Preparation method of 1, 2, 3, 3, 3-pentafluoropropylene

Abstract

The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 1, 2, 3, 3, 3-pentafluoropropylene. By designing the perovskite type catalyst doped with the noble metal or synergistically constructing the supported metal catalyst, the electronic structure and the surface activity of the catalyst are innovatively improved, and further the catalytic performance on the reaction of CF2 = CH2 and CF3Cl is enhanced. The process of synthesizing the 1, 2, 3, 3, 3-pentafluoropropylene through the reaction of CF2 = CH2 and CF3Cl is realized through a selective catalytic reaction instead of a traditional complex process, so that the method has the characteristics of simplicity, convenience and high efficiency, and particularly shows unique advantages in the aspects of catalytic selectivity and reaction condition control. The precious metal-doped perovskite type catalyst or the supported metal catalyst designed by the invention can realize high-selectivity and high-yield synthesis reaction under mild conditions, and has great technical breakthrough.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to a method for preparing 1,2,3,3,3-pentafluoropropene. Background Art

[0002] With the improvement of global environmental protection requirements, traditional refrigerants such as hydrochlorofluorocarbons (HCFCs) and chlorofluorocarbons (CFCs) have been gradually phased out due to their high ozone depletion potential (ODP) and global warming potential (GWP). Although hydrofluorocarbons (HFCs) do not damage the ozone layer, their global warming potential is still relatively high, making it difficult to meet the global emission reduction requirements. Therefore, the demand for new refrigerants with low GWP and no ODP is becoming increasingly urgent.

[0003] 1,1,3,3,3-Pentafluoropropene (HFO-1225zc), with a boiling point of -21°C, a freezing point of -153°C, an ODP value of 0, and a low GWP value, is considered an effective substitute for hydrofluorocarbon (HFCs) refrigerants. It can also be mixed with HFO-1234ze (CF3CH=CHF), HFO-1234yf (CF3CF=CH2), HFC-152a (CH3CHF2), etc. to form azeotropes. In addition, 1,2,3,3,3-pentafluoropropene can also be used as a blowing agent, aerosol propellant, solvent, cleaning agent, and a synthetic intermediate for preparing HFO-1234yf and HFO-1234ze, having broad application prospects and market value. Studying its preparation process is of great significance for promoting the development of environmentally friendly refrigerants.

[0004] Currently, the main methods for preparing 1,2,3,3,3-pentafluoropropene are as follows:

[0005] Patents such as US6031141, US6093859, and US6369284 describe a method for preparing pentafluoropropene by gas-phase catalytic dehydrofluorination using hexafluoropropane as a raw material. The catalysts used in these patents include metal oxides, fluorides, and oxyfluorides such as aluminum, neodymium, chromium, and magnesium, and their mixtures. The reaction temperature range is 300°C to 450°C, the raw material conversion rate is about 30% to 50%, and the product selectivity is between 80% and 90%. However, these technologies have problems such as high catalyst cost, low efficiency, and poor stability.

[0006] The patent CN101628849B proposes a method for synthesizing pentafluoropropene using a catalyst containing magnesium, zinc oxides or fluorides combined with aluminum. The reaction is achieved by dehydrofluorination under high-temperature conditions of 250°C to 380°C. Although this catalyst shows certain catalytic activity, its ability to control by-products is limited, and it is prone to catalyst sintering at high temperatures, shortening the service life. In addition, the use of corrosive oxides and fluorides increases the corrosion resistance requirements of the equipment, further increasing the reaction cost.

[0007] The patent CN103804122A proposes a process for converting trifluoropropene to pentafluoropropene using a cobalt fluoride (CoF2 / CoF3) catalyst. This process relies on the oxidation-reduction cycle of cobalt fluoride to achieve continuous reaction through cyclic regeneration. However, the cobalt fluoride catalyst needs to handle highly toxic fluorine gas during operation, with strict operating conditions and high requirements for safety management. In addition, this catalyst is easily deactivated by impurities such as moisture, resulting in frequent replacement, thus increasing the production cost.

[0008] The patent CN101479218B describes a supported palladium catalyst for dehydrochlorination and hydrogenation of chlorine-containing precursors to produce pentafluoropropene. Although the palladium catalyst has good catalytic performance, it is prone to generating by-products such as alkynes during the reaction, reducing the selectivity of the target product. In addition, the palladium catalyst is easily poisoned by chloride ions, thus affecting the ability for long-term continuous operation.

[0009] The method described in the patent CN102887812A uses an alkali metal oxide or hydroxide as a catalyst for dehydrofluorination reaction with pentafluorohalopropane as the raw material. Although this method is effective, the reaction conditions are harsh, by-products such as alkynes are easily generated, and the control requirements for catalyst concentration and ratio are relatively high, with a complex process, which is not conducive to industrial scale production.

