A process for the preparation of 1,1,3,3,3-pentafluoropropene

Abstract

This invention belongs to the field of organic synthesis technology, specifically relating to a method for preparing 1,1,3,3,3-pentafluoropropylene. This invention designs a perovskite-type catalyst doped with noble metals or synergistically constructs a supported metal catalyst. Through a collaborative mechanism where the support provides strong Lewis acidity and fluorination activity, while the noble metal provides dehydrogenation activity, the interfacial interactions and reaction matching of the catalytic system are precisely controlled. This allows for highly efficient catalysis of the integrated "telomerization-fluorination-dehydrogenation" reaction of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF). The reaction can be carried out continuously in the same reactor and with the same synergistic catalyst system, without the need to change equipment or catalysts, resulting in outstanding production efficiency. Furthermore, the selectivity and controllability of the reaction conditions are significantly optimized, enabling high-selectivity and high-yield synthesis of the target product under mild conditions. Simultaneously, it achieves the resource utilization of industrial waste carbon tetrachloride, representing a major technological breakthrough in terms of raw material cost, process simplification, and environmental friendliness.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a method for preparing 1,1,3,3,3-pentafluoropropylene. Background Technology

[0002] With increasing global environmental protection requirements, traditional refrigerants such as hydrochlorofluorocarbons (HCFCs) and chlorofluorocarbons (CFCs) are gradually being phased out due to their high ozone depletion potential (ODP) and global greenhouse effect potential (GWP). Although HFCs do not damage the ozone layer, their greenhouse effect potential is still too high, making it difficult to meet 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-Pentafluoropropylene (HFO-1225zc), with a boiling point of -21℃, a freezing point of -153℃, an ODP value of 0, and a low GWP value, is considered an effective alternative to hydrofluorocarbon (HFC) refrigerants. It can be miscible with HFO-1234ze (CF3CH=CHF), HFO-1234yf (CF3CF=CH2), and HFC-152a (CH3CHF2) to form azeotropes. In addition, 1,1,3,3,3-Pentafluoropropylene can be used as a foaming agent, aerosol propellant, solvent, cleaning agent, and a synthetic intermediate for preparing HFO-1234yf and HFO-1234ze, demonstrating broad application prospects and market value. Researching its preparation process is of great significance for promoting the development of environmentally friendly refrigerants.

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

[0005] Patent CN107434759A proposes a method for preparing 1,1,3,3,3-pentafluoropropylene (HFO-1225zc). Using CF3X (where X is Cl or Br) and CH2=CF2 as raw materials, the reaction produces the intermediate CF3CH2CF2X under the action of a catalyst, which is then subjected to a de-HX reaction to obtain HFO-1225zc. While the raw materials are readily available, this method suffers from harsh reaction conditions, a complex catalytic system, and high energy consumption. It also poses risks of equipment corrosion and environmental safety, hindering its industrial application. Furthermore, the raw material CF3X is an ozone-depleting substance and has been banned; while vinylidene fluoride is expensive and prone to self-polymerization explosions, further limiting the practical feasibility of this process.

[0006] Patent CN101133008A discloses a method for preparing 1,1,3,3,3-pentafluoropropylene (HFO-1225zc) from 1,1,1,3,3,3-hexafluoropropane (HFC-236fa) via non-catalytic thermal cracking, directly removing hydrogen fluoride (HF) at 700–1000 °C. The conversion rate of HFC-236fa using this method is 25–75%, and the selectivity of HFO-1225zc is approximately 90%. The advantage of this high-temperature cracking process is its relatively simple flow, directly yielding the target product from HFC-236fa; however, its disadvantages include high reaction temperature, high energy consumption, and stringent requirements for equipment materials (such as the need for special nickel-based materials), thus increasing production costs. Furthermore, the conversion rate and selectivity of this method are still limited, resulting in poor overall economic efficiency.

[0007] Patent CN111454120A discloses a method for preparing 1,1,3,3,3-pentafluoropropene (HFO-1225zc) using 1,1,1,2,3,3-hexachloropropane and anhydrous hydrogen fluoride as raw materials. The mixture undergoes liquid-phase fluorination to produce 2-chloro-1,1,1,3,3-pentafluoropropane, followed by gas-phase dehydrochlorination to obtain HFO-1225zc. While this method allows for the resource utilization of raw materials, the process is complex, requires highly corrosion-resistant equipment, carries significant risks associated with the use of HF, has high energy consumption during separation, and imposes a heavy environmental burden, making it unsuitable for industrial application.

[0008] Patent CN101597208A discloses a method for producing HFC-1225cz from hydrofluoroalkane via wet high-temperature pyrolysis at 600–1000°C and atmospheric pressure in a steam or ammonia vapor atmosphere. This method achieves an R236fa conversion rate of 10–30% and a maximum HFC-1225cz selectivity of 92.3%. However, this method involves high reaction temperatures and high energy consumption, and the reactor requires the use of specialized materials such as nickel, making it expensive and unsuitable for industrial application.

[0009] The patent CN102887812A describes a defluorination reaction using pentafluorohalopropane as a raw material and alkali metal oxides or hydroxides as catalysts. Although this method is effective, the reaction conditions are harsh, it easily generates alkynes as byproducts, and it requires high control over catalyst concentration and ratio, making the process complex and unsuitable for large-scale industrial production.

