Method for generating 1234yf through one-step fluorination of 240db

Abstract

The invention discloses a method for generating 1234yf through one-step fluorination of 240db. The method comprises the following step: reacting 240db and hydrogen fluoride under the action of a fluorinated catalyst to generate 1234yf, the catalyst comprises a Ce-Zr composite oxide carrier and one or more than two of Ni, La, Cr, Co, Fe, Sb, Mo and Cu loaded on the carrier. The method disclosed by the invention has the characteristics of stable and controllable process and long service life of the catalyst while ensuring high selectivity and high yield, effectively reduces material consumption and equipment maintenance cost in industrial production, and overcomes the problems of economy and stability in large-scale production in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of 2,3,3,3-tetrafluoropropene (1234yf) synthesis, in particular to a method for one-step fluorination of 1,1,1,2,3-pentachloropropane (240db) to generate 1234yf. BACKGROUND

[0002] In the continuous evolution of refrigeration technology, finding high-efficiency, environmentally friendly and economical refrigerants has become the focus of the industry. With the increasing awareness of environmental protection around the world, reducing greenhouse gas emissions and ozone layer destruction has become an international consensus. In this context, 2,3,3,3-tetrafluoropropene (referred to as HFO-1234yf) is recognized as an ideal substitute for traditional refrigerants such as HFC-134a due to its extremely low global warming potential (GWP <1), zero ozone depletion potential (ODP =0) and short atmospheric lifetime (only 11 days), marking the fourth generation of innovation in the refrigerant industry.

[0003] However, despite the significant environmental advantages of HFO-1234yf, its current industrial production route faces many challenges. Existing technologies mainly rely on multi-step, high-energy consumption synthesis routes, such as complex conversion processes using hexafluoropropylene, trifluoropropylene, tetrachloropropylene and other starting materials.

[0004] For example, patent CN109796300B reports a continuous preparation method for 2,3,3,3-tetrafluoropropene, using carbon tetrachloride and ethylene as raw materials, CCl4 and ethylene are polymerized to form CCl3CH2CH2Cl, then CCl3CH2CH2Cl is dehydrochlorinated to form CCl2=CHCH2Cl, CCl2=CHCH2Cl is chlorinated to obtain CCl3CHClCH2Cl, CCl3CHClCH2Cl is dehydrochlorinated to obtain CCl2=CClCH2Cl, CCl2=CClCH2Cl is reacted with hydrogen fluoride to form 2-chloro-3,3,3-trifluoropropene (CF3CCl=CH2, 1233xf), and CF3CCl=CH2 is subjected to fluorine-chlorine exchange to obtain the final product HFO-1234yf.

[0005] For example, patent application CN117377646A reports the formation of HFO-1234yf, CCl3CH2CH2Cl undergoes fluorination to form CF3CH=CH2, CF3CH=CH2 undergoes chlorination to form CF3CHClCH2Cl, CF3CHClCH2Cl undergoes dehydrochlorination to form CF3CCl=CH2, CF3CCl=CH2 is contacted with hydrogen fluoride in the presence of a catalyst and undergoes hydrofluorination to form CF3CFClCH3, and CF3CFClCH3 undergoes dehydrochlorination to finally form HFO-1234yf. This route requires a total of 6 steps of reactions, not only the process is long, but also the reaction conditions are harsh, especially operating at high temperature, not only increases the equipment investment cost, but also significantly increases the energy consumption level.

[0006] Patent specification CN107074697A discloses a method for producing 2,3,3,3-tetrafluoropropene, comprising: reacting a composition comprising at least 99% by weight of 1,1,1,2,3-pentachloropropane with hydrofluoric acid in the gas phase, which can be a catalytic fluorination step, the catalyst can use supported or unsupported catalysts containing metals such as Cr, Ni, Fe, Zn, Ti, V, Zr, Mo, Ge, Sn, Pb, Mg, Sb, chromium oxyfluoride, aluminum fluoride or aluminum oxyfluoride. SUMMARY

[0007] The present application provides a method for one-step fluorination of 240db to generate 1234yf, which simplifies the process flow, improves the reaction effect, and solves the problems of complicated process flow, many intermediate substances, low yield of final product 1234yf, and easy deactivation of catalyst in the prior art.

