser through a condensation pump for a circulation reaction to synthesize the target product 2,3,3,3-tetrafluoropropylene crude product. The reaction formula is:

[0029] .

[0030] (4) The crude 2,3,3,3-tetrafluoropropene product is further condensed through the 3# condenser, and then passed through the alkali washing tower to remove the acidic gas, and finally dried to obtain a high-purity gas 2,3,3,3-tetrafluoropropene product.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The method for synthesizing 2,3,3,3-tetrafluoropropene of the present invention has a simple synthesis route, effectively reduces the complexity of the process, has high activity of the reaction site, high reaction conversion rate, high selectivity, and few side reactions.

[0033] (2) The synthesis device of 2,3,3,3-tetrafluoropropene of the present invention has a simple structure, is highly compatible with the reaction process, is easy to operate, and is convenient for controlling the reaction process of each link, thereby reducing the difficulty of subsequent industrial operations.

[0034] (3) The 2,3,3,3-tetrafluoropropene synthesized by the method of the present invention has good conversion rate and selectivity, the product is easy to purify, and the product has high yield and high purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the synthesis device of 2,3,3,3-tetrafluoropropene of the present invention.

[0036] In the figure: 1. dispersion and dissolution kettle; 2. 1# inlet pump; 3. 1# reactor; 4. 1# condenser; 5. 2# inlet pump; 6. filtering and washing kettle; 7. solvent adding pipe; 8. 2# reactor; 9. 2# condenser; 10. 3# condenser; 11. alkali washing tower; 12. alkali washing pump; 13. trifluoroacetyl fluoride tank; 14. condensation pump; 15. circulation pump; 16. hydrogen treatment device. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with specific embodiments.

[0038] The synthesis device of the present invention, such as Figure 1 As shown, the synthesis device of 2,3,3,3-tetrafluoropropylene includes a dispersion dissolving kettle 1, a 1# reactor 3, a filtering and washing kettle 6, and a 2# reactor 8. The dispersion dissolving kettle 1 is connected to the 1# reactor 3, the 1# reactor 3 is connected to the filtering and washing kettle 6, the filtering and washing kettle 6 is connected to the 2# reactor 8, the 2# reactor 8 is connected to the 2# condenser 9, the 2# condenser 9 is connected to the 3# condenser 10, the 3# condenser 10 is connected to the alkali washing tower 11, and the alkali washing tower 11 is provided with an alkali washing pump 12.

[0039] The No. 1 reactor 3 is provided with a No. 1 condenser 4 , which is connected to a hydrogen processing device 16 .

[0040] The bottom and top of the filtering and washing kettle 6 are connected with a circulation pipeline, and a circulation pump 15 is arranged on the circulation pipeline.

[0041] The bottom of the 2# reaction kettle 8 is connected to a trifluoroacetyl fluoride tank 13 , and the top of the 2# reaction kettle 8 is connected to the 2# condenser 9 via a condensation pump 14 .

[0042] The circulation pipeline of the alkali washing tower 11 is provided with an alkali washing pump 12 .

[0043] A 1# introduction pump 2 is provided between the dispersion and dissolution kettle 1 and the 1# reaction kettle 3 .

[0044] A 2# inlet pump 5 is provided between the 1# reaction kettle 3 and the filtering and washing kettle 6 .

[0045] The filtering and washing kettle 6 is provided with a solvent adding pipe 7 .

[0046] The following embodiments are all completed using the above device.

[0047] Example 1

[0048] The synthesis method of 2,3,3,3-tetrafluoropropene comprises the following steps:

[0049] (1) Add 25 kg of toluene into the dispersion and dissolution kettle 1 and stir, and add 4.01 kg (12.72 mol) of triphenylmethylphosphonium chloride for dispersion and dissolution; add 25 kg of toluene solvent into the 1# reactor 3 and stir, and add 0.3149 kg (13.1 mol) of sodium hydride for dispersion and dissolution; set the condensation temperature in the 1# condenser 4 to -3°C, and continuously inject the toluene solution of triphenylmethylphosphonium chloride in the dispersion and dissolution kettle 1 into the 1# reactor 3, control the temperature of the 1# reactor 3 to -6°C, and stir and react for 45 minutes after injection.

[0050] (2) After the reaction in reactor 1#3 is completed, the reaction liquid is introduced into filter-washing reactor 6, and circulated desalination is carried out through circulating pump 15 until the reaction liquid is free of salt crystals. The temperature of the filtration process is controlled at -6°C, and the filtrate is introduced into reactor 2#8. Toluene solvent is added to filter-washing reactor 6 through solvent adding pipe 7, and circulated washing, flushing and settling are carried out. The washing liquid is also introduced into reactor 2#8.