[0010] Therefore, how to provide a method for preparing 1,1,3,3,3-pentafluoropropylene that is inexpensive and readily available, has a milder reaction, high yield, simple process, fewer steps, and is easy to industrialize is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

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

[0012] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing 1,1,3,3,3-pentafluoropropylene, the method being as follows: 1,1,3,3,3-pentafluoropropylene was synthesized by reacting vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF). The synthetic route is as follows: The overall reaction formula is: (1) The specific reaction steps are as follows: First, vinyl chloride (CHCl=CH2) and carbon tetrachloride (CCl4) spontaneously undergo a telomerization reaction to produce the intermediate 1,1,1,3,3-pentachloropropane (CCl3CH2CCl2H). (2) Under the influence of the fluorination active sites of the bifunctional catalyst, CCl3CH2CCl2H undergoes a selective fluorine-chlorine substitution reaction with HF to generate 1,1,1,3,3-pentafluoropropane (CF3CH2CF2H). (3) Under the action of the dehydrogenation active site of the same bifunctional catalyst, CF3CH2CF2H removes H2 to generate the target product 1,1,3,3,3-pentafluoropropylene (CF3CH=CF2). (4) Furthermore, the catalyst is either a noble metal-doped perovskite-type fluoride oxidase catalyst or a metal-supported fluorination functional carrier catalyst. Both types of catalysts possess both fluorine-chlorine replacement catalytic activity and CH bond activation dehydrogenation catalytic activity to adapt to the continuous "fluorination-dehydrogenation" reaction. The noble metal-doped fluorinated perovskite catalyst uses a fluorinated perovskite material as a functionalized support, whose chemical composition can be expressed as LaNiO3-XF2X or LaCoO3-XF2X (where 1≤X≤3). The fluorination treatment enables the support to possess the strong Lewis acidity and surface fluorine species required for catalytic fluorine-chlorine replacement. The supported dehydrogenation noble metal is one of Pd, Pt, Rh, and Ru, and the noble metal loading accounts for 0.1~5 wt% of the total catalyst mass, based on the total catalyst mass. The metal-supported fluorinated functional carrier catalyst has a support selected from AlF3, MgF2, fluorinated alumina Al2O3-F, fluorinated chromium trioxide Cr2O3-F, fluorinated ZSM-5 molecular sieve, titanium-based fluoride TiF4, cerium-based composite fluoride CeO2-F2O3, and aluminum-based fluorinated spinel, wherein the aluminum-based spinel has the chemical formula BAl2O4- X F 2X (0≤X≤4); the dehydrogenation metal active component is selected from one of Pd, Pt, Rh, Ru, Ir, Co, Ni, Fe, Cr-Mn composite system, Co-Ni composite system, and Fe-K composite system; the metal loading accounts for 0.1 ~ 10 wt% of the total mass of the catalyst.

[0013] Furthermore, for noble metal-doped fluorinated perovskite catalysts, the noble metal loading is preferably 0.5 to 2 wt%; for metal-supported fluorinated functional carrier catalysts, the metal loading is preferably 3 to 8 wt%.

[0014] The preparation method of noble metal-doped fluorinated perovskite catalyst is as follows: First, using the sol-gel method, lanthanum nitrate (La(NO3)3), nickel nitrate (Ni(NO3)2), or cobalt nitrate (Co(NO3)2) as precursors are dissolved in deionized water to form a homogeneous solution. Then, dehydrogenated noble metal precursors (such as PdCl2, PtCl4, Rh(NO3)3) are added. 2H2O, RuCl3 One of the three H₂O components is added according to the required loading ratio and thoroughly mixed. Next, citric acid is added at 70°C to adjust the pH to 5-7, forming a sol. After aging, it is dried at 80-100°C for 6-8 hours, followed by pre-calcination in air at 200°C for 1-2 hours. The pre-calcined sample is then heated to 700°C at a rate of 5°C / min under nitrogen or argon atmosphere and calcined for 4-6 hours to obtain the perovskite oxide precursor. Key step: The obtained perovskite precursor is treated at 200-400°C with a mixture of anhydrous HF and inert gas (or fluorocarbon compounds such as CHClF₂) for 2-6 hours to fluorinate, obtaining a fluorinated perovskite support (LaNiO₃-XF₂X or LaCoO₃-XF₂X, 1≤X≤3). Finally, a dehydrogenated noble metal is loaded onto this fluorinated support using an impregnation method, followed by drying and reduction activation to obtain the final catalyst.

[0015] Metal-supported fluorinated functionalized catalysts were prepared by impregnation method, as follows: First, prepare a precursor solution of the dehydrogenating metal active component by dissolving the corresponding metal salt (such as PdCl2, PtCl4, Co(NO3)2, NiCl2, etc.) in deionized water or ethanol in a specific ratio, adjusting the pH to 3-6 to optimize dispersion. Then, add a fluorination-enabled support (such as AlF3, MgF2, fluorinated alumina, fluorinated ZSM-5 molecular sieve, aluminum-based fluorinated spinel, etc.) to the solution and stir and impregnate at 40-80℃ for 4-12 hours. After impregnation, perform solid-liquid separation and dry at 80-120℃ for 6-12 hours. Finally, calcine in a nitrogen atmosphere. The calcination temperature is determined based on the support stability (300-500℃ for fluoride supports, 500-700℃ for oxide supports), and the calcination time is 2-6 hours, allowing the metal precursor to decompose and form dehydrogenating active centers. If the fluorination degree of the support is insufficient, supplementary fluorination treatment can be performed before or after metal loading.

[0016] Furthermore, the volume ratio of CHCl=CH2 (ethylene chloride), CCl4 (carbon tetrachloride), and HF (hydrogen fluoride) is 1:1:(2~50), preferably 1:1:10. This ratio ensures that the telomerization reaction proceeds fully and provides a sufficient fluorine source for fluorine-chlorine replacement, while excess HF can be recovered and reused.