[0010] Therefore, how to provide a preparation method of 1,2,3,3,3-pentafluoropropene with cheap and easily available raw materials, milder reaction, high yield, simple process, fewer steps and easy industrialization is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0011] In view of this, the present invention discloses a preparation method of 1,2,3,3,3-pentafluoropropene, which is a method for preparing 1,2,3,3,3-pentafluoropropene with high conversion rate, low energy consumption, fewer by-products, and being green and environmentally friendly.

[0012] To achieve the above object, the present invention adopts the following technical solutions:

[0013] A preparation method of 1,2,3,3,3-pentafluoropropene, the method is as follows:

[0014] 1,2,3,3,3 - pentafluoropropene is synthesized by the reaction of CF2=CH2 (vinylidene fluoride) and CF3Cl (chlorotrifluoromethane). The preparation method includes the following steps:

[0015]

[0016] Furthermore, the catalyst is one of a perovskite - type material doped with noble metal or a supported metal catalyst; wherein,

[0017] The perovskite - type material is LaNiO3 or LaCoO3, the doped noble metal is Pd or Pt, and the doping ratio of the noble metal is 0.1 - 10 wt%, based on the total mass of the perovskite material.

[0018] The metal of the supported metal catalyst is selected from one or a combination of Mg, Al, Fe, Zn, Co, Ni, etc., and the carrier is one of AlF3, MgF2, Al2O3, Cr2O3, ZrO2, activated carbon, AlCl3, FeCl3 or aluminum - based spinel, and the chemical formula of the aluminum - based spinel is BAl2O 4-X F 2X (0≤X≤4); the metal loading accounts for 0.1 - 10 wt% of the total mass of the catalyst.

[0019] Furthermore, the doping ratio of the noble metal is 1 - 6 wt%, and the metal loading accounts for 3 - 8 wt% of the total mass of the catalyst.

[0020] Among them, the preparation method of the LaNiO3 or LaCoO3 catalyst doped with noble metal (Pd or Pt) is as follows:

[0021] First, using the sol - gel method, with lanthanum nitrate (La(NO3)3), nickel nitrate (Ni(NO3)2) or cobalt nitrate (Co(NO3)2) as precursors, deionized water is added to form a uniform precursor solution. Then, a certain amount of noble - metal precursor (such as PdCl2 or PtCl4) is added to the solution according to the required doping ratio, and the solution is stirred well to mix evenly. Next, at a temperature of 70°C, the pH of the solution is adjusted to about 6 by adding a small amount of citric acid to form a sol gradually. After the sol polymerizes, it is dried and pre - calcined in air pressure at 200°C for 1 - 2 hours to consume moisture and organic pollutants. Then, the pre - calcined sample is placed in a tubular furnace, heated to 700°C at a rate of 5°C / min in a specified atmosphere (such as nitrogen), and baked for 4 to 6 hours to form the required perovskite - structured catalyst, that is, the LaNiO3 or LaCoO3 catalyst doped with noble metal, which has a stable perovskite structure and high active sites.

[0022] Moreover, the supported metal catalyst is prepared by the impregnation method, and the preparation method is as follows:

[0023] First, prepare a metal precursor solution by dissolving metal salts such as Mg(NO3)2, AlCl3, FeCl3, ZnCl2, Co(NO3)2, and NiCl2 in deionized water or ethanol according to a set ratio, and adjust the pH of the solution as needed to enhance the interaction between metal ions and the support. Subsequently, add supports such as AlF3, MgF2, Al2O3, Cr2O3, ZrO2, activated carbon, AlCl3, FeCl3, or aluminum-based spinel to the metal precursor solution, and stir and impregnate at 40 - 80 °C for 2 - 12 hours to promote the uniform dispersion of metal components and enhance the binding with the support. After the impregnation is completed, perform solid-liquid separation and dry at 80 - 120 °C for 6 - 12 hours to remove the residual solvent. Subsequently, calcine in a nitrogen (N2) atmosphere at 300 - 700 °C for 2 - 6 hours to thermally decompose the metal precursor and form the active components of the catalyst.

[0024] Further, the volume ratio of CF2=CH2 (vinylidene fluoride) to CF3Cl (chlorotrifluoromethane) is 0.1 - 10:1, preferably 0.5 - 2:1.

[0025] Further, the reaction temperature is 100 °C - 1000 °C, preferably 300 °C - 600 °C; the reaction pressure is atmospheric pressure, and the reaction time is 1 - 300 s, preferably 5 - 60 s.

