A zinc-based metal organic framework material and its preparation method and application

Abstract

The present invention provides a zinc-based metal organic framework material and its preparation method and application. The zinc-based metal organic framework material includes a mixed coordination framework with pcu topology formed by the simultaneous presence of N and O coordination, and its minimum asymmetric unit is composed of three zinc ions, three deprotonated 1H-indazole-5-carboxylic acids and bridging water molecules. Its preparation method includes: heating a zinc salt aqueous solution to a reaction temperature, keeping it for 30-40 minutes, cooling it, and filtering it for standby use; dissolving an organic ligand in an organic solvent to obtain a ligand solution, heating it to a reaction temperature for 30-40 minutes, and filtering it for standby use; mixing and removing impurities from the standby solutions obtained by filtering them separately, adding a regulator to obtain a mixed solution; and performing a standing reaction and purification treatment. The zinc-based metal organic framework material provided by the present invention is a porous material formed by self-assembly of organic ligands and zinc ions, having a large specific surface area and pore walls modified with aromatic rings, which is more conducive to the adsorption of propylene and propane, weakening the adsorption of other low-carbon hydrocarbons, and having high separation selectivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of separation materials for mixed gases, and in particular relates to a zinc-based metal organic framework material and a preparation method and application thereof. Background Art

[0002] Since the beginning of the 21st century, global CO2 emissions have continued to increase, and extreme weather events have become frequent. Natural gas (primarily composed of methane) is a clean fossil energy source that can replace oil, characterized by high efficiency and low CO2 emissions. Furthermore, the production of high-value-added chemicals from methane has attracted considerable attention and significance in its comprehensive application in the chemical industry. Therefore, separating high-purity methane from natural gas is essential. In addition to methane, natural gas also contains propane and ethane, which reduce its energy density and utilization efficiency. Furthermore, propane and ethane are also important raw materials for the production of other high-value-added petrochemical products. Efficiently separating and recovering propane and ethane from natural gas can improve methane quality while also yielding high-value propane and ethane, achieving multiple goals at once.

[0003] The MTO process, which converts natural gas into synthesis gas and then converts the synthesis gas into light olefins through methanol, produces the chemical products propylene and ethylene. Propylene and ethylene are important raw materials for the synthesis of polypropylene and polyethylene and are of great commercial value. Therefore, efficient and complete separation of the propylene and ethylene produced in the MTO process to obtain polymerization-grade individual products is of great importance.

[0004] Until now, conventional separation processes have relied on cryogenic distillation, a process with high energy consumption. Conventional adsorbents used in pressure swing adsorption processes for C1 / C2 / C3 separations have limitations in terms of adsorption capacity and selectivity.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a zinc-based metal organic framework material and a preparation method and application thereof to solve the above problems.

[0007] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0008] The present invention provides a zinc-based metal-organic framework material, which includes a mixed coordination framework with a pcu topology formed by the simultaneous presence of N and O coordination, and its minimum asymmetric unit is composed of three zinc ions, three deprotonated 1H-indazole-5-carboxylic acids and bridging water molecules.

[0009] Three zinc ions coordinate with water molecules and the nitrogen element of 1H-indazole-5-carboxylic acid to form a trinuclear zinc cluster. The oxygen element of 1H-indazole-5-carboxylic acid further coordinates with zinc to form a hexalinked Zn3N6O7 cluster. The clusters are connected by deprotonated 1H-indazole-5-carboxylic acid, forming a network of interconnected channels. This network provides more adsorption sites for C3 hydrocarbons, thereby increasing the adsorption capacity and achieving excellent separation performance for lower hydrocarbons.

[0010] The present invention also provides a method for preparing the zinc-based metal organic framework material, comprising the following steps:

[0011] S1: Heat the zinc salt aqueous solution to the reaction temperature and maintain it for 30-40 minutes, then cool, filter and set aside;

[0012] S2: dissolving an organic ligand in an organic solvent to obtain a ligand solution, then heating the solution to a reaction temperature and maintaining the temperature for 30-40 minutes, filtering the solution, and setting aside for later use; the organic ligand comprises 1H-indazole-5-carboxylic acid and / or a 1H-indazole-5-carboxylic acid derivative;

[0013] The structural formula of the 1H-indazole-5-carboxylic acid is:

[0014]

[0015] Since the organic ligand 1H-indazole-5-carboxylic acid contains two coordination elements, N and O, according to the theory of hard and soft acid-base, the metal ions of its coordination center can be Mn 2+ 、Fe 2+ 、Co 2+ 、Ni 2+ 、Cu 2+ 、Zn 2+ 、Mo 2+ 、Tc 2+ 、In 3+ , Pb 2+ 、Bi 3+ , but the preferred coordination metal is zinc because it can form 6-connected Zn3N6O7 clusters and thus construct a three-dimensional framework with pcu topology.