[0017] Furthermore, the reaction temperature is 100℃~1000℃, preferably 300℃~600℃; the reaction pressure is atmospheric pressure; and the reaction time is 1~300s, preferably 5~60s.

[0018] Furthermore, the above-mentioned method for preparing 1,1,3,3,3-pentafluoropropylene also includes: the product is purified by alkali washing, water washing, drying, compression, and distillation to obtain high-purity 1,1,3,3,3-pentafluoropropylene.

[0019] It is worth noting that the reaction mechanism of the method for preparing 1,1,3,3,3-pentafluoropropylene claimed in this invention involves two types of catalytic systems, the specific mechanisms of which are as follows: First type of catalytic system: Mechanism of action of noble metal-doped perovskite fluoride catalysts This catalytic system utilizes a perovskite-type catalyst (such as LaNiO3 or LaCoO3) doped with a noble metal (one of Pd, Pt, Rh, Ru, or Ir) to promote the reaction of CHCl=CH2 (ethylene chloride) and CCl4 (carbon tetrachloride). This promotes the continuous reaction of the intermediate 1,1,1,3,3-pentachloropropane (CCl3CH2CCl2H) generated by the telomerization of vinyl chloride (CHCl=CH2) and carbon tetrachloride (CCl4) with hydrogen fluoride (HF), ultimately producing 1,1,3,3,3-pentafluoropropylene (CF3CH=CHF). Its core mechanism lies in the catalysis of the fluorinated functional support and the dehydrogenation functional metal. Firstly, the fluorinated perovskite support (LaMO3-XF2X, M=Ni, Co) has abundant strong Lewis acidic sites and active fluorine species on its surface. These sites efficiently adsorb and polarize the C-Cl bonds in the intermediate CCl3CH2CCl2H, while simultaneously activating HF molecules. This leads to a stepwise Cl→F substitution reaction via an ionic pathway, generating the fluorinated intermediate CF3CH2CF2H. Subsequently, this fluorinated intermediate rapidly migrates to the surface of adjacent, highly dispersed dehydrogenation noble metal (e.g., Pt, Pd) nanoparticles. Utilizing their unique surface electronic properties, the noble metal sites specifically adsorb and activate the CH bonds in CF3CH2CF2H, promoting the desorption of hydrogen atoms to form H2 via a dehydrogenation reaction. This induces intramolecular rearrangement to form carbon-carbon double bonds, ultimately yielding the target product. The close contact between the support and the noble metal at the nanoscale ensures the rapid and continuous execution of the fluorination-dehydrogenation reaction. The fluorine species consumed by the support can be continuously replenished and regenerated by excess HF, forming a highly efficient catalytic cycle.

[0020] Type II catalytic systems: Mechanism of action of metal-supported fluorinated functionalized catalysts This catalytic system employs a bifunctional supported metal catalyst to promote the addition reaction of CHCl=CH2 (ethylene chloride), CCl4 (carbon tetrachloride), and HF (hydrogen fluoride) to synthesize 1,1,3,3,3-pentafluoropropylene. Specifically, it utilizes a bifunctional supported catalyst to promote the continuous fluorine-chlorine substitution and dehydrogenation reaction between the intermediate 1,1,1,3,3-pentafluoropropylene and HF. Fluorination-catalyzing supports, such as AlF3, fluorinated alumina, and fluorinated molecular sieves, are the dominant agents in the fluorination reaction. Their surface strong acidic sites and fluorine species activate the C-Cl bond with HF, efficiently catalyzing the Cl→F substitution to generate CF3CH2CF2H. The dehydrogenation metal active components supported on these supports, such as Pd, Pt, Co, Ni, or their composites, serve as dehydrogenation centers. These metal sites (or alloys / composite oxides) selectively adsorb fluorinated intermediates and catalyze the cleavage and dehydrogenation of their CH bonds to generate the final olefin product.

[0021] When using metal composite systems (such as Co-Ni, Fe-K), the synergistic effect stems from the functional emphasis and electronic modulation of different metal species at the nanoscale, rather than the formation of a single "bifunctional" site. By precisely controlling the degree of fluorination, acidity, and loading and dispersion state of the metal components on the support, the rate matching of the two-step reaction can be optimized, side reactions can be suppressed, and thus a highly selective and stable continuous catalytic process can be achieved.

[0022] Compared with the prior art, the beneficial effects of the present invention are: 1. Synergistic and Efficient Reaction Process: Employing a functionally differentiated composite catalyst, the integrated "telomerization-fluorination-dehydrogenation" reaction is carried out continuously and efficiently in a single reactor through the synergistic relay catalysis of the fluorination functional support and the dehydrogenation functional metal. This design allows the fluorine-chlorine replacement and dehydrogenation reactions to be completed efficiently and continuously at their respective optimal active sites, increasing the reaction rate by more than 50% compared to traditional stepwise processes. High selectivity can be achieved within the preferred temperature range of 300~600℃, with a target product selectivity ≥91.7%.

[0023] 2. Raw materials are readily available and cost-effective: The raw materials used are vinyl chloride (CHCl=CH2) and carbon tetrachloride (CCl4), both of which are bulk industrial chemicals with mature preparation and supply channels, and are inexpensive and readily available. Carbon tetrachloride is a traditional industrial waste, and this invention achieves its resource utilization, reducing both raw material costs and environmental pressure. Using HF as a fluorine source, precise Cl→F substitution is achieved under the action of a bifunctional catalyst, eliminating the need to purchase expensive or restricted fluorine-containing intermediates. The overall raw material cost is reduced by more than 70% compared to existing processes.

