WO2021169764A1

WO2021169764A1 - Layered porous material for adsorbing and separating allylene and propylene, preparation method therefor and application thereof

Info

Publication number: WO2021169764A1
Application number: PCT/CN2021/075163
Authority: WO
Inventors: 杨启炜; 柯天; 任其龙; 杨亦文; 张治国; 鲍宗必
Original assignee: 浙江大学
Priority date: 2020-02-27
Filing date: 2021-02-04
Publication date: 2021-09-02
Also published as: CN111298772A; CN111298772B

Abstract

A layered porous material for adsorbing and separating allylene and propylene, wherein the layered porous material has periodic intra-layer rhombic pore channels and inter-layer broken line type pore channels, is formed by metal ion M, inorganic anion A and organic ligand L by means of coordination bond and supramolecular interaction, and has a structural general formula of ML₂A. The metal ion M is at least one of Fe²⁺, Co²⁺, Ni²⁺, Cu ²⁺, and Zn ²⁺. The inorganic anion A is at least one of TiF₆ ^2-, GeF₆ ^2-, NbOF₅ ^-, ZrF₆ ^2-, and SnF ₆ ^2-. The structural formula of the organic ligand L is: (I), where R₁-R₈ are each independently selected from H, F, Cl, Br, I, CH₃, NH₂, OH, or COOH. The layered porous material is an adsorbent, and the adsorbent is in contact with a mixed gas containing allylene and propylene to selectively adsorb the allylene, thereby implementing the separation of the propylene and the allylene.

Description

Layered porous material for adsorption and separation of propyne and propylene, and preparation method and application thereof

Technical field

The invention relates to the technical field of chemical engineering, in particular to a layered porous material used for the adsorption and separation of propargylpropene, and a preparation method and application thereof.

Background technique

Propylene is an important olefin product in the world's petrochemical industry. It is mainly derived from steam cracking in industry. It is mainly used for the production of polymerized monomers such as polypropylene and other downstream products. It is widely used in various national economic industries such as plastics, pharmaceuticals, textiles, and coatings. Propyne is a by-product obtained with the production of propylene. The separation of propyne and propylene is a crucial step in industrial production. Since the molecular size of propyne/propylene is similar and the physical properties are similar, the separation between propyne/propylene gas exists Considerable technical challenge.

At present, the industrial separation methods of propylene and propyne are mainly cryogenic rectification and selective catalytic hydrogenation. Cryogenic rectification has very high requirements on operating conditions and equipment. The relatively high pressure and extremely low temperature required for this separation method have high energy consumption, and the process flow is complex, so the equipment investment is large. Selective catalytic hydrogenation is the selective catalytic hydrogenation of propyne in propylene and propyne under the action of a catalyst to obtain propylene to achieve the purpose of olefin purification, but because the concentration ratio of propylene component in the mixed gas is usually higher than that of propyne component High, so that the reaction exists in the transitional hydrogenation of propylene to obtain low-value-added propane, and the energy consumption of the separation method is relatively high, so it is extremely important to develop a new type of high-efficiency and energy-saving separation method.

Adsorption separation technology is a low-energy gas separation technology. It has the advantages of low cost, simple process flow and high separation efficiency. It can realize the separation of low-carbon hydrocarbons under normal temperature and pressure conditions, and has good industrial application prospects.

In recent years, metal-organic framework materials have made great progress in the separation of propylene and propyne due to their pore structure diversity and fine controllability. Some existing metal-organic framework materials have been able to achieve high propyne adsorption capacity, but at the same time they also adsorb a certain amount of propylene, which requires repeated separation after desorption, which increases separation energy consumption and theoretical trays. number. The ideal adsorbent material not only needs to have a certain amount of propyne adsorption, but also completely exclude propylene. The current metal-organic framework materials are difficult to achieve adsorption of propyne while exclusion of propylene.

The patent specification with publication number CN 105944680 A discloses a method for the adsorption and separation of propylene and propyne, using an anion-containing metal-organic framework material adsorbent. Ordered microporous organic-inorganic hybrid material, the pore volume can be adjusted ^{from 0.1 to 1.2 cm 3 /g.} A large number of anionic active sites and their highly ordered spatial arrangement make it show excellent propyne adsorption performance. However, it has been found through experiments that when the adsorbent used in this patented technology is applied to the adsorption and separation of propylene and propyne, there essentially exists simultaneous adsorption of propylene and propyne, and it is impossible to achieve the simultaneous exclusion of propylene while adsorbing propyne.

