Tetrazolyl hydrogen bond organic framework material as well as preparation method and application thereof

Abstract

The invention relates to a tetrazolyl hydrogen-bond organic framework material and a preparation method and application thereof, and belongs to the technical field of functional organic crystalline materials. The tetrazolyl hydrogen-bond organic framework material is formed by assembling monomer molecules and solvent molecules through hydrogen-bond interaction and has a three-dimensional structure; four tetrazole functional groups of each monomer molecule are connected with solvent molecules through N-H... O hydrogen bonds, adjacent monomer molecules are stacked to form a three-dimensional hydrogen bond organic framework through a synergistic effect of pi-pi stacking between tetrazole rings and benzene rings, the hydrogen bond organic framework has one-dimensional continuous pore channels, and the pore channels are filled with guest molecules. The tetrazolyl hydrogen bond organic framework material disclosed by the invention can be used for selectively and statically adsorbing p-xylene in various xylene mixtures.

Description

Technical Field

[0001] The present invention relates to the technical field of functional organic crystalline materials, and in particular to a tetrazolyl hydrogen-bonded organic framework material and a preparation method and application thereof. Background Art

[0002] Xylene is an important organic chemical raw material, among which p-xylene, as the most valuable isomer, is the main raw material for the production of terephthalic acid, which is widely used in the production of polyester plastics such as polyethylene terephthalate and polybutylene terephthalate. With the development of my country's polyester industry, the demand for p-xylene is increasing day by day. How to separate p-xylene from industrially produced C8 aromatic mixtures (industrially refers to aromatic mixtures containing eight carbon atoms, among which C8 aromatics from different sources, the main components are o-xylene, p-xylene, m-xylene and ethylbenzene, and sometimes styrene) with low cost and high efficiency is of great significance to the sustainable development of the chemical industry.

[0003] However, the structures and physical and chemical properties of xylene isomers are very similar, making them difficult to separate by distillation. Currently, most p-xylene is obtained by adsorption separation based on simulated moving bed, which has limited adsorption capacity and selectivity and needs to operate under high temperature and high pressure conditions. Developing adsorbents with high adsorption capacity and high selectivity that can separate p-xylene from liquid C8 aromatic mixtures at room temperature and pressure can greatly reduce the energy consumption and cost of xylene separation, and has broad application prospects.

[0004] Hydrogen-Bonded Organic Frameworks (HOFs) are a type of crystalline porous framework materials formed by organic or metal-organic building blocks connected by hydrogen bonds. They have the advantages of low density, high specific surface area, high crystallinity, solution processing, simple preparation and regeneration, etc. They have broad application prospects in the fields of gas separation and storage, isomer separation, molecular recognition, proton conduction, biomedicine, etc. However, due to the weak hydrogen bonding force and poor directionality, the organic building blocks have a strong tendency to be densely packed during the crystallization process. How to control the self-assembly process of the organic building blocks driven by hydrogen bonds so that they crystallize into crystalline porous materials rather than dense non-porous crystals is still a major challenge.

[0005] At present, although the prior art discloses that metal-organic framework materials can be used to separate p-xylene from C8 aromatic hydrocarbon mixtures, metal-organic framework materials have the problems of complex preparation, poor renewability, and high requirements for separation conditions, and the separation effect of p-xylene / ethylbenzene still needs to be improved. Summary of the invention

[0006] In view of the above analysis, the present invention aims to provide a tetrazolyl hydrogen-bonded organic framework material and a preparation method and application thereof, so as to solve at least one of the problems of the existing metal organic framework materials, such as complex preparation, high conditions for separating paraxylene and poor separation effect of ethylbenzene.

[0007] In a first aspect, the present invention provides a tetrazolyl hydrogen-bonded organic framework material, wherein the molecular formula of the tetrazolyl hydrogen-bonded organic framework material is as follows:

[0008] [(C 29 H 20 N 16 ) a ·(C3H7NO) b (G) c ] n , wherein a, b, and c are all positive integers, n is the number of crystal repeating units, and G is the molecular formula of the guest molecule, wherein the guest molecule includes but is not limited to one or more of 1,4-dioxane, p-xylene, m-xylene, o-xylene, mesitylene, 1,2,4-trichlorobenzene, methyl benzoate, toluene, N,N'-dimethylformamide, etc.

[0009] Furthermore, the tetrazolyl hydrogen-bonded organic framework material belongs to the orthorhombic system, the space group is Pbcn or Cmcm, and the unit cell parameter is α=β=γ=90°;

[0010] And / or, the tetrazolyl hydrogen-bonded organic framework material belongs to the orthorhombic system, the space group is Pccn, and the unit cell parameter is α=β=γ=90°;

[0011] And / or, the tetrazolyl hydrogen-bonded organic framework material belongs to the orthorhombic system, the space group is Pbca, and the unit cell parameter is α=β=γ=90°.