[0016] Therefore, the zinc salt includes any one or more of zinc nitrate, zinc sulfate, zinc acetate, zinc formate, zinc chloride, zinc bromide, zinc perchlorate, zinc phosphate, zinc acetylacetonate, zinc trifluoromethanesulfonate, and zinc oxalate; considering that different metal salts have different solubilities in solvents, zinc nitrate having better solubility is preferred;

[0017] Preferably, the concentration of the zinc salt aqueous solution is 0.1 to 0.5 mol L -1 ; A further preferred concentration is 0.3 molL -1;

[0018] The organic solvent includes any one or more of N,N-diethylformamide, N,N-dimethylacetamide, and N,N-dimethylformamide;

[0019] Preferably, the concentration of the ligand solution is 0.01 to 0.1 mol L -1 ; A further preferred concentration is 0.025molL -1 ;

[0020] S3: The standby solutions obtained by filtering S1 and S2 respectively are mixed and impurities are removed, and then a regulator is added to obtain a mixed solution; the regulator includes any one or more of nitric acid, hydrochloric acid, sulfuric acid, formic acid, and acetic acid; the regulator is an acid, and the acid used should correspond to the anion of the zinc salt used. For example, zinc nitrate is used as the zinc salt, and nitric acid is used as the regulator, and so on, to promote the dissolution of the reactants and better react to form grid channels.

[0021] Preferably, the volume ratio of the zinc salt aqueous solution to the ligand solution is 1-10:1-10; in order to improve the crystallinity of the metal organic framework material during the static reaction and obtain metal organic framework materials with larger particles, the volume ratio of the zinc salt aqueous solution to the ligand solution is further preferably 1:4.

[0022] S4: The mixed solution obtained in S3 is allowed to stand for a reaction, and the reaction product is purified to obtain the zinc-based metal organic framework material. The temperature of the standing reaction, i.e., the reaction temperature described in S1 and S2, is 60 to 140° C., and the reaction time is 1 to 7 days to form a long-range ordered three-dimensional network structure.

[0023] The purification process includes: soaking the reaction product in solvent I for three days, replacing solvent I at least three times a day to dissolve and remove unreacted raw materials; then soaking the product in solvent II for three days, replacing solvent II at least three times a day to replace the high-boiling-point solvent I in the pores; and finally performing vacuum activation;

[0024] The solvent I includes any one of N,N-diethylformamide, N,N-dimethylacetamide, N,N-dimethylformamide or water, preferably N,N-dimethylformamide;

[0025] The solvent II is any one of methanol, ethanol, acetone, dichloromethane, chloroform or tetrahydrofuran, preferably methanol;

[0026] The temperature of the vacuum activation is 25 to 60° C., and the time is 1 to 24 hours.

[0027] The purpose of preparing both the zinc salt and the organic ligand into a low-concentration dilute solution and then mixing them is to, on the one hand, create a dilute solution environment that facilitates the gradual crystallization of the metal-organic framework material during its growth into single crystals, forming long-range ordered channels and reducing the generation of defects that would otherwise affect the material's adsorption and separation properties; on the other hand, it reduces the coordination rate between the metal ions and the organic ligands. Excessive rates can form precipitation, hindering the formation of the three-dimensional network-transforming channels. The concentration and rate set according to the present invention can form high-quality, large-particle single-crystal metal-organic framework materials, effectively realizing the material's actual adsorption potential.

[0028] At the same time, the dilute solutions of the zinc salt aqueous solution and the organic ligand solution are heated to the reaction temperature and then filtered, so as to remove the precipitates produced in each process respectively, so as to minimize the generation of impurities and improve the purity of the product. At the same time, the negative impact of impurities on the formation of large-particle metal-organic framework material single crystals is minimized, and the formation of high-quality, large-particle single crystals is further promoted.