Therefore, it is necessary to fine-tune the size of the pores, and further design new porous materials that can completely exclude propylene and also maintain a certain propyne adsorption capacity.

Summary of the invention

In view of the shortcomings in the field, the present invention provides a layered porous material for the adsorption and separation of propargyl propylene, which is prepared by cleverly combining specific metal ions, inorganic anions, and special organic ligands. With the two pore structures between layers and layers, the degree of layer-to-layer stacking and the pore size within the layer can be precisely controlled by changing the metal site or the type of inorganic anion, which is the first time to achieve propylene exclusion.

The kinetic diameters of propyne and propylene are

with

The difference is smaller than the difference in the dynamic diameter of acetylene and ethylene, and both propyne molecules and propylene molecules contain methyl groups, and their structures are very similar, making the separation of propyne and propylene more difficult than the separation of acetylene and ethylene. The pore size of the adsorbent can be controlled more precisely to achieve efficient separation.

A layered porous material for the adsorption and separation of propargyl propylene. It has periodic intralayer diamond-shaped pores and interlayer fold-line pores. It consists of metal ions M, inorganic anions A and organic ligands L through coordination bonds and supramolecular The function is formed, and the general structure is ML ₂ A;

The metal ion M is at least one ^{of Fe 2+} , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , and Zn ^2+;

The inorganic anion A is _{^{_{^{TiF 6 2-, GeF 6 2-,}}}} NbOF 5 -, ZrF 6 2-, at least one of SnF ₆ ^2-;

The structural formula of the organic ligand L is:

Wherein, R ₁ to R ₈ are each independently selected from H, F, Cl, Br, I, CH ₃ , NH ₂ , OH, or COOH.

The metal ion M is simultaneously bridged with the organic ligand L and the inorganic anion A through coordination bonds to form a two-dimensional network, and adjacent two-dimensional networks are stacked by supramolecular action to form a layered porous structure.

The research of the present invention found that this type of layered material can achieve the adsorption of propyne molecules and the exclusion of propylene molecules through the selective response mechanism of ligand conformation and interlayer stacking mode to different guest molecules, and through the distribution in the pores The high-density anion sites have strong hydrogen bond interactions with propyne molecules, achieving high propyne capacity while achieving propylene exclusion. For example, the present invention finds that _{a layered porous material with the structural formula Cu(C 12} H ₈ N ₂ S) ₂ GeF ₆ (denoted as GeFSIX-dps-Cu) excludes propylene, and the adsorption capacity for propylene under normal temperature and pressure is only 0.08mmol/g, while the adsorption capacity for propyne is as high as 3.73mmol/g, and the IAST (Ideal Adsorbed Solution Theory) selectivity for propyne/propylene mixed gas with a volume ratio of 50:50 and 10:90 is as high as 10 ⁷ , Much higher than other adsorbents. This type of material can obtain higher propyne adsorption capacity under low pressure. For example, the present invention has found that _{the layered porous material with the structural formula Cu(C 12} H ₈ N ₂ S) ₂ GeF _{6 has} a positive effect on propyne at 298K and 0.1bar. Its adsorption capacity is 3.15mmol/g, and its adsorption capacity for propylene is almost 0, achieving high propyne adsorption capacity while completely exclusion of propylene.

Preferably, the metal ion M is at least one ^{of Cu 2+} and Zn ^2+;

The inorganic anion A is at least one _{of TiF 6} ^2- and GeF ₆ ^2-;

In the organic ligand L, R ₁ , R ₄ , R ₅ , and R ₈ are independently selected from any one of H, Cl, Br, I, OH, NH ₂ , and CH ₃ , R ₂ , R ₃ , R ₆ and R ₇ are each independently selected from any one of H, OH, and NH _2. Further preferably, the organic ligand L is 4,4'-dipyridine sulfide (dps).

Under the combination of the metal ion M, the inorganic anion A and the organic ligand L, the obtained layered porous material can better realize the exclusion of propylene while ensuring a larger propyne adsorption capacity.

The layered porous material can be synthesized by any one of the solid-phase grinding method, the interface slow diffusion method, the solvothermal method, and the room temperature co-precipitation method commonly used in the art, and the following preparation method is preferably used:

The layered porous material is prepared by hydrothermal synthesis with the precursor of metal ion M, inorganic anion A and organic ligand L. Using a mixed solvent of water and alcohol, the organic ligand L and metal ion M in the initial reaction system The molar ratio and the molar ratio of the organic ligand L to the inorganic anion A are both 2:1, and the reaction temperature is 25-85°C.