[0008] The specific technical solutions are as follows: A method for one-step fluorination of 240db to generate 1234yf, comprising: one-step reaction of 240db and hydrogen fluoride under the action of a fluorination-treated catalyst to generate 1234yf; The catalyst comprises a Ce-Zr composite oxide carrier and one or more than two of Ni, La, Cr, Co, Fe, Sb, Mo, Cu supported on the carrier. Further, the supported carrier preferably comprises one or more than two of Ni, Cr, Co, Cu, which has excellent activation capacity for fluorine source (such as HF, etc.), can effectively promote the reaction of 240db with fluorine to generate 1234yf in one step.

[0009] Fluorination treatment can convert the active components of the catalyst into fluorides, and form a fluorine-oxygen layer on the surface of the Ce-Zr composite oxide carrier.

[0010] The 240db one-step fluorination method for generating 1234yf preferably includes: fluorination reaction of the catalyst in the HF-containing gas at 280-360℃ (for example, 300℃, 340℃, 350℃, etc., preferably 300-350℃).

[0011] Further, the HF-containing gas can include HF and an inert gas.

[0012] In the present application, the inert gas refers to a gas that does not participate in the reaction, such as nitrogen and the like.

[0013] In some preferred examples, the volume fraction of HF in the HF-containing gas is 5%-10%.

[0014] In some preferred examples, the fluorination reaction time is 2-3 hours.

[0015] The preparation method of the catalyst preferably includes: using an impregnation method, immersing a Ce-Zr composite oxide carrier in a precursor solution containing one or more than two of Ni, La, Cr, Co, Fe, Sb, Mo, and Cu, taking the solid after impregnation, drying, and calcining to obtain the catalyst. The calcination temperature is preferably 340-400℃, for example, 350℃, 380℃, etc., and is further preferably 350-380℃. The calcination time is preferably 3-4 hours. The precursor solution can be a salt solution, etc., and can further be a nitrate solution, a chloride solution, etc.

[0016] The preparation method of the Ce-Zr composite oxide carrier preferably includes: using a co-precipitation-hydrothermal method, adjusting the pH of a solution containing Ce(III) and Zr(IV) to 9-10, then performing a hydrothermal reaction at 160-200℃ (for example, 180℃, 190℃, etc., preferably 180-190℃), taking the solid after the hydrothermal reaction, and calcining to obtain the Ce-Zr composite oxide carrier. The hydrothermal reaction time is preferably 12-18 hours. The calcination temperature is preferably 480-520℃, and is further preferably 500℃. The calcination time is preferably 4-5 hours.

[0017] In the preparation method of the Ce-Zr composite oxide carrier, Ce(III) is preferably derived from cerium nitrate.

[0018] In the preparation method of the Ce-Zr composite oxide carrier, Zr(IV) is preferably derived from zirconium nitrate.

[0019] In the preparation method of the Ce-Zr composite oxide carrier, the pH is preferably adjusted using ammonia.

[0020] The mass percentage of one or more than two of the Ni, La, Cr, Co, Fe, Sb, Mo, Cu in the catalyst, based on 100% of the mass of the Ce-Zr composite oxide carrier, is preferably 5% to 15%, for example 10% or the like.

[0021] The molar ratio of Ce to Zr in the Ce-Zr composite oxide carrier is preferably 1:1 to 5, for example 1:3 or the like.

[0022] The molar ratio of 240db to hydrogen fluoride in the method for one-step fluorination of 240db to generate 1234yf is preferably 1:5 to 30, for example 1:10, 1:15, 1:20, 1:25, 1:30 or the like.

[0023] The reaction temperature for one-step reaction to generate 1234yf in the method for one-step fluorination of 240db to generate 1234yf is preferably 250 to 390°C, for example 300°C or the like.

[0024] The reaction pressure for one-step reaction to generate 1234yf in the method for one-step fluorination of 240db to generate 1234yf is preferably 0.1 to 0.6 MPa, for example 0.4 MPa or the like.

[0025] The catalyst volume space velocity for one-step reaction to generate 1234yf in the method for one-step fluorination of 240db to generate 1234yf is preferably 500 to 1500 h -1 , for example 1000 h -1 or the like.