[0024] 3. Material stability and durability: The fluorinated perovskite support and the dedicated fluorinated support possess excellent thermal stability and resistance to HF corrosion; the supported dehydrogenation metal components are highly dispersed and stable through strong interaction with the support. The catalyst can be used for a long time in a reaction environment of 200~800℃, with an activity decay of ≤5% after 1000 hours of continuous operation, and its service life is 2~3 times that of traditional catalysts.

[0025] 4. Process Safety and Environmental Advantages: Utilizing an "in-situ intermediate generation - continuous catalytic conversion" model eliminates the need for intermediate separation, reducing the risks associated with the handling and storage of hazardous chemicals. The recovery and utilization of carbon tetrachloride reduces ozone-depleting emissions, complying with the Montreal Protocol. Excess HF can be recovered and recycled through distillation, with a recovery rate ≥95%. Combined with alkaline and water washing processes, the risk of HF leakage is effectively controlled. Byproducts are only HCl and H2. HCl can be recycled to produce industrial hydrochloric acid, and H2 can be used as a clean energy source, with no hazardous waste emissions.

[0026] 5. Economic Efficiency: The composite catalyst of this invention eliminates the need for two different catalytic systems, reducing catalyst preparation and usage costs. By employing a partially low-cost transition metal composite system and optimizing the noble metal loading (0.5~2wt%), catalyst costs are effectively controlled while maintaining activity. The integrated continuous process also reduces equipment investment and operating energy consumption. Furthermore, the simplified process flow and mild reaction conditions further reduce equipment investment and energy consumption, enhancing the economic efficiency for industrial applications.

[0027] 6. Catalyst Selectivity Design: By designing a fluorinated support and a composite dehydrogenation metal system, the activity of fluorine-chlorine replacement and dehydrogenation is simultaneously enhanced. The strongly acidic sites of the support can catalyze Cl / F exchange with high selectivity, while the dehydrogenation metal center can effectively suppress side reactions such as C / C bond breaking, thus ensuring the high selectivity of the target product from the source. This avoids the selectivity fluctuations caused by switching between multiple catalysts in traditional processes.

[0028] 7. Novel Reaction Route: An innovative three-step integrated route of "telomerization (spontaneous) - fluorination - dehydrogenation" is adopted, and a two-step catalytic process is proposed to complete the integrated reaction through a functionally differentiated composite catalyst. The entire reaction is completed continuously in the same reactor and under the same catalyst system, simplifying the process and exhibiting greater convenience and efficiency, especially demonstrating unique advantages in catalytic selectivity and reaction condition control.

[0029] 8. Catalyst Modification: This patent innovatively modifies perovskite materials such as LaNiO3 or LaCoO3 by fluorination to endow them with the necessary fluorination function, and combines them with dehydrogenation metals to adapt them to continuous fluorine-chlorine replacement and dehydrogenation reactions; the supported catalyst can flexibly adjust the catalytic activity window by selecting different metals and supports, which can not only efficiently activate intermediates and HF, but also precisely control the dehydrogenation reaction rate, thus achieving efficient coupling of fluorination and dehydrogenation reactions.

[0030] 9. Application of perovskite catalysts: For the first time, perovskite materials were combined with noble metal doping and applied to the continuous "fluorination-dehydrogenation" reaction of fluorinated olefins, demonstrating a brand-new catalytic mechanism and application direction; The metal-support synergistic design of the supported bifunctional catalyst provides a new technical approach for multi-step continuous catalytic reactions. It has strong adaptability and can be extended to the fluorination and dehydrogenation coupling reactions of other halogenated compounds. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 This is the GC-MS detection spectrum of the pentafluoropropylene product synthesized in this invention. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] The term "embodiment" used herein, as an example, is not necessarily to be construed as superior to or better than other embodiments. Performance testing in the embodiments of this application, unless otherwise specified, employs conventional testing methods in the art. It should be understood that the terminology used in this application is merely for describing particular implementations and is not intended to limit the scope of this disclosure.

[0035] Unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; other experimental methods and technical means not specifically mentioned herein refer to experimental methods and technical means commonly used by one of ordinary skill in the art.

[0036] To better illustrate the content of this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented even without certain specific details. In the embodiments, some methods, means, instruments, and devices well-known to those skilled in the art are not described in detail in order to highlight the main points of this application.

[0037] Without conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solution belongs to the content disclosed in the embodiments of this application.

[0038] This invention discloses a method for preparing 1,1,3,3,3-pentafluoropropylene.

[0039] To better understand the present invention, the following embodiments are provided for further detailed description of the present invention, but they should not be construed as limiting the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are also considered to fall within the protection scope of the present invention.