The layered porous material obtained by the preferred preparation method is more conducive to the adsorption and separation of propargylpropene.

The invention also provides the application of the layered porous material in the adsorption and separation of propargyl propylene.

In a preferred example, the layered porous material is GeFSIX-dps-Zn, that is, the metal ion M is Zn ²⁺ , the inorganic anion A is GeF ₆ ^2- , and the organic ligand L is 4,4-dipyridine sulfide. Ether (dps). The materials under 1bar, 298K conditions propynyl, propene adsorption capacity were 3.48mmol g ^{^-1,} 0.12mmol g ^-1.

In another preferred example, the layered porous material is GeFSIX-dps-Cu, that is, the metal cation is Cu ²⁺ , the inorganic anion is GeF ₆ ^2- , and the organic ligand is 4,4-dipyridine sulfide. The materials under 1bar, 298K conditions propynyl, propene adsorption capacity were 3.73mmol g ^{^-1,} 0.08mmol g ^-1.

The adsorption capacity of the above two preferred materials for propylene is less than 0.1 propylene molecules/unit cell, and it can be considered that the complete exclusion of propylene is achieved.

The present invention also provides a method for adsorbing and separating propyne and propylene. The layered porous material is used as an adsorbent, and the adsorbent is in contact with a mixed gas containing propyne and propylene to selectively adsorb propyne to achieve propylene and propylene. Separation of alkynes.

When the mixed gas containing propylene and propyne is in contact with the layered porous material, the adsorbent selectively adsorbs propyne molecules and excludes propylene molecules due to the difference in propylene/propyne molecular size and hydrogen bond acidity.

Preferably, in the mixed gas containing propyne and propylene, the volume ratio of propyne to propylene is 1:99 to 99:1.

The volume ratio of the propyne component and the propylene component in the mixed gas is 1:99 to 99:1 (such as 50:50, 10:90, etc.), and the mixed gas may also contain hydrogen, nitrogen, oxygen, and carbon oxides ( Impurity components such as carbon monoxide, carbon dioxide, etc.), moisture and other low-carbon hydrocarbons (such as methane, propane, etc.) do not affect the adsorption and separation performance of the layered porous material for propyne/propylene components.

By using the layered porous material, propylene with a purity (relative to the purity of propyne) greater than 99.99% can be separated from a mixed gas containing propyne and propylene.

Preferably, in the method for adsorbing and separating propargyl propylene, the adsorption temperature is -20 to 60° C., and the adsorption pressure is 0.5 to 10 bar. Lowering the adsorption temperature is beneficial to increase the propyne adsorption capacity, and increasing the adsorption temperature is conducive to narrowing the temperature difference between the desorption process, reducing the energy consumption required for the separation process, and increasing the diffusion rate of propyne in the pores. Therefore, considering the above two factors comprehensively, it is more preferable that the adsorption temperature is 0 to 35°C.

The adsorption pressure is further preferably 1 to 5 bar.

In the method for adsorbing and separating propyne and propylene, the adsorbent selectively adsorbs propyne and then desorbs to obtain propyne-rich gas;

The desorption temperature is preferably 25 to 120°C, more preferably 45 to 100°C;

The desorption pressure is preferably 0 to 0.1 bar.

The contact mode of the adsorbent and the mixed gas containing propyne and propylene can be at least one of fixed bed adsorption, fluidized bed adsorption, and moving bed adsorption.

Preferably, the contact mode between the adsorbent and the mixed gas containing propyne and propylene is fixed bed adsorption, which specifically includes the steps: under a set adsorption temperature and pressure, the mixed gas containing propyne and propylene is passed through Into the fixed-bed adsorption column filled with the adsorbent, the propylene component preferentially penetrates the bed, and the propylene gas with a propyne content of less than 0.01 vol% is directly obtained from the outlet of the adsorption column, and the propyne component is enriched in the bed. Propyne-rich gas is obtained by desorption.

The propylene component has a weak interaction with the layered porous material, has a small amount of adsorption, and preferentially penetrates the fixed bed, and can directly obtain propylene gas containing very low content of propyne (less than 0.01 vol%).

The propyne component has a strong interaction with the layered porous material and is enriched in a fixed bed. After it penetrates (adsorption saturation), it is decompressed, heated, purged with inert gas, purged with product gas, or various desorptions. The combined method decomposes and absorbs the adsorbed propyne group to obtain high-purity (greater than 99.99%) propyne gas.