[0026] Further, the preparation method of 1,2,3,3,3-pentafluoropropene further includes: the product is obtained as high-purity 1,2,3,3,3-pentafluoropropene after alkali washing, water washing, drying, compression, and rectification and purification.

[0027] It should be noted that the reaction mechanism of the preparation method of 1,2,3,3,3-pentafluoropropene claimed in the present invention involves two types of catalytic systems, and the specific mechanism is as follows:

[0028] The first type of catalytic system: the action mechanism of perovskite-type catalysts doped with noble metals

[0029] This catalytic system uses a perovskite-type catalyst doped with noble metals (Pd or Pt) (such as LaNiO3 or LaCoO3) to promote the reaction of CF2=CH2 (vinylidene fluoride) with CF3Cl (chlorotrifluoromethane) to produce 1,2,3,3,3-pentafluoropropene (CF3CF=CHF). The reaction first occurs on the catalyst surface. CF2=CH2 and CF3Cl molecules are adsorbed on the active sites of the catalyst through electrostatic interactions, and the metal (such as Pd or Pt) activates the electronic structure of the reactants. In particular, the carbon-fluorine double bond and carbon-hydrogen double bond in the CF2=CH2 molecule form strong interactions under the action of the metal center, making the fluorine atoms in the molecule more likely to migrate and form reaction intermediates.

[0030] During this process, the chlorine atom in the CF3Cl molecule first dissociates with the help of the metal to generate Cl - ions. This dissociation step is achieved through the electronic action of the metal. The metal ions provide electrons through their d orbitals, form coordination with the chlorine atom, reduce the bond energy of the Cl atom, and thus promote the desorption of the chloride ion. The dissociated CF3Cl molecule exhibits stronger electrophilic properties and can undergo an exchange reaction with the fluorine atoms on the catalyst surface.

[0031] During this chlorine-fluorine exchange reaction process, the fluorine atoms on the catalyst surface exchange with the Cl atoms in CF3Cl to generate an intermediate of 1,2,3,3,3-pentafluoropropene. This intermediate is further stabilized by the action of the metal catalyst and maintains sufficient reaction activity. The exchanged product molecules will quickly desorb and enter the reaction system. The crystal structure of the perovskite-type catalyst provides a high specific surface area and stability, ensuring the long-term activity of the catalyst. In addition, doping with noble metals (Pd or Pt) not only increases the electron density on the catalyst surface, enhances the adsorption ability of CF3Cl, but also improves the catalytic selectivity and reaction rate of the catalyst for the chlorine-fluorine exchange reaction. Therefore, this catalytic system can efficiently synthesize 1,2,3,3,3-pentafluoropropene under relatively mild conditions while maintaining the stability and durability of the catalyst.

[0032] The second type of catalytic system: The mechanism of action of supported metal catalysts

[0033] This catalytic system uses a supported metal catalyst to promote the addition reaction of CF2=CH2 with CF3Cl to synthesize 1,2,3,3,3-pentafluoropropene. The metal components of the catalyst (such as Mg, Al, Fe, Zn, Co, Ni) can provide Lewis acid sites or redox active centers, and the support (such as AlF3, MgF2, Al2O3, Cr2O3 or aluminum-based spinel, etc.) regulates the adsorption and activation of CF2=CH2 through polar surface effects.

[0034] During the reaction process, the metal component of the catalyst can induce the polarization of the C-Cl bond in CF3Cl, promoting the dissociation of Cl - to generate highly reactive CF3 + or CF3 radicals (·CF3). Meanwhile, the support material strengthens the adsorption and activation of CF2=CH2 through the polar surface effect, making it easier to react with CF3 + or ·CF3. In the electrophilic addition pathway, CF3 + preferentially attacks the double bond of CF2=CH2 to form a CF3-CH2-CF2 + intermediate, and then the target product is obtained through proton elimination. In the radical addition pathway, ·CF3 attacks the π bond of CF2=CH2 to form a CF3-CH2-CF2· radical intermediate, which then undergoes electron rearrangement or hydrogen transfer to generate CF3CF=CHF. Finally, the product desorbs from the catalyst surface to achieve the catalytic cycle.

[0035] The combination of different metals and supports can regulate the Lewis acid-base and redox properties of the catalyst to optimize the activation efficiency of CF3Cl and improve the addition selectivity, reducing side reactions (such as C-C coupling or HCl elimination), thereby enhancing the yield and purity of the target product. In particular, the aluminum-based spinel BAl2O4-XF2X (0 ≤ X ≤ 4) can adjust the acidity and electronic structure of the catalyst surface by precisely controlling the F - concentration, further enhancing the catalytic performance, improving the selectivity of the reaction, and enhancing the stability of the catalyst. By optimizing the selection of metal components and support materials, precise control of the catalyst performance can be achieved, ensuring the efficient activation of CF3Cl, improving the selectivity of the reaction, and effectively suppressing side reactions, ultimately achieving the synthesis of 1,2,3,3,3-pentafluoropropene with high yield and high purity.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] 1. Efficient reaction process: The perovskite-type catalyst doped with noble metals or the supported metal catalyst is used, which has good catalytic activity and high reaction rate, and can achieve highly selective reactions of CF2=CH2 and CF3Cl at relatively low temperatures.