[0026] As a general inventive concept, the present application also provides a catalyst and a preparation method and application thereof, which can refer to the description in the above method for one-step fluorination of 240db to generate 1234yf. The catalyst can be used to catalyze one-step reaction of 240db and hydrogen fluoride to generate 1234yf. Preferably, the catalyst is subjected to fluorination treatment before being used to catalyze one-step reaction of 240db and hydrogen fluoride to generate 1234yf. The fluorination treatment can refer to the description in the above method for one-step fluorination of 240db to generate 1234yf.

[0027] The catalyst subjected to fluorination treatment in the present application has the following characteristics: 1. Anti-sintering: Solid solution stabilization: the co-precipitation-hydrothermal-calcination method is used to form Ce 4+ and make Ce 4+ enter the ZrO2 crystal lattice, increase the lattice distortion energy, and inhibit the grain growth at high temperature; Strong metal-support interaction: the active component is converted into fluoride, and a chemical bond is formed between the Ce-Zr composite oxide carrier interface which forms a fluorine-oxygen layer on the surface, limiting the migration and agglomeration of the active component; the strong metal-support interaction greatly improves the 1234yf yield and selectivity, and also makes the catalyst have super-long service life.

[0028] 2, Anti-carbon deposition: Surface acidity regulation: carbon deposition precursors mainly polymerize through strong acid sites, and the cerium oxide in the catalyst can reduce the density of strong acid sites on the surface of the carrier, reducing the adsorption of olefin substances; Oxidation scavenging: the oxygen storage capacity of cerium oxide can oxidize deposited carbon species into CO, CO2, etc., inhibiting the generation of carbon deposition.

[0029] Compared with the prior art, the present application has the following beneficial effects: (1) By constructing a 240db one-step fluorination reaction system for preparing 1234yf, the depth integration of the traditional multi-step reaction process is realized, the reaction path is effectively shortened, and the process complexity of intermediate product separation and purification is reduced, laying a structural foundation for improving reaction efficiency. (2) The application of a specific catalyst significantly improves the generation selectivity and target product yield of 1234yf, and by enhancing the anti-inactivation ability of the catalyst, the stable operation period is greatly prolonged, solving the technical bottlenecks of fast activity decay and difficult product distribution regulation in traditional catalytic processes. (3) The method of the present application has the characteristics of stable and controllable process, long service life of catalyst, and effectively reduces the material consumption and equipment maintenance cost in industrial production, overcoming the economic and stability problems faced by the prior art in large-scale production. DETAILED DESCRIPTION

[0030] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application.

[0031] The operation methods not specified in the following examples are usually carried out according to conventional conditions or according to the conditions recommended by the manufacturer.

[0032] Example 1: A solution containing cerium nitrate and zirconium nitrate is adjusted to pH 9-10 with ammonia water, then hydrothermal reaction is carried out at 180℃ for 12 hours, and after the hydrothermal reaction is completed, the solid is calcined at 500℃ for 4 hours to obtain a Ce-Zr composite oxide carrier. In the Ce-Zr composite oxide carrier, the molar ratio of Ce to Zr is 1:1.

[0033] The Ce-Zr composite oxide carrier obtained above was immersed in a nickel nitrate solution by impregnation, and after impregnation, the solid was dried and calcined at 350°C for 3 hours to obtain a Ni catalyst. In the Ni catalyst, the mass percentage of Ni was 5% based on 100% of the mass of the Ce-Zr composite oxide carrier.

[0034] The Ni catalyst obtained above was subjected to fluorination reaction at 340°C for 2 hours in a HF / N2mixed gas containing 5vol% HF to obtain a fluorination-treated Ni catalyst.

[0035] 240db and hydrogen fluoride were reacted in one step in the presence of the fluorination-treated Ni catalyst to generate 1234yf. The reaction parameters such as reaction pressure, reaction temperature, molar ratio of raw materials, and the composition of the outlet gas after 20 hours of reaction are shown in Table 1.

[0036] Example 2: A solution containing cerium nitrate and zirconium nitrate was adjusted to pH 9-10 with ammonia water, and then subjected to hydrothermal reaction at 180°C for 12 hours. After the hydrothermal reaction, the solid was calcined at 500°C for 4 hours to obtain a Ce-Zr composite oxide carrier. In the Ce-Zr composite oxide carrier, the molar ratio of Ce to Zr was 1:3.

