A method for separating hexafluoropropylene and octafluoropropane

Abstract

This application relates to a method for separating octafluoropropane and hexafluoropropene, comprising using an adsorbent containing a metal-organic framework (MOF) material to adsorb and separate a mixture of hexafluoropropene and octafluoropropane. The MOF material comprises metal ions and organic ligands, wherein the organic ligands include compounds represented by Formula I; the metal ions are selected from one or more transition metal ions and alkaline earth metal ions. The MOF material of this application exhibits good material stability, mild and simple synthesis conditions, and low raw material costs. The MOF material of this application shows high adsorption and separation selectivity for hexafluoropropene and octafluoropropane, and has good prospects for industrial application.

Description

Technical Field

[0001] This application relates to the field of adsorption separation, specifically to a method for separating hexafluoropropylene and octafluoropropane. Background Technology

[0002] Specialty gases for electronics are essential raw materials for the development of integrated circuits, microelectronics, optoelectronics, and other electronic industries. The purity of specialty gases directly affects the yield and reliability of optoelectronic and microelectronic components, and is of great significance to the quality and performance of semiconductor integrated circuit chips. Octafluoropropane (C3F8), also known as perfluoropropane, is a halogenated hydrocarbon with good chemical and thermal stability. It has attracted much attention due to its non-toxic, odorless, highly stable, thermally conductive, electrically insulating, and physiologically resistant properties. In recent years, octafluoropropane has been widely used in semiconductor manufacturing due to its good etching and cleaning properties, relatively low atmospheric lifetime, and low greenhouse effect potential. With the accelerated pace of domestic chip research and industrial production in my country in recent years, the demand for octafluoropropane has been increasing year by year. As chip manufacturing process dimensions decrease, the purity requirements for octafluoropropane are also becoming increasingly stringent.

[0003] Existing literature reports the following synthetic routes for octafluoropropane: (1) Direct reaction of carbon with fluorine: This is a method for mass production of carbon tetrafluoride and hexafluoroethane, with octafluoropropane generated as a byproduct, yielding approximately 10%. This method is quite mature and can be achieved by recovering octafluoropropane from the product; (2) Direct fluorination of heptafluoropropane: This is a commonly used industrial synthetic route, where octafluoropropane is prepared by reacting heptafluoropropane (C3HF7) with fluorine. The purity of the raw material heptafluoropropane is very high, and the purity of the fluorine is also sufficient, so it can be used directly; (3) Fixed-bed reaction: Using CoF3 as a fluorinating agent, octafluoropropane is synthesized through a series of reactions. In this process, the crude product generated needs to be purified by washing, adsorption, and distillation; (4) Fluorination addition of perfluoropropylene: Octafluoropropane is produced by reacting perfluoropropylene (C3F6) with fluorine. Of the above synthesis methods: the direct fluorination of heptafluoropropane requires high purity of fluorine gas and may generate HF during the preparation process, which is corrosive to equipment and the environment; the fixed-bed reaction method uses CoF3 as a fluorinating agent, and may generate HF and other byproducts during the reaction process, requiring purification through washing, adsorption, and distillation, which increases production costs and complexity. At the same time, the reaction mechanism is complex, requiring high control of reaction conditions and high corrosion resistance of equipment; the fluorination addition method of perfluoropropylene generates a large amount of heat during the reaction, making the reaction conditions difficult to control and posing safety hazards. Furthermore, the byproducts such as fluorocarbons and polymers with different carbon atom numbers generated in the reaction are difficult to separate, affecting the purity and yield of the product.

[0004] Currently, the main purification methods for octafluoropropane include distillation, adsorption separation, membrane separation, and catalytic conversion. Distillation is one of the most widely used and mature separation processes in industry, suitable for separating impurity components with significant differences in boiling points. However, for components like hexafluoropropene and octafluoropropane, which have very similar physicochemical properties and similar boiling points, distillation is energy-intensive, requires high equipment investment, and struggles to remove trace impurities to meet electronic-grade application standards. Membrane separation technology provides a mild separation environment, suitable for separating heat-sensitive substances and molecules with large differences in molecular size. However, balancing the selectivity and permeability of membrane materials remains a key challenge restricting the development and application of membrane separation technology; membrane stability and durability also need to be considered. Catalytic conversion uses chemical conversion to transform impurities with similar boiling points to the target product into impurities with significantly different boiling points. This method is only effective for certain impurities, and side reactions can easily occur during the chemical reaction, reducing yield. In comparison, adsorption separation is simple to operate, has lower operating costs, and the adsorbent is easy to recover, making it an environmentally friendly green separation technology. Currently, the most widely used adsorbent materials are molecular sieves, activated carbon, and carbon molecular sieves, but these adsorbents are not very effective at separating hexafluoropropylene and octafluoropropane. Developing adsorbent materials with high adsorption selectivity for a mixture of hexafluoropropylene and octafluoropropane at atmospheric pressure remains a challenge. Summary of the Invention

[0005] To address the aforementioned problems, this application proposes a method for separating hexafluoropropylene and octafluoropropane.

