MOF (Metal Organic Framework) material for separating low-carbon hydrocarbon and preparation method of MOF material
By using the metal-organic framework (MOF) material MInL4, the problems of low adsorption capacity, low selectivity, and complex synthesis in the separation of low-carbon hydrocarbons have been solved, achieving efficient and low-energy separation of low-carbon hydrocarbons and reducing synthesis costs.
Patent Information
- Application Number
- CN202411410906.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-10
- Publication Date
- 2026-04-10
AI Technical Summary
Existing low-carbon hydrocarbon separation technologies suffer from problems such as low adsorption capacity, low selectivity, complex synthesis conditions, and high cost. In particular, it is difficult to achieve efficient and low-energy separation in the separation of CH4/N2, C2H4/C2H6, and C2H2/CO2/CH4.
Using the metal-organic framework (MOF) material MInL4, one-dimensional channels are formed by tetrahedral units linked by isonicotinic acid. Hydrogen bonds and van der Waals forces are formed by combining amino groups and other groups, which improves the adsorption capacity and selectivity for low-carbon hydrocarbons. A simple synthesis method is used to reduce costs.
It achieves efficient separation of CH4/N2, C2H6/C2H4 and C2H2/CO2/CH4, reduces energy consumption, improves the stability and synthesis efficiency of the adsorbent, and reduces the synthesis cost.
Smart Images
Figure CN121824966A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the field of adsorption separation technology, and particularly relates to a metal organic framework (MOF) material for separating low-carbon hydrocarbons and a preparation method thereof. BACKGROUND
[0002] The separation and purification of low-carbon hydrocarbons have important application value, and the products are important cornerstones of industrial production. The low-carbon hydrocarbon separation products are regarded as the blood of the industry, with an annual output of hundreds of millions of tons, and are widely used in the further synthesis of various industrial products, which are ubiquitous in human life, such as fibers, plastics, rubbers, etc. Therefore, such a high annual output is accompanied by a very high energy consumption problem, and it is usually necessary to achieve high-temperature and high-pressure conditions to separate light hydrocarbons with abnormal physical and chemical properties. In today's increasingly serious energy and environmental problems, energy saving and emission reduction in various fields urgently need more attention. It is necessary to find more efficient and energy-saving separation methods to replace the traditional high-energy low-temperature rectification method.
[0003] Under this background, metal organic frameworks (MOFs) as a new type of porous material with extremely high specific surface area, structural sustainability, linker customizability and controllability, this method has the advantages of simple operation, high product purity and low energy consumption. Especially in the separation of light hydrocarbons, MOF is considered as a green separation material with great potential and prospect, and is widely studied by many researchers. However, to realize the wide application of MOFs, several challenges still need to be overcome: 1) there is a low adsorption capacity or low selectivity when separating gas, which cannot meet the requirements of having both adsorption capacity and certain selectivity. 2) there are the disadvantages of complex synthesis conditions (long reaction time, high reaction temperature, and material easy to deteriorate) and expensive raw materials. There is the disadvantage of low synthesis yield, which is not easy to scale up.
[0004] In particular, the separation of low carbon hydrocarbons is a very challenging process, for example, the separation of CH4 is difficult because of the small difference in their physical and chemical properties, the low amount of methane adsorption and low selectivity in CH4 / N2 separation, the stability of the adsorbent, and the difficulty of the synthesis method, which still limits the industrial application of the adsorbent. And the affinity and adsorption capacity of C2 hydrocarbons are generally C2H4 > C2H6. In the separation process of C2H4 / C2H6 mixture, C2H4 / C2H6 mixture accounts for most of the C2 hydrocarbon separation, and the energy consumption is very large. Due to the interaction between C2 hydrocarbons and the skeleton, most MOFs selectively adsorb C2H4, and then further desorption and a series of subsequent steps are required to obtain purified C2H4 product. Therefore, the purification process and energy consumption of C2H4 still need to be optimized. And acetylene is an inevitable byproduct in the industrial production process of ethylene, which will block the active metal sites of the polymerization catalyst and cause the catalyst to be deactivated. Acetylene is usually produced by partial combustion of natural gas or hydrocarbon cracking, and carbon dioxide and unreacted methane often exist as impurity components in acetylene. Therefore, it is of great significance to effectively separate C2H2 / CO2 and C2H2 / CO2 / CH4.
[0005] In summary, it is necessary to develop an adsorbent with excellent adsorption capacity, high selectivity, excellent structural stability, and easy synthesis for the efficient separation of low carbon hydrocarbon mixtures.
[0006] Therefore, the present application is proposed. SUMMARY
[0007] The present application proposes a metal organic framework (MOF) material for low carbon hydrocarbon separation and a preparation method thereof to solve the problems in the prior art.