[0012] Furthermore, the tetrazolyl hydrogen-bonded organic framework material comprises a one-dimensional continuous channel, and the one-dimensional continuous channel extends along the

[010] or

[001] crystal plane direction;

[0013] Preferably, the size of the one-dimensional continuous channel is p×m, wherein:

[0014] Preferably, the porosity of the tetrazolyl hydrogen-bonded organic framework material is 16.1-32.5%.

[0015] In a second aspect, the present invention provides a method for preparing the above-mentioned tetrazolyl hydrogen-bonded organic framework material, comprising the following steps:

[0016] (1) dissolving tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane in an organic solvent and filtering to obtain a clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane;

[0017] (2) The tetrakis(4-2H-tetrazolyl-5-phenyl)methane clarified solution and guest molecules are subjected to gas phase diffusion method or liquid phase diffusion method to obtain the tetrazolyl-based hydrogen bond organic framework material.

[0018] Furthermore, in step (1), the organic solvent is N,N'-dimethylformamide;

[0019] And / or, the concentration of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane in the organic solvent is 16-24 mg / mL.

[0020] Furthermore, in step (2), the volume ratio of the guest molecule to the organic solvent is ≥2.

[0021] Furthermore, in step (2), the vapor diffusion method is specifically as follows: placing the tetrakis(4-2H-tetrazolyl-5-phenyl)methane clarified solution in an uncovered device, and then placing the uncovered device in a covered device containing guest molecules, performing constant temperature diffusion crystallization to obtain the tetrazolyl hydrogen-bonded organic framework material.

[0022] Furthermore, in step (2), the liquid phase diffusion method is specifically as follows: placing the tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane clear solution in a container, slowly spreading the guest molecules on the surface of the tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane clear solution, sealing the container, and performing diffusion crystallization at room temperature to obtain the tetrazolyl hydrogen bonded organic framework material.

[0023] In a third aspect, the present invention provides an activated material for separating paraxylene, wherein the activated material is prepared by the following method: removing guest molecules from the above-mentioned tetrazolyl hydrogen-bonded organic framework material by a solvent exchange method, and vacuum activating the material to obtain the activated material.

[0024] In a fourth aspect, the present invention provides an application of the above-mentioned tetrazolyl hydrogen-bonded organic framework material in the static adsorption of p-xylene or the separation of p-xylene from a mixture.

[0025] Furthermore, the application comprises the following steps:

[0026] (a) removing guest molecules from a tetrazolyl hydrogen-bonded organic framework material by a solvent exchange method, and vacuum activating the material to obtain an activated material;

[0027] (b) soaking the activated material in a C8 aromatic hydrocarbon mixture, centrifuging, removing the supernatant, washing, and drying to obtain a tetrazolyl hydrogen-bonded organic framework material that adsorbs p-xylene.

[0028] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0029] (1) The tetrazolyl hydrogen-bonded organic framework material of the present invention is assembled from monomer molecules and solvent molecules through hydrogen bonding, and has a three-dimensional structure, and the molecular formula is [(C 29 H 20 N 16 ) a ·(C3H7NO) b (G) c ] n The four tetrazole functional groups of each monomer molecule are connected to the solvent molecules through NH…O hydrogen bonds, and the adjacent monomer molecules are stacked through the synergistic effect of π-π stacking between the tetrazole ring and the benzene ring to form a three-dimensional hydrogen-bonded organic framework. The hydrogen-bonded organic framework has one-dimensional continuous channels, which are filled with guest molecules.

[0030] (2) The method for preparing the tetrazolyl hydrogen-bonded organic framework material of the present invention is characterized in that the guest-induced template method is used to realize the assembly of the porous hydrogen-bonded organic framework material, avoiding the close packing of the organic building units during the crystallization process, and the porosity can reach up to 32.5%. In comparison, if the guest-induced template method is not used, tetrakis (4-2H-tetrazolyl-5-ylphenyl) methane can only be crystallized into non-porous crystals in dimethyl sulfoxide. The guest-induced template method proposed in the present invention has mild preparation conditions and a simple process, and is suitable for large-scale preparation of hydrogen-bonded organic framework materials;

[0031] (3) The tetrazolyl hydrogen-bonded organic framework material disclosed in the present invention can be used to selectively statically adsorb p-xylene in a variety of xylene mixtures. The pore size is commensurate with that of p-xylene, so that p-xylene molecules can be efficiently arranged in the pores through π…π interactions, but there is a size exclusion effect on o-xylene and m-xylene. In addition, this tetrazolyl hydrogen-bonded organic framework material has multiple groups of CH…π weak interactions with p-xylene, which enhances its selectivity for p-xylene. The present invention provides a new green adsorbent for achieving low energy consumption and high efficiency selective separation of p-xylene from C8 aromatic mixtures under normal temperature and pressure conditions.