[0051] (3) Open the 2# condenser 9 and the 3# condenser 10 and set the temperatures at 2°C and -13°C respectively. The temperature in the 2# reactor 8 is controlled at 2°C. 1.5603 kg (13.356 mol) of trifluoroacetyl fluoride is continuously added to the 2# reactor 8. The obtained reaction liquid is pumped into the upper end of the 2# condenser 9 through the condensation pump 14 for circulation reaction to synthesize the target product 2,3,3,3-tetrafluoropropene crude product.

[0052] (4) The crude 2,3,3,3-tetrafluoropropene product is further condensed through the 3# condenser 10, and then passed through the alkali washing tower 11 to remove the acid gas, and finally dried to obtain 1.3577 kg of high-purity gas 2,3,3,3-tetrafluoropropene product.

[0053] Example 2

[0054] The synthesis method of 2,3,3,3-tetrafluoropropene comprises the following steps:

[0055] (1) Add 25 kg of toluene into the dispersion and dissolution kettle 1 and stir, and add 3.949 kg (12.524 mol) of triphenylmethylphosphonium chloride for dispersion and dissolution; add 25 kg of toluene solvent into the 1# reactor 3 and stir, and add 0.304 kg (12.65 mol) of sodium hydride for dispersion and dissolution; set the condensation temperature in the 1# condenser 4 to 0°C, and continuously inject the toluene solution of triphenylmethylphosphonium chloride in the dispersion and dissolution kettle 1 into the 1# reactor 3, control the temperature of the 1# reactor 3 to 0°C, and stir and react for 60 minutes after injection.

[0056] (2) After the reaction in reactor 1#3 is completed, the reaction liquid is introduced into filter-washing reactor 6, and circulated desalination is carried out through circulating pump 15 until the reaction liquid is free of salt crystals. The temperature of the filtration process is controlled at -5°C, and the filtrate is introduced into reactor 2#8. Toluene solvent is added to filter-washing reactor 6 through solvent adding pipe 7, and circulated washing, flushing and settling are carried out. The washing liquid is also introduced into reactor 2#8.

[0057] (3) Open the 2# condenser 9 and the 3# condenser 10 and set the temperatures at 5°C and -10°C respectively. The temperature in the 2# reactor 8 is controlled at 5°C. 1.492 kg (12.774 mol) of trifluoroacetyl fluoride is continuously added to the 2# reactor 8. The obtained reaction liquid is pumped into the upper end of the 2# condenser 9 through the condensation pump 14 for circulation reaction to synthesize the target product 2,3,3,3-tetrafluoropropene crude product.

[0058] (4) The crude 2,3,3,3-tetrafluoropropene product is further condensed through the 3# condenser 10, and then passed through the alkali washing tower 11 to remove the acid gas, and finally dried to obtain 1.318 kg of high-purity gas 2,3,3,3-tetrafluoropropene product.

[0059] Example 3

[0060] The synthesis method of 2,3,3,3-tetrafluoropropene comprises the following steps:

[0061] (1) Add 25 kg of ether to the dispersing and dissolving kettle 1 and stir, and add 4.091 kg (12.974 mol) of triphenylmethylphosphonium chloride for dispersing and dissolving; add 25 kg of ether solvent to the 1# reactor 3 and stir, and add 0.317 kg (13.752 mol) of metallic sodium for dispersing and dissolving; set the condensing temperature in the 1# condenser 4 to -5°C, and continuously inject the ether solution of triphenylmethylphosphonium chloride in the dispersing and dissolving kettle 1 into the 1# reactor 3, control the temperature of the 1# reactor 3 to -10°C, and stir and react for 30 minutes after injection.

[0062] (2) After the reaction in reactor 1#3 is completed, the reaction liquid is introduced into filter-washing reactor 6, and circulated desalination is carried out through circulating pump 15 until the reaction liquid is free of salt crystals. The temperature of the filtration process is controlled at -10°C, and the filtrate is introduced into reactor 2#8. Ether solvent is added to filter-washing reactor 6 through solvent adding pipe 7, and circulated washing, flushing and settling are carried out. The washing liquid is also introduced into reactor 2#8.

[0063] (3) Open the 2# condenser 9 and the 3# condenser 10 and set the temperatures at 0°C and -15°C respectively. The temperature in the 2# reactor 8 is controlled at 0°C. 1.622 kg (13.88 mol) of trifluoroacetyl fluoride is continuously added to the 2# reactor 8. The obtained reaction liquid is pumped into the upper end of the 2# condenser 9 through the condensation pump 14 for circulation reaction to synthesize the target product 2,3,3,3-tetrafluoropropene crude product.

[0064] (4) The crude 2,3,3,3-tetrafluoropropene product is further condensed through the 3# condenser 10, and then passed through the alkali washing tower 11 to remove the acid gas, and finally dried to obtain 1.34 kg of high-purity gas 2,3,3,3-tetrafluoropropene product.