[0008] The present application provides a metal organic framework (MOF) material for low carbon hydrocarbon separation, characterized in that the metal organic framework (MOF) material is as shown in the following formula:
[0009] MInL4 formula I;
[0010] M is a positive univalent transition metal ion;
[0011] L is an organic ligand containing isonicotinic acid, and the organic ligand is selected from any one of formula II;
[0012]
[0013] wherein R is a substituent selected from any one of methyl, hydroxyl, amino, nitro, fluorine, bromine, and chlorine.
[0014] Preferably, the positive univalent transition metal ion includes Ag + or Cu+ .
[0015] Preferably, the metal-organic framework (MOF) material comprises two special tetrahedral units linked by isonicotinic acid, each M + The center is a tetrahedron [MN4]. + It has four pyridine N atoms from four isonicotinic acid ligands, each In 3+ The center is coordinated by four carboxylic acid groups from four isonicotinic acid ligands to form 1D channels. These tetrahedral units are alternately connected by linear isonicotinic acid ligands to form a three-dimensional neutral framework.
[0016] This invention provides a method for preparing the aforementioned metal-organic framework (MOF) material for low-carbon hydrocarbon separation, comprising the following steps:
[0017] A monovalent transition metal salt, an indium salt hydrate, and a compound containing isonicotinic acid ligands are mixed, heated, cooled, washed, dried, and activated to obtain a metal-organic framework (MOF) material.
[0018] Preferably, the monovalent transition metal salt includes CuI, AgI, CuCl, or AgCl;
[0019] The indium salt hydrates include In(NO3)3 hydrate, In(Cl)3 hydrate or In2(SO4)3 hydrate;
[0020] The compounds containing isonicotinic acid ligands include 3-aminoisonicotinic acid, 3-bromoisonicotinic acid, or 3-nitroisonicotinic acid.
[0021] Preferably, the molar ratio of the monovalent transition metal, metallic indium, and isonicotinic acid ligand is 1–5:1–5:4–20.
[0022] Preferably, the mixture is ultrasonically mixed for 2-10 minutes, and the solvent added is N,N-dimethylformamide (DMF).
[0023] Preferably, the heating reaction temperature is 90-120℃, and the heating reaction time is 24-72 hours;
[0024] Then, the powder was cooled to room temperature at a rate of 5℃ / h⁻¹–20℃ / h⁻¹, collected, washed with DMF, and then dried in a vacuum.
[0025] Preferably, activation is performed at 25-150°C for 1-24 hours under high vacuum.
[0026] This invention employs MOF adsorbents for adsorption separation, saving separation costs. Furthermore, structurally, this invention utilizes a bimetallic structure (a monovalent transition metal M and indium), proposing a unique tetrahedral unit linked by isonicotinic acid, where each M... + The center is a tetrahedron [MN4].+ It has four pyridine N atoms from four isonicotinic acid ligands, each In 3+ The center is coordinated by four carboxylic acid groups from four isonicotinic acid ligands, forming a 1D channel. These tetrahedral units are alternately connected by linear isonicotinic acid ligands to form a three-dimensional neutral framework. Since isonicotinic acid has two coordination sites, nitrogen can coordinate with monovalent ions, and the positively charged structure excited by the metal can be neutralized by the carboxylate. The tetrahedral structural units formed by isonicotinic acid and the bimetallic compound constitute a one-dimensional channel, which can better separate mixtures of low-carbon hydrocarbons. Simultaneously, the addition of amino groups and other groups to the material allows amino and fluorine atoms to form more hydrogen bonds with alkanes, and other groups to form stronger van der Waals forces with alkanes, resulting in better separation. Therefore, it exhibits excellent recognition ability for the separation of low-carbon hydrocarbons such as methane, nitrogen, ethane, and ethylene.
[0027] The beneficial effects of this invention are:
[0028] 1. The metal-organic framework material used in this invention has excellent recognition ability for CH4 / N2, excellent adsorption capacity for CH4, and a certain degree of selectivity.
[0029] 2. The metal-organic framework material used in this invention has excellent reverse selection ability for C2H6 / C2H4, directly adsorbing C2H6 and purifying C2H4.
[0030] 3. The metal-organic framework material used in this invention has a certain separation ability for C2H2 / CO2 and C2H2 / CO2 / CH4, and can separate and purify acetylene.
[0031] 4. The adsorption separation process used in this invention has the advantages of low energy consumption and low cost compared with traditional low-temperature distillation.