[0006] Specifically, this application provides a method for separating hexafluoropropylene and octafluoropropane, comprising: using an adsorbent comprising a metal-organic framework material to adsorb and separate a mixed gas containing hexafluoropropylene and octafluoropropane, wherein the metal-organic framework material comprises metal ions and organic ligands.

[0007] The organic ligands include compounds represented by Formula I.

[0008]

[0009] In Formula I, R is selected from hydrogen, halogen, or C1-C4 alkyl;

[0010] The metal ion is selected from one or more transition metal ions and alkaline earth metal ions.

[0011] In some embodiments, in Formula I, R is selected from hydrogen, fluorine, chlorine, bromine, methyl, ethyl, or propyl.

[0012] In some embodiments, the organic ligand is 2,5-dihydroxy-1,4-benzoquinone (H2dhbq).

[0013] In some embodiments, the metal ion is selected from one or more of scandium ions, vanadium ions, zinc ions, iron ions, cobalt ions, nickel ions, magnesium ions, tin ions, manganese ions, copper ions, zirconium ions, or titanium ions.

[0014] In some embodiments, the metal ion is selected from one or more of zinc ions, magnesium ions, iron ions, cobalt ions, and manganese ions.

[0015] The metal-organic framework material prepared in this application is a three-dimensional or two-dimensional network framework structure formed by transition metal ions or alkaline earth metal ions and organic ligands (such as 2,5-dihydroxy-1,4-benzoquinone) through coordination bonds or intermolecular forces. The pore size is approximately 0.50-0.70 nm. Hexafluoropropylene, with its smaller molecular diameter, can interact strongly with open metal sites and hydrogen atoms in the framework, as well as through hydrogen bonding, while octafluoropropane, with its larger molecular diameter, has difficulty entering the pores. The intermolecular interactions and exclusion mechanisms result in a significant difference in the adsorption capacity of the two gases on the material surface. When the mixed gas passes through the adsorption device, octafluoropropane has a weaker adsorption force and a smaller adsorption capacity, and preferentially flows out of the device outlet. In contrast, hexafluoropropylene has a stronger adsorption force and a larger adsorption capacity with the metal-organic framework material, and takes longer to flow out of the device outlet, thus achieving the separation of hexafluoropropylene and octafluoropropane.

[0016] In some embodiments, the adsorption separation temperature is -5°C to 50°C, for example, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, or any value between them. In some embodiments, the adsorption separation temperature is 0°C to 40°C. In some embodiments, the adsorption separation temperature is 20°C to 30°C.

[0017] In some embodiments, the adsorption separation pressure is 100 kPa-1000 kPa, for example, 150 kPa, 200 kPa, 250 kPa, 300 kPa, 400 kPa, 500 kPa, 600 kPa, 700 kPa, 800 kPa, 900 kPa, or any value between them. In some embodiments, the adsorption separation pressure is 100 kPa-300 kPa.

[0018] In some embodiments, the adsorption separation temperature is 25°C and the total pressure of the mixed gas is 100 kPa. The separation in the method provided in this application can be carried out at atmospheric pressure, exceeding that of most existing adsorbents.

[0019] In some embodiments, the pore size of the metal-organic framework material is 0.4 nm to 1.0 nm, for example, 0.45 nm, 0.5 nm, 0.53 nm, 0.55 nm, 0.57 nm, 0.59 nm, 0.6 nm, 0.63 nm, 0.65 nm, 0.67 nm, 0.69 nm, 0.7 nm, 0.75 nm, 0.8 nm, 0.85 nm, 0.9 nm, 0.95 nm, or any value between them. In some embodiments, the pore size of the metal-organic framework material is 0.5 nm to 0.7 nm.

[0020] In some embodiments, the specific surface area of ​​the metal-organic framework material is 100-1000 m². 2 / g, for example, 150m 2 / g、200m 2 / g、250m 2 / g、300m 2 / g, 350m 2 / g、400m 2 / g、450m 2 / g、500m 2 / g、550m 2 / g、600m 2 / g、650m 2 / g、700m 2 / g、750m 2 / g、800m 2 / g、850m 2 / g、900m 2 / g or 950m 2 / g. In some embodiments, the specific surface area of ​​the metal-organic framework material is 150m². 2 / g-800m 2 / g.

[0021] In some embodiments, the microporous specific surface area of ​​the metal-organic framework material is 100-800 m². 2 / g, for example, 150m 2 / g、200m 2 / g、250m 2 / g、300m 2 / g, 350m 2 / g、400m 2 / g、450m 2 / g、500m 2 / g、550m 2 / g、600m 2 / g、650m 2 / g、700m 2 / g or 750m 2 / g. In some embodiments, the microporous specific surface area of ​​the metal-organic framework material is 120 m². 2 / g-800m 2 / g.

