Application of linear nonporous swelling material in adsorption and separation of low-carbon hydrocarbon

Abstract

The invention discloses application of a linear nonporous swelling material in adsorption and separation of low-carbon hydrocarbons. The low-carbon hydrocarbons refer to one or more of C2-C4 hydrocarbons. The linear nonporous swelling material is formed by self-assembly of an organic ligand L, an inorganic anion S and a metal ion M and is formed by spatial expansion of a plurality of structural units with the composition of [MS2L] L. The metal ion M is any one of Co < 2 + >, Ni < 2 + >, Cu < 2 + > and Zn < 2 + >; the organic ligand L is 4, 4 '-dipyridyl, and the inorganic anion S is any one of ClO4 <->, BF4 <-> and CF3SO3 <->. The linear nonporous swelling material has an excellent separation effect on different hydrocarbon systems, can efficiently separate alkyne, alkadiene and the like, and is easy to desorb and regenerate.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical separation, and in particular to the application of a type of linear non-porous swelling material in the adsorption and separation of low-carbon hydrocarbons. Background Art

[0002] The sustainable development of the chemical industry depends crucially on the implementation of low-carbon emission technologies. Separation and purification processes account for 10%-15% of global energy consumption. Accelerating innovation in adsorption separation technology, replacing heat-driven separation with adsorption, will save significant energy. The application of new adsorbents with improved separation properties will improve separation efficiency, and researchers are committed to identifying adsorbents with ideal separation characteristics: high selectivity, high capacity, rapid adsorption / desorption kinetics, and gentle regeneration.

[0003] Based on the different molecular recognition methods, adsorption separation mechanisms are categorized as thermodynamic equilibrium, molecular sieving, and kinetic separation. Thermodynamic equilibrium adsorbents separate molecules by varying binding affinities, but separation selectivity is limited due to co-adsorption. Molecular sieving adsorbents exhibit ideal, highest separation selectivity, and rigid molecular sieves (such as zeolites) show great potential in gas separation. Furthermore, the emergence of metal-organic frameworks (MOFs) has greatly facilitated the development of flexible molecular sieve porous materials. Flexibility, such as connector rotation and subnetwork displacement, allows these porous materials to adapt to diverse gas molecules and exhibit precise recognition based on molecular size and properties. Therefore, flexible porous molecular sieve materials exhibit high separation selectivity for molecules of similar or even identical molecular size, such as C2H2 / CO2 (UTSA-300: Journal of the American Chemical Society, 2017, 139, 8022-8028), C2H2 / C2H4 (GeFSIX-dps-Cu: Angewandte Chemie International Edition, 2020, 59, 12725-12730), and C3H4 / C3H6 (NTU-88: Angewandte Chemie International Edition, 2023, 62, e202316792). However, the size dependence of rigid or flexible molecular sieves dictates that they can only achieve separation efficiency within a narrow range of molecular sizes. Furthermore, optimizing the adsorption kinetics of molecular sieve adsorbents remains a long-standing challenge. Designing molecular sieve adsorbents with optimal separation properties remains a pressing task. Summary of the Invention

[0004] In response to the above-mentioned technical problems and the shortcomings in the field, the present invention provides a type of linear non-porous swelling material for use in the adsorption and separation of low-carbon hydrocarbons. The linear non-porous swelling material of the present invention has excellent separation effects on different hydrocarbon systems, can efficiently separate alkynes, dienes, etc., and is easy to desorb and regenerate.

[0005] Application of linear non-porous swelling materials in the adsorption and separation of low-carbon hydrocarbons, wherein the low-carbon hydrocarbons refer to one or more C2-C4 hydrocarbons; The linear non-porous swelling material is self-assembled from an organic ligand L, an inorganic anion S, and a metal ion M, and is formed by spatial expansion of a plurality of structural units composed of [MS2L]L, wherein: Metal ion M is Co 2+ 、Ni 2+ 、Cu 2+ 、Zn 2+ Any of the following; The organic ligand L is 4,4'-bipyridine; Inorganic anion S is ClO4 - 、BF4 - CF3SO3 - Any one of .

[0006] The linear non-porous swelling material of the present invention can be prepared by selecting appropriate raw materials according to the prior art, and can be prepared by using the interface diffusion method, stirring method, etc. The raw materials are easy to obtain and the preparation method is simple. For example, when the metal ion M is Cu 2+ , the inorganic anion S is ClO4 - When the linear non-porous swelling material is a prior art, for details, see ANAL. SCI. 18,1179-1180 (2002), Aust. J. Chem. 1996, 49, 835-838, etc.