[0065] Example 4

[0066] The synthesis method of 2,3,3,3-tetrafluoropropene comprises the following steps:

[0067] (1) Add 25 kg of tetrahydrofuran to the dispersing and dissolving kettle 1 and stir, and add 4.562 kg (12.669 mol) of triphenylmethyl phosphonium bromide for dispersing and dissolving; add 25 kg of tetrahydrofuran solvent to the 1# reactor 3 and stir, and add 0.3149 kg (13.1 mol) of sodium hydride for dispersing and dissolving; set the condensing temperature in the 1# condenser 4 to -4°C, and continuously inject the tetrahydrofuran solution of triphenylmethyl phosphonium bromide in the dispersing and dissolving kettle 1 into the 1# reactor 3, control the temperature of the 1# reactor 3 to -8°C, and stir and react for 40 minutes after injecting.

[0068] (2) After the reaction in reactor #1 3 is completed, the reaction liquid is introduced into the filter-washing reactor 6, and the circulating desalination is carried out by the circulating pump 15 until the reaction liquid is free of salt crystals. The temperature of the filtration process is controlled at -7°C. The filtrate is introduced into reactor #2 8, and tetrahydrofuran solvent is added to the filter-washing reactor 6 through the solvent adding pipe 7. The filtrate is circulated, washed, rinsed and settled, and the washing liquid is also introduced into reactor #2 8.

[0069] (3) Open the 2# condenser 9 and the 3# condenser 10 and set the temperatures at 1°C and -13°C respectively. The temperature in the 2# reactor 8 is controlled at 1°C. 1.569 kg (13.429 mol) of trifluoroacetyl fluoride is continuously added to the 2# reactor 8. The obtained reaction liquid is pumped into the upper end of the 2# condenser 9 through the condensation pump 14 for circulation reaction to synthesize the target product 2,3,3,3-tetrafluoropropene crude product.

[0070] (4) The crude 2,3,3,3-tetrafluoropropene product is further condensed through the 3# condenser 10, and then passed through the alkali washing tower 11 to remove the acid gas, and finally dried to obtain 1.348 kg of high-purity gas 2,3,3,3-tetrafluoropropene product.

[0071] Example 5

[0072] The synthesis method of 2,3,3,3-tetrafluoropropene comprises the following steps:

[0073] (1) Add 25 kg of propyl ether to the dispersing and dissolving kettle 1 and stir, and add 5.281 kg (12.957 mol) of triphenylmethyl phosphonium iodide for dispersing and dissolving; add 25 kg of propyl ether solvent to the 1# reactor 3 and stir, and add 0.327 kg (13.604 mol) of sodium hydride for dispersing and dissolving; set the condensing temperature in the 1# condenser 4 to -4°C, and continuously inject the propyl ether solution of triphenylmethyl phosphonium iodide in the dispersing and dissolving kettle 1 into the 1# reactor 3, control the temperature of the 1# reactor 3 to -8°C, and stir and react for 35 minutes after injecting.

[0074] (2) After the reaction in reactor 1#3 is completed, the reaction liquid is introduced into filter-washing reactor 6, and circulated desalination is carried out through circulating pump 15 until the reaction liquid is free of salt crystals. The temperature of the filtration process is controlled at -6°C, and the filtrate is introduced into reactor 2#8. Propyl ether solvent is added to filter-washing reactor 6 through solvent adding pipe 7, and circulated washing, flushing and settling are carried out. The washing liquid is also introduced into reactor 2#8.

[0075] (3) Open the 2# condenser 9 and the 3# condenser 10 and set the temperatures at 1°C and -14°C respectively. The temperature in the 2# reactor 8 is controlled at 0°C. 1.62 kg (13.864 mol) of trifluoroacetyl fluoride is continuously added to the 2# reactor 8. The obtained reaction liquid is pumped into the upper end of the 2# condenser 9 through the condensation pump 14 for circulation reaction to synthesize the target product 2,3,3,3-tetrafluoropropene crude product.

[0076] (4) The crude 2,3,3,3-tetrafluoropropene product is further condensed through the 3# condenser 10, and then passed through the alkali washing tower 11 to remove the acid gas, and finally dried to obtain 1.361 kg of high-purity gas 2,3,3,3-tetrafluoropropene product.

[0077] Comparative Example 1

[0078] This comparative example is the same as Example 1, except that "add 0.3149 kg (13.1 mol) of sodium hydride to disperse and dissolve" in step (1) is replaced by "add 0.428 kg (17.8 mol) of sodium hydride to disperse and dissolve", and the other preparation conditions and parameters are the same.