[0022] In some embodiments, the microporosity of the metal-organic framework material is 70%-98%, for example, 72%, 75%, 77%, 79%, 80%, 83%, 85%, 87%, 89%, 90%, 93%, or 95%. In some embodiments, the microporosity of the metal-organic framework material is 75%-90%.

[0023] In this application, the microporosity of the metal-organic framework material is the ratio of the specific surface area of ​​the micropores to the total surface area (total specific surface area).

[0024] In some embodiments, the metal-organic framework material is in the form of powder, spheres, columns, particles, or films. The metal-organic framework material used in this application can be prepared into adsorption and separation materials such as powder, spheres, columns, particles, or films through different processing techniques.

[0025] In some embodiments, the preparation method of the metal-organic framework material includes: reacting a metal-soluble salt and a compound of Formula I in a solvent, and centrifuging, washing and drying the reaction product.

[0026] In this application, the metal-organic framework (MOF) material is prepared by reacting a series of metal inorganic salts with inexpensive and easily synthesized H₂dhbq as the organic ligand in deionized water. This eliminates the need for any toxic, volatile, or expensive organic solvents. The raw materials are inexpensive, the synthesis conditions are mild, the operation is convenient, the post-processing is simple, and the synthesis cost is low. The MOF material disclosed in this application exhibits high adsorption and separation selectivity for hexafluoropropene and octafluoropropane. Furthermore, the material's structure and adsorption performance are stable, maintaining its original adsorption and separation performance even after prolonged exposure to air or water vapor environments, demonstrating promising prospects for industrial application.

[0027] In some embodiments, the metal-soluble salt is selected from one or more of the following: chlorides, nitrates, acetates, carbonates, sulfates, or perchlorates of metal ions. In some embodiments, the metal-soluble salt is selected from one or more of the following: ferric chloride, ferric nitrate, ferric acetate, ferric sulfate, ferric perchlorate, manganese chloride, manganese nitrate, manganese acetate, manganese sulfate, manganese perchlorate, zinc chloride, zinc nitrate, zinc acetate, zinc sulfate, cobalt chloride, cobalt nitrate, cobalt acetate, cobalt sulfate, magnesium chloride, magnesium nitrate, magnesium acetate, and magnesium sulfate.

[0028] In some embodiments, the compound represented by Formula I is 2,5-dihydroxy-1,4-benzoquinone.

[0029] In some embodiments, the molar ratio of the metal-soluble salt to the compound shown in Formula I, based on metal ions, is 1:(0.5-10), for example, 1:0.7, 1:1, 1:1.3, 1:1.5, 1:1.7, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:6, 1:7, 1:8, 1:9, or any value between them. In some embodiments, the molar ratio of the metal-soluble salt to the compound shown in Formula I is 1:(1-3).

[0030] In some embodiments, the reaction temperature is 20°C-120°C, for example, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, or 100°C. In some embodiments, the reaction temperature is 60°C-50°C. The reaction temperature affects the crystal formation process and reaction rate; excessively high or low temperatures will affect the quality and performance of the formed crystals.

[0031] In some embodiments, the reaction time is 12h-72h, for example 15h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 65h, or 70h. In some embodiments, the reaction time is 24h-30h.

[0032] In some embodiments, the reaction is carried out under stirred conditions. In some embodiments, the stirring speed is 500 rpm to 1000 rpm, for example, 600 rpm, 700 rpm, 800 rpm, or 900 rpm. Inhomogeneous mixing can lead to irregular crystal structures in the resulting metal-organic framework material.

[0033] In some embodiments, the solvent is selected from one or more of methanol, ethanol, acetonitrile, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, and water, preferably water.

[0034] In some embodiments, the molar ratio of the metal-soluble salt to the solvent, based on metal ions, is 1:(100-6000), for example, 1:200, 1:500, 1:700, 1:1000, 1:1500, 1:2000, 1:3000, 1:4000, or 1:5000. In some embodiments, the molar ratio of the metal-soluble salt to the solvent is 1:(300-2000).

[0035] In some embodiments, the drying is vacuum drying. In some embodiments, the vacuum drying temperature is 30°C-120°C. In some embodiments, the vacuum drying time is 6 hours-24 hours. In some embodiments, the vacuum degree of vacuum drying is -0.1 MPa to -0.08 MPa.

[0036] In some implementations, the centrifugation conditions are: 6000-10000 rpm for 5-15 minutes.

[0037] In some embodiments, the washing includes washing several times with deionized water until the filtrate is colorless and clear, replacing the residual inorganic salts and organic ligands in the pores, and then washing several times with anhydrous ethanol, replacing the residual organic ligands and water in the pores.