[0007] The linear non-porous swelling material of the present invention has a one-dimensional anionic linear chain and an uncoordinated organic ligand, and is a non-porous structure. After desolventization (for example, one or more of methanol, ethanol, ethylene glycol, water, etc.) and activation, it still has a non-porous structure. For example Figure 1 and Figure 2 shown.

[0008] In the application, low-carbon hydrocarbons can be adsorbed and separated by the linear non-porous swelling material. After the adsorption is completed, the linear non-porous swelling material adsorbed with the strongly adsorbed components can be regenerated by desorption.

[0009] In some preferred examples, the linear non-porous swelling material can preferentially adsorb alkynes and dienes having carbon-carbon triple bonds and double carbon-carbon double bonds, and desorption can produce high-purity butadiene and alkynes, thereby achieving purification of hydrocarbon mixtures within a wider range of molecular sizes.

[0010] The linear non-porous swelling material provided by the present invention is rich in high-density inorganic anions in its pores and has excellent molecular recognition function. At the same time, the diamond-shaped cavities formed between the chains are occupied by uncoordinated organic ligand molecules, so that the series of materials maintain a non-porous structure after synthesis and degassing. Through the precise recognition of inorganic anions, alkynes and dienes with richer functional groups can be preferentially identified from a multi-system hydrocarbon mixture, showing specific swelling and high adsorption capacity, while showing negligible adsorption of carbon dioxide molecules and some alkanes and alkenes, thereby achieving the current highest adsorption capacity ratio, which is conducive to the preparation of high-purity hydrocarbon substances.

[0011] The linear, non-porous, swellable material provided by the present invention exhibits strong adsorption for alkynes and dienes, while having essentially negligible adsorption for carbon dioxide and some lower alkanes. It can be used to separate C2-C4 hydrocarbon mixtures to obtain high-purity products. In some preferred embodiments, the linear, non-porous, swellable material is used to adsorb at least one of alkynes and dienes.

[0012] In some preferred embodiments, the metal ion M is Cu 2+ , the inorganic anion S is ClO4 - The linear non-porous swelling material is used to adsorb at least one of acetylene, propyne and butadiene. Further, the metal ion M is Cu 2+ , the inorganic anion S is ClO4 - The linear non-porous swelling material can be used for adsorption separation of a mixture containing alkynes and / or butadiene, wherein the alkynes include at least one of acetylene and propyne, and the mixture containing alkynes may also include at least one of ethane, ethylene, propane, propylene, carbon dioxide, n-butene, trans-2-butene, cis-2-butene, isobutene, n-butane, isobutane, etc.

[0013] In some preferred embodiments, the metal ion M is Zn 2+ , the inorganic anion S is ClO4 - The linear non-porous swelling material is used to adsorb acetylene. Further, the metal ion M is Zn 2+ , the inorganic anion S is ClO4 - The linear non-porous swelling material can be used for adsorption separation of a mixture containing acetylene, and the mixture containing acetylene may also include carbon dioxide and the like.

[0014] In some preferred embodiments, the metal ion M is Cu 2+ , the inorganic anion S is BF4- The linear non-porous swelling material is used to adsorb at least one of butadiene, trans-2-butene, cis-2-butene, n-butene, and n-butane. Further, the metal ion M is Cu 2+ , the inorganic anion S is BF4 - The linear non-porous swellable material can be used for adsorption separation of a butadiene-containing mixture, which may further include other C4 hydrocarbons, such as one or more of n-butene, trans-2-butene, cis-2-butene, isobutene, n-butane, and isobutane. Furthermore, the butadiene-containing mixture is a C4 hydrocarbon mixture.

[0015] In some preferred embodiments, the metal ion M is Co 2+ , the inorganic anion S is ClO4 - The linear non-porous swelling material is used to adsorb propyne. Further, the metal ion M is Co 2+ , the inorganic anion S is ClO4 - The linear non-porous swelling material can be used for adsorption separation of a mixture containing propyne, and the mixture containing propyne may also include propylene and the like.

[0016] In some preferred embodiments, the metal ion M is Ni 2+ , the inorganic anion S is CF3SO3 - The linear non-porous swelling material is used to adsorb butadiene. Further, the metal ion M is Ni 2+ , the inorganic anion S is CF3SO3 - The linear non-porous swelling material can be used for adsorption separation of a butadiene-containing mixture, and the butadiene-containing mixture may also include other C4 hydrocarbons, such as one or more of n-butene, trans-2-butene, cis-2-butene, isobutene, n-butane, isobutane, etc.

[0017] In the above application, the adsorption temperature may be 0-60°C, such as 15°C, 25°C, etc., and the adsorption pressure is preferably not more than 2 bar.