[0079] Comparative Example 2

[0080] This comparative example is the same as Example 1, except that the step (1) of "continuously injecting the toluene solution of triphenylmethylphosphonium chloride in the dispersion and dissolution kettle 1 into the 1# reaction kettle 3, and controlling the temperature of the 1# reaction kettle 3 to -6°C" is replaced by controlling the temperature of the 1# reaction kettle 3 to 15°C for reaction, and the other preparation conditions and parameters are the same.

[0081] Comparative Example 3

[0082] This comparative example is the same as Example 1, except that the internal circulation operation of the condensation pump 14 is eliminated in step (3) of "the obtained reaction liquid is pumped into the upper end of the second condenser 9 through the condensation pump 14 for circulation reaction", and the other preparation condition parameters are the same.

[0083] The purity of 2,3,3,3-tetrafluoropropene prepared in the above examples and comparative examples was tested and its yield was calculated. The yields were all calculated based on mol of triphenylmethylphosphonium halide. The test results are shown in Table 1.

[0084] Table 1 Test results

[0085]

[0086] From the results in Table 1, it can be seen that in Comparative Examples 1 and 2, by changing the molar ratio of sodium hydride input and the initial reaction temperature, there is a significant effect on the yield and purity of the product synthesis, especially after the initial temperature is increased. The comparison yield decreases significantly. Comparative Example 3 cancels the internal circulation operation of the condensation pump 14, cancels the reaction promotion mode of the liquid-falling reaction and only retains the stirring of the kettle body, and the yield and purity of 2,3,3,3-tetrafluoropropene are significantly reduced, especially in terms of the yield of the reaction. In the embodiments of the present invention, the temperature and pressure variables of each reaction process section are changed in a limited range, which has little effect on the yield and purity of the 2,3,3,3-tetrafluoropropene product.

Claims

1. A method for synthesizing 2,3,3,3-tetrafluoropropene, characterized in that: Firstly, triphenylmethylphosphonium halide is reacted with sodium hydride or sodium metal in a solvent environment at a reaction temperature of -10-0°C for a reaction time of 30-60 minutes to prepare a methylenetriphenylphosphine solution, and then the treated methylenetriphenylphosphine solution is reacted with trifluoroacetyl fluoride to generate a crude 2,3,3,3-tetrafluoropropene product and triphenylphosphine oxide, and finally the crude 2,3,3,3-tetrafluoropropene product is treated to obtain 2,3,3,3-tetrafluoropropene; The solvent is one of diethyl ether, toluene, tetrahydrofuran and propyl ether; The molar ratio of the sodium hydride or metallic sodium to the triphenylmethylphosphonium halide is 1.01-1.06:

1.

2. The method for synthesizing 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that: The molar ratio of trifluoroacetyl fluoride to triphenylmethyl phosphorus halide is 1.02-1.07:

1.

3. The method for synthesizing 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that: The prepared methylenetriphenylphosphine solution is filtered to remove salt, and the filtering temperature is -10~-5℃.

4. The method for synthesizing 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that: The reaction temperature of the treated methylenetriphenylphosphine and trifluoroacetyl fluoride is 0-5°C.

5. The method for synthesizing 2,3,3,3-tetrafluoropropene according to claim 1, characterized in that: The treatment process of the crude 2,3,3,3-tetrafluoropropene product includes condensation, acid removal and drying to obtain 2,3,3,3-tetrafluoropropene.

6. A synthesis device used in the method for synthesizing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 5, characterized in that: The invention comprises a dispersion and dissolution kettle (1), a No. 1 reactor (3), a filtering and washing kettle (6), and a No. 2 reactor (8); the dispersion and dissolution kettle (1) is connected to the No. 1 reactor (3), the No. 1 reactor (3) is connected to the filtering and washing kettle (6), the filtering and washing kettle (6) is connected to the No. 2 reactor (8), the No. 2 reactor (8) is connected to the No. 2 condenser (9), the No. 2 condenser (9) is connected to the No. 3 condenser (10), the No. 3 condenser (10) is connected to the alkali washing tower (11), and the alkali washing tower (11) is provided with an alkali washing pump (12); The bottom of the No. 2 reaction kettle (8) is connected to a trifluoroacetyl fluoride tank (13), and the top of the No. 2 reaction kettle (8) is connected to the No. 2 condenser (9) via a condensation pump (14).

7. The synthesis device used in the synthesis method of 2,3,3,3-tetrafluoropropene according to claim 6, characterized in that: The No. 1 reactor (3) is provided with a No. 1 condenser (4), and the No. 1 condenser (4) is connected to a hydrogen processing device (16).

8. The synthesis device used in the synthesis method of 2,3,3,3-tetrafluoropropene according to claim 6, characterized in that: The bottom and top of the filtering and washing kettle (6) are connected to a circulation pipeline, and a circulation pump (15) is arranged on the circulation pipeline.

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