Compared with the prior art, the main advantages of the present invention include:

(1) The present invention provides a new method for the adsorption and separation of propyne and propylene by using a layered porous material. The adsorption capacity of the material for propyne under equilibrium conditions is significantly higher than that of propylene, thereby realizing effective separation of propyne and propylene.

(2) Compared with conventional adsorbents, the layered porous material used in the present invention can achieve exclusion of propylene and has a higher propyne adsorption capacity, so that it can obtain high-purity propylene at the same time after desorption. High-purity propyne can be obtained.

(3) The layered porous material used in the present invention has a simple synthesis method, has the advantages of large adsorption capacity, high selectivity, recyclability, etc., and has excellent stability. The thermal decomposition temperature is close to 200 ℃, and it is exposed to the air ( 25℃, relative humidity 70%) The crystal structure remains intact and the specific surface area does not decrease significantly after being immersed in water for 72 hours, which has a good industrial application prospect;

(4) The separation method provided by the present invention can simultaneously obtain propylene gas with a purity of up to 99.99% and propyne gas with a purity of up to 99.99%;

(5) Compared with the conventional cryogenic rectification method and catalytic hydrogenation method, the separation method provided by the present invention has outstanding advantages such as mild operating conditions, energy saving and environmental protection, and small equipment investment, and is expected to bring economic benefits to small and medium-sized enterprises.

Description of the drawings

Figure 1 is a thermogravimetric curve diagram of the layered porous material GeFSIX-dps-Cu obtained in Example 1;

2 is the adsorption isotherm of the layered porous material GeFSIX-dps-Cu obtained in Example 1 at 298K for propargylpropene;

3 is the adsorption isotherm of the layered porous material GeFSIX-dps-Cu obtained in Example 1 at 273K for propargylpropene adsorption;

4 is a thermogravimetric curve diagram of the layered porous material GeFSIX-dps-Zn obtained in Example 2;

5 is the adsorption isotherm of the layered porous material GeFSIX-dps-Zn obtained in Example 2 for propargylpropene at 298K;

6 is the adsorption isotherm of the layered porous material GeFSIX-dps-Zn obtained in Example 2 for propargylpropene at 273K;

Figure 7 is a fixed bed penetration curve of the layered porous material GeFSIX-dps-Cu obtained in Example 1 to a propylene/propyne (50:50) mixed gas; where C ₀ represents the component concentration of the raw material at the outlet of the adsorption column, C _A represents the initial concentration of raw materials;

FIG. 8 is a fixed bed penetration curve diagram of the layered porous material GeFSIX-dps-Cu obtained in Example 1 to a propylene/propyne (10:90) mixed gas;

9 is a fixed bed penetration curve of the layered porous material GeFSIX-dps-Zn obtained in Example 2 to a propylene/propyne (10:90) mixed gas.

Detailed ways

The present invention will be further described below in conjunction with the drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The operating methods without specific conditions in the following examples are usually in accordance with conventional conditions or in accordance with the conditions recommended by the manufacturer.

Example 1

Add 10 mL of an aqueous solution containing 0.25 mmol Cu(BF ₄ ) ₂ ·H ₂ O, (NH ₄ ) ₂ GeF ₆ dropwise to 10 mL of methanol solution containing 0.5 mmol 4,4-dipyridine sulfide, and then dissolve 20 mL of The mixed solution of metal salt, inorganic anion and organic ligand is placed in an oven at 80° C. for reaction for 48 hours. After the reaction, blue crystals are obtained. The obtained product is filtered and then washed with methanol and allowed to stand for 3 days. The methanol is replaced every other day, and then vacuum activated at 100°C for 24 hours to obtain a GeFSIX-dps-Cu layered porous material.

The thermogravimetric curve of the GeFSIX-dps-Cu layered porous material obtained in this embodiment is shown in FIG. 1, and has high thermal stability.

The adsorption isotherm of the GeFSIX-dps-Cu layered porous material obtained in this example for propyne propylene at 298K is shown in Figure 2. The material has a relatively high propyne adsorption capacity (3.73 mmol/g) at room temperature and pressure. ) And at the same time exclude propylene.

The adsorption isotherm of the GeFSIX-dps-Cu layered porous material obtained in this example for propyne propylene at 273K is shown in Figure 3. The material has a high propyne adsorption capacity (3.87mmol/ g) and at the same time exclude propylene.