[0038] 2. Environmental friendliness: This catalytic system not only reduces the generation of by-products but also avoids environmental pollution in the use of traditional catalysts through selective catalytic reactions, conforming to the principles of green chemistry. At the same time, CF3Cl is an ozone-depleting substance. Using it as a raw material to produce the environmentally friendly refrigerant pentafluoropropene has important environmental significance for the comprehensive utilization of ODS.

[0039] 3. Stability and durability of materials: The perovskite-structured catalyst has good thermal and chemical stability, can be used for a long time in high-temperature and highly reactive environments, is not easily deactivated, and significantly extends the service life of the catalyst.

[0040] 4. Low cost and easy availability of reactants: As reactants, CF2=CH2 and CF3Cl have relatively superior cost and easy availability. CF2=CH2 (vinylidene fluoride) is widely used in the fluorine chemical industry, has a low cost and is easy to synthesize. CF3Cl (chlorotrifluoromethane), as a fluoride chemical, usually has good market supply channels, so the cost control of the reactants is relatively ideal.

[0041] 5. Economy: Compared with other expensive catalysts (such as noble metal catalysts), the perovskite-type catalyst doped with metals not only provides excellent catalytic performance but also has competitiveness in terms of cost.

[0042] 6. Selective design of the catalyst: By using the perovskite-type catalyst doped with noble metals, the electronic structure and surface activity of the catalyst are innovatively improved, thereby enhancing the catalytic performance for the reaction of CF2=CH2 and CF3Cl. At the same time, the supported metal catalyst can not only induce the electrophilic addition of CF3 through Lewis acid sites + but also promote the addition of CF3 radicals through the metal active center, enhancing the catalytic applicability, adapting to different reaction environments, and improving the overall catalytic efficiency.

[0043] 7. New reaction route: The process of synthesizing 1,2,3,3,3-pentafluoropropene from CF2=CH2 and CF3Cl is through a selective catalytic reaction rather than a traditional complex process, which is simpler and more efficient, and shows unique advantages especially in catalytic selectivity and reaction condition control.

[0044] 8. Modification of the catalyst: This patent innovatively modifies the perovskite-type materials such as LaNiO3 or LaCoO3 by metal doping to regulate the acidity, basicity and redox properties of the catalyst, and improve its catalytic effect on fluoride reactants. At the same time, the supported metal catalyst precisely adjusts the surface acidity of the catalyst by regulating the metal-support synergy, enabling it to efficiently activate CF2=CH2 and reduce side reactions to ensure the high-selectivity formation of the target product.

[0045] 9. Application of the perovskite-type catalyst: The application of perovskite-type materials in fluoride reactions is for the first time, and the strategy of doping with Pd or Pt effectively improves the catalytic activity and selectivity, demonstrating a new catalytic mechanism and application direction.

[0046] 10. New Route for the Synthesis of Fluoroolefins: The traditional synthesis of 1,2,3,3,3-pentafluoropropene usually requires complex reaction conditions. However, this method uses a perovskite-type catalyst doped with noble metals or a supported metal catalyst to achieve a synthesis reaction with high selectivity and high yield under mild conditions, representing a significant technological breakthrough. Description of the Drawings

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings described below are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0048] Figure 1 It is the GC-MS detection spectrum of the pentafluoropropene product synthesized by the present invention. Detailed Embodiments

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0050] The special term "embodiment" used here does not necessarily mean that any embodiment described as "exemplary" is superior to or better than other embodiments. For the performance index tests in the embodiments of the present application, unless otherwise specified, conventional test methods in the art are used. It should be understood that the terms described in the present application are only used to describe specific embodiments and are not intended to limit the content disclosed in the present application.

[0051] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as those commonly understood by those of ordinary skill in the technical field to which this application belongs; other test methods and technical means not specifically mentioned in this application refer to the experimental methods and technical means commonly used by those of ordinary skill in the art.

[0052] To better illustrate the content of this application, numerous specific details are given in the following detailed embodiments. Those skilled in the art should understand that the present application can still be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well-known to those skilled in the art are not described in detail to highlight the gist of this application.