[0029] The present invention also provides an application of the zinc-based metal organic framework material, which is used for separating mixed gases of low-carbon hydrocarbons at a separation temperature of -50 to 100° C. and a pressure of 0 to 1 bar.

[0030] When the zinc-based metal organic framework material provided by the present invention is used to adsorb and separate propane from a propane-containing mixed gas, the propane-containing mixed gas includes: a mixed gas of propane and ethane, a mixed gas of propane and methane, or a mixed gas of propane, ethane and methane;

[0031] Optionally, in the mixed gas of propane and ethane, the volume ratio of propane to ethane is 1:99 to 99:1; in the mixed gas of propane and methane, the volume ratio of propane to methane is 1:99 to 99:1; or, in the mixed gas of propane, ethane and methane, the volume ratio of propane, ethane and methane is 5:10:85;

[0032] When used for adsorption separation of propylene in a propylene / ethylene mixed gas, the volume ratio of propylene to ethylene in the propylene and ethylene mixed gas is 1:99 to 99:1.

[0033] Beneficial effects of the present invention:

[0034] The present invention provides a novel metal organic framework material, which is a porous material formed by coordination self-assembly of an organic ligand 1H-indazole-5-carboxylic acid or its derivatives with zinc ions, and has a large specific surface area and pore walls modified with aromatic rings.

[0035] The preparation method provided by the present invention has cheap and readily available raw materials, a simple process, mild reaction conditions, and is suitable for large-scale production.

[0036] The metal-organic framework material provided by the present invention features a simple preparation and purification process, extremely low degassing requirements, and is suitable for a wider range of operating conditions such as temperature and pressure, making it easy to industrially apply. Its unique structure enables it to adsorb more propylene and propane while reducing adsorption of methane, ethane, and ethylene. While increasing the adsorption of propane and propylene, it also enhances the adsorption selectivity for propane / ethane, propane / methane, and propylene / ethylene. It has excellent potential for separating propane / ethane, propane / methane, and propylene / ethylene gas mixtures, with separation efficiencies reaching 100%. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 This is a physical appearance picture of the zinc-based metal organic framework material crystal provided in Example 1;

[0039] Figure 2 A structural diagram of the zinc-based metal organic framework material crystal provided in Example 1;

[0040] Figure 3 Single-component adsorption curves of propane, ethane, and methane measured at 273K for the zinc-based metal organic framework material provided in Example 1;

[0041] Figure 4 Single-component adsorption curves of propane, ethane, and methane measured at 298K for the zinc-based metal organic framework material provided in Example 1;

[0042] Figure 5 Calculation diagram of adsorption heat of propane, ethane and methane for the zinc-based metal organic framework material provided in Example 1;

[0043] Figure 6 Calculation diagram of the IAST selectivity of the zinc-based metal organic framework material provided in Example 1 to propane, ethane and methane;

[0044] Figure 7 Single-component adsorption curves of propylene and ethylene measured at 273K for the zinc-based metal organic framework material provided in Example 1;

[0045] Figure 8Single-component adsorption curves of propylene and ethylene measured at 298K for the zinc-based metal organic framework material provided in Example 1;

[0046] Figure 9 Calculation diagram of the adsorption heat of propylene and ethylene by the zinc-based metal organic framework material provided in Example 1;

[0047] Figure 10 Calculation diagram of the IAST selectivity of the zinc-based metal organic framework material to propylene and ethylene provided in Example 1;

[0048] Figure 11 (a) is a physical appearance picture of the zinc-based metal organic framework material crystal provided in Example 2;

[0049] Figure 11 (b) is a physical appearance picture of the zinc-based metal organic framework material crystal provided in Comparative Example 1;

[0050] Figure 11 (c) is an appearance diagram of the product provided in Comparative Example 2;

[0051] Figure 11 (d) is an appearance diagram of the product provided in Comparative Example 6;

[0052] Figure 11 (e) is the appearance of the product provided in Comparative Example 7. DETAILED DESCRIPTION

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0054] Example 1

[0055] This embodiment provides a zinc-based metal organic framework material, the preparation method of which includes the following steps:

