Photo-responsive porous liquid adsorbent and preparation method and application thereof

Abstract

The application discloses a kind of light response porous liquid adsorbents and its preparation method and application.Light response porous liquid adsorbents with the mass fraction of 0.2% to 10% of porous main body and macromolecular ionic liquid space steric solvent are prepared after dissolving.Light response metal organic cage is obtained by the coordination self-assembly of isomolar transition metal salt and mixed m-phenylenediamine derivative ligand with photoresponsive azobenzene derivative ligand and long-chain alkyl ligand under the promotion of 2,6-dimethylpyridine.Azobenzene ligand gives the light response of porous liquid, and long-chain alkyl ligand creates a suitable environment for the isomerization of azobenzene, significantly improving the light response efficiency of porous liquid.The number of external pores and the opening and closing of internal pore windows are adjusted under light conditions using light response molecules, the gas adsorption capacity is changed, and the remote control of material on gas adsorption is realized, so that it can be applied to olefin / alkane separation.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of adsorbent and its preparation and application, more specifically, it relates to a kind of intelligent light response porous liquid adsorbent and its preparation method and application in olefin / alkane separation. BACKGROUND

[0002] Energy problem is a major problem in today's world, due to the similar molecular size of olefins and alkanes, similar physical and chemical properties, separation of such mixtures is particularly harsh. Adsorption separation technology has become a research hotspot due to its mild operating conditions, simple process and low cost. However, the development of adsorbents with high adsorption capacity and high selectivity is still the core of the application of this technology. Although the adsorption separation method can significantly reduce the energy consumption in the separation process, there are still high energy consumption and complicated process in the regeneration of adsorbents. Specifically, for most adsorbents, although active sites can be used to selectively adsorb adsorbates, traditional pressure reduction or temperature swing desorption methods are required for desorption, which has high energy consumption and complicated operation, thereby limiting the application of adsorbents.

[0003] Azobenzene derivatives, as a kind of organic matter with good photosensitivity, play an important role in the study of light-responsive functional materials. By using light-responsive molecules that undergo reversible cis-trans isomerization under ultraviolet-visible light conditions and cause size changes, light-responsive molecules can be introduced into porous materials to regulate adsorption sites and reduce the energy required for gas desorption. Although the known intelligent light-responsive adsorbents have shown gas regulation, they also have some shortcomings, such as poor light transmittance of solid materials, azobenzene groups inside the material may not isomerize, which may result in low isomerization rate. In addition, these solid-state intelligent response adsorption materials are difficult to adapt to existing chemical pipelines. SUMMARY

[0004] The purpose of the present application is to provide a light-responsive porous liquid adsorbent to improve the shortcomings of the prior art. Another purpose of the present application is to provide a preparation method for the above-mentioned light-responsive porous liquid adsorbent. The present application also aims to provide the application of the above-mentioned adsorbent in olefin / alkane separation.

[0005] The technical solution of the present application is: a light-responsive porous liquid adsorbent, characterized by: using light-responsive metal organic cage as the main porous body, and macromolecular ionic liquid as the space steric solvent, the light-responsive porous liquid adsorbent with a mass fraction of 0.2%-10% of the porous main body is prepared after dissolution.

[0006] Preferably, the above-mentioned light-responsive metal organic cage is a light-responsive double-ligand metal organic cage obtained by mixing isophthalic acid derivative ligand and equimolar amount of transition metal salt, and coordinating self-assembly under the promotion of 2,6-dimethylpyridine, and its skeleton structure schematic diagram is as followsFigure 1

[0007] Preferably, the transition metal salt is copper nitrate, copper chloride, rhodium acetate, cobalt chloride, manganese nitrate or manganese chloride.

[0008] Preferably, the 2,6-dimethylpyridine is used in an amount of 10-50% of the mass of the metal salt.

[0009] Preferably, the isophthalic acid derivative ligand is an azobenzene derivative ligand and a long-chain alkyl ligand with photoresponsive properties, and the molar ratio of the azobenzene derivative ligand to the long-chain alkyl ligand is 1:(0.42-2.34).