[0038] In some embodiments, adsorption separation includes passing a mixed gas containing hexafluoropropylene and octafluoropropane through an adsorption tower or column packed with adsorbent material. In some embodiments, the adsorption tower may consist of one or more components. In some embodiments, separation is achieved using existing pressure swing adsorption (PSA), vacuum pressure swing adsorption (VSA), or temperature swing adsorption (TSA).

[0039] In some embodiments, the adsorption separation is carried out in a fixed bed, wherein the adsorbent is filled in the fixed bed adsorption column.

[0040] In some embodiments, the adsorption separation includes the following steps:

[0041] (1) A mixed gas containing hexafluoropropylene and octafluoropropane is passed through a fixed bed adsorption column. Strongly adsorbed hexafluoropropylene is adsorbed on the adsorbent, and weakly adsorbed octafluoropropane permeates the adsorption column to obtain weakly adsorbed octafluoropropane.

[0042] (2) Desorb the strongly adsorbed hexafluoropropylene from the adsorbent to obtain strongly adsorbed hexafluoropropylene.

[0043] In some embodiments, the flow rate of the mixed gas containing hexafluoropropylene and octafluoropropane through the fixed-bed adsorption column is 1-100 mL / min / g adsorbent, for example, 5 mL / min / g adsorbent, 10 mL / min / g adsorbent, 20 mL / min / g adsorbent, 30 mL / min / g adsorbent, 40 mL / min / g adsorbent, 50 mL / min / g adsorbent, 60 mL / min / g adsorbent, 70 mL / min / g adsorbent, 80 mL / min / g adsorbent, or 90 mL / min / g adsorbent.

[0044] In some embodiments, the method further includes regenerating the adsorbent after the adsorption separation is completed.

[0045] In some embodiments, the regeneration includes heating the adsorbent to 50°C-200°C and holding it therefor 2 hours to 72 hours under vacuum or inert atmosphere conditions. In some embodiments, the regeneration includes holding the adsorbent at 5°C-30°C for 2 hours to 72 hours under vacuum or inert atmosphere conditions. In some embodiments, the regeneration includes holding the adsorbent at room temperature for 2 hours to 72 hours under vacuum or inert atmosphere conditions.

[0046] Excessive heating temperature or time can damage the adsorbent structure; insufficient temperature or time will prevent the complete removal of residual adsorbate.

[0047] Compared with the prior art, this application has the following advantages:

[0048] (1) The organic ligands and metal salts used in the preparation of the metal-organic framework materials involved in this application are inexpensive and readily available, the synthesis conditions are green and mild, the purification steps are simple, and they are easy to operate and synthesize on a large scale.

[0049] (2) The metal-organic framework material involved in this application has a stable structure, extremely high air, hydrothermal and chemical stability, and very high adsorption and separation selectivity for a mixture of hexafluoropropylene and octafluoropropane.

[0050] (3) The metal-organic framework material involved in this application has stable performance and good regeneration cycle performance. It can still maintain its original separation performance after multiple adsorption-regeneration cycles. Its performance in the adsorption and separation of hexafluoropropylene and octafluoropropane is far superior to that of most adsorbent materials. Attached Figure Description

[0051] Figure 1 The adsorption isotherms of hexafluoropropylene and octafluoropropane by the metal-organic framework material in Example 1 are shown.

[0052] Figure 2 The adsorption isotherms of hexafluoropropylene and octafluoropropane by the metal-organic framework material in Example 2 are shown.

[0053] Figure 3 The adsorption isotherms of hexafluoropropylene and octafluoropropane by the metal-organic framework material in Example 3 are shown.

[0054] Figure 4 The adsorption isotherms of hexafluoropropylene and octafluoropropane by the metal-organic framework material in Example 4 are shown.

[0055] Figure 5 The adsorption isotherms of hexafluoropropylene and octafluoropropane by the metal-organic framework material in Example 5 are shown.

[0056] Figure 6The low-temperature nitrogen adsorption-desorption curves of the metal-organic framework material in Example 1 are shown.

[0057] Figure 7 The low-temperature nitrogen adsorption-desorption curves of the metal-organic framework material in Example 2 are shown.

[0058] Figure 8 The low-temperature nitrogen adsorption-desorption curves of the metal-organic framework material in Example 3 are shown.

[0059] Figure 9 The low-temperature nitrogen adsorption-desorption curves of the metal-organic framework material in Example 4 are shown.

[0060] Figure 10 The low-temperature nitrogen adsorption-desorption curves of the metal-organic framework material in Example 5 are shown.

[0061] Figure 11 The fixed-bed breakthrough curves of the metal-organic framework material in Example 1 for a mixture of hexafluoropropylene and octafluoropropane are shown.

[0062] Figure 12 The fixed-bed breakthrough curves of the metal-organic framework material in Example 2 for a mixture of hexafluoropropylene and octafluoropropane are shown.

[0063] Figure 13 The fixed-bed breakthrough curves of the metal-organic framework material in Example 3 for a mixture of hexafluoropropylene and octafluoropropane are shown.