[0056] S1: Dissolve 9 g of zinc nitrate hexahydrate in 100 mL of deionized water, sonicate to dissolve the solid completely, seal the reaction bottle, heat it in a constant temperature oven to 100 °C for 30 minutes, cool it to room temperature, and filter it to obtain 0.3 mol L -1 of aqueous zinc nitrate solution;

[0057] S2: Dissolve 2.8 g of 1H-indazole-5-carboxylic acid in 1000 mL of N,N-diethylformamide, sonicate to dissolve the solid completely, seal the reaction bottle, heat to 100 °C for 30 minutes, cool to room temperature, and filter to obtain 0.025 mol L -1 1H-indazole-5-carboxylic acid solution;

[0058] S3: Add 1 mL of 0.3 mol L-1 zinc nitrate aqueous solution prepared in S1 and 4 mL of 0.025 mol L-1 zinc nitrate aqueous solution prepared in S2 to a 20 mL sample bottle. -1 1H-indazole-5-carboxylic acid solution was mixed uniformly by ultrasonication, filtered, and then 0.125 mL of concentrated nitric acid was added to obtain a colorless and transparent mixed solution;

[0059] S4: The colorless, transparent mixed solution obtained in S3 was sealed and placed in a constant temperature oven at 100°C for 5 days. The crystals were collected by filtration. The crystals were first washed with N'N-diethylformamide for three days, with the solvent changed three times a day. The crystals were then washed with methanol for three days, with the solvent changed three times a day. The crystals were then vacuum dried for 12 hours to obtain purified and dried [Zn3(C8H4N2O2)3·H2O] n The crystals were vacuum activated at 60° C. for 12 hours on an activation station of an adsorption instrument to obtain the zinc-based metal organic framework material provided in this embodiment.

[0060] The physical appearance of the zinc-based metal organic framework material crystal prepared in this embodiment is shown in the figure below: Figure 1 As shown by Figure 1 It can be seen that the zinc-based metal organic framework material prepared in this embodiment has larger crystal particles and better crystal morphology.

[0061] The crystal structure diagram of the zinc-based metal organic framework material prepared in this embodiment is shown in FIG. Figure 2 As shown by Figure 2 It is known that the zinc-based metal organic framework provided in the present embodiment is a mixed coordination framework with pcu topology in which N and O coordination are simultaneously present, and it is known from single crystal structure analysis that its minimum asymmetric unit is composed of three zinc ions, three deprotonated 1H-indazole-5-carboxylic acids and bridging water molecules. The three zinc ions coordinate with the N element in the water molecule and 1H-indazole-5-carboxylic acid to form a trinuclear zinc cluster, and the O element in the further 1H-indazole-5-carboxylic acid coordinates with zinc to form a six-connected Zn3N6O7 cluster, which is connected to the clusters by deprotonated 1H-indazole-5-carboxylic acid to form an interconnected network of channels. The network channel so formed can provide more adsorption sites for C3 hydrocarbons, thereby increasing the adsorption capacity of C3 hydrocarbons and having good separation performance for low-carbon hydrocarbons.

[0062] Take 100 mg of the activated product sample and measure the single component adsorption curves of propane, ethane and methane at 273K. The results are as follows: Figure 3 As shown, the single component adsorption curves of propane, ethane and methane were measured at 298K. The results are as follows Figure 4 As shown. Figure 3-4 It can be seen that the adsorption trend of the material provided in this embodiment for the three gases propane, ethane, and methane is propane>ethane>methane.

[0063] Figure 5 The adsorption heat of propane, ethane and methane for the material provided in this embodiment is calculated by fitting the single component adsorption curves of propane, ethane and methane at 273K and 298K using the Ville equation. Figure 5 It can be seen that the order of adsorption heat of the material for propane, ethane and methane is Qst(propane)>Qst(ethane)>Qst(methane), which shows that the material has a strong interaction with propane, making it have a larger propane adsorption capacity.

[0064] Figure 6 The IAST selectivity is calculated by fitting the single-component adsorption curves of propane, ethane, and methane of the material provided in this embodiment at 298K with a two-point Langmuir equation. Figure 6 It can be seen that it has high propane / ethane and propane / methane selectivity, indicating that the material has very strong propane / ethane and propane / methane selective separation performance.