[0010] The azobenzene derivative ligand endows the porous host with photoresponsive properties, and preferably has one of the following a1, b1, c1, d1, e1 or f1 structures:

[0011]

[0012] The long-chain alkyl ligand enhances the photoresponsive properties of the porous host, and these molecules have one of the following a2, b2, c2, d2, e2 or f2 structures:

[0013]

[0014] Preferably, the macromolecular ionic liquid is an imidazole-type macromolecular ionic liquid of polyethylene glycol, and has one of the following IL-1 to IL-12 structures:

[0015]

[0016] The above-mentioned ionic liquid IL-1 is synthesized according to the reference (Dinker, Manish Kumar, et al. Angewandte Chemie 135.31 (2023): e202306495), and the synthesis of other ionic liquids is consistent with the synthesis mechanism of this ionic liquid. The ionic liquids IL-2 to IL-12 are synthesized by changing the type of raw material polyethylene glycol and changing the counter anion based on the synthesis method of IL-1.

[0017] The present application also provides a preparation method of the above-mentioned photoresponsive porous liquid adsorbent, characterized in that: the porous host is dissolved in an ionic liquid diluted with a low-boiling-point solvent, and the low-boiling-point solvent is removed to obtain the photoresponsive porous liquid adsorbent.

[0018] Preferably, the low-boiling-point solvent is methanol, ethanol or dichloromethane, and the amount used is 2-10 times the mass of the ionic liquid.

[0019] ​The application also provides the application of the above-mentioned photoresponsive porous liquid adsorbent in olefin / alkane separation, preferably in ethylene / ethane or propylene / propane separation.

[0020] The gas adsorption condition of the porous liquid adsorbent is as follows: 0.1 g of the photoresponsive porous liquid adsorbent is weighed and placed in a gas adsorption instrument BELSORP MAX II, the instrument has a gas inlet amount of 0.5 cm 3 / g each time, after the gas adsorption is completed, 0.5 cm 3 / g of gas is injected, and the above adsorption process is repeated until the material is saturated with olefin or alkane gas adsorption under visible light irradiation. After degassing activation, the photoresponsive porous liquid adsorbent is placed under ultraviolet light irradiation and the adsorption amount is repeatedly measured. The difference between the gas adsorption amounts under visible light and ultraviolet light irradiation is calculated, and the value is the desorption amount of the adsorbent under the light irradiation condition.

[0021] Beneficial effects:

[0022] The application utilizes the reversible cis-trans isomerization behavior of the photoresponsive molecules under ultraviolet-visible light conditions, thereby achieving the purpose of adjusting the opening and closing of the internal pores and the number of external pores of the material. The introduction of long-chain alkyl ligands provides a more suitable environment for the isomerization of azobenzene. The synergistic effect of the two ligands significantly improves the isomerization efficiency of azobenzene, and further improves the photoresponsive efficiency of the porous liquid material. The porous liquid has a high change in gas adsorption amount of propylene and ethylene under different light conditions, effectively controlling the separation ratio of gas adsorption. The application obtains a photoresponsive porous liquid adsorbent that can remotely control the adsorption amount. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a schematic diagram of the skeleton structure of the photoresponsive bidentate metal organic cage. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the specific embodiments of the application will be described in detail below.

[0025] In the following description, many specific details are set forth in order to provide a thorough understanding of the application, but the application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the application, therefore the application is not limited by the specific embodiments disclosed below.

[0026] Second, the "one embodiment" or "an embodiment" referred to herein means a particular feature, structure, or characteristic including an implementation that can be included in at least one implementation of the application. The appearances of "in one embodiment" or "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all referring to a single, alternative embodiment, or a single implementation.

[0027] The ionic liquid IL-1 used in the following examples was synthesized according to the reference (Dinker, Manish Kumar, et al. Angewandte Chemie 135.31 (2023): e202306495), and the synthesis of other ionic liquids is consistent with the synthesis mechanism of the ionic liquid. Ionic liquids IL-2 to IL-12 are synthesized by changing the type of raw material polyethylene glycol and changing the counter anion based on the synthesis method of IL-1.

[0028] In addition, the gas adsorption conditions of the porous liquid adsorbent in the following examples are as follows: 0.1 g of the light-responsive porous liquid adsorbent is weighed and placed in a gas adsorption instrument BELSORP MAX II, and the instrument has a gas inlet amount of 0.5 cm 3 / g each time, and after the gas adsorption is complete, 0.5 cm 3 / g of gas is injected, and the above adsorption process is repeated until the material is saturated with olefin or alkane gas under visible light irradiation. After degassing and activation, the light-responsive porous liquid adsorbent is placed under ultraviolet light irradiation and its adsorption amount is repeatedly measured. The difference between the gas adsorption amounts under visible light and ultraviolet light irradiation is calculated, which is the desorption amount of the adsorbent under the light irradiation conditions.