[0040] Example 1 High-purity 1,1,3,3,3-pentafluoropropylene was prepared using vinyl chloride as a raw material. The reaction apparatus included a heating system, a temperature controller, a mass flow meter, and a gas collection device. First, a lanthanum-cobalt fluoride composite catalyst supported on dehydrogenated noble metal Pt was prepared using the sol-gel method and subsequent fluorination treatment: Lanthanum nitrate (La(NO3)3) and cobalt nitrate (Co(NO3)2) were added to deionized water and stirred to dissolve them, forming a homogeneous precursor solution; a certain amount of noble metal precursor PtCl4 was added to the solution at a loading ratio of 2%, and stirred thoroughly until homogeneous; at 70°C, the pH of the solution was adjusted to about 6 by adding a small amount of citric acid, and the solution was stirred continuously to allow the sol to gradually form; after the sol polymerized and gelled, it was dried in a 90°C oven for 7 hours, and then pre-calcined at 200°C in air for 1 hour to consume moisture and organic contaminants; then the pre-calcined sample was placed in a tube furnace and heated to 700°C at a rate of 5°C / min under a nitrogen atmosphere, and baked at a constant temperature for 4 hours to form a perovskite oxide precursor. The crucial fluorination process was then carried out: the baked sample was placed in another tube furnace and treated with a mixture of 20% anhydrous HF and nitrogen at 300-350°C for 4 hours to obtain a fluorinated lanthanum cobalt oxide support (LaCoO3-XF2X, where 1≤X≤3) on both the surface and bulk phase.

[0041] 10 g of the composite catalyst was loaded into a tubular reactor, and the temperature was increased from room temperature to 500°C at a rate of 5°C / min. At this temperature, the catalyst was reduced with hydrogen for 2 hours to activate the dehydrogenated noble metal active centers. 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 stable reaction atmosphere.

[0042] The volume ratio of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF) was set at 1:1:10, and the total flow rate was controlled at 400 mL / min using a mass flow meter. The reaction time was 60 s. After the reaction time was reached, the nitrogen gas supply was stopped. The tail gas generated by the reaction was purified by rapid cooling, alkali washing, water washing, drying, compression, and distillation to finally obtain high-purity 1,1,3,3,3-pentafluoropropylene.

[0043] In this reaction, the selectivity for 1,1,3,3,3-pentafluoropropylene was 96.8%, the conversion rate of vinyl chloride was 98.5%, and the conversion rate of carbon tetrachloride was 97.2%.

[0044] Example 2 High-purity 1,1,3,3,3-pentafluoropropylene was prepared using vinyl chloride as a raw material. The reaction apparatus included a heating system, a temperature controller, a mass flow meter, and a gas collection device. First, a lanthanum-cobalt fluoride composite catalyst supported on dehydrogenated noble metal Pd was prepared using the sol-gel method: Lanthanum nitrate (La(NO3)3) and cobalt nitrate (Co(NO3)2) were used as perovskite precursors, and deionized water was added and stirred to dissolve them, forming a homogeneous precursor solution. A certain amount of noble metal precursor PdCl2 was added to the solution at a loading ratio of 2%, and stirred thoroughly until homogeneous. At 70°C, the pH of the solution was adjusted to about 6 by adding a small amount of citric acid, and the solution was stirred continuously to allow the sol to gradually form. After the sol polymerized and gelled, it was dried in an oven at 80°C for 8 hours, and then pre-calcined at 200°C for 1 hour in an air atmosphere to consume moisture and organic contaminants. The pre-calcined sample was then placed in a tube furnace and heated to 700°C at a rate of 5°C / min under a nitrogen atmosphere, and baked at a constant temperature for 4 hours to form a perovskite oxide precursor. The precursor was then subjected to the same fluorination treatment as in Example 1 (300-350°C, 20% HF / N2, 4 hours) to convert it into a lanthanum cobalt fluoride support.

[0045] 10 g of the catalyst was loaded into a tubular reactor, and the temperature was increased from room temperature to 500°C at a rate of 5°C / min. The reactor was then subjected to reduction treatment at this temperature for 2 hours to activate the dehydrogenation active centers. After reduction, the catalyst was cooled to the reaction temperature of 300°C. An inert gas was first introduced into the reactor under atmospheric pressure to create a stable reaction atmosphere.

[0046] The volume ratio of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF) was set at 1:1:8, and the total flow rate was controlled at 400 mL / min using a mass flow meter. The reaction time was 80 s. After the reaction time was reached, the nitrogen gas supply was stopped. The tail gas generated by the reaction was purified by rapid cooling, alkali washing, water washing, drying, compression, and distillation to finally obtain high-purity 1,1,3,3,3-pentafluoropropylene.

[0047] In this reaction, the selectivity for 1,1,3,3,3-pentafluoropropylene was 97.3%, the conversion rate of vinyl chloride was 96.9%, and the conversion rate of carbon tetrachloride was 95.3%.

[0048] Example 3 High-purity 1,1,3,3,3-pentafluoropropylene was prepared using vinyl chloride as a raw material. The reaction apparatus included a heating system, a temperature controller, a mass flow meter, and a gas collection device. First, a lanthanum-nickel fluoride composite catalyst supported on the dehydrogenation noble metal Rh was prepared using the sol-gel method: lanthanum nitrate (La(NO3)3) and nickel nitrate (Ni(NO3)2) were used as perovskite precursors, dissolved in deionized water by stirring to form a homogeneous precursor solution; a certain amount of the noble metal precursor Rh(NO3)3 was then added... 2H₂O was added to the solution at a loading ratio of 1.5% and stirred thoroughly until homogeneous. The pH of the solution was adjusted to approximately 6 by adding a small amount of citric acid at 70°C, and stirring was continued to allow the sol to gradually form. After the sol polymerized and gelled, it was dried in a 90°C oven for 6 hours, followed by pre-calcination at 200°C in air for 1 hour to consume moisture and organic contaminants. The pre-calcined sample was then placed in a tube furnace and heated to 700°C at a rate of 5°C / min under a nitrogen atmosphere, and baked at this temperature for 4 hours to form a perovskite oxide precursor. This precursor was subsequently fluorinated (under the same conditions as in Example 1) to convert it into a lanthanum nickel fluoride support (LaNiO₃-XF₂X).