[0065] Take 100 mg of the activated product sample and measure the single component adsorption curves of propylene and ethylene at 273K. The results are as follows: Figure 7 As shown, the single component adsorption curves of propylene and ethylene were measured at 298K, and the results are as follows Figure 8 As shown. Figure 7-8 It can be seen that the adsorption trend of the material provided in this embodiment for propane, ethane and methane is propylene > ethylene.

[0066] Figure 9 The adsorption heat of propylene and ethylene is calculated by fitting the single component adsorption curves of propylene and ethylene of the material provided in this embodiment at 273K and 298K using the Ville equation. Figure 9 It can be seen that the order of adsorption heat of propylene and ethylene of the material is Qst(propylene)>Qst(ethylene), which shows that the material has a strong interaction with propylene, making it have a larger propylene adsorption capacity.

[0067] Figure 10 The IAST selectivity is calculated by fitting the single-component adsorption curves of propylene and ethylene of the material provided in this embodiment at 298K with a two-point Langmuir equation. Figure 10 It can be seen that it has a very high propylene / ethylene selectivity, indicating that the material has very strong propylene / ethylene selective separation performance.

[0068] Example 2

[0069] The difference from Example 1 is that the zinc salt used in S1 is zinc chloride, and correspondingly, the regulator used in S3 is hydrochloric acid.

[0070] The physical appearance of the zinc-based metal organic framework material crystal prepared in this embodiment is shown in the figure below: Figure 11 As shown in (a), Figure 11 (a) It can be seen that the zinc-based metal organic framework material crystal was successfully prepared in this embodiment, and the appearance is acceptable; Figure 11 (a) with Figure 1 It can be seen from the comparison that the morphology of the crystal particles in this embodiment is slightly worse than that of the crystals obtained using zinc nitrate in Example 1.

[0071] Comparative Example 1

[0072] The only difference from Example 1 is that S1 dissolves 9 g of zinc nitrate hexahydrate in 100 mL of deionized water and filters to obtain 0.3 mol L -1 The zinc nitrate aqueous solution is then directly involved in the subsequent reaction without being subjected to a temperature-raising and static treatment.

[0073] The obtained product crystal particles are very small, such as Figure 11 (b) shown.

[0074] Comparative Example 2

[0075] The only difference from Example 1 is that S2 is to dissolve 2.8 g of 1H-indazole-5-carboxylic acid in 1000 mL of N,N-diethylformamide, ultrasonicate the solid to completely dissolve, and filter to obtain 0.025 mol L -1 The 1H-indazole-5-carboxylic acid solution is directly used in the subsequent reaction without being heated and allowed to stand.

[0076] The crystal particles of the product obtained are too small, such as Figure 11 As shown in (c), the expected effect cannot be achieved.

[0077] Comparative Example 3

[0078] The only difference from Example 1 is that no concentrated nitric acid is added after filtration in step S3.

[0079] Result: No metal organic framework material crystals were obtained during the reaction cycle.

[0080] Comparative Example 4

[0081] The only difference from Example 1 is that the regulator added after filtration in step S3 is hydrochloric acid.

[0082] Result: No metal organic framework material crystals were obtained during the reaction cycle.

[0083] Comparative Example 5

[0084] The only difference from Example 1 is that the regulator added after filtration in step S3 is sulfuric acid.

[0085] Result: No metal organic framework material crystals were obtained during the reaction cycle.

[0086] Comparative Example 6

[0087] The only difference from Example 1 is that in step S1, 90 g of zinc nitrate hexahydrate was dissolved in 100 mL of deionized water, and the solid was completely dissolved by ultrasonication. The reaction bottle was sealed and placed in a constant temperature oven, heated to 100 ° C for 30 minutes, and then filtered after cooling to room temperature to obtain 3 mol L -1 of aqueous zinc nitrate solution.

[0088] Results: No metal organic framework crystals were obtained during the reaction cycle. Figure 11 As shown in (d), this is because the salt solution concentration is too high, resulting in a too fast reaction rate and failure to form a crystalline structure.