[0029] Example 1

[0030] Preparation of porous host MOC-1: 1.6 g (5 mmol) of long-chain ligand a2 and 1.49 g (5 mmol) of azobenzene ligand a1 are weighed and dissolved in 15 mL of methanol solution, and ultrasonic treatment is performed for 10 minutes to ensure complete dissolution. Then, 1.88 g (10 mmol) of copper nitrate is weighed and dissolved in 45 mL of methanol. After mixing the two, 0.2 g of 2,6-dimethylpyridine is added and mixed thoroughly. After centrifugation, the MOC-1 is washed with methanol three times.

[0031] Preparation of light-responsive porous liquid PL-1: 2 g of IL-1 is diluted with 5 g of methanol, and then 5 mg of MOC-1 is added to the above mixed solution and ultrasonic treatment is performed until the solid is dissolved. After that, the mixed solution is heated to remove the methanol inside, and after the solvent is completely removed, PL-1 is obtained.

[0032] The intelligent light-responsive porous liquid adsorbent exhibits obvious adsorption difference under visible light and ultraviolet light, and the adsorption amount of propylene under visible light is 7.8 cm3 / g, the adsorption amount under ultraviolet light was 6.5 cm 3 / g, the change of the adsorption amount under different light conditions was 20.0%; at the same time, the adsorption amount of propane under visible light was 4.7 cm 3 / g, the adsorption amount under ultraviolet light was 4.4 cm 3 / g, the change of the adsorption amount was 7.6%, and the separation ratio of propylene / propane was increased from 1.4 under ultraviolet light to 1.8 under visible light.

[0033] Example 2

[0034] Preparation of the bulk ionic liquid IL-2: 5 g of IL-1 was dissolved in 50 mL of methanol, and then 15 mL of prepared lithium bis(trifluoromethanesulfonyl)imide (5 g) aqueous solution was added dropwise. After stirring at room temperature for 6 h, the reaction was stopped, the methanol was removed, and the organic phase was removed after multiple extractions with water and ethyl acetate to obtain yellow viscous liquid IL-2.

[0035] Preparation of the light-responsive porous liquid PL-2: 2 g of IL-2 was diluted with 6 g of ethanol, and then 20 mg of MOC-1 was weighed and added to the above mixed solution, and ultrasonic was performed until the solid was dissolved. After heating to remove the ethanol in the mixed solution, PL-2 was obtained after the solvent was completely removed.

[0036] The intelligent light-responsive porous liquid adsorbent showed obvious adsorption difference under visible light and ultraviolet light. The adsorption amount of propylene under visible light was 11.8 cm 3 / g, the adsorption amount under ultraviolet light was 6.6 cm 3 / g, the change of the adsorption amount of propylene under different light conditions was 78.0%; at the same time, the adsorption amount of propane under visible light was 5.9 cm 3 / g, the adsorption amount under ultraviolet light was 5.0 cm 3 / g, the change of the adsorption amount was 18.0%, and the separation ratio of propylene / propane was increased from 1.3 under ultraviolet light to 2.1 under visible light.

[0037] Example 3

[0038] Preparation of the bulk ionic liquid IL-3: 6 g of IL-1 was dissolved in 50 mL of methanol solution, and then 30 mL of prepared iron chloride hydrochloric acid aqueous solution (6 g) solution was added dropwise. After stirring at room temperature for 4 h, the reaction was stopped, the methanol solvent was removed, and the organic phase was obtained by multiple extractions with 1M hydrochloric acid aqueous solution and ethyl acetate, and then rotary evaporation to obtain yellow viscous liquid IL-3.

[0039] Preparation of photo-responsive porous liquid PL-3: Take 2 g of IL-3 and dilute it with 10 g of dichloromethane, then take 90 mg of MOC-1 and add it to the above mixed solution, ultrasonic until the solid is dissolved, then heat the mixed solution to remove the dichloromethane inside, and after the solvent is completely removed, PL-3 is obtained.

[0040] The intelligent photo-responsive porous liquid adsorbent shows obvious adsorption difference under visible light and ultraviolet light. The adsorption amount of propylene under visible light is 15.2 cm 3 / g, and the adsorption amount under ultraviolet light is 10.4 cm 3 / g, and the adsorption amount of propylene under visible light is 9.5 cm 3 / g, and the adsorption amount under ultraviolet light is 8.7 cm 3 / g, and the change in adsorption amount is 9.2%, and the separation ratio of propylene / propane is increased from 1.2 under ultraviolet light to 1.8 under visible light.