[0032] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be achieved and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0034] Figure 1 A schematic diagram of the crystal structure of a tetrazolyl hydrogen-bonded organic framework material prepared in Example 1 of the present invention;

[0035] Figure 2 A schematic diagram of the crystal structure of a tetrazolyl hydrogen-bonded organic framework material prepared in Example 2 of the present invention;

[0036] Figure 3 A schematic diagram of the crystal structure of a tetrazolyl hydrogen-bonded organic framework material prepared in Example 5 of the present invention;

[0037] Figure 4 Schematic diagram of the crystal structure prepared in Comparative Example 2 of the present invention;

[0038] Figure 5 The activated HOF-PX of Application Example 1 and the HOF-PX prepared in Example 2 of the present invention are 1 H NMR comparison spectra;

[0039] Figure 6 The XRD comparison chart of the activated HOF-PX of Application Example 1 and the HOF-PX prepared in Example 2 of the present invention;

[0040] Figure 7 This is a graph showing the adsorption of p-xylene by the hydrogen-bonded organic framework material at different temperatures in Application Example 1 of the present invention;

[0041] Figure 8 The activated HOF-PX in Application Example 2 of the present invention is adsorbed in different xylene mixtures. 1 H NMR spectrum;

[0042] Fig. 9 The activated HOF-PX in Application Example 3 of the present invention is adsorbed in a simulated C8 aromatic mixture. 1 H NMR spectrum. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0044] A specific embodiment of the present invention discloses a tetrazolyl hydrogen-bonded organic framework material, and the molecular formula of the tetrazolyl hydrogen-bonded organic framework material is as follows:

[0045] [(C 29 H 20 N 16 ) a ·(C3H7NO) b (G) c ] n , wherein a, b, and c are all positive integers, n is the number of crystal repeating units, and G is the molecular formula of the guest molecule, wherein the guest molecule includes but is not limited to one or more of 1,4-dioxane, p-xylene, m-xylene, o-xylene, mesitylene, 1,2,4-trichlorobenzene, methyl benzoate, toluene, N,N'-dimethylformamide, etc.

[0046] It should be noted that the novel tetrazolyl hydrogen-bonded organic framework material of the present invention is assembled by monomer molecules and solvent molecules through hydrogen bonding, and has a three-dimensional structure. The four tetrazolyl functional groups of each monomer molecule are connected to the solvent molecules through NH...O hydrogen bonds, and the adjacent monomer molecules are stacked through the synergistic action of π-π stacking between the tetrazolyl ring and the benzene ring to form a three-dimensional hydrogen-bonded organic framework. The hydrogen-bonded organic framework has a one-dimensional continuous channel, and the channel is filled with guest molecules. Among them, the tetrazolyl hydrogen-bonded organic framework material is a crystal structure, and a, b, and c are represented by a ratio without a common divisor, for example, a is 1, 2, b is 4, 6, 8, 12, c is 1, 4, 2, and n represents that the crystal structure is an infinitely repeated unit structure, and n can be infinite.

[0047] In a specific embodiment, the tetrazolyl hydrogen-bonded organic framework material belongs to the orthorhombic system, the space group is Pbcn or Cmcm, and the unit cell parameter is α=β=γ=90°;

[0048] And / or, the tetrazolyl hydrogen-bonded organic framework material belongs to the orthorhombic system, the space group is Pccn, and the unit cell parameter is α=β=γ=90°;

[0049] And / or, the tetrazolyl hydrogen-bonded organic framework material belongs to the orthorhombic system, the space group is Pbca, and the unit cell parameter is α=β=γ=90°.

[0050] In a specific embodiment, the tetrazolyl-based hydrogen-bonded organic framework material comprises one-dimensional continuous channels, and the one-dimensional continuous channels extend along the

[010] or

[001] crystal plane direction.

[0051] In a specific embodiment, the size of the one-dimensional continuous channel is p×m, where For example,

[0052] For example,

[0053] Preferably, the porosity of the tetrazolyl hydrogen-bonded organic framework material is 16.1-32.5%, for example, 16.1%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 32.5%.

[0054] Another specific embodiment of the present invention discloses a method for preparing the above-mentioned tetrazolyl hydrogen-bonded organic framework material, comprising the following steps:

[0055] (1) dissolving tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane in an organic solvent, filtering the solution to obtain a clear tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane solution;

[0056] (2) The tetrakis(4-2H-tetrazolyl-5-phenyl)methane clarified solution and guest molecules are subjected to gas phase diffusion method or liquid phase diffusion method to obtain the tetrazolyl-based hydrogen bond organic framework material.