[0064] Figure 14 The fixed-bed breakthrough curves of the metal-organic framework material in Example 4 for a mixture of hexafluoropropylene and octafluoropropane are shown.

[0065] Figure 15 The fixed-bed breakthrough curves of the metal-organic framework material in Example 5 for a mixture of hexafluoropropylene and octafluoropropane are shown.

[0066] Figure 16 The cyclic adsorption isotherms of hexafluoropropylene and octafluoropropane for the metal-organic framework material in Example 5 are shown. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the described embodiments of this application without creative effort are within the scope of protection of this application.

[0068] Unless otherwise specified, all pressures in the following examples and comparative examples are gauge pressures.

[0069] Example 1

[0070] 2,5-Dihydroxy-1,4-p-dibenzoquinone (H2dhbq, 1.5 mmol, 0.21 g) and zinc acetate dihydrate (Zn(CH3COO)2·2H2O, 1.5 mmol, 0.33 g) were weighed and dissolved in 10 mL of deionized water. The mixture was heated and stirred in an oil bath at 80 °C for 24 hours. After the reaction, the sample was washed repeatedly by centrifugation with deionized water until the supernatant was colorless and clear. Then, the sample was washed repeatedly by centrifugation with anhydrous ethanol. The washed sample was dried in a vacuum drying oven at 60 °C for 6 hours to obtain the zinc metal-organic framework material. The obtained zinc material was then degassed under vacuum at 150 °C for 12 hours, followed by a low-temperature nitrogen adsorption-desorption experiment. The low-temperature nitrogen adsorption-desorption curve is shown below. Figure 6 As shown.

[0071] The zinc material prepared in this embodiment has a microporosity of 82.4% and a specific surface area of ​​409.39 m². 2 / g, microporous specific surface area is 337.35m² 2 / g, with the main pore size distribution concentrated in 0.51-0.62nm.

[0072] To test the adsorption and separation performance of the zinc material prepared in this embodiment, single-component static adsorption experiments were conducted using the zinc material as the adsorbent for hexafluoropropylene and octafluoropropane gases, respectively. Specifically, 100 mg of adsorbent was used, and the adsorption temperature was set to 25 °C. Figure 1 The results show that at 25 °C and 1 bar, the adsorption capacity of hexafluoropropylene reached 1.86 mmol / g, while the adsorption capacity of octafluoropropane was 0.08 mmol / g. At 1 bar, the ratio of the adsorption capacity of the adsorbent material for the two gases reached 23.3.

[0073] To test the actual effect of the zinc material prepared in this embodiment on the separation of a mixture of hexafluoropropylene and octafluoropropane, a fixed-bed breakthrough experiment was conducted using the zinc material as an adsorbent. In this embodiment, the gas mixture of hexafluoropropylene and octafluoropropane was adsorbed and separated at a volume ratio of 10:90, a breakthrough temperature of 25°C, and a pressure of 0.1 MPa. The test results are as follows: Figure 11 As shown, when the volume ratio of hexafluoropropylene to octafluoropropane is 10:90 and the mixed gas flow rate is 1.0 mL / min, octafluoropropane breaks through immediately, while hexafluoropropylene only begins to break through after 96 minutes. Theoretically, a single adsorption can yield 104.0 bed volumes of high-purity octafluoropropane (product purity > 99.999%), with a product yield close to 100.0%.

[0074] Example 2

[0075] 2,5-Dihydroxy-1,4-p-dibenzoquinone (H2dhbq, 1.5 mmol, 0.21 g) and magnesium acetate tetrahydrate (Mg(CH3COO)2·4H2O, 1.5 mmol, 0.16 g) were weighed and dissolved in 10 mL of deionized water. The mixture was heated and stirred in an oil bath at 80 °C for 24 hours. After the reaction, the sample was washed repeatedly by centrifugation with deionized water until the supernatant was colorless and clear. Then, the sample was washed repeatedly by centrifugation with anhydrous ethanol. The washed sample was dried in a vacuum drying oven at 60 °C for 6 hours to obtain the magnesium metal-organic framework material. The obtained magnesium material was then degassed under vacuum at 150 °C for 12 hours, followed by a low-temperature nitrogen adsorption-desorption experiment. The low-temperature nitrogen adsorption-desorption curve is shown below. Figure 7 As shown.

[0076] The magnesium metal-organic framework material prepared in this embodiment has a microporosity of 83.2% and a specific surface area of ​​536.59 m². 2 / g, microporous specific surface area is 446.67m² 2 / g, with the main pore size distribution concentrated in 0.50-0.59nm.