[0041] Example 4

[0042] Preparation of bulk ionic liquid IL-4: 10 g (30 mmol) of polyethylene glycol monomethyl ether is added to 25 mL of tetrahydrofuran solution, and after stirring at room temperature for a certain time, 25 mL of prepared sodium hydroxide solution (2.5 g) is added, then 7.6 g (40 mmol) of p-toluenesulfonyl chloride is dissolved in the mixed solution, and after stirring at room temperature for 4 h, dichloromethane and deionized water are extracted and separated, and the obtained organic layer is removed under vacuum to obtain a colorless sticky liquid. Take 8 g (20 mmol) of the solution and dissolve it in 20 mL of tetrahydrofuran, then add 20 mL of prepared sodium hydroxide solution (3 g), then add 2.1 g (30 mmol) of imidazole to the mixed solution, heat the solution to 80°C and reflux for 8 h, then after the reaction is completed, the solution is cooled to room temperature, extracted with dichloromethane and water, and separated, and the obtained organic layer is rotary evaporated under vacuum to remove the solvent to obtain a light yellow sticky liquid. Dissolve 8 g (20 mmol) of the solution from the previous step in 15 mL of acetonitrile solution and add 4.8 g (35 mmol) of n-butyl bromide under light protection, heat the solution to 80°C and reflux under nitrogen atmosphere for 24 h, then remove the acetonitrile after the reaction is completed and the solution is cooled to room temperature to obtain ionic liquid IL-4.

[0043] Preparation of porous MOC-2: 1.08 g (4 mmol) of long-chain b2 ligand and 2.83 g (6 mmol) of azobenzene ligand b1 were weighed and dissolved in 10 mL of methanol. The solution was sonicated for 10 minutes until fully dissolved. Then, 1.61 g (10 mmol) of rhodium acetate was weighed and dissolved in 8 mL of methanol. The two solutions were then mixed, and 0.3 g of 2,6-dimethylpyridine was added dropwise to the mixture. The solid was obtained by centrifugation and washed three times with ethyl acetate to obtain rhodium-based photoresponsive metal-organic cage MOC-2.

[0044] Preparation of responsive porous liquid PL-4: 1g of IL-4 was diluted with 8g of dichloromethane, and then 100mg of MOC-2 was weighed and added to the above mixed solution. The mixture was sonicated until the solid dissolved. The mixed solution was then heated to remove the dichloromethane. After the solvent was completely removed, PL-4 was obtained.

[0045] This intelligent photoresponsive porous liquid adsorbent exhibits significant adsorption differences under visible and ultraviolet light, with an adsorption capacity of 39.2 cm³ for propylene under visible light. 3 / g, with an adsorption capacity of 23.8cm under ultraviolet light. 3 / g, the adsorption capacity of propylene under different light conditions varied by 64.7%; meanwhile, the adsorption capacity of propane under visible light was 19.3cm. 3 / g, with an adsorption capacity of 13.7cm under ultraviolet light. 3 / g, the adsorption amount changed by 40.9%, and the separation ratio of propylene / propane increased from 1.4 under ultraviolet light to 2.0 under visible light.

[0046] Example 5

[0047] Preparation of large-volume ionic liquid IL-5: 5g of IL-4 was dissolved in 50mL of methanol, and then 15mL of prepared bis(trifluoromethanesulfonyl)imide lithium (5g) aqueous solution was added dropwise. After stirring at room temperature for 6h, the methanol was removed after the reaction stopped. The mixture was extracted multiple times with water and ethyl acetate to remove the organic phase and obtain yellow viscous liquid IL-5.

[0048] Preparation of photoresponsive porous liquid PL-5: 2g of IL-5 was diluted with 10g of methanol, and then 130mg of MOC-2 was weighed and added to the above mixed solution. The mixture was sonicated until the solid dissolved. The mixed solution was then heated to remove the methanol. PL-5 was obtained after the solvent was completely removed.

[0049] This intelligent photoresponsive porous liquid adsorbent exhibits significant adsorption differences under visible and ultraviolet light, with an adsorption capacity of 20.4 cm³ for propylene under visible light. 3 / g, the adsorption capacity under ultraviolet light is 14.6cm. 3 / g, the adsorption amount of propylene under visible light was 9.2 cm 3 / g, the adsorption amount under ultraviolet light was 8.3 cm 3 / g, the change of the adsorption amount was 10.8%, and the separation ratio of propylene / propane was increased from 1.7 under ultraviolet light to 2.3 under visible light.