[0032] 5. The metal-organic framework material used in this invention has a simple preparation method and low synthesis cost, further solving the problem of low-carbon hydrocarbon separation. The metal-organic framework material used in this invention has a stable structure, excellent performance, and good regeneration performance. Attached Figure Description
[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0034] Figure 1 The PXRD pattern of the CuIn(NH2)ina material of this invention;
[0035] Figure 2 The following are PXRD patterns of CuIn(NH2)ina material at different temperatures according to the present invention;
[0036] Figure 3 This is a comparison of the adsorption isotherms of the material of the present invention for CH4 and N2 at 298K;
[0037] Figure 4 The CH4 / N2 selectivity of CuIn(NH2)ina at 298K is predicted by the ideal solution adsorption theory of this invention.
[0038] Figure 5 This is a comparison of the adsorption isotherms of CuIn(NH2)ina material of the present invention for C2H6 and C2H4 at 298K;
[0039] Figure 6 The C2H6 / C2H4 selectivity of CuIn(NH2)ina at 298K is predicted by the ideal solution adsorption theory of this invention.
[0040] Figure 7 This is a comparison of the adsorption isotherms of the CuIn(NH2)ina material of the present invention for C2H2, CO2 and CH4 at 298K;
[0041] Figure 8 The TGA curve of the CuIn(NH2)ina material of this invention;
[0042] Figure 9 This is a physical image of the CuIn(NH2)ina material of this invention;
[0043] Figure 10 This is a physical image of the CuIn(NH2)ina crystal of the present invention;
[0044] Figure 11(a) is a structural unit diagram of the CuIn(NH2)ina material of the present invention;
[0045] Figure 11(b) One-dimensional extension diagram of CuIn(NH2)ina material;
[0046] Figure 11(c) Two-dimensional packing diagram of CuIn(NH2)ina material. Detailed Implementation
[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0048] Example 1
[0049] This invention provides a method for preparing metal-organic framework (MOF) materials for separating low-carbon hydrocarbons, comprising the following steps:
[0050] Material Synthesis: CuI, In(NO3)3 hydrate, and 3-aminoisonicotinic acid were placed in a glass vial, with the molar ratio of the two metals to the organic ligand being 1–5:1–5:4–20. The mixture was sonicated for 2–10 min in N,N-dimethylformamide (DMF) at a temperature of 90–120 °C for 24–72 hours. The mixture was then cooled to room temperature at a rate of 5 °C / h⁻¹–20 °C / h⁻¹. The resulting orange powder was collected, washed with DMF, and then dried under vacuum.
[0051] Sample activation: Activate at 25-150℃ for 1-24 hours under high vacuum.
[0052] CuI (0.5 mmol), In(NO3)3 hydrate (0.5 mmol), 3-aminoisonicotinic acid (2 mmol), and DMF (5 ml) were placed in a 20 ml glass vial, sonicated for 10 min, and then placed in a 100 °C oven for 72 h. The mixture was then cooled to room temperature at a rate of 5 °C / h⁻¹. The resulting orange powder was collected, washed with DMF, and then dried under vacuum. Sample activation: Activation was performed at 100 °C for 12 h under high vacuum. The metal-organic framework (MOF) material was obtained. Figure 1-1 As shown in Figure 1, where,
[0053] Figure 1 This invention relates to a novel material, so it is necessary to grow crystals and solve for their crystal structure. The XRD pattern of CuIn(NH2)ina is the X-ray diffraction pattern of the synthesized powder, and the corresponding pattern below is the X-ray diffraction pattern of the synthesized CuIn(NH2)ina crystal.
[0054] Figure 3 To evaluate the actual separation capability of CuIn(NH2)ina for CH4 / N2 mixtures, the static single-component adsorption isotherms of CuIn(NH2)ina for CH4 / N2 were measured. The adsorption capacities of this material for CH4 / N2 were 26 cm⁻¹. 3 / g and 7cm3 / g, this material has a high methane adsorption capacity and separation selectivity.
[0055] Figure 5 The material CuIn(NH2)ina exhibits extremely high ethane adsorption capacity and high selectivity under low pressure (0.1 bar), enabling efficient separation of ethane and ethylene.
[0056] Figure 7 The prepared CuIn(NH2)ina material had an acetylene adsorption capacity of 57 cm⁻¹. 3 g -1 The carbon dioxide adsorption capacity is 50.0 cm³. 3 g -1 The methane adsorption capacity is 26 cm⁻¹ 3 g -1 The material exhibits stronger interactions with alkynes, resulting in greater adsorption of alkynes. Furthermore, the isotherm curves demonstrate that the material adsorbs more acetylene than carbon dioxide and methane, indicating a superior adsorption capacity for acetylene in mixed gases.
[0057] Figure 11: (a) shows the Cu in the material structure + The center is tetrahedral [CuN4]. + Having four pyridine N atoms from four aminoisonicotinic acid ligands, each In 3+ The center is coordinated by four carboxylic acid groups from four aminoisonicotinic acid ligands, forming a 1D channel. These tetrahedral units are alternately linked by the linear ligand 3-aminoisonicotinic acid to form a three-dimensional neutral framework. Figures 11(b) and 11(c) are one-dimensional extension diagrams and two-dimensional packing diagrams, respectively. The ligands contain amino groups, which form hydrogen bonds with alkanes, resulting in a stronger adsorption capacity for ethane, thus enabling the reverse selection of ethane.