[0057] The method for preparing the tetrazolyl hydrogen-bonded organic framework material of the present invention is characterized in that the assembly of the porous hydrogen-bonded organic framework material is realized by applying the guest-induced template method, and the close packing of the organic building units in the crystallization process is avoided, and the porosity can reach up to 32.5%. In comparison, if the guest-induced template method is not adopted, tetrakis (4-2H-tetrazolyl-5-ylphenyl) methane can only crystallize into non-porous crystals in dimethyl sulfoxide. The guest-induced template method proposed by the present invention has mild preparation conditions and simple process, and is suitable for large-scale preparation of hydrogen-bonded organic framework materials. The yield of the tetrazolyl hydrogen-bonded organic framework material in the method of the present invention is ≥36.4%, preferably 36.4-67.8%, for example, 37%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%.

[0058] The structural formula of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane described in the present invention is as follows:

[0059]

[0060] Specifically, in step (1), the organic solvent is N,N'-dimethylformamide.

[0061] Preferably, the concentration of tetrakis(4-2H-tetrazolyl-5-phenyl)methane in the organic solvent is 16-24 mg / mL, for example, 16 mg / mL, 17 mg / mL, 18 mg / mL, 19 mg / mL, 20 mg / mL, 21 mg / mL, 22 mg / mL, 23 mg / mL, 24 mg / mL. It should be noted that no crystals are produced below this concentration range, and a powdery precipitate is produced above this concentration instead of a crystalline material.

[0062] Specifically, in step (2), the volume ratio of the guest molecule to the organic solvent is ≥2, for example, 2, 3, 4, 5, 6, 7, and preferably, the volume ratio is 3-5.

[0063] It should be noted that the guest molecule is also a poor solvent for the monomer molecule tetrakis(4-2H-tetrazolyl-5-phenyl)methane. Below this volume ratio, the solubility of the monomer molecule in the organic solvent cannot be sufficiently reduced, thereby failing to crystallize.

[0064] Specifically, in step (2), the vapor diffusion method is as follows: placing the tetrakis(4-2H-tetrazolyl-5-phenyl)methane clarified solution in an uncovered device, and then placing the uncovered device in a covered device containing guest molecules, performing constant temperature diffusion crystallization to obtain the tetrazolyl hydrogen-bonded organic framework material.

[0065] Preferably, the temperature of the isothermal diffusion is 40-70°C, for example, 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, and the isothermal diffusion crystallization is 1-4 weeks, for example, 1 week, 2 weeks, 3 weeks, 4 weeks.

[0066] It should be noted that below this temperature, the guest molecules can hardly diffuse into the monomer molecule solution through the gas phase, resulting in a long crystallization time or no crystallization. Above this temperature, a large number of guest molecules enter the monomer molecule solution, the solubility drops rapidly, and a powdery precipitate is produced rather than a crystalline material.

[0067] Specifically, in step (2), the liquid phase diffusion method is as follows: placing the tetrakis(4-2H-tetrazolyl-5-phenyl)methane clear solution in a container, slowly spreading the guest molecule on the surface of the tetrakis(4-2H-tetrazolyl-5-phenyl)methane clear solution, sealing the container, and performing diffusion crystallization at room temperature for 1 to 5 days, for example, 1 day, 2 days, 3 days, 4 days, or 5 days, to obtain the tetrazolyl hydrogen bonded organic framework material.

[0068] Another specific embodiment of the present invention discloses an activated material for separating p-xylene, wherein the activated material is prepared by the following method: removing guest molecules from the above-mentioned tetrazolyl hydrogen-bonded organic framework material by a solvent exchange method, and vacuum activating the material to obtain the activated material. Another specific embodiment of the present invention discloses an application of the above-mentioned tetrazolyl hydrogen-bonded organic framework material in the static adsorption of p-xylene.

[0069] The structural unit of the tetrazolyl hydrogen-bonded organic framework material of the present invention is tetrakis(4-2H-tetrazolyl-5-phenyl)methane, N,N'-dimethylformamide and guest molecules connected to each other through intermolecular hydrogen bonds, and assembled into a crystalline material under the synergistic effect of π-π stacking. The hydrogen-bonded organic framework material has a one-dimensional through-hole channel, and its pore size and porosity can be regulated by the selection of guest molecules. Tetrazolyl functional groups are introduced into the hydrogen-bonded organic framework material, and the open nitrogen atoms that are not involved in the hydrogen-bonding formation can provide adsorption sites for the selective separation of xylene isomers.

[0070] The tetrazolyl hydrogen-bonded organic framework material disclosed in the present invention can be used for selective static adsorption of p-xylene in a variety of xylene mixtures. The pore size is commensurate with the size of p-xylene, so that p-xylene molecules can be efficiently arranged in the pores through π...π interactions, but there is a size exclusion effect on o-xylene and m-xylene. In addition, this tetrazolyl hydrogen-bonded organic framework material has multiple groups of CH...π weak interactions with p-xylene, which enhances its selectivity for p-xylene. The present invention provides a new green adsorbent for achieving low energy consumption and high efficiency selective separation of p-xylene in C8 aromatic mixtures under normal temperature and pressure conditions.