[0050] Example 6

[0051] Preparation of the bulk ionic liquid IL-6: 5 g of IL-4 was dissolved in 50 mL of a methanol solution, and then a prepared 30 mL iron chloride hydrochloric acid aqueous solution (5 g) was added dropwise. After stirring at room temperature for 4 h, the methanol solvent was removed after the reaction stopped, and 1M hydrochloric acid aqueous solution and ethyl acetate were extracted multiple times. The organic phase was rotary evaporated to obtain yellow viscous liquid IL-6.

[0052] Preparation of the photoresponsive porous liquid PL-6: 2 g of IL-6 was diluted with 12 g of ethanol, and then 200 mg of MOC-2 was weighed and added to the above mixed solution and ultrasonicated until the solid was dissolved. After that, the mixed solution was heated to remove the ethanol inside, and PL-6 was obtained after the solvent was completely removed.

[0053] The intelligent photoresponsive porous liquid adsorbent showed obvious adsorption difference under visible light and ultraviolet light. The adsorption amount of propylene under visible light was 29.3 cm 3 / g, the adsorption amount under ultraviolet light was 19.2 cm 3 / g, the change of the adsorption amount of propylene under different light conditions was 52.6%; at the same time, the adsorption amount of propane under visible light was 20.4 cm 3 / g, the adsorption amount under ultraviolet light was 18.3 cm 3 / g, the change of the adsorption amount was 11.5%, and the separation ratio of propylene / propane was increased from 1.1 under ultraviolet light to 2.1 under visible light.

[0054] Example 7

[0055] Preparation of bulky ionic liquid IL-7: 20 g (60 mmol) of polyethylene glycol monoethyl ether was added to 50 mL of tetrahydrofuran solution, after stirring at room temperature for a certain time, 50 mL of sodium hydroxide solution (5 g) was added, then 17.1 g (90 mmol) of p-toluenesulfonyl chloride was dissolved in the mixed solution, after stirring at room temperature for 4 h, it was extracted and separated with dichloromethane and deionized water, and the obtained organic layer was removed under vacuum to obtain a colorless viscous liquid. 6 g of the solution was dissolved in 15 mL of tetrahydrofuran, and 15 mL of sodium hydroxide solution (3 g) was prepared and added, then 2.8 g (40 mmol) of imidazole was dissolved in the mixed solution, and the solution was heated to 80°C and stirred for 12 h. After the reaction was completed and the temperature was lowered to room temperature, it was extracted and separated with dichloromethane and water, and the obtained organic layer was rotary evaporated under vacuum to remove the solvent to obtain a light yellow viscous liquid. 8 g of the solution of the above step was dissolved in 20 mL of toluene solution and added to 8 g of n-butyl bromide in the dark, and the solution was heated to 80°C and stirred for 24 h under nitrogen atmosphere. After the reaction was completed and the temperature was lowered to room temperature, the mixture was washed with toluene several times, and after removing the excess toluene, a brown viscous ionic liquid IL-7 was obtained.

[0056] Preparation of porous host MOC-3: 1.58 g (6 mmol) of long-chain ligand c2 and 1.31 g (4 mmol) of azobenzene ligand c1 were weighed and dissolved in 20 mL of methanol solution, and ultrasonic was applied for 10 minutes to make them fully dissolved. Then 1.79 g of manganese nitrate (10 mmol) was weighed and dissolved in 15 mL of methanol, and then the two were mixed. Then 0.8 g of 2,6-dimethylpyridine was added dropwise to the mixture, and after fully mixing, it was centrifuged and washed with methanol three times to obtain a manganese-based photoresponsive metal-organic cage MOC-3.

[0057] Preparation of photoresponsive porous liquid PL-7: 1 g of IL-7 was diluted with 10 g of methanol, and then 30 mg of MOC-3 was added to the above mixed solution and ultrasonic was applied until the solid was dissolved. Then the mixed solution was heated to remove the methanol inside, and after the solvent was completely removed, PL-7 was obtained.