Example 2

Put 10mL methanol solution containing 0.25mmol ZnGeF ₆ dropwise into 10mL methanol solution containing 0.5mmol 4,4-dipyridine sulfide, and then 20mL mixed solution containing metal salt, inorganic anion and organic ligand was reacted at room temperature for 72h . After the reaction, white crystals are obtained. The obtained product is filtered and then washed with methanol and allowed to stand for 3 days. The methanol is replaced every other day, and then vacuum activated at room temperature for 24 hours to obtain the GeFSIX-dps-Zn layered porous material.

The thermogravimetric curve of the GeFSIX-dps-Zn layered porous material obtained in this embodiment is shown in FIG. 4, which has high thermal stability.

The adsorption isotherm of the GeFSIX-dps-Zn layered porous material obtained in this example for propynepropene at 298K is shown in Figure 5. This material has a relatively high propyne adsorption capacity (3.48mmol/g) at room temperature and pressure. ) And at the same time exclude propylene.

The adsorption isotherm of the GeFSIX-dps-Zn layered porous material obtained in this example for propyne propylene at 273K is shown in Figure 6. The material has a high propyne adsorption capacity (3.78mmol/ g) and at the same time exclude propylene.

Example 3

Add 10 mL of an aqueous solution containing 0.25 mmol of Cu(BF ₄ ) ₂ ·H ₂ O and (NH ₄ ) ₂ TiF ₆ dropwise to 10 mL of methanol solution containing 0.5 mmol of 4,4-dipyridine sulfide, and then dissolve 20 mL of The mixed solution of metal salt, inorganic anion and organic ligand is placed in an oven at 80° C. for reaction for 48 hours. After the reaction, blue crystals are obtained, the obtained product is filtered, washed with methanol, and allowed to stand for 3 days. The methanol is replaced every other day, and then vacuum activated at 100°C for 24 hours to obtain TiFSIX-dps-Cu layered porous material.

Example 4

The GeFSIX-dps-Cu obtained in Example 1 was loaded into a 10cm-long fixed-bed adsorption column, and a mixed gas of propyne/propylene (50:50 by volume) was passed into the adsorption column at a flow rate of 0.5mL/min at room temperature. High-purity propylene (highest purity greater than 99.99%) is obtained from the effluent gas. When the propyne penetrates, the adsorption is stopped, and high-purity propyne (greater than 99.99%) can be obtained by desorption with He gas purging at 80°C for 15 hours. Adsorption column Can be recycled.

The penetration curve of this example is shown in Figure 7. The propylene component penetrates at 7 min/g and the retention time of the propyne component reaches 156 min/g. The material has a high dynamic propyne adsorption capacity and at the same time excludes propylene. .

Example 5

The GeFSIX-dps-Cu obtained in Example 1 was loaded into a 10cm-long fixed-bed adsorption column, and the propyne/propylene (volume ratio 10:90) mixed gas was passed into the adsorption column at a flow rate of 2mL/min at room temperature, and then flowed out Obtain high-purity propylene from the gas (the highest purity is greater than 99.99%). When the propyne penetrates, stop the adsorption, and desorb with He gas for 15h at 80°C to obtain high-purity propyne (greater than 99.99%). The adsorption column can be recycled. use.

The penetration curve of this example is shown in Figure 8. When the propylene component penetrates at 3.6 min/g and the retention time of the propyne component reaches 36.5 min/g, the material has a relatively high dynamic propyne adsorption capacity and discharges at the same time. Propylene resistance.

Example 6

The GeFSIX-dps-Zn obtained in Example 2 was loaded into a 5 cm long fixed-bed adsorption column, and the propyne/propylene (volume ratio 50:50) mixed gas was passed into the adsorption column at a flow rate of 0.5 mL/min at room temperature. High-purity propylene (highest purity greater than 99.99%) is obtained from the effluent gas. When the propyne penetrates, the adsorption is stopped, and high-purity propyne (greater than 99.99%) can be obtained by desorption with He gas purging at 80°C for 15 hours. Adsorption column Can be recycled.

Example 7

The GeFSIX-dps-Zn obtained in Example 2 was loaded into a 5cm-long fixed-bed adsorption column, and the propyne/propylene (volume ratio 10:90) mixed gas was passed into the adsorption column at a flow rate of 2mL/min at room temperature, and flowed out Obtain high-purity propylene from the gas (the highest purity is greater than 99.99%). When the propyne penetrates, stop the adsorption, and desorb with He gas for 15h at 80°C to obtain high-purity propyne (greater than 99.99%). The adsorption column can be recycled. use.

The penetration curve of this embodiment is shown in FIG. 9, the propylene component penetrates at 0.1 min/g and the retention time of the propyne component reaches 10.7 min/g.