[0058] This invention employs a bimetallic compound (copper and indium) and proposes a unique tetrahedral unit linked by isonicotinic acid. The one-dimensional channel allows for better separation of mixtures of low-carbon hydrocarbons. Simultaneously, the addition of amino groups to the material forms more hydrogen bonds with alkanes and stronger van der Waals forces, resulting in even better separation. Therefore, it exhibits excellent recognition capabilities for separating low-carbon hydrocarbons such as methane, nitrogen, ethane, and ethylene.
[0059] Example 2:
[0060] AgI (1.5 mmol), In(NO3)3 hydrate (1.5 mmol), 3-bromoisonicotinic acid (6 mmol), and DMF (15 ml) were placed in a glass bottle, sonicated for 8 min, and then heated in a 120 °C oven for 48 h. The mixture was then cooled to room temperature at a rate of 5 °C / h⁻¹. The resulting orange powder was collected, washed with DMF, and then dried under vacuum. Sample activation: Activation was performed at 80 °C for 10 h under high vacuum. Isomorphic MOF materials were also obtained, and bromine atoms could form van der Waals forces with the gas, exhibiting a certain separation effect for CH₄ and C₂.
[0061] Example 3:
[0062] CuCl (0.8 mmol), In(Cl)3 hydrate (0.8 mmol), 3-nitroisonicotinic acid (3.2 mmol), and DMF (8 ml) were placed in a glass bottle, sonicated for 6 min, and then heated in a 95 °C oven for 60 h. The mixture was then cooled to room temperature at a rate of 5 °C / h⁻¹. The resulting orange powder was collected, washed with DMF, and then dried under vacuum. Sample activation: Activation was performed at 80 °C for 10 h under high vacuum. Isomorphic MOF materials were obtained, exhibiting a certain separation effect for CH₄ and C₂.
[0063] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A metal-organic framework (MOF) material for separating low-carbon hydrocarbons, characterized in that, The metal-organic framework (MOF) material is shown below: MInL4 formula I; M is a monovalent transition metal ion; L is an organic ligand containing isonicotinic acid, wherein the organic ligand is selected from any one of Formula II; Wherein, R is a substituent, selected from any one of methyl, hydroxyl, amino, nitro, fluorine, bromine, and chlorine.
2. The metal-organic framework (MOF) material for low-carbon hydrocarbon separation according to claim 1, characterized in that, The monovalent transition metal ions include Ag. + or Cu + .
3. The metal-organic framework (MOF) material for low-carbon hydrocarbon separation according to claim 1, characterized in that, The metal-organic framework (MOF) material consists of two special tetrahedral units linked by isonicotinic acid, each M... + The center is a tetrahedron [MN4]. + It has four pyridine N atoms from four isonicotinic acid ligands, each In 3+ The center is coordinated by four carboxylic acid groups from four isonicotinic acid ligands to form 1D channels. These tetrahedral units are alternately connected by linear isonicotinic acid ligands to form a three-dimensional neutral framework.
4. A method for preparing a metal-organic framework (MOF) material for low-carbon hydrocarbon separation as described in any one of claims 1-3, comprising the following steps: A monovalent transition metal salt, an indium salt hydrate, and a compound containing isonicotinic acid ligands are mixed, heated, cooled, washed, dried, and activated to obtain a metal-organic framework (MOF) material.
5. The preparation method according to claim 4, characterized in that, The monovalent transition metal salts include CuI, AgI, CuCl, or AgCl; The indium salt hydrates include In(NO3)3 hydrate, In(Cl)3 hydrate or In2(SO4)3 hydrate; The compounds containing isonicotinic acid ligands include 3-aminoisonicotinic acid, 3-bromoisonicotinic acid, or 3-nitroisonicotinic acid.
6. The preparation method according to claim 5, characterized in that, The molar ratio of the monovalent transition metal, metallic indium, and isonicotinic acid ligand is 1–5:1–5:4–20.
7. The preparation method according to claim 4, characterized in that, Ultrasonic mixing for 2-10 minutes, with N,N-dimethylformamide as the solvent.
8. The preparation method according to claim 4, characterized in that, The heating reaction temperature is 90-120℃, and the heating reaction time is 24-72 hours. Then, the powder was cooled to room temperature at a rate of 5℃ / h⁻¹–20℃ / h⁻¹, collected, washed with DMF, and then dried in a vacuum.
9. The preparation method according to claim 4, characterized in that, Activation: Activate at 25-150℃ for 1-24 hours under high vacuum.