[0058] The intelligent photoresponsive porous liquid adsorbent showed obvious adsorption difference under visible light and ultraviolet light. The adsorption capacity of ethylene under visible light was 12.3 cm 3 / g, and the adsorption capacity under ultraviolet light was 7.6 cm 3 / g, and the change of adsorption capacity was 61.8%. At the same time, the adsorption capacity of ethane under visible light was 7.1 cm 3 / g, and the adsorption capacity under ultraviolet light was 6.3 cm 3 / g, and the change of adsorption capacity was 12.7%. The separation ratio of ethylene / ethane was increased from 1.2 under ultraviolet light to 1.9 under visible light.

[0059] Example 8

[0060] Preparation of bulk ionic liquid IL-8: 5 g of IL-7 was dissolved in 50 mL of methanol, then a prepared 15 mL solution of lithium bistrifluoromethanesulfonimide (5 g) was added dropwise, after stirring at room temperature for 6 h, the reaction was stopped, the methanol was removed, and the organic phase was removed after multiple extractions with water and ethyl acetate to obtain yellow viscous liquid IL-8.

[0061] Preparation of photoresponsive porous liquid PL-8: 2 g of IL-8 was diluted with 12 g of methanol, then 70 mg of MOC-3 was weighed and added to the above mixed solution, and ultrasonic was performed until the solid was dissolved, then the mixed solution was heated to remove the methanol inside, and PL-8 was obtained after the solvent was completely removed.

[0062] The intelligent photoresponsive porous liquid adsorbent showed obvious adsorption difference under visible light and ultraviolet light, the adsorption capacity of ethylene under visible light was 9.8 cm 3 / g, the adsorption capacity under ultraviolet light was 5.4 cm 3 / g, and the change in adsorption capacity was 81.5%; At the same time, the adsorption capacity of ethane under visible light was 6.2 cm 3 / g, the adsorption capacity under ultraviolet light was 5.3 cm 3 / g, and the change in adsorption capacity was 17.0%, and the separation ratio of ethylene / ethane was increased from 1.0 under ultraviolet light to 1.8 under visible light.

[0063] Example 9

[0064] Preparation of bulk ionic liquid IL-9: 5 g of IL-7 was dissolved in 50 mL of methanol, then a prepared 30 mL solution of iron chloride in hydrochloric acid (5 g) was added dropwise, after stirring at room temperature for 4 h, the reaction was stopped, the methanol solvent was removed, and the organic phase was removed after multiple extractions with 1 M aqueous hydrochloric acid and ethyl acetate to obtain yellow viscous liquid IL-9.

[0065] Preparation of photoresponsive porous liquid PL-9: 1 g of IL-9 was diluted with 6 g of methanol, then 90 mg of MOC-3 was weighed and added to the above mixed solution, and ultrasonic was performed until the solid was dissolved, then the mixed solution was heated to remove the methanol inside, and PL-9 was obtained after the solvent was completely removed.

[0066] The intelligent photoresponsive porous liquid adsorbent showed obvious adsorption difference under visible light and ultraviolet light, the adsorption capacity of ethylene under visible light was 13.2 cm 3 / g, the adsorption capacity under ultraviolet light was 8.4 cm 3 / g, the adsorption amount of ethylene under different light conditions changed by 57.1%; at the same time, the adsorption amount of ethane under visible light was 7.2 cm 3 / g, the adsorption amount under ultraviolet light was 5.3 cm 3 / g, the adsorption amount changed by 35.8%, and the separation ratio of ethylene / ethane increased from 1.5 under ultraviolet light to 2.0 under visible light.

[0067] Example 10

[0068] Preparation of bulk ionic liquid IL-10: 10 g (50 mmol) of PEG-200 was added to 100 mL of tetrahydrofuran solution, after stirring at room temperature for a certain time, 100 mL of sodium hydroxide solution (10 g) was added, then 22.8 g (120 mmol) of p-toluenesulfonyl chloride was dissolved in the mixed solution, after stirring at room temperature for 4 h, dichloromethane and deionized water were used for extraction and separation, and the obtained organic layer was removed under vacuum to obtain a colorless viscous liquid. 7 g (28 mmol) of the solution was dissolved in 30 mL of tetrahydrofuran, and then 15 mL of sodium hydroxide solution (6 g) was added, followed by the addition of 5 g of imidazole dissolved in the mixed solution. The solution was heated to 80°C and refluxed for 12 h. After the reaction was completed and the temperature was lowered to room temperature, dichloromethane and water were used for extraction and separation, and the obtained organic layer was rotary evaporated to obtain a light yellow viscous liquid. 8 g (40 mmol) of the solution from the previous step was dissolved in 20 mL of toluene solution and added to 12.3 g (90 mmol) of n-butyl bromide under light protection. The solution was heated to 80°C and refluxed for 24 h under nitrogen atmosphere. After the reaction was completed and the temperature was lowered to room temperature, the mixture was washed with methanol solution several times, and after the solvent was removed, a brown viscous ionic liquid IL-10 was obtained.