[0053] On the premise of no conflict, the technical features disclosed in the embodiments of this application can be arbitrarily combined, and the obtained technical solutions belong to the content disclosed in the embodiments of this application.

[0054] The present invention discloses a method for preparing 1,2,3,3,3 - pentafluoropropene.

[0055] For a better understanding of the present invention, the following specific embodiments are used to further elaborate the present invention, but it should not be construed as a limitation of the present invention. For those skilled in the art, some non - essential improvements and adjustments made according to the above - mentioned invention content are also considered to fall within the protection scope of the present invention.

[0056] Example 1

[0057] Using hexafluoropropane as a raw material to prepare high - purity 1,2,3,3,3 - pentafluoropropene, the reaction device configuration includes a heating system, a temperature controller, a mass flowmeter, and a gas collection device:

[0058] First, prepare a LaCoO3 catalyst doped with noble metal Pt by the sol - gel method: Using lanthanum nitrate (La(NO3)3) and cobalt nitrate (Co(NO3)2) as precursors, adding deionized water to form a homogeneous precursor solution; adding a certain amount of noble metal precursor PtCl4 into the solution according to a doping ratio of 2%, and stirring the solution thoroughly to mix evenly; at a temperature of 70 °C, adjusting the pH of the solution to about 6 by adding a small amount of citric acid to gradually form a sol; after the sol polymerizes, dry it and pre - burn it in air pressure at 200 °C for 1 hour to consume moisture and organic pollutants, then place the pre - burned sample in a tube furnace, and heat it to 700 °C at a rate of 5 °C / min in a specified atmosphere (such as nitrogen), and bake for 4 hours to form the required perovskite - structured catalyst.

[0059] Weigh 10 g and load it into a tube reactor, raise the temperature from room temperature to 500 °C at a rate of 5 °C / min, and carry out a reduction treatment at this temperature for 2 hours to activate the active centers of the catalyst; after the reduction is completed, cool the catalyst to the reaction temperature of 400 °C. Under normal pressure, an inert gas is first introduced into the reactor to form a suitable atmosphere to ensure the stability of the reaction environment.

[0060] Set the volume ratio of vinylidene fluoride (CF2 = CH2) to chlorotrifluoromethane (CF3Cl) to 0.8:1 to ensure the high efficiency and selectivity of the reaction. Use a mass flowmeter to control the total flow rate to 400 mL / min to ensure a suitable inert atmosphere, and the reaction time is 60 s. After reaching the reaction time, stop the nitrogen introduction. The tail gas generated by the reaction is subjected to rapid cooling, alkali washing, water washing, drying, compression, and rectification purification to finally obtain 1,2,3,3,3 - pentafluoropropene with a purity ≥ 99%.

[0061] In this reaction, the selectivity of pentafluoropropene is 91.2%, the conversion rate of vinylidene fluoride is 85.1%, and the conversion rate of chlorotrifluoromethane is 81.1%.

[0062] Example 2

[0063] Using hexafluoropropane as raw material, high-purity 1,2,3,3,3-pentafluoropropene is prepared. The reaction device configuration includes a heating system, a temperature controller, a mass flow meter and a gas collection device:

[0064] First, a LaCoO3 catalyst doped with the precious metal Pd is prepared by a sol-gel method: lanthanum nitrate (La(NO3)3) and nickel nitrate (Co(NO3)2) are used as precursors, and deionized water is added to the solution to form a uniform precursor solution; a certain amount of precious metal precursor PdCl2 is added to the solution at a doping ratio of 2%, and the solution is fully stirred for uniform mixing; at a temperature of 70°C, the pH of the solution is adjusted to about 6 by adding a small amount of citric acid, so that a sol is gradually formed; after the sol is polymerized, it is dried and pre-fired at 200°C in air pressure for 1 hour to consume moisture and organic pollutants, and then the pre-fired sample is placed in a tubular furnace, heated to 700°C at 5°C / min under a specified atmosphere (such as nitrogen), and baked for 4 hours to form the desired perovskite structure catalyst.

[0065] Take 10g of the catalyst and load it into a tubular reactor. Raise the temperature from room temperature to 500℃ at a rate of 5℃ / min. Perform reduction treatment at this temperature for 2 hours to activate the activity of the catalyst. After the reduction is completed, cool the catalyst to the reaction temperature of 200℃. Under normal pressure, inert gas is first introduced into the reactor to form a suitable atmosphere to ensure a stable reaction environment.

[0066] The volume ratio of vinylidene fluoride (CF2=CH2) to trifluorochloromethane (CF3Cl) is set to 8:1 to ensure the high efficiency and selectivity of the reaction. The total flow rate is controlled to 400mL / min using a mass flow meter to ensure the provision of a suitable inert atmosphere. The reaction time is 200s. After the reaction time is reached, the nitrogen is stopped, and the tail gas generated by the reaction is quenched, alkali washed, washed with water, dried, compressed and distilled to finally obtain 1,2,3,3,3-pentafluoropropylene with a purity of ≥99%.