[0077] To test the adsorption and separation performance of the magnesium material prepared in this embodiment, single-component static adsorption experiments were conducted using the prepared magnesium material as an adsorbent for hexafluoropropylene and octafluoropropane gases, respectively. Specifically, 100 mg of adsorbent was used, and the adsorption temperature was set to 25 °C. Figure 2 The results showed that at 25 °C and 1 bar, the adsorption capacity of hexafluoropropylene reached 2.26 mmol / g, while the adsorption capacity of octafluoropropane was 0.64 mmol / g. At 1 bar, the ratio of the adsorption capacity of the adsorbent material for the two gases reached 3.5.

[0078] To test the actual effect of the magnesium material prepared in this embodiment on the separation of a mixture of hexafluoropropylene and octafluoropropane, a fixed-bed breakthrough experiment was conducted using the magnesium material as an adsorbent. In this embodiment, the gas mixture of hexafluoropropylene and octafluoropropane was adsorbed and separated at a volume ratio of 10:90, a breakthrough temperature of 25°C, and a pressure of 0.1 MPa. The test results are as follows: Figure 12 As shown, when the volume ratio of hexafluoropropylene to octafluoropropane is 10:90 and the mixed gas flow rate is 1.0 mL / min, octafluoropropane begins to break through after 27 minutes, while hexafluoropropylene begins to break through after 63 minutes. Theoretically, a single adsorption can yield 108.3 bed volumes of high-purity octafluoropropane (product purity >99.999%), with a product yield of 57.1%.

[0079] Example 3

[0080] 2,5-Dihydroxy-1,4-p-dibenzoquinone (H2dhbq, 1.5 mmol, 0.21 g) and ferric acetate tetrahydrate (Fe(CH3COO)2·4H2O, 1.5 mmol, 0.26 g) were weighed and dissolved in 10 mL of deionized water. The mixture was heated and stirred in an oil bath at 80 °C for 24 hours. After the reaction, the sample was washed repeatedly by centrifugation with deionized water until the supernatant was colorless and clear. Then, the sample was washed repeatedly by centrifugation with anhydrous ethanol. The washed sample was dried in a vacuum drying oven at 60 °C for 6 hours to obtain the metal-organic framework iron material. The obtained iron material was then degassed under vacuum at 150 °C for 12 hours, followed by a low-temperature nitrogen adsorption-desorption experiment. The low-temperature nitrogen adsorption-desorption curve is shown below. Figure 8 As shown.

[0081] The iron material prepared in this embodiment has a microporosity of 78.0% and a specific surface area of ​​191.51 m². 2 / g, microporous specific surface area is 149.44m² 2 / g, with the main pore size distribution concentrated in 0.52-0.60nm.

[0082] To test the adsorption and separation performance of the iron material prepared in this embodiment, single-component static adsorption experiments were conducted using the iron material as the adsorbent for hexafluoropropylene and octafluoropropane gases, respectively. Specifically, 100 mg of adsorbent was used, and the adsorption temperature was set to 25 °C. Figure 3 The results showed that at 25 °C and 1 bar, the adsorption capacity of hexafluoropropylene reached 0.57 mmol / g, while the adsorption capacity of octafluoropropane was 0.04 mmol / g. At 1 bar, the ratio of the adsorption capacity of the adsorbent material for the two gases reached 14.3.

[0083] To test the actual effect of the iron material prepared in this embodiment on the separation of a mixture of hexafluoropropylene and octafluoropropane, a fixed-bed breakthrough experiment was conducted using the iron material as an adsorbent. In this embodiment, the adsorbed and separated gas mixture of hexafluoropropylene and octafluoropropane had a volume ratio of 10:90, a breakthrough temperature of 25°C, and a pressure of 0.1 MPa. The test results are as follows: Figure 13 As shown, when the volume ratio of hexafluoropropylene to octafluoropropane is 10:90 and the mixed gas flow rate is 1.0 mL / min, octafluoropropane immediately breaks through, while hexafluoropropylene only begins to break through after 18 minutes. Theoretically, a single adsorption can yield 25.4 bed volumes of high-purity octafluoropropane (product purity >99.999%), with a product yield of 100.0%.

[0084] Example 4

[0085] 2,5-Dihydroxy-1,4-p-dibenzoquinone (H2dhbq, 1.5 mmol, 0.21 g) and cobalt chloride hexahydrate (CoCl2·6H2O, 1.5 mmol, 0.36 g) were weighed and dissolved in 10 mL of deionized water. The mixture was heated and stirred in an oil bath at 80 °C for 24 hours. After the reaction, the sample was washed repeatedly by centrifugation with deionized water until the supernatant was colorless and clear. Then, the sample was washed repeatedly by centrifugation with anhydrous ethanol. The washed sample was dried in a vacuum drying oven at 60 °C for 6 hours to obtain the cobalt metal-organic framework material. The obtained cobalt material was then degassed under vacuum at 150 °C for 12 hours, followed by a low-temperature nitrogen adsorption-desorption experiment. The low-temperature nitrogen adsorption-desorption curve is shown below. Figure 9 As shown.