[0037] The Ce-Zr composite oxide carrier obtained above was immersed in a lanthanum nitrate solution by impregnation, and after impregnation, the solid was dried and calcined at 350°C for 3 hours to obtain a La catalyst. In the La catalyst, the mass percentage of La was 10% based on 100% of the mass of the Ce-Zr composite oxide carrier.

[0038] The La catalyst obtained above was subjected to fluorination reaction at 340°C for 2 hours in a HF / N2mixed gas containing 5vol% HF to obtain a fluorination-treated La catalyst.

[0039] 240db and hydrogen fluoride were reacted in one step in the presence of the fluorination-treated La catalyst to generate 1234yf. The reaction parameters such as reaction pressure, reaction temperature, molar ratio of raw materials, and the composition of the outlet gas after 20 hours of reaction are shown in Table 1.

[0040] Example 3: A solution containing cerium nitrate and zirconium nitrate was adjusted to pH 9-10 with ammonia water, and then subjected to hydrothermal reaction at 180°C for 12 hours. After the hydrothermal reaction, the solid was calcined at 500°C for 4 hours to obtain a Ce-Zr composite oxide carrier. In the Ce-Zr composite oxide carrier, the molar ratio of Ce to Zr was 1:5.

[0041] The Ce-Zr composite oxide carrier obtained above is immersed in a chromium chloride solution by impregnation, and after impregnation, the solid is dried and calcined at 350 DEG C for 3 hours to obtain a Cr catalyst. In the Cr catalyst, the mass percentage of Cr is 15% based on 100% of the mass of the Ce-Zr composite oxide carrier.

[0042] The Cr catalyst obtained above is subjected to fluorination reaction at 340 DEG C for 2 hours in a HF / N2 mixed gas containing 5 vol% HF to obtain a fluorination-treated Cr catalyst.

[0043] 240db and hydrogen fluoride are reacted in one step in the presence of the fluorination-treated Cr catalyst to generate 1234yf, and reaction parameter conditions such as reaction pressure, reaction temperature, and molar ratio of raw materials, and gas composition at the outlet after 20 hours of reaction are shown in Table 1.

[0044] Table 1 Example 4: The difference from Example 1 is that cobalt nitrate solution is used instead of nickel nitrate solution during impregnation to obtain a Co catalyst, and in the Co catalyst, the mass percentage of Co is 5% based on 100% of the mass of the Ce-Zr composite oxide carrier, and the rest is the same. Reaction parameter conditions such as reaction pressure, reaction temperature, and molar ratio of raw materials for one-step fluorination of 240db to generate 1234yf, and gas composition at the outlet after 20 hours of reaction are shown in Table 2.

[0045] Example 5: The difference from Example 2 is that chromium nitrate and copper nitrate solution (molar ratio of chromium to copper is 1:1) is used instead of lanthanum nitrate solution during impregnation to obtain a Cr-Cu catalyst, and in the Cr-Cu catalyst, the total mass percentage of Cr and Cu is 10% based on 100% of the mass of the Ce-Zr composite oxide carrier, and the molar ratio of Cr to Cu is the same. Reaction parameter conditions such as reaction pressure, reaction temperature, and molar ratio of raw materials for one-step fluorination of 240db to generate 1234yf, and gas composition at the outlet after 20 hours of reaction are shown in Table 2.

[0046] Example 6: The difference from Example 3 is that iron nitrate and molybdenum nitrate solution (molar ratio of iron to molybdenum is 1:1) is used instead of chromium chloride solution during impregnation to obtain a Fe-Mo catalyst, and in the Fe-Mo catalyst, the total mass percentage of Fe and Mo is 15% based on 100% of the mass of the Ce-Zr composite oxide carrier, and the molar ratio of Fe to Mo is the same. Reaction parameter conditions such as reaction pressure, reaction temperature, and molar ratio of raw materials for one-step fluorination of 240db to generate 1234yf, and gas composition at the outlet after 20 hours of reaction are shown in Table 2.

[0047] Table 2 Example 7 Referring to Example 5, a long-term experiment of 240db one-step fluorination to produce 1234yf was carried out, and a total of 500 hours of catalytic reaction was carried out. The results are shown in Table 3.

[0048] Table 3 It can be seen that the catalyst of the present application has strong deactivation resistance, and the activity does not decrease after 500 hours of continuous catalytic reaction, which has very good industrial application value.