[0018] In the aforementioned application, the linear non-porous swellable material is reusable and can be regenerated by desorption. The desorption temperature can be 20-100°C, and the pressure is preferably no more than 1 bar. Regeneration can be achieved by desorption using a combination of one or more of the following methods: room temperature vacuum desorption, heated vacuum desorption, and heated inert gas desorption.

[0019] The low-carbon hydrocarbons may be in a gaseous state, such as a C2 gas mixture, a C3 gas mixture, a C4 gas mixture, etc. The contacting method between the linear non-porous swelling material and the low-carbon hydrocarbons may include any one or more combinations of fixed bed adsorption, fluidized bed adsorption, and simulated moving bed adsorption. The adsorption operation may include any one or more combinations of temperature swing adsorption and pressure swing adsorption.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1) The linear non-porous swelling material provided by the present invention has the advantages of simple structure and strong specific recognition ability. It can selectively identify gas molecules based on functional group differences and achieve selective adsorption and separation of mixed gases; 2) The linear non-porous swelling material provided by the present invention has the advantages of simple synthesis method, mild conditions, and easy batch preparation; 3) The linear non-porous swelling material provided by the present invention can separate alkynes and dienes from other hydrocarbons in a C2-C4 hydrocarbon mixture, thereby obtaining a high-purity product; 4) The linear non-porous swelling material provided by the present invention has fast adsorption kinetics as an adsorbent, low regeneration energy consumption, and can be reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the crystal structure of the linear non-porous swelling material obtained in Example 1 before activation.

[0022] Figure 2 Schematic diagram of the crystal structure of the linear non-porous swelling material obtained in Example 1 after activation.

[0023] Figure 3 This is the X-ray diffraction (XRD) pattern of the linear non-porous swelling material obtained in Example 1 before activation.

[0024] Figure 4 1 is a thermogravimetric analysis (TGA) curve of the linear non-porous swelling material obtained in Example 1 before and after activation.

[0025] Figure 5 This is the adsorption isotherm of the activated linear non-porous swelling material obtained in Example 1 for C2-C3 hydrocarbons at 298K.

[0026] Figure 6 This is the adsorption isotherm of the activated linear non-porous swelling material obtained in Example 1 for C2-C3 hydrocarbons at 273K.

[0027] Figure 7 This is the acetylene / carbon dioxide penetration curve of the activated linear non-porous swelling material obtained in Example 1 at 273K.

[0028] Figure 8 This is a desorption curve of the activated linear non-porous swelling material obtained in Example 1 after acetylene / carbon dioxide penetration at 298K.

[0029] Figure 9 This is the acetylene / carbon dioxide penetration curve of the activated linear non-porous swelling material obtained in Example 3 at 273K.

[0030] Figure 10 This is the adsorption isotherm diagram of C4 hydrocarbons at 298K for the activated linear non-porous swelling material obtained in Example 5.

[0031] Figure 11 This is the adsorption isotherm of the activated linear non-porous swelling material obtained in Example 5 for C4 hydrocarbons at 288K.

[0032] Figure 12 This is the penetration curve of the activated linear non-porous swelling material obtained in Example 6 for propyne / propylene at 273K.

[0033] Figure 13 This is a penetration curve of the activated linear non-porous swelling material obtained in Example 8 at 288K for the three components C4.

[0034] Figure 14 This is a penetration curve of the activated linear non-porous swelling material in Example 1 at 288K for the seven components C4. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings and specific examples. It should be understood that these examples are intended to illustrate the present invention and are not intended to limit the scope of the invention. The operating methods in the following examples where no specific conditions are specified are generally performed under conventional conditions or as recommended by the manufacturer.

[0036] Example 1: 1 mmol of Cu(ClO4)2 was dissolved in 10 mL of water, and 2 mmol of 4,4'-bipyridine was dissolved in 10 mL of ethanol. The two were mixed and allowed to stand for 48 hours. The resulting precipitate was filtered to obtain a linear non-porous swelling material before activation (or "synthetic sample"). The linear non-porous swelling material before activation was activated at 150°C under vacuum conditions for 24 hours to obtain an activated linear non-porous swelling material, which was recorded as CuClO4bipy.

[0037] The crystal structures of the linear non-porous swelling material obtained in Example 1 before and after activation are shown in FIG. Figure 1 、 Figure 2 Before activation, the Cu metal in the linear nonporous swelling material is six-coordinated, with each Cu metal coordinating with two N on 4,4'-bipyridine ligands and each Cu metal coordinating with two ClO4 - The O on the anion is coordinated by the O from two water molecules; the metal and organic ligands form an infinitely extending linear chain. Due to the presence of uncoordinated 4,4'-bipyridine molecules in the structure, the overall material exhibits a nonporous structure. Upon activation, the Cu metal in CuClO4bipy becomes tetracoordinated, losing bound water while still maintaining a linear, nonporous structure.