[0071] Specifically, the application comprises the following steps:

[0072] (a) removing guest molecules from a tetrazolyl hydrogen-bonded organic framework material by a solvent exchange method, and vacuum activating the material to obtain an activated material;

[0073] (b) soaking the activated material in a C8 aromatic hydrocarbon mixture, centrifuging, removing the supernatant, washing, and drying to obtain a tetrazolyl hydrogen-bonded organic framework material that adsorbs p-xylene.

[0074] Specifically, in step (a), the solvent is n-hexane or n-pentane, preferably n-pentane.

[0075] Preferably, in step (a), the number of solvent exchanges is 4 to 6 times, for example, 4 times, 5 times, 6 times, and each time interval is 2 to 4 hours, for example, 2 hours, 2.5 hours, 3.0 hours, 3.5 hours, 4 hours. To maintain the crystallinity of the material, the total solvent exchange time should not exceed 24 hours.

[0076] Specifically, in step (a), the temperature of vacuum activation is less than 50°C, for example, 48°C, 46°C, 44°C, 42°C, 40°C, 38°C, 36°C, 34°C, 32°C, 30°C, 28°C, 26°C, 24°C. Above this temperature, the crystallinity decreases, and the activation time is ≥24h, for example, 24h, 25h, 26h, 27h, 28h, 29h, 30h. Preferably, the temperature is 30°C and the activation time is 48h.

[0077] The tetrazolyl hydrogen-bonded organic framework material of the present invention has the following selectivity coefficients for xylene: the selectivity coefficient for p-xylene / m-xylene is ≥2.9, the selectivity coefficient for p-xylene / o-xylene is ≥3, and the selectivity coefficient for p-xylene / ethylbenzene is ≥4.9.

[0078] The technical solution of the present invention is further explained below in conjunction with specific embodiments.

[0079] Example 1

[0080] A tetrazolyl-based hydrogen-bonded organic framework material of this embodiment is prepared by gas phase diffusion, and the specific steps include the following:

[0081] (1) Weigh 50 mg of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane and dissolve it in 3 mL of N,N'-dimethylformamide. After ultrasonic dissolution, filter it with a 0.45 μm nylon filter to obtain a clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane;

[0082] (2) The clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane was placed in a 10 mL uncovered glass bottle, which was then placed in a 50 mL covered wide-mouth glass bottle containing 10 mL 1,4-dioxane. The bottle cap was tightened and the reaction was carried out in a constant temperature oven at 40°C for two weeks to obtain colorless and transparent block crystals of HOF-Dio (tetrazolyl hydrogen-bonded organic framework material) with a yield of 54.4% (calculated based on the mass of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane).

[0083] The crystal structure diagram of the tetrazolyl hydrogen-bonded organic framework material prepared in this example is shown in FIG. Figure 1As shown, HOF-Dio has a one-dimensional channel in the

[001] crystal plane direction, and the channel size is The porosity is 19.4%.

[0084] Its structure was determined by single crystal X-ray diffractometry, and the space group was Pbcn, and the unit cell parameters were α=β=γ=90°, Z=4.

[0085] The molecular formula of the tetrazolyl hydrogen-bonded organic framework material prepared in this embodiment is as follows: 29 H 20 N 16 ) a ·(C3H7NO) b (G) c ] n , where a=1, b=4, c=4, n is the infinite number of crystal repeating units, and G is 1,4-dioxane with the molecular formula C4H8O2.

[0086] Example 2

[0087] A tetrazolyl-based hydrogen-bonded organic framework material of this embodiment is prepared by liquid phase diffusion, and the specific steps include the following:

[0088] (1) Weigh 100 mg of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane and dissolve it in 5 mL of N,N'-dimethylformamide. After ultrasonic dissolution, filter it with a 0.45 μm nylon filter to obtain a clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane;

[0089] (2) A clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane was placed in a 20 mL glass bottle with a lid, 15 mL of p-xylene was slowly spread on top of the solution, the bottle cap was tightened, and the reaction was carried out at room temperature for 24 hours to obtain colorless and transparent block crystals of HOF-PX (tetrazolyl hydrogen-bonded organic framework material) with a yield of 46.4% (calculated based on the mass of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane).

[0090] The crystal structure diagram of the tetrazolyl hydrogen-bonded organic framework material prepared in this example is shown in FIG. Figure 2 As shown, HOF-PX has a one-dimensional channel in the

[010] crystal plane direction, and the channel size is The porosity is 32.1%.