[0067] In the reaction, the selectivity of pentafluoropropylene was 85.8%, the conversion of vinylidene fluoride was 76.9%, and the conversion of trifluorochloromethane was 70.4%.

[0068] Example 3

[0069] Using hexafluoropropane as raw material, high-purity 1,2,3,3,3-pentafluoropropene is prepared. The reaction device configuration includes a heating system, a temperature controller, a mass flow meter and a gas collection device:

[0070] First, prepare the LaNiO3 catalyst doped with noble metal Pt by the sol-gel method: Using lanthanum nitrate (La(NO3)3) and nickel nitrate (Ni(NO3)2) as precursors, add deionized water to form a homogeneous precursor solution; Add a certain amount of the noble metal precursor PtCl4 into the solution according to a doping ratio of 2%, and stir the solution thoroughly to mix evenly; At a temperature of 70 °C, adjust the pH of the solution to about 6 by adding a small amount of citric acid to gradually form a sol; After the sol polymerizes, dry it and pre-burn it in air pressure at 200 °C for 1 hour to consume moisture and organic pollutants, then place the pre-burned sample in a tubular furnace, and heat it to 700 °C at a rate of 5 °C / min under a specified atmosphere (such as nitrogen), and bake for 4 hours to form the required perovskite structure catalyst.

[0071] Weigh 10 g and load it into a tubular reactor, heat the temperature from room temperature to 500 °C at a rate of 5 °C / min, and carry out reduction treatment at this temperature for 2 hours to activate the active centers of the catalyst; After the reduction is completed, heat the catalyst to the reaction temperature of 700 °C. Under normal pressure, an inert gas is first introduced into the reactor to form a suitable atmosphere to ensure the stability of the reaction environment.

[0072] Set the volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) to 6:1 to ensure the high efficiency and selectivity of the reaction. Use a mass flowmeter to control the total flow rate to 400 mL / min to ensure a suitable inert atmosphere, and the reaction time is 200 s. After reaching the reaction time, stop the introduction of nitrogen. The tail gas generated by the reaction undergoes rapid cooling, alkali washing, water washing, drying, compression, and rectification purification to finally obtain 1,2,3,3,3-pentafluoropropene with a purity of ≥99%.

[0073] In this reaction, the selectivity of pentafluoropropene is 87.1%, the conversion rate of vinylidene fluoride is 83.9%, and the conversion rate of chlorotrifluoromethane is 76.3%.

[0074] Example 4

[0075] In this experiment, hexafluoropropane is used as the raw material to prepare high-purity 1,2,3,3,3-pentafluoropropene. The reaction device configuration includes a heating system, a temperature controller, a mass flowmeter, and a gas collection device:

[0076] First, a LaNiO3 catalyst doped with the precious metal Pd is prepared by a sol-gel method: lanthanum nitrate (La(NO3)3) and nickel nitrate (Ni(NO3)2) are used as precursors, and deionized water is added to the solution to form a uniform precursor solution; a certain amount of precious metal precursor PdCl2 is added to the solution at a doping ratio of 2%, and the solution is fully stirred and evenly mixed; at a temperature of 70°C, the pH of the solution is adjusted to about 6 by adding a small amount of citric acid, so that a sol is gradually formed; after the sol is polymerized, it is dried and pre-fired at 200°C in air pressure for 1 hour to consume moisture and organic pollutants, and then the pre-fired sample is placed in a tubular furnace, heated to 800°C at 5°C / min under a specified atmosphere (such as nitrogen), and baked for 4 hours to form the desired perovskite structure catalyst.

[0077] 10g of the catalyst was loaded into a tubular reactor, and the temperature was raised from room temperature to 500°C at a rate of 5°C / min. The catalyst was reduced at this temperature for 2 hours to activate the active center of the catalyst. After the reduction was completed, the catalyst was cooled to the reaction temperature of 400°C. Under normal pressure, an inert gas was first introduced into the reactor to form a suitable atmosphere to ensure a stable reaction environment.

[0078] The volume ratio of vinylidene fluoride (CF2=CH2) to trifluorochloromethane (CF3Cl) is set to 10:1 to ensure the high efficiency and selectivity of the reaction. The total flow rate is controlled to 400mL / min using a mass flow meter to ensure the provision of a suitable inert atmosphere. The reaction time is 100s. After the reaction time is reached, the nitrogen is stopped, and the tail gas generated by the reaction is quenched, alkali washed, washed with water, dried, compressed and distilled to finally obtain 1,2,3,3,3-pentafluoropropylene with a purity of ≥99%.