[0038] The powder X-ray diffraction of the linear non-porous swelling material before activation in Test Example 1 showed the following results: Figure 3 As shown, the peak position and relative intensity of the spectrum of the material are basically consistent with those of the crystal simulation spectrum, and the peak shape is sharp, indicating that the linear non-porous swelling material prepared by the present invention has high purity and good crystallinity.

[0039] Thermogravimetric analysis of the linear non-porous swelling material obtained in Example 1 before and after activation was performed. The results were as follows: Figure 4 As shown, it is shown that the thermal stability of the linear non-porous swelling material prepared by the present invention reaches 280°C.

[0040] The adsorption isotherms of CuClO4bipy obtained in Example 1 for single components of C2-C3 hydrocarbons at 298K and 273K are as follows: Figure 5 and Figure 6 Test results show that CuClO4bipy exhibits strong interactions with acetylene and propyne, resulting in high adsorption capacities of 3.33 mmol / g and 3.43 mmol / g, respectively, at 298 K. In contrast, CuClO4bipy exhibits negligible adsorption of alkenes and carbon dioxide. Therefore, the linear, nonporous, swellable material provided by this invention can achieve efficient separation of C2-C3 hydrocarbons, yielding high-purity alkynes.

[0041] Example 2: The CuClO4bipy obtained in Example 1 was loaded into a 10 cm adsorption column. A mixture of acetylene and carbon dioxide (50 / 50 by volume) was introduced into the adsorption column at 2 mL / min at 273 K. The breakthrough curve was as shown in FIG. Figure 7 As shown in the figure, carbon dioxide flows out immediately after 2.7 minutes, and acetylene begins to flow out after 40 minutes. When acetylene penetrates, adsorption is stopped and the adsorption column is purged with helium to obtain acetylene with a purity of 99.999%. Figure 8 As shown, the adsorption column can be recycled.

[0042] Example 3: 1 mmol Zn(ClO4)2 was dissolved in 10 mL water, and 2 mmol 4,4'-bipyridine was dissolved in 10 mL ethanol. The two were mixed and allowed to stand for 72 h. The resulting precipitate was filtered to obtain a linear non-porous swelling material before activation. The linear non-porous swelling material before activation was activated at 150°C under vacuum conditions for 24 h to obtain an activated linear non-porous swelling material, which was recorded as ZnClO4bipy.

[0043] Example 4: The ZnClO4bipy obtained in Example 3 was loaded into a 10 cm adsorption column. A mixture of acetylene and carbon dioxide (50 / 50 by volume) was introduced into the adsorption column at 4 mL / min at 273 K. The penetration curve was as shown in FIG. Figure 9 As shown, carbon dioxide immediately flows out at 1.8 minutes, and acetylene begins to flow out after 23 minutes.

[0044] Example 5: 1 mmol of Cu(BF4)2 was dissolved in 10 mL of water, and 2 mmol of 4,4'-bipyridine was dissolved in 10 mL of ethanol. The two were mixed and allowed to stand for 72 h. The resulting precipitate was filtered to obtain a linear non-porous swelling material before activation. The linear non-porous swelling material before activation was activated at 150°C under vacuum conditions for 24 h to obtain an activated linear non-porous swelling material, which was recorded as CuBF4bipy.

[0045] The adsorption isotherms of CuBF4bipy obtained in Example 5 for single components of C4 hydrocarbons at 298K and 288K are as follows: Figure 10 and Figure 11 Test results show that CuBF4bipy exhibits a stronger interaction with butadiene (C4H6) and a higher adsorption capacity, reaching 4.61 mmol / g at 298K. In comparison, the adsorption of other C4 hydrocarbons by CuBF4bipy requires higher pressures and does not adsorb as much as butadiene. Therefore, the linear, nonporous, swellable material provided by this invention can achieve efficient separation of C4 hydrocarbons, yielding high-purity butadiene.

[0046] Example 6: 1 mmol Co(ClO4)2 was dissolved in 10 mL water, and 2 mmol 4,4'-bipyridine was dissolved in 10 mL ethanol. The two were mixed and allowed to stand for 24 hours. The resulting precipitate was filtered to obtain a linear non-porous swelling material before activation. The linear non-porous swelling material before activation was activated at 150°C under vacuum conditions for 24 hours to obtain an activated linear non-porous swelling material, which was recorded as CoClO4bipy.