[0069] Preparation of porous host MOC-4: 0.97 g (3 mmol) of long-chain ligand d2 and 1.99 g (7 mmol) of azobenzene ligand d1 were weighed and dissolved in 20 mL of methanol solution, and ultrasonic was applied for 10 minutes to ensure complete dissolution. Then 1.26 g of manganese chloride (10 mmol) was dissolved in 15 mL of methanol, and then the two were mixed. Then 0.5 g of 2,6-dimethylpyridine was added dropwise to the mixture, and after thorough mixing, centrifugation was performed and the mixture was washed with methanol three times to obtain a manganese-based photoresponsive metal-organic cage MOC-4.

[0070] Preparation of photoresponsive porous liquid PL-10: 1 g of IL-10 was diluted with 8 g of ethanol, and then 40 mg of MOC-4 was added to the above mixed solution and ultrasonic was applied until the solid was dissolved. Then the ethanol in the mixed solution was removed by heating, and after the solvent was completely removed, PL-10 was obtained.

[0071] The intelligent light-responsive porous liquid adsorbent PL-10 exhibits obvious adsorption difference under visible light and ultraviolet light, and the adsorption amount of ethylene under visible light is 8.7 cm 3 / g, and the adsorption amount under ultraviolet light is 4.9 cm 3 / g, and the adsorption amount of ethylene under different light conditions changes by 77.6%; At the same time, the adsorption amount of ethane under visible light is 5.1 cm 3 / g, and the adsorption amount under ultraviolet light is 3.9 cm 3 / g, and the change of the adsorption amount is 30.8%, and the separation ratio of ethylene / ethane is increased from 1.2 under ultraviolet light to 1.9 under visible light.

[0072] Example 11

[0073] Preparation of a large volume of ionic liquid IL-11: 5 g of IL-10 is dissolved in 50 mL of methanol, and then a prepared 15 mL lithium bis(trifluoromethanesulfonyl)imide (5 g) solution is added dropwise. After stirring at room temperature for 6 h, the methanol solvent is removed after the reaction stops, and the organic phase is removed after being extracted with water and ethyl acetate for several times to obtain yellow viscous liquid IL-11.

[0074] Preparation of porous host MOC-5: 0.88 g (3 mmol) of long-chain ligand e2 and 2.19 g (7 mmol) of azobenzene ligand e1 are dissolved in 20 mL of methanol solution, and ultrasonic is performed for 10 minutes to make them fully dissolved. Then, 1.34 g of copper chloride (10 mmol) is dissolved in 15 mL of methanol, and then the two are mixed. Then, 0.6 g of 2,6-dimethylpyridine is added dropwise to the mixture, and after fully mixing, the copper-based light-responsive metal organic cage MOC-5 is obtained by centrifugation and washing with methanol for three times.

[0075] Preparation of light-responsive porous liquid PL-11: 1 g of IL-11 is diluted with 8 g of methanol, and then 90 mg of MOC-5 is added to the above mixed solution and ultrasonic is performed until the solid is dissolved. Then, the mixed solution is heated to remove the methanol inside, and after the solvent is completely removed, PL-11 is obtained.

[0076] The intelligent light-responsive porous liquid adsorbent PL-11 exhibits obvious adsorption difference under visible light and ultraviolet light, and the adsorption amount of ethylene under visible light is 13.4 cm 3 / g, and the adsorption amount under ultraviolet light is 8.8 cm 3 / g, and the adsorption amount of ethylene under different light conditions changes by 52.3%; At the same time, the adsorption amount of ethane under visible light is 9.1 cm 3 / g, and the adsorption amount under ultraviolet light is 7.2 cm 3 / g, the change of adsorption capacity was 26.4%, and the separation ratio of ethylene / ethane was increased from 1.1 under UV light to 1.7 under visible light.

[0077] Example 12

[0078] Preparation of bulk ionic liquid IL-12: 5 g of IL-10 was dissolved in 50 mL of methanol, and then a prepared 30 mL of iron chloride hydrochloric acid aqueous solution (5 g) solution was added dropwise. After stirring at room temperature for 4 h, the methanol solvent was removed after the reaction stopped, and 1 M hydrochloric acid aqueous solution and ethyl acetate were extracted several times. After removing the organic phase, yellow viscous liquid IL-12 was obtained.