[0091] Its structure was determined by single crystal X-ray diffractometer and it belongs to the orthorhombic system, the space group is Pccn, and the unit cell parameters are α=β=γ=90°, Z=8.

[0092] The molecular formula of the tetrazolyl hydrogen-bonded organic framework material prepared in this embodiment is as follows: 29 H 20 N 16 ) a ·(C3H7NO) b (G) c ] n , where a=1, b=4, c=2, n is the number of infinite crystal repeating units, and G is the molecular formula of p-xylene, C8H 10 .

[0093] Example 3

[0094] A tetrazolyl-based hydrogen-bonded organic framework material of this embodiment is prepared by gas phase diffusion, and the specific steps include the following:

[0095] (1) Weigh 72 mg of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane and dissolve it in 3 mL of N,N'-dimethylformamide. After ultrasonic dissolution, filter with a 0.45 μm nylon filter to obtain a clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane;

[0096] (2) The clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane was placed in a 10 mL uncovered glass bottle, and the glass bottle was then placed in a 50 mL covered wide-mouth glass bottle containing 12 mL of methyl benzoate. The bottle cap was tightened and the reaction was carried out in a 70° C. constant temperature oven for one week to obtain colorless and transparent block crystals of HOF-MB (tetrazolyl hydrogen-bonded organic framework material) with a yield of 50.9% (calculated based on the mass of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane). The tetrazolyl hydrogen-bonded organic framework material HOF-MB prepared in this example has a one-dimensional pore in the

[001] crystal plane direction, and the pore size is The porosity is 31.9%.

[0097] Its structure was determined by single crystal X-ray diffractometry, and the space group was Pbcn, and the unit cell parameters were α=β=γ=90°, Z=8.

[0098] The molecular formula of the tetrazolyl hydrogen-bonded organic framework material prepared in this embodiment is as follows: 29 H 20 N 16 ) a ·(C3H7NO) b (G) c ]n , where a=2, b=8, c=1, n is the infinite number of crystal repeating units, and G is the molecular formula of methyl benzoate C8H8O2.

[0099] Example 4

[0100] A tetrazolyl-based hydrogen-bonded organic framework material of this embodiment is prepared by gas phase diffusion, and the specific steps include the following:

[0101] (1) Weigh 50 mg of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane and dissolve it in 3 mL of N,N'-dimethylformamide. After ultrasonic dissolution, filter it with a 0.45 μm nylon filter to obtain a clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane;

[0102] (2) The clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane was placed in a 10 mL uncovered glass bottle, which was then placed in a 50 mL wide-mouthed glass bottle with a lid and filled with 15 mL of mesitylene. The bottle cap was tightened and the mixture was reacted in a constant temperature oven at 50°C for four weeks to obtain colorless and transparent block crystals of HOF-TMB (tetrazolyl hydrogen-bonded organic framework material) with a yield of 52.4% (calculated based on the mass of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane).

[0103] The tetrazolyl hydrogen-bonded organic framework material HOF-TMB prepared in this example has a one-dimensional pore in the

[001] crystal plane direction, and the pore size is The porosity is 31.4%.

[0104] Its structure was determined by single crystal X-ray diffractometry, and the space group was Pbcn, and the unit cell parameters were α=β=γ=90°,V= Z=4.

[0105] The molecular formula of the tetrazolyl hydrogen-bonded organic framework material prepared in this embodiment is as follows: 29 H 20 N 16 ) a ·(C3H7NO) b (G) c ] n , where a=1, b=6, c=1, n is the number of infinite crystal repeating units, and G is the molecular formula of mesitylene C9H 12 .

[0106] Example 5

[0107] A tetrazolyl-based hydrogen-bonded organic framework material of this embodiment is prepared by liquid phase diffusion, and the specific steps include the following:

[0108] (1) Weigh 100 mg of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane and dissolve it in 5 mL of N,N'-dimethylformamide. After ultrasonic dissolution, filter it with a 0.45 μm nylon filter to obtain a clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane;

[0109] (2) A clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane was placed in a 20 mL glass bottle with a lid, 15 mL of 1,2,4-trichlorobenzene was slowly spread on top of the solution, the bottle cap was tightened, and the reaction was carried out at room temperature for 5 days to obtain colorless and transparent block crystals of HOF-TCB (tetrazolyl hydrogen-bonded organic framework material) with a yield of 41.9% (calculated based on the mass of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane).

[0110] The crystal structure diagram of the tetrazolyl hydrogen-bonded organic framework material prepared in this example is shown in FIG. Figure 3 As shown, HOF-TCB has a one-dimensional channel in the

[010] crystal plane direction, and the channel size is The porosity is 32.5%.