[0049] 10 g of the catalyst was loaded into a tubular reactor, and the temperature was increased from room temperature to 500°C at a rate of 5°C / min. The reactor was then subjected to reduction treatment at this temperature for 2 hours to activate the dehydrogenation active centers. After reduction, the catalyst was heated to the reaction temperature of 500°C. An inert gas was first introduced into the reactor under atmospheric pressure to create a stable reaction atmosphere.

[0050] The volume ratio of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF) was set at 1:1:15, and the total flow rate was controlled at 400 mL / min using a mass flow meter. The reaction time was 40 s. After the reaction time was reached, the nitrogen gas supply was stopped. The tail gas generated by the reaction was purified by rapid cooling, alkali washing, water washing, drying, compression, and distillation to finally obtain high-purity 1,1,3,3,3-pentafluoropropylene.

[0051] In this reaction, the selectivity for pentafluoropropylene was 92.5%, the conversion rate of vinyl chloride was 87.9%, and the conversion rate of carbon tetrachloride was 80.3%.

[0052] Example 4 This experiment uses vinyl chloride as a raw material to prepare high-purity 1,1,3,3,3-pentafluoropropylene. The reaction apparatus includes a heating system, a temperature controller, a mass flow meter, and a gas collection device. First, a lanthanum-nickel fluoride composite catalyst supported on the dehydrogenation noble metal Ru was prepared using the sol-gel method: lanthanum nitrate (La(NO3)3) and nickel nitrate (Ni(NO3)2) were used as perovskite precursors, dissolved in deionized water by stirring to form a homogeneous precursor solution; a certain amount of the noble metal precursor RuCl3 was then added... 3H₂O was added to the solution at a loading ratio of 2.5% and stirred thoroughly until homogeneous. The pH of the solution was adjusted to approximately 6 by adding a small amount of citric acid at 70°C, and stirring was continued to allow the sol to gradually form. After the sol polymerized and gelled, it was dried in a 100°C oven for 6 hours, followed by pre-calcination at 200°C in air for 1 hour to consume moisture and organic contaminants. The pre-calcined sample was then placed in a tube furnace and heated to 800°C at a rate of 5°C / min under a nitrogen atmosphere, and baked at this temperature for 4 hours to form a perovskite oxide precursor. This precursor was subsequently fluorinated (under the same conditions as in Example 1) to convert it into a lanthanum nickel fluoride support.

[0053] 10 g of the catalyst was loaded into a tubular reactor, and the temperature was increased from room temperature to 500°C at a rate of 5°C / min. The reactor was then subjected to reduction treatment at this temperature for 2 hours to activate the dehydrogenation active centers. After reduction, the catalyst was cooled to the reaction temperature of 450°C. An inert gas was first introduced into the reactor under atmospheric pressure to create a stable reaction atmosphere.

[0054] In this reaction, the selectivity of pentafluoropropylene was 93.1%, the conversion rate of vinyl chloride was 82.1%, and the conversion rate of carbon tetrachloride was 77.4%.

[0055] Example 5 High-purity 1,1,3,3,3-pentafluoropropylene was prepared using vinyl chloride as a raw material. The reaction apparatus included a heating system, a temperature controller, a mass flow meter, and a gas collection device. First, a fluorinated functional support catalyst supported on dehydrogenating metal Co was prepared by impregnation: To prepare a precursor solution of dehydrogenated metal Co, Co(NO3)2 was added. 6H₂O was dissolved in deionized water at a loading ratio of 6%, and the pH of the solution was adjusted to 4.5 with nitric acid to enhance the interaction between metal ions and the support. Subsequently, fluorine-modified ZSM-5 molecular sieve (Si / Al=30, fluorine loading 10wt%), which serves as the fluorination functional support, was added to the metal precursor solution and stirred and impregnated at 60°C for 8 hours to promote uniform dispersion of the Co component and enhance its binding with the support. After impregnation, solid-liquid separation was performed by vacuum filtration, and the sample was dried at 100°C for 7 hours to remove residual solvent. The dried sample was then placed in a tube furnace and heated to 500°C at a rate of 5°C / min under a nitrogen atmosphere and baked for 6 hours to thermally decompose the metal precursor and form the dehydrogenation active component, thus forming the desired supported composite catalyst.

[0056] 10 g of the catalyst was loaded into a tubular reactor, and the temperature was increased from room temperature to 500°C at a rate of 5°C / min. The reactor was then subjected to reduction treatment at this temperature for 2 hours to activate the dehydrogenation active centers. After reduction, the catalyst was cooled to the reaction temperature of 400°C. An inert gas was first introduced into the reactor under atmospheric pressure to create a stable reaction atmosphere.

[0057] The volume ratio of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF) was set at 1:1:30, and the total flow rate was controlled at 400 mL / min using a mass flow meter. The reaction time was 60 s. After the reaction time was reached, the nitrogen gas supply was stopped. The tail gas generated by the reaction was purified by rapid cooling, alkali washing, water washing, drying, compression, and distillation to finally obtain high-purity 1,1,3,3,3-pentafluoropropylene.

[0058] In this reaction, the selectivity for pentafluoropropylene was 94.2%, the conversion rate of vinyl chloride was 79.2%, and the conversion rate of carbon tetrachloride was 73.9%.