Example 8

The GeFSIX-dps-Cu obtained in Example 1 was loaded into a 10cm-long fixed-bed adsorption column, and the propyne/propylene mixed gas containing low-concentration water (volume ratio propyne:propylene:water=10:90:0.1 ) Pass into the adsorption column at a flow rate of 2mL/min, and obtain high-purity propylene (the highest relative purity is greater than 99.99%) in the effluent gas. When propyne penetrates, stop the adsorption and desorption by He gas purging at 100℃ for 15h. High-purity propyne (greater than 99.99%), the adsorption column maintains its desorption performance and can be recycled.

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

Claims

An application of a layered porous material for the adsorption and separation of propyne and propyne in the adsorption and separation of propyne and propene, characterized in that the layered porous material for the adsorption and separation of propyne and propene has periodic intralayer rhomboid pores And the interlayer broken-line pores are formed by metal ions M, inorganic anions A and organic ligands L through coordination bonds and supramolecular interactions. The general structural formula is ML 2 A;

The metal ion M is at least one of Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ , and Zn 2+;

The inorganic anion A is TiF 6 2-, GeF 6 2-, NbOF 5 -, ZrF 6 2-, at least one of SnF 6 2-;

The structural formula of the organic ligand L is:

Wherein, R 1 to R 8 are each independently selected from H, F, Cl, Br, I, CH 3 , NH 2 , OH, or COOH.
The application according to claim 1, wherein the metal ion M is at least one of Cu 2+ and Zn 2+;

The inorganic anion A is at least one of TiF 6 2- and GeF 6 2-;

In the organic ligand L, R 1 , R 4 , R 5 , and R 8 are independently selected from any one of H, Cl, Br, I, OH, NH 2 , and CH 3 , R 2 , R 3 , R 6 and R 7 are each independently selected from any one of H, OH, and NH 2.
The application according to claim 1 or 2, characterized in that the preparation method of the layered porous material for the adsorption and separation of propargyl propylene: pass the precursor of the metal ion M, the inorganic anion A and the organic ligand L The layered porous material is prepared by the hydrothermal synthesis method, using a mixed solvent of water and alcohol, the molar ratio of the organic ligand L to the metal ion M and the molar ratio of the organic ligand L to the inorganic anion A in the initial reaction system are both 2. :1, the reaction temperature is 25～85℃.
A method for adsorbing and separating propyne and propylene, characterized in that a layered porous material is used as an adsorbent, and the adsorbent is in contact with a mixed gas containing propyne and propylene to selectively adsorb propyne to realize the separation of propylene and propyne;

The layered porous material has periodic intralayer diamond-shaped pores and interlayer broken-line pores, formed by metal ions M, inorganic anions A and organic ligands through coordination bonds and supramolecular interactions, and the general structural formula is ML 2 A;

The metal ion M is at least one of Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ , and Zn 2+;

The inorganic anion A is TiF 6 2-, GeF 6 2-, NbOF 5 -, ZrF 6 2-, at least one of SnF 6 2-;

The structural formula of the organic ligand L is:

Wherein, R 1 to R 8 are each independently selected from H, F, Cl, Br, I, CH 3 , NH 2 , OH, or COOH.
The method according to claim 4, wherein in the mixed gas containing propyne and propylene, the volume ratio of propyne to propylene is 1:99 to 99:1.
The method according to claim 4, characterized in that the adsorption temperature is -20-60°C, and the adsorption pressure is 0.5-10 bar.
The method according to claim 4, characterized in that, after the adsorbent selectively adsorbs propyne, it desorbs to obtain a propyne-rich gas;

The desorption temperature is 25～120℃, and the desorption pressure is 0～0.1bar.
The method according to any one of claims 4 to 7, wherein the contact mode of the adsorbent and the mixed gas containing propyne and propylene is one of fixed bed adsorption, fluidized bed adsorption, and moving bed adsorption. At least one.
The method according to claim 8, characterized in that the contact mode of the adsorbent and the mixed gas containing propyne and propylene is fixed-bed adsorption, which specifically includes the step of: at a set adsorption temperature and adsorption pressure, The mixed gas containing propyne and propylene is passed into the fixed-bed adsorption column filled with the adsorbent, the propylene component preferentially penetrates the bed, and the propylene gas with the propyne content less than 0.01 vol% is directly obtained from the outlet of the adsorption column. The alkyne component is enriched in the bed and desorbed to obtain propyne-rich gas.