[0111] Its structure was determined by single crystal X-ray diffractometer and it belongs to the orthorhombic system, the space group is Pbca, and the unit cell parameters are α=β=γ=90°, Z=8.

[0112] The molecular formula of the tetrazolyl hydrogen-bonded organic framework material prepared in this embodiment is as follows: 29 H 20 N 16 ) a ·(C3H7NO) b (G) c ] n , where a=1, b=4, c=2, n is the infinite number of crystal repeating units, and G is the molecular formula of 1,2,4-trichlorobenzene C6H6Cl3.

[0113] Example 6

[0114] A tetrazolyl-based hydrogen-bonded organic framework material of this embodiment is prepared by liquid phase diffusion, and the specific steps include the following:

[0115] (1) Weigh 50 mg of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane and dissolve it in 3 mL of N,N'-dimethylformamide. After ultrasonic dissolution, filter it with a 0.45 μm nylon filter to obtain a clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane;

[0116] (2) A clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane was placed in a 20 mL glass bottle with a lid, 15 mL of toluene was slowly spread on top of the solution, the bottle cap was tightened, and the reaction was carried out at room temperature for 3 days to obtain colorless and transparent block crystals of HOF-Tol (tetrazolyl hydrogen-bonded organic framework material) with a yield of 52.3% (calculated based on the mass of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane).

[0117] The tetrazolyl hydrogen-bonded organic framework material HOF-Tol prepared in this example has a one-dimensional pore in the

[001] crystal plane direction, and the pore size is The porosity is 16.1%.

[0118] Its structure was determined by single crystal X-ray diffractometer and it belongs to the orthorhombic system, the space group is Cmcm, and the unit cell parameters are α=β=γ=90°, Z=4.

[0119] The molecular formula of the tetrazolyl hydrogen-bonded organic framework material prepared in this embodiment is as follows: 29 H 20 N 16 ) a ·(C3H7NO) b (G) c ] n , where a=2, b=8, c=1, n is the infinite number of crystal repeating units, and G is the molecular formula of toluene C7H8.

[0120] Comparative Example 1

[0121] The method for preparing the organic framework material of this comparative example is the same as that of Example 1, except that in step (2), the guest molecule 1,4-dioxane is replaced by a poor solvent acetone or ethyl acetate, and the reaction is carried out at room temperature for 1 month until the poor solvent is completely diffused into the monomer solution, and no crystals are produced.

[0122] Comparative Example 2

[0123] The method for preparing the organic framework material of this comparative example is the same as that of Example 1, except that in step (1), N,N'-dimethylformamide is replaced by dimethyl sulfoxide. Placed in an uncovered 10 mL glass bottle, CP-DMSO can be obtained by evaporation at room temperature to obtain colorless transparent flaky crystals. Its structure is determined by single crystal X-ray diffractometer, and the unit cell parameters are α=β=γ=90°, Z=8.

[0124] Figure 4The crystal structure diagram of the crystal shows that CP-DMSO is a densely packed crystal without a porous structure. This comparative example illustrates that the method for preparing the hydrogen-bonded organic framework material disclosed in the present invention can successfully obtain a porous hydrogen-bonded organic framework material that cannot be obtained by conventional crystallization methods through the guest-induced template effect.

[0125] Application Example 1

[0126] The application of a tetrazolyl-based hydrogen-bonded organic framework material in the static adsorption of p-xylene in this application example is as follows:

[0127] (a) The tetrazolyl hydrogen-bonded organic framework material (HOF-PX) prepared in Example 2 was immersed in n-pentane for 8 h, and fresh n-pentane solvent was replaced every 2 h until the p-xylene molecules in the pores were completely replaced. The replaced material was vacuum activated at 30° C. for 24 h to obtain an activated material. The activated material (activated HOF-PX) was compared with the HOF-PX prepared in Example 2. 1 H NMR comparison spectra Figure 5 As shown, the p-xylene in the surface pores has been completely removed.

[0128] The XRD comparison of the activated HOF-PX and the HOF-PX prepared in Example 2 is shown in Figure 6 As shown, the crystallinity of the hydrogen-bonded organic framework material did not decrease significantly before and after activation, and the framework structure did not change significantly, which proved the stability of the material.

[0129] (b) Weigh 30 mg of activated HOF-PX and place it in four 10 mL glass bottles with lids, add 3 mL of p-xylene to completely immerse the activated HOF-PX, and tighten the lids. Place the four glass bottles at 4°C, 25°C, 60°C, and 80°C for 72 hours. Use a syringe with a needle to remove the liquid from the glass bottle and discard it. Wash the remaining solid in the bottle quickly with n-pentane three times and dry it at room temperature. Dissolve 10 mg of hydrogen-bonded organic framework material adsorbed with xylene in 0.75 mL of DMSO-d6. 1 H NMR test, calculate the amount of p-xylene adsorption. The results show that ( Figure 7 ), the maximum adsorption capacity of hydrogen-bonded organic framework materials for p-xylene is 1.25 mmol / g at 60 °C.