[0086] The cobalt material prepared in this embodiment has a microporosity of 86% and a specific surface area of ​​284.81 m². 2 / g, microporous specific surface area is 245.2m² 2 / g, with the main pore size distribution concentrated in 0.54-0.68nm.

[0087] To test the adsorption and separation performance of the cobalt material prepared in this embodiment, single-component static adsorption experiments were conducted using the prepared cobalt material as an adsorbent for hexafluoropropylene and octafluoropropane gases, respectively. 100 mg of adsorbent was used, and the adsorption temperature was set to 25 °C. Figure 4 The results show that at 25℃ and 1 bar, the adsorption capacity of hexafluoropropylene reaches 1.80 mmol / g, while the adsorption capacity of octafluoropropane is 0.05 mmol / g. At 1 bar, the ratio of the adsorption capacity of the adsorbent material for the two gases reaches 3600.

[0088] To test the actual effect of the iron material prepared in this embodiment on the separation of a mixture of hexafluoropropylene and octafluoropropane, a fixed-bed breakthrough experiment was conducted using the iron material as an adsorbent. In this embodiment, the adsorbed and separated gas mixture of hexafluoropropylene and octafluoropropane had a volume ratio of 10:90, a breakthrough temperature of 25°C, and a pressure of 0.1 MPa. The test results are as follows: Figure 14 As shown, when the volume ratio of hexafluoropropylene to octafluoropropane is 10:90 and the mixed gas flow rate is 1.0 mL / min, octafluoropropane breaks through immediately, while hexafluoropropylene only begins to break through after 69 minutes. Theoretically, a single adsorption can yield 87.7 bed volumes of high-purity octafluoropropane (product purity >99.999%), with a product yield of 100.0%.

[0089] Example 5

[0090] 2,5-Dihydroxy-1,4-p-dibenzoquinone (H2dhbq, 1.5 mmol, 0.21 g) and manganese acetate tetrahydrate (Mn(CH3COO)2·4H2O, 1.5 mmol, 0.37 g) were weighed and dissolved in 10 mL of deionized water. The mixture was heated and stirred in an oil bath at 80 °C for 24 hours. After the reaction, the sample was washed repeatedly by centrifugation with deionized water until the supernatant was colorless and clear. Then, the sample was washed repeatedly by centrifugation with anhydrous ethanol. The washed sample was dried in a vacuum drying oven at 60 °C for 6 hours to obtain the metal-organic framework manganese material. The obtained manganese material was then degassed under vacuum at 150 °C for 12 hours, followed by a low-temperature nitrogen adsorption-desorption experiment. The low-temperature nitrogen adsorption-desorption curve is shown below. Figure 10 As shown.

[0091] The manganese material prepared in this embodiment has a microporosity of 85.0% and a specific surface area of ​​329.98 m². 2 / g, microporous specific surface area is 280.36m² 2 / g, with the main pore size distribution concentrated in 0.53-0.59nm.

[0092] To test the adsorption and separation performance of the manganese material prepared in this embodiment, single-component static adsorption experiments were conducted using the prepared manganese material as an adsorbent for hexafluoropropylene and octafluoropropane gases, respectively. Specifically, 100 mg of adsorbent was used, and the adsorption temperature was set to 25 °C. Figure 5 The results show that at 25 °C and 1 bar, the adsorption capacity of hexafluoropropylene reached 2.01 mmol / g, while the adsorption capacity of octafluoropropane was 0.18 mmol / g. At 1 bar, the ratio of the adsorption capacity of the adsorbent material for the two gases reached 11.2.

[0093] To test the actual effect of the manganese material prepared in this embodiment on the separation of a mixture of hexafluoropropylene and octafluoropropane, a fixed-bed breakthrough experiment was conducted using the aforementioned manganese material as an adsorbent. In this embodiment, the gas mixture of hexafluoropropylene and octafluoropropane was adsorbed and separated at a volume ratio of 10:90, with a breakthrough temperature of 25°C and a pressure of 0.1 MPa. The test results are as follows... Figure 15 As shown, when the volume ratio of hexafluoropropylene to octafluoropropane is 10:90 and the mixed gas flow rate is 1.0 mL / min, octafluoropropane breaks through immediately, while hexafluoropropylene only begins to break through after 105 minutes. Theoretically, a single adsorption can yield 109.4 bed volumes of high-purity octafluoropropane (product purity > 99.999%), with a product yield close to 100.0%.

[0094] like Figure 16 As shown, the metal-organic framework material maintains stable adsorption performance after five adsorption-regeneration breakthrough cycles, and can still effectively separate mixed gases.

[0095] The preferred embodiments of this application have been described in detail above; however, this application is not limited thereto. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in this application and are all within the protection scope of this application.