[0079] In the reaction, the selectivity of pentafluoropropylene was 81.1%, the conversion of vinylidene fluoride was 72.9%, and the conversion of trifluorochloromethane was 70.2%.

[0080] Example 5

[0081] Using hexafluoropropane as raw material, high-purity 1,2,3,3,3-pentafluoropropene is prepared. The reaction device configuration includes a heating system, a temperature controller, a mass flow meter and a gas collection device:

[0082] First, the Mg-loaded Al2O3 metal catalyst was prepared by impregnation method:

[0083] Prepare a metal precursor solution, dissolve Mg(NO3) metal salt in deionized water or ethanol at a ratio of 5%, and adjust the solution pH to 6 as needed to enhance the interaction between metal ions and the carrier; then, add the Al2O3 carrier to the metal precursor. The bulk solution was stirred and impregnated at 80 °C for 5 hours to promote the uniform dispersion of the metal components and enhance the bonding with the support; combination;After the impregnation is completed, solid-liquid separation is carried out, and drying is performed at 100 °C for 7 hours to remove the residual solvent; then the pre-calcined sample is placed in a tubular furnace and heated to 700 °C at a rate of 5 °C / min under a specified atmosphere (such as nitrogen), and baked for 6 hours to form the required supported metal catalyst.

[0084] Take 10 g and load it into a tubular reactor. Heat the temperature from room temperature to 500 °C at a rate of 5 °C / min, and perform a reduction treatment at this temperature for 2 hours to activate the active centers of the catalyst; after the reduction is completed, cool the catalyst to the reaction temperature of 400 °C. Under atmospheric pressure, an inert gas is first introduced into the reactor to form a suitable atmosphere to ensure the stability of the reaction environment.

[0085] The volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) is set to 2:1 to ensure the high efficiency and selectivity of the reaction. Use a mass flow meter to control the total flow rate to 400 mL / min to ensure a suitable inert atmosphere, and the reaction time is 60 s. After reaching the reaction time, stop the nitrogen introduction, and the tail gas generated by the reaction is subjected to rapid cooling, alkali washing, water washing, drying, compression, and rectification purification to finally obtain 1,2,3,3,3-pentafluoropropene with a purity ≥ 99%.

[0086] In this reaction, the selectivity of pentafluoropropene is 61.2%, the conversion rate of vinylidene fluoride is 58.1%, and the conversion rate of chlorotrifluoromethane is 55.1%.

[0087] Example 6

[0088] Add PdCl2 to the solution to prepare the catalyst at a doping ratio of 1%. The reaction temperature is stabilized at 500 °C. The volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) is set to 2:1, and the reaction time is 30 s. The rest is the same as in Example 1. The selectivity of pentafluoropropene is 95.5%, the conversion rate of vinylidene fluoride is 86.8%, and the conversion rate of chlorotrifluoromethane is 76.1%.

[0089] Example 7

[0090] Add PdCl2 to the solution to prepare the catalyst at a doping ratio of 1%. The reaction temperature is stabilized at 850 °C. The volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) is set to 0.3:1, and the reaction time is 60 s. The rest is the same as in Example 2. The selectivity of pentafluoropropene is 92.2%, the conversion rate of vinylidene fluoride is 84.8%, and the conversion rate of chlorotrifluoromethane is 74.1%.

[0091] Example 8

[0092] The catalyst was prepared by adding PtCl4 to the solution at a doping ratio of 1%. The reaction temperature was stabilized at 400 °C. The volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) was set at 2:1. The reaction time was 30 s. The rest was the same as in Example 3. The selectivity of pentafluoropropene was 98.3%, the conversion rate of hexafluoropropane was 96.8%, and the conversion rate of chlorotrifluoromethane was 92.8%.

[0093] Example 9

[0094] The catalyst was prepared by adding PtCl4 to the solution at a doping ratio of 0.5%. The reaction temperature was stabilized at 200 °C. The volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) was set at 0.1:1. The reaction time was 100 s. The rest was the same as in Example 4. The selectivity of pentafluoropropene was 84.7%, the conversion rate of vinylidene fluoride was 67.8%, and the conversion rate of chlorotrifluoromethane was 62.5%.

[0095] Example 10

[0096] The catalyst was prepared by adding PdCl2 to the solution at a doping ratio of 3%. The reaction temperature was stabilized at 400 °C. The volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) was set at 2:1. The reaction time was 30 s. The rest was the same as in Example 1. The selectivity of pentafluoropropene was 75.5%, the conversion rate of vinylidene fluoride was 66.8%, and the conversion rate of chlorotrifluoromethane was 56.1%.