[0079] Preparation of porous host MOC-6: 1.86 g (7 mmol) of long-chain ligand f2 and 0.89 g (3 mmol) of azobenzene ligand f1 were weighed and dissolved in 20 mL of methanol solution, and ultrasonic was applied for 10 min to fully dissolve them. Then, 1.30 g of cobalt chloride (10 mmol) was dissolved in 15 mL of methanol, and then the two were mixed. Then, 0.3 g of 2,6-dimethylpyridine was added dropwise to the mixture, and after fully mixing, centrifugation was performed and washing with methanol was performed three times to obtain the cobalt-based photoresponsive metal organic cage MOC-6.

[0080] Preparation of photoresponsive porous liquid PL-12: 1 g of IL-12 was diluted with 6 g of dichloromethane, and then 90 mg of MOC-6 was weighed and added to the above mixed solution. Ultrasonic was applied until the solid was dissolved, and then the mixed solution was heated to remove the dichloromethane inside. After completely removing the solvent, PL-12 was obtained.

[0081] The intelligent photoresponsive porous liquid adsorbent PL-12 showed obvious adsorption difference under visible light and ultraviolet light. The adsorption capacity of ethylene under visible light was 16.2 cm 3 / g, and the adsorption capacity under ultraviolet light was 11.3 cm 3 / g, and the change of adsorption capacity was 43.4%. At the same time, the adsorption capacity of ethane under visible light was 8.9 cm 3 / g, and the adsorption capacity under ultraviolet light was 7.3 cm 3 / g, and the change of adsorption capacity was 22.0%, and the separation ratio of ethylene / ethane was increased from 1.5 under ultraviolet light to 2.1 under visible light.

Claims

1. A photoresponsive porous liquid adsorbent, characterized in that: A photoresponsive porous liquid adsorbent with a porous matrix of 0.2%-10% by mass was prepared by using a photoresponsive metal-organic cage as the porous host and a macromolecular ionic liquid as the steric hindrance solvent.

2. The photoresponsive porous liquid adsorbent according to claim 1, characterized in that: The photoresponsive metal-organic cage is a photoresponsive dual-ligand metal-organic cage obtained by coordination self-assembly of a mixture of isophthalic acid-derived ligands and an equimolar amount of transition metal salts under the promotion of 2,6-dimethylpyridine.

3. The photoresponsive porous liquid adsorbent according to claim 2, characterized in that: The transition metal salts mentioned are copper nitrate, copper chloride, rhodium acetate, cobalt chloride, manganese nitrate, or manganese chloride.

4. The photoresponsive porous liquid adsorbent according to claim 2, characterized in that: The amount of 2,6-dimethylpyridine used is 10%-50% of the mass of the metal salt.

5. The photoresponsive porous liquid adsorbent according to claim 2, characterized in that: The isophthalic acid-derived ligands are photoresponsive azobenzene-derived ligands and long-chain alkyl ligands, wherein the molar ratio of azobenzene-derived ligands to long-chain alkyl ligands is 1:(0.42-2.34).

6. The photoresponsive porous liquid adsorbent according to claim 5, characterized in that: The azobenzene-derived ligand described herein has one of the following structures: a1, b1, c1, d1, e1, or f1: The long-chain alkyl ligands enhance the photoresponse properties of the porous host, and these molecules have one of the following structures: a2, b2, c2, d2, e2, or f2.

7. The photoresponsive porous liquid adsorbent according to claim 1, characterized in that: The macromolecular ionic liquid is an imidazole-type macromolecular ionic liquid of polyethylene glycol, having one of the following structures from IL-1 to IL-12:

8. A method for preparing the photoresponsive porous liquid adsorbent as described in claim 1, comprising the following steps: dissolving the porous bulk in an ionic liquid diluted with a low-boiling-point solvent, and removing the low-boiling-point solvent to obtain the photoresponsive porous liquid adsorbent.

9. The method according to claim 8, characterized in that: The low-boiling-point solvent is methanol, ethanol, or dichloromethane, and its amount is 2-10 times the mass of the ionic liquid.

10. The application of a photoresponsive porous liquid adsorbent as described in claim 1 in the separation of ethylene / ethane or propylene / propane.

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