Claims

1. A method for separating hexafluoropropylene and octafluoropropane, comprising: An adsorbent containing a metal-organic framework material is used to adsorb and separate a mixture of hexafluoropropylene and octafluoropropane. The metal-organic framework material comprises metal ions and organic ligands, wherein the metal ions are selected from one or more of zinc ions, magnesium ions, iron ions, cobalt ions and manganese ions, and the organic ligand is 2,5-dihydroxy-1,4-benzoquinone; The pore size of the metal-organic framework material is 0.5 nm to 0.7 nm; The specific surface area of ​​the micropores in the metal-organic framework material is 100 m². 2 / g-800m 2 / g; The microporosity of the metal-organic framework material is 70%-98%.

2. The method according to claim 1, characterized in that, The adsorption separation temperature is from -5℃ to 50℃.

3. The method according to claim 1, characterized in that, The adsorption separation temperature is from 0°C to 40°C.

4. The method according to claim 1, characterized in that, The adsorption separation temperature is 20°C to 30°C.

5. The method according to claim 1, wherein The pressure for adsorption separation is 100kPa-1000kPa.

6. The method according to claim 1, characterized in that, The pressure for adsorption separation is 100kPa-300kPa.

7. The method according to any one of claims 1-6, characterized in that, The specific surface area of ​​the metal-organic framework material is 100 m². 2 / g-1000m 2 / g; and / or The specific surface area of ​​the micropores in the metal-organic framework material is 120 m². 2 / g-500m 2 / g; and / or The microporosity of the metal-organic framework material is 75%-90%; and / or The metal-organic framework material can be in the form of powder, sphere, column, granules, or film.

8. The method according to claim 7, characterized in that, The specific surface area of ​​the metal-organic framework material is 150 m². 2 / g-800m 2 / g.

9. The method according to any one of claims 1-6, characterized in that, The preparation method of the metal-organic framework material includes: reacting a metal-soluble salt and 2,5-dihydroxy-1,4-benzoquinone in a solvent, and centrifuging, washing and drying the reaction product.

10. The method according to claim 9, characterized in that, The metal-soluble salt is selected from one or more of the following: chloride, nitrate, acetate, sulfate, or perchlorate of metal ions.

11. The method according to claim 10, characterized in that, The metal-soluble salt is selected from one or more of the following: ferric chloride, ferric nitrate, ferric acetate, ferric sulfate, ferric perchlorate, manganese chloride, manganese nitrate, manganese acetate, manganese sulfate, manganese perchlorate, zinc chloride, zinc nitrate, zinc acetate, zinc sulfate, cobalt chloride, cobalt nitrate, cobalt acetate, cobalt sulfate, magnesium chloride, magnesium nitrate, magnesium acetate, and magnesium sulfate.

12. The method according to claim 9, characterized in that, The molar ratio of the metal-soluble salt to 2,5-dihydroxy-1,4-benzoquinone, calculated as metal ions, is 1:(0.5-10); the molar ratio of the metal-soluble salt to the solvent is 1:(100-6000); and / or The reaction temperature is 20℃-120℃; and / or The reaction time is 12h-72h; and / or The reaction is carried out under stirring conditions; and / or The solvent is water; and / or The drying process is vacuum drying.

13. The method according to claim 12, characterized in that, The molar ratio of the metal-soluble salt to 2,5-dihydroxy-1,4-benzoquinone, calculated as metal ions, is 1:(1-3); the molar ratio of the metal-soluble salt to the solvent is 1:(300-2000); and / or The reaction temperature is 60℃-100℃; and / or The reaction time is 24-30 hours; and / or The stirring speed is 500 rpm-1000 rpm; and / or The vacuum drying temperature is 30℃-120℃, the time is 6h-24h, and the vacuum degree is -0.1MPa to -0.08MPa.

14. The method according to any one of claims 1-6, characterized in that, The adsorption separation is carried out in a fixed bed, wherein the adsorbent is filled in the fixed bed adsorption column.

15. The method according to claim 14, characterized in that, The method includes the following steps: (1) A mixed gas containing hexafluoropropylene and octafluoropropane is passed through a fixed bed adsorption column. Strongly adsorbed hexafluoropropylene is adsorbed on the adsorbent, and weakly adsorbed octafluoropropane permeates the adsorption column to obtain weakly adsorbed octafluoropropane. (2) Desorb the strongly adsorbed hexafluoropropylene from the adsorbent to obtain strongly adsorbed hexafluoropropylene.

16. The method according to claim 15, characterized in that, The flow rate of the mixed gas containing hexafluoropropylene and octafluoropropane through the fixed-bed adsorption column is 1-100 mL / min / g adsorbent.

17. The method according to any one of claims 1-6, characterized in that, The method further includes regenerating the adsorbent after the adsorption separation is completed.

18. The method according to claim 17, characterized in that, The regeneration includes heating the adsorbent to 50℃-200℃ and holding it for 2h-72h under vacuum or inert atmosphere conditions; or the regeneration includes holding the adsorbent at 5℃-30℃ for 2h-72h under vacuum or inert atmosphere conditions.

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