[0049] In addition, it should be understood that, after reading the above description of the present application, those skilled in the art can make various modifications or modifications to the present application, and these equivalent forms also fall within the scope defined by the claims attached hereto.

Claims

1. A process for the one-step fluorination of 240 db to produce 1234yf, characterized in that, The method comprises the following steps: 240db and hydrogen fluoride are reacted to generate 1234yf under the action of a fluorination catalyst; The catalyst comprises a Ce-Zr composite oxide carrier and one or more than two of Ni, La, Cr, Co, Fe, Sb, Mo and Cu supported on the carrier.

2. The process for the 240 db one-step fluorination to 1234yf according to claim 1, characterized in that, The fluorination treatment comprises fluorination reaction of the catalyst in a gas containing HF at 280-360 DEG C.

3. The process for the 240 db one-step fluorination to 1234yf according to claim 2, characterized in that, The fluorination treatment comprises fluorination reaction of the catalyst in a gas containing HF at 300-350 DEG C.

4. The process for the 240 db one-step fluorination to 1234yf according to claim 2 or 3, characterized in that, The gas containing HF comprises HF and an inert gas.

5. The process for the 240 db one-step fluorination to 1234yf according to claim 2 or 3, characterized in that, The volume fraction of HF in the gas containing HF is 5-10%.

6. The process for the 240 db one-step fluorination to 1234yf according to claim 2 or 3, characterized in that, The fluorination reaction time is 2-3 hours.

7. The process for the 240 db one-step fluorination to 1234yf according to claim 1, characterized in that, The preparation method of the catalyst comprises the following steps: a Ce-Zr composite oxide carrier is immersed in a precursor solution containing one or more than two of Ni, La, Cr, Co, Fe, Sb, Mo and Cu by using an impregnation method, and the solid is dried and calcined after impregnation to obtain the catalyst.

8. The process for the 240 db one-step fluorination to 1234yf according to claim 7, characterized in that, The calcination temperature is 340-400 DEG C.

9. The process for the 240 db one-step fluorination to 1234yf according to claim 8, characterized in that, The calcination temperature is 350-380 DEG C.

10. The process for the one-step fluorination of 240 db to 1234yf according to any one of claims 7 to 9, characterized in that, The calcination time is 3-4 hours.

11. The process for the 240 db one-step fluorination to 1234yf according to claim 1, characterized in that, The preparation method of the Ce-Zr composite oxide carrier comprises the following steps: a solution containing Ce(III) and Zr(IV) is adjusted to a pH of 9-10, and then hydrothermal reaction is carried out at 160-200 DEG C, and the solid is calcined after the hydrothermal reaction to obtain the Ce-Zr composite oxide carrier.

12. The process for the 240 db one-step fluorination to 1234yf according to claim 11, characterized in that, The hydrothermal reaction is carried out at 180-190 DEG C.

13. The process for the 240 db one-step fluorination to 1234yf according to claim 11 or 12, characterized in that, The hydrothermal reaction time is 12-18 hours.

14. The process for the 240 db one-step fluorination to 1234yf of claim 11 wherein, The calcination temperature is 480-520 DEG C, and the calcination time is 4-5 hours.

15. The process for the 240 db one-step fluorination to 1234yf of claim 1 wherein, In the catalyst, the mass fraction of one or more than two of Ni, La, Cr, Co, Fe, Sb, Mo and Cu in the Ce-Zr composite oxide carrier is 5-15% based on 100% of the mass of the Ce-Zr composite oxide carrier.

16. The process for the 240 db one-step fluorination to 1234yf according to claim 1 or 15, characterized in that, In the Ce-Zr composite oxide carrier, the molar ratio of Ce to Zr is 1:1-5.

17. The process for the 240 db one-step fluorination to 1234yf of claim 1 wherein, The molar ratio of 240db to hydrogen fluoride is 1:5-30.

18. The process for the 240 db one-step fluorination to 1234yf of claim 1 wherein, The reaction temperature for one-step reaction to generate 1234yf is 250-390 DEG C.

19. The process for the 240 db one-step fluorination to 1234yf of claim 1 wherein, The reaction pressure for one-step reaction to generate 1234yf is 0.1-0.6 MPa.

20. The process for the one-step fluorination of 240 db to 1234yf according to claim 1, wherein, The catalyst volume space velocity for one-step reaction to generate 1234yf is 500-1500 h -1 .

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