[0089] Comparative Example 7

[0090] The only difference from Example 1 is that in step S2, 28 g of 1H-indazole-5-carboxylic acid was dissolved in 1000 mL of N,N-diethylformamide, and the solid was completely dissolved by ultrasonication. The mixture was sealed in a reaction flask and heated to 100° C. for 30 minutes. After cooling to room temperature, the mixture was filtered to obtain 0.25 mol L -1 1H-indazole-5-carboxylic acid solution.

[0091] Results: No metal organic framework crystals were obtained during the reaction cycle. Figure 11 As shown in (e), this is because the ligand concentration is too high, resulting in low polymerization degree during the coordination reaction, making it difficult to generate a crystalline structure for precipitation.

[0092] The zinc-based metal-organic framework material provided by the present invention has high propane and propylene adsorption performance and has the potential to separate propane from propane / ethane and propane / methane mixtures, ethane from ethane / methane, and purify methane by adsorbing propane and ethane from propane / ethane / methane mixtures. The zinc-based metal-organic framework material can also be used to separate propylene from propylene / ethylene mixtures.

[0093] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above embodiments only express several implementation methods of the present application. The description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of this application, several variations and improvements can be made, which all fall within the scope of protection of this application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A zinc-based metal organic framework material, characterized in that The zinc-based metal organic framework material includes a mixed coordination framework with pcu topology formed by the simultaneous presence of N and O coordination, and its minimum asymmetric unit is composed of three zinc ions, three deprotonated 1H-indazole-5-carboxylic acids and bridging water molecules.

2. A method for preparing a zinc-based metal organic framework material according to claim 1, characterized in that: The following steps are involved: S1: Heat the zinc salt aqueous solution to the reaction temperature and maintain it for 30-40 minutes, then cool, filter and set aside; S2: dissolving the organic ligand in an organic solvent to obtain a ligand solution, then heating to the reaction temperature and maintaining for 30-40 minutes, filtering, and setting aside; S3: The standby solutions obtained by filtering S1 and S2 are mixed and impurities are removed, and then a regulator is added to obtain a mixed solution; S4: allowing the mixed solution obtained in S3 to stand for reaction, and purifying the reaction product to obtain the zinc-based metal organic framework material; The zinc salt includes any one or more of zinc nitrate, zinc sulfate, zinc acetate, zinc formate, zinc chloride, zinc bromide, zinc perchlorate, zinc phosphate, zinc acetylacetonate, zinc trifluoromethanesulfonate, and zinc oxalate; the concentration of the zinc salt aqueous solution is 0.1 to 0.5 mol L -1 ; The regulator includes any one or more of nitric acid, hydrochloric acid, sulfuric acid, formic acid, and acetic acid; the acid of the regulator used corresponds to the anion of the zinc salt used; The concentration of the ligand solution is 0.01-0.1 mol L -1 ; The volume ratio of the zinc salt aqueous solution to the ligand solution is 1-10:1-10.

3. The preparation method according to claim 2, characterized in that The organic ligand includes 1H-indazole-5-carboxylic acid and / or 1H-indazole-5-carboxylic acid derivatives; The structural formula of the 1H-indazole-5-carboxylic acid is: The organic solvent includes any one or more of N,N-diethylformamide, N,N-dimethylacetamide, and N,N-dimethylformamide.

4. The preparation method according to claim 2, characterized in that The temperature of the static reaction, i.e., the reaction temperature described in S1 and S2, is 60-140° C., and the reaction time is 1-7 days.

5. The preparation method according to claim 2, characterized in that The purification process includes: soaking the reaction product in solvent I for three days, replacing solvent I at least three times a day to dissolve and remove unreacted raw materials; then soaking the product in solvent II for three days, replacing solvent II at least three times a day to replace the high-boiling-point solvent I in the pores; and finally performing vacuum activation; The solvent I includes any one of N,N-diethylformamide, N,N-dimethylacetamide, N,N-dimethylformamide or water; The solvent II is any one of methanol, ethanol, acetone, dichloromethane, chloroform or tetrahydrofuran; The temperature of the vacuum activation is 25 to 60° C., and the time is 1 to 24 hours.

6. A use of the zinc-based metal organic framework material according to claim 1, characterized in that: Used for separation of low-carbon hydrocarbon mixed gases, the separation temperature is -50 to 100°C and the pressure is 0 to 1 bar.

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