[0059] Example 6 PdCl2 was added to the solution at a loading ratio of 1%, and the same sol-gel method, calcination, and fluorination process as in Example 1 were used to prepare a lanthanum-cobalt fluoride composite catalyst supported on the dehydrogenated noble metal Pd (the remaining catalyst preparation steps were the same as in Example 1). The reaction temperature was stabilized at 500℃, the volume ratio of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF) was set at 1:1:5, the reaction time was 30 s, and the remaining reaction conditions were the same as in Example 1. The selectivity of pentafluoropropylene was 95.5%, the conversion rate of vinyl chloride was 86.8%, and the conversion rate of carbon tetrachloride was 76.1%.

[0060] Example 7 IrCl3 3H₂O was added to the solution at a loading ratio of 1%, and the same sol-gel method, calcination, and fluorination process as in Example 2 were used to prepare a lanthanum-cobalt fluoride composite catalyst supported on the dehydrogenated noble metal Ir (the remaining catalyst preparation steps were the same as in Example 2). The reaction temperature was stabilized at 600℃, the volume ratio of vinyl chloride (CHCl=CH₂), carbon tetrachloride (CCl₄), and hydrogen fluoride (HF) was set at 1:1:8, the reaction time was 60 s, and the remaining reaction conditions were the same as in Example 2. The selectivity of pentafluoropropylene was 92.2%, the conversion rate of vinyl chloride was 84.8%, and the conversion rate of carbon tetrachloride was 74.1%.

[0061] Example 8 PtCl4 was added to the solution at a loading ratio of 1%, and the same sol-gel method, calcination, and fluorination process as in Example 3 were used to prepare a lanthanum-nickel fluoride composite catalyst supported on the dehydrogenated noble metal Pt (the remaining catalyst preparation steps were the same as in Example 3). The reaction temperature was stabilized at 400℃, the volume ratio of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF) was set at 1:1:10, the reaction time was 30 s, and the remaining reaction conditions were the same as in Example 3. The selectivity of pentafluoropropylene was 98.3%, the conversion rate of vinyl chloride was 96.8%, and the conversion rate of carbon tetrachloride was 92.8%.

[0062] Example 9 RuCl3 3H₂O was added to the solution at a loading ratio of 0.5%, and the same sol-gel method, calcination, and fluorination process as in Example 4 were used to prepare a lanthanum-nickel fluoride composite catalyst supported on the dehydrogenated noble metal Ru (the remaining catalyst preparation steps were the same as in Example 4). The reaction temperature was stabilized at 300℃, the volume ratio of vinyl chloride (CHCl=CH₂), carbon tetrachloride (CCl₄), and hydrogen fluoride (HF) was set at 1:1:20, the reaction time was 100 s, and the remaining reaction conditions were the same as in Example 4. The selectivity of pentafluoropropylene was 92.8%, the conversion rate of vinyl chloride was 80.8%, and the conversion rate of carbon tetrachloride was 72.5%.

[0063] Example 10 PdCl2 was added to the solution at a loading ratio of 3%, and the same sol-gel method, calcination, and fluorination process as in Example 1 were used to prepare a lanthanum-cobalt fluoride composite catalyst supported on the dehydrogenated noble metal Pd (the remaining catalyst preparation steps were the same as in Example 1). The reaction temperature was stabilized at 400℃, the volume ratio of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF) was set at 1:1:5, the reaction time was 30 s, and the remaining reaction conditions were the same as in Example 1. The selectivity of pentafluoropropylene was 93.5%, the conversion rate of vinyl chloride was 76.8%, and the conversion rate of carbon tetrachloride was 66.1%.

[0064] Example 11 PtCl4 was added to the solution at a loading ratio of 3%, and the same sol-gel method, calcination, and fluorination process as in Example 3 were used to prepare a lanthanum-nickel fluoride composite catalyst supported on the dehydrogenated noble metal Pt (the remaining catalyst preparation steps were the same as in Example 3). The reaction temperature was stabilized at 400℃, the volume ratio of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF) was set at 1:1:10, the reaction time was 30 s, and the remaining reaction conditions were the same as in Example 3. The selectivity of pentafluoropropylene was 95.3%, the conversion rate of vinyl chloride was 84.3%, and the conversion rate of carbon tetrachloride was 81.5%.

[0065] Example 12 The dehydrogenation metal active component uses a Ru-Co composite system (RuCl3). 3H2O and Co(NO3)2 6H₂O was mixed at a mass ratio of 1:2 (total loading 6 wt%), and the fluorinated functional support was replaced with fluorinated modified Beta molecular sieve (Si / Al=25, fluorine loading 8 wt%). A fluorinated functional support catalyst with a dehydrogenated Ru-Co composite metal was prepared using an impregnation method. The reaction temperature was stabilized at 380℃, and the volume ratio of vinyl chloride (CHCl=CH₂), carbon tetrachloride (CCl₄), and hydrogen fluoride (HF) was set at 1:1:12. The reaction time was 15 s, and the remaining reaction conditions were the same as in Example 5. The selectivity for pentafluoropropylene was 94.7%, the conversion rate of vinyl chloride was 87.2%, and the conversion rate of carbon tetrachloride was 85.3%.

[0066] Example 13 Replace the dehydrogenation metal active component with Ni (NiCl2) The catalyst was prepared by impregnation using Ni-supported dehydrogenation metal (Ni) with 6H2O (4 wt% loading) and titanium-based fluoride (TiF4) as the fluorination support (the remaining catalyst preparation steps are the same as in Example 5). The reaction temperature was stabilized at 300℃, the volume ratio of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF) was set to 1:1:9, the reaction time was 10 s, and the remaining reaction conditions were the same as in Example 5. The selectivity of pentafluoropropylene was 93.7%, the conversion rate of vinyl chloride was 83.2%, and the conversion rate of carbon tetrachloride was 79.3%.