[0097] Example 11

[0098] The catalyst was prepared by adding PtCl4 to the solution at a doping ratio of 3%. The reaction temperature was stabilized at 400 °C. The volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) was set at 2:1. The reaction time was 30 s. The rest was the same as in Example 3. The selectivity of pentafluoropropene was 78.3%, the conversion rate of hexafluoropropane was 71.8%, and the conversion rate of chlorotrifluoromethane was 62.8%.

[0099] Example 12

[0100] The supported Mg Al2O3 metal catalyst was replaced with a supported Co AlF3 metal catalyst. The reaction temperature was stabilized at 300 °C. The volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) was set at 0.5:1. The reaction time was 10 s. The rest was the same as in Example 5. The selectivity of pentafluoropropene was 74.7%, the conversion rate of vinylidene fluoride was 67.2%, and the conversion rate of chlorotrifluoromethane was 60.3%.

[0101] Example 13

[0102] Replace the metal catalyst of Mg-loaded Al2O3 with the metal catalyst of Ni-loaded AlF3, adjust the metal loading to 2 wt%, keep the reaction temperature stable at 300 °C, set the volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) to 0.5:1, set the reaction time to 10 s, and the rest is the same as in Example 5. The selectivity of pentafluoropropene is 84.7%, the conversion rate of vinylidene fluoride is 77.2%, and the conversion rate of chlorotrifluoromethane is 70.3%.

[0103] Example 14

[0104] Replace the metal catalyst of Mg-loaded Al2O3 with the metal catalyst of Zn-loaded aluminum spinel, adjust the metal loading to 8 wt%, keep the reaction temperature stable at 500 °C, set the volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) to 2:1, set the reaction time to 80 s, and the rest is the same as in Example 5. The selectivity of pentafluoropropene is 64.7%, the conversion rate of vinylidene fluoride is 57.2%, and the conversion rate of chlorotrifluoromethane is 59.3%.

[0105] Example 15

[0106] Replace the metal catalyst of Mg-loaded Al2O3 with the metal catalyst of Fe-loaded Cr2O3, adjust the metal loading to 5 wt%, keep the reaction temperature stable at 400 °C, set the volume ratio of vinylidene fluoride (CF2=CH2) to chlorotrifluoromethane (CF3Cl) to 2:1, set the reaction time to 30 s, and the rest is the same as in Example 5. The selectivity of pentafluoropropene is 86.7%, the conversion rate of vinylidene fluoride is 81.2%, and the conversion rate of chlorotrifluoromethane is 79.3%.

[0107] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing 1,2,3,3,3-pentafluoropropene, characterized in that, 1,2,3,3,3 - pentafluoropropene is synthesized by the reaction of vinylidene fluoride CF2=CH2 with chlorotrifluoromethane CF3Cl, and the synthesis route is as follows:

2. The method for preparing 1,2,3,3,3-pentafluoropropene according to claim 1, wherein The catalyst is one of a perovskite - type material doped with noble metal or a supported metal catalyst; wherein, The perovskite - type material is LaNiO3 or LaCoO3, the doped noble metal is Pd or Pt, and the doping ratio of the noble metal is 0.1 - 10 wt%, based on the total mass of the perovskite material; The metal of the supported metal catalyst is selected from one or more combinations of Mg, Al, Fe, Zn, Co, and Ni, and the carrier is one of AlF3, MgF2, Al2O3, Cr2O3, ZrO2, activated carbon, AlCl3, FeCl3, or aluminum-based spinel. The chemical formula of the aluminum-based spinel is BAl2O 4-X F 2X (0 ≤ X ≤ 4); the metal loading accounts for 0.1 - 10 wt% of the total mass of the catalyst.

3. The preparation method of 1,2,3,3,3-pentafluoropropene according to claim 2, characterized in that, The doping ratio of the noble metal is 1 - 6 wt%, and the metal loading accounts for 3 - 8 wt% of the total mass of the catalyst.

4. The method for preparing 1,2,3,3,3-pentafluoropropene according to claim 1, characterized in that, The volume ratio of vinylidene fluoride to chlorotrifluoromethane is 0.1 - 10:

1.

5. The preparation method of 1,2,3,3,3-pentafluoropropene according to claim 1, wherein The reaction temperature is 100°C - 1000°C, the reaction pressure is atmospheric pressure, and the reaction time is 1 - 300 s.

6. The preparation method of 1,2,3,3,3-pentafluoropropene according to any one of claims 1-5, characterized in that, It also includes: The product is obtained as high - purity 1,2,3,3,3 - pentafluoropropene after alkali washing, water washing, drying, compression, and rectification purification.

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