[0047] Example 7: The CoClO4bipy obtained in Example 6 was loaded into a 10 cm adsorption column. A propyne / propylene (50 / 50 by volume) mixture was passed into the adsorption column at 2 mL / min at 273 K. The breakthrough curve was as shown in FIG. Figure 12 As shown, propylene breaks through immediately and the retention time of propyne is as long as 50 minutes, showing an excellent separation effect of propyne and propylene.

[0048] Example 8: 1 mmol Ni(CF3SO3)2 was dissolved in 10 mL water, and 2 mmol 4,4'-bipyridine was dissolved in 10 mL ethanol. The two were mixed and allowed to stand for 48 hours. The resulting precipitate was filtered to obtain a linear non-porous swelling material before activation. The linear non-porous swelling material before activation was activated at 150°C under vacuum conditions for 24 hours to obtain an activated linear non-porous swelling material, which was recorded as NiCF3SO3bipy.

[0049] Example 9: The NiCF3SO3bipy obtained in Example 8 was loaded into a 5 cm adsorption column. A mixture of butadiene (C4H6) / isobutylene / n-butene / helium (50% / 30% / 15% / 5% by volume) was introduced into the adsorption column at 1.125 mL / min at 288 K. The penetration curve is shown in FIG. Figure 13 As shown, butadiene did not completely break through until 75 min, showing an excellent three-component C4 separation effect.

[0050] Example 10: The CuClO4bipy obtained in Example 1 was loaded into a 10 cm adsorption column. A mixture of butadiene / cis-butylene / isobutylene / n-butylene / trans-butylene / n-butane / isobutane (44.32% / 5.51% / 24.1% / 13.4% / 6.59% / 5.04% / 1.04% by volume) was introduced into the adsorption column at 1.125 mL / min at 288 K. The breakthrough curve is shown in FIG. Figure 14 As shown, butadiene did not completely break through until 180 min, showing an excellent seven-component C4 separation effect.

[0051] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. Application of linear non-porous swelling materials in the adsorption and separation of low-carbon hydrocarbons, characterized in that: The low carbon hydrocarbons refer to one or more C2-C4 hydrocarbons; The linear non-porous swelling material is self-assembled from an organic ligand L, an inorganic anion S, and a metal ion M, and is formed by spatial expansion of a plurality of structural units composed of [MS2L]L, wherein: Metal ion M is Co 2+ 、Ni 2+ 、Cu 2+ 、Zn 2+ Any of the following; The organic ligand L is 4,4'-bipyridine; Inorganic anion S is ClO4 - 、BF4 - CF3SO3 - Any one of .

2. The use according to claim 1, characterized in that The linear non-porous swelling material is used for adsorbing at least one of alkynes and dienes.

3. The use according to claim 1, characterized in that Metal ion M is Cu 2+ , the inorganic anion S is ClO4 - The linear non-porous swelling material is used to adsorb at least one of acetylene, propyne, and butadiene.

4. The use according to claim 1, characterized in that Metal ion M is Zn 2+ , the inorganic anion S is ClO4 - , the linear non-porous swelling material is used for adsorbing acetylene.

5. The use according to claim 1, characterized in that Metal ion M is Cu 2+ , the inorganic anion S is BF4 - The linear non-porous swelling material is used to adsorb at least one of butadiene, trans-2-butene, cis-2-butene, n-butene, and n-butane.

6. The use according to claim 1, characterized in that Metal ion M is Co 2+ , the inorganic anion S is ClO4 - , the linear non-porous swelling material is used to adsorb propyne.

7. The use according to claim 1, characterized in that Metal ion M is Ni 2+ , the inorganic anion S is CF3SO3 - , the linear non-porous swelling material is used for adsorbing butadiene.

8. The use according to any one of claims 1 to 7, characterized in that The adsorption temperature is 0~60℃ and the adsorption pressure does not exceed 2 bar.

9. The use according to any one of claims 1 to 7, characterized in that The linear non-porous swelling material is reused and regenerated by desorption; The desorption temperature is 20-100°C and the pressure does not exceed 1 bar; Regeneration is achieved by combining desorption with one or more of room temperature vacuum desorption, heated vacuum desorption, and heated inert gas desorption.

10. The use according to any one of claims 1 to 7, characterized in that: The low-carbon hydrocarbon is in gaseous state, and the contact mode between the linear non-porous swelling material and the low-carbon hydrocarbon includes any one or more combinations of fixed bed adsorption, fluidized bed adsorption, and simulated moving bed adsorption. The adsorption operation includes one or more combinations of temperature swing adsorption and pressure swing adsorption.

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