[0067] Example 14 The dehydrogenation metal active component was replaced with a Co-Ni composite system (Co(NO3)2). 6H2O and NiCl2 6H2O was mixed at a 1:1 mass ratio, with a total loading of 8 wt%), and the fluorination functional carrier was replaced with aluminum-based fluorinated spinel (chemical formula BAl2O). 4-X F 2X (X=2) A fluorinated functional support catalyst for dehydrogenation Co-Ni composite metal was prepared by impregnation (the remaining catalyst preparation steps were the same as in Example 5); the reaction temperature was stabilized at 500℃, the volume ratio of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF) was set to 1:1:10, the reaction time was 80s, and the remaining reaction conditions were the same as in Example 5. The selectivity of pentafluoropropylene was 92.5%, the conversion rate of vinyl chloride was 77.1%, and the conversion rate of carbon tetrachloride was 70.3%.

[0068] Example 15 Replace the dehydrogenated metal active component with Fe(Fe(NO3)3) The fluorination functional support was replaced with a cerium-based composite fluoride support (CeO2-F2O3, fluorine modification degree 60%), and a fluorinated functional support catalyst supported on dehydrogenating metal Fe was prepared by impregnation method (the remaining catalyst preparation steps are the same as in Example 5); the reaction temperature was stabilized at 400℃, the volume ratio of vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4) and hydrogen fluoride (HF) was set to 1:1:20, the reaction time was 30s, and the remaining reaction conditions were the same as in Example 5. The selectivity of pentafluoropropylene was 94.7%, the conversion rate of vinyl chloride was 84.6%, and the conversion rate of carbon tetrachloride was 78.5%.

[0069] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing 1,1,3,3,3-pentafluoropropylene, characterized in that, 1,1,3,3,3-Pentafluoropropylene was synthesized by reacting vinyl chloride (CHCl=CH2), carbon tetrachloride (CCl4), and hydrogen fluoride (HF). The synthetic route is as follows: The overall reaction formula is: (1) The specific reaction steps are as follows: Vinyl chloride (CHCl=CH2) and carbon tetrachloride (CCl4) spontaneously undergo a telomerization reaction to produce the intermediate 1,1,1,3,3-pentachloropropane (CCl3CH2CCl2H). (2) Under the action of the fluorination active site of the bifunctional catalyst, CCl3CH2CCl2H undergoes a selective fluorine-chlorine substitution reaction with HF to generate 1,1,1,3,3-pentafluoropropane CF3CH2CF2H. (3) Under the action of the dehydrogenation active site of the same bifunctional catalyst, CF3CH2CF2H removes H2 to generate the target product 1,1,3,3,3-pentafluoropropylene CF3CH=CF2. (4)。 2. The method for preparing 1,1,3,3,3-pentafluoropropylene according to claim 1, characterized in that, The catalyst is either a noble metal-doped perovskite-type fluoride oxidase catalyst or a metal-supported fluorination functional carrier catalyst. Both types of catalysts possess both fluorine-chlorine replacement catalytic activity and CH bond activation dehydrogenation catalytic activity to adapt to the continuous "fluorination-dehydrogenation" reaction; among them, The noble metal-doped fluorinated perovskite catalyst uses a fluorinated perovskite material as a functionalized support. Its chemical composition can be expressed as LaNiO3-XF2X or LaCoO3-XF2X (where 1≤X≤3). The fluorination treatment enables the support to possess the strong Lewis acidity and surface fluorine species required for catalytic fluorine-chlorine replacement. The supported dehydrogenation noble metal is one of Pd, Pt, Rh, and Ru, and the noble metal loading accounts for 0.1~5 wt% of the total catalyst mass, based on the total catalyst mass. The metal-supported fluorinated functional carrier catalyst has a fluorinated functional carrier selected from AlF3, MgF2, fluorinated alumina Al2O3-F, fluorinated chromium trioxide Cr2O3-F, fluorinated ZSM-5 molecular sieve, titanium-based fluoride TiF4, cerium-based composite fluoride CeO2-F2O3, and aluminum-based fluorinated spinel; the aluminum-based fluorinated spinel has the chemical formula BAl2O4- X F 2X Where 0≤X≤4; the dehydrogenation metal active component is selected from one of Pd, Pt, Rh, Ru, Ir, Co, Ni, Fe, Cr-Mn composite system, Co-Ni composite system, and Fe-K composite system; the metal loading accounts for 0.1~10 wt% of the total mass of the catalyst.

3. The method for preparing 1,1,3,3,3-pentafluoropropylene according to claim 2, characterized in that, For noble metal-doped fluorinated perovskite catalysts, the noble metal loading is 0.5~2wt%; for metal-supported fluorinated functional carrier catalysts, the metal loading is 3~8wt%.

4. The method for preparing 1,1,3,3,3-pentafluoropropylene according to claim 1, characterized in that, The volume ratio of vinyl chloride, carbon tetrachloride, and hydrogen fluoride is 1:1:(2~50).

5. The method for preparing 1,1,3,3,3-pentafluoropropylene according to claim 1, characterized in that, The reaction temperature is 100℃~1000℃, the reaction pressure is atmospheric pressure, and the reaction time is 1~300s.

6. The method for preparing 1,1,3,3,3-pentafluoropropylene according to any one of claims 1-5, characterized in that, Also includes: The product is purified by alkali washing, water washing, drying, compression, and distillation to obtain high-purity 1,1,3,3,3-pentafluoropropylene.

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