[0130] Application Example 2

[0131] This application example is the same as application example 1, except that in step (b), the p-xylene in the four glass bottles is replaced with a p-xylene / m-xylene, a p-xylene / o-xylene, a p-xylene / ethylbenzene mixture with a molar ratio of 1:1, and a p-xylene / m-xylene / o-xylene mixture with a molar ratio of 1:1:1. The adsorption is carried out at 25°C for 72 hours.

[0132] The adsorption of activated HOF-PX in different xylene mixtures 1 H NMR spectrum Figure 8 As shown, after calculation, the selectivity coefficients of p-xylene / meta-xylene, p-xylene / o-xylene, and p-xylene / ethylbenzene in the binary mixture are 3.6, 4.9, and 21.7, respectively, and the selectivity coefficients of p-xylene / meta-xylene and p-xylene / o-xylene in the ternary mixture are 3.7 and 3.1, respectively.

[0133] The inventors also conducted the above test on tetrazolyl hydrogen-bonded organic framework materials prepared in other embodiments, and the results were basically the same. Due to limited space, they are not listed one by one.

[0134] Application Example 3

[0135] This application example is the same as application example 1, except that in step (b), 30 mg of activated HOF-PX is weighed and placed in a 10 mL glass bottle with a cover, and 2 mL of a C8 aromatic mixture is added, the composition of which is 19% ethylbenzene, 44% m-xylene, 20% o-xylene, and 17% p-xylene by mass. The results show that ( Fig. 9 ), the selectivity coefficients of p-xylene / m-xylene, p-xylene / o-xylene, and p-xylene / ethylbenzene in the C8 aromatic mixture are 3.2, 3.9, and 4.9, respectively.

[0136] The inventors also conducted the above test on tetrazolyl hydrogen-bonded organic framework materials prepared in other embodiments, and the results were basically the same. Due to limited space, they are not listed one by one.

[0137] Application Example 4

[0138] This application example is the same as application example 2, except that in step (a), the tetrazolyl hydrogen-bonded organic framework material (HOF-PX) prepared in example 2 is replaced by the existing MIL-125(Ti)-NH2.

[0139] After calculation, the selectivity coefficients of p-xylene / meta-xylene, p-xylene / o-xylene, and p-xylene / ethylbenzene in the binary mixture are 3.4, 2.8, and 1.6, respectively; and the selectivity coefficients of p-xylene / meta-xylene and p-xylene / o-xylene in the ternary mixture are 3.0 and 2.2, respectively.

[0140] Compared with Application Example 2, the tetrazolyl hydrogen-bonded organic framework material of the present invention has higher selectivity for p-xylene than the existing organic framework materials, especially the separation effect for ethylbenzene is more obvious.

[0141] The inventors also conducted the above test on tetrazolyl hydrogen-bonded organic framework materials prepared in other embodiments, and the results were basically the same. Due to limited space, they are not listed one by one.

[0142] Application Example 5

[0143] The tetrazolyl hydrogen-bonded organic framework materials prepared in Examples 1-6 were respectively placed at 60° C. for 72 hours using the method of Application Example 1 to test the maximum adsorption capacity of the tetrazolyl hydrogen-bonded organic framework materials for p-xylene, o-xylene, m-xylene and ethylbenzene. The results are shown in Table 1.

[0144] Table 1

[0145]

[0146] It can be seen from the above table that the adsorption capacity of p-xylene by the tetrazolyl hydrogen-bonded organic framework material prepared by the present invention is significantly better than that of o-xylene, m-xylene and ethylbenzene.

[0147] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A tetrazolyl-based hydrogen-bonded organic framework material, characterized in that: The molecular formula of the tetrazolyl hydrogen-bonded organic framework material is as follows: [(C 29 H 20 N 16 ) a ·(C3H7NO) b (G) c ] n , wherein a, b, and c are all positive integers, n is the number of crystal repeating units, and G is the molecular formula of the guest molecule, wherein the guest molecule includes but is not limited to one or more of 1,4-dioxane, p-xylene, m-xylene, o-xylene, mesitylene, 1,2,4-trichlorobenzene, methyl benzoate, toluene, N,N'-dimethylformamide, etc.

2. A tetrazolyl hydrogen-bonded organic framework material according to claim 1, characterized in that: The tetrazolyl hydrogen-bonded organic framework material belongs to the orthorhombic system, the space group is Pbcn or Cmcm, and the unit cell parameters are α=β=γ=90°; And / or, the tetrazolyl hydrogen-bonded organic framework material belongs to the orthorhombic system, the space group is Pccn, and the unit cell parameter is α=β=γ=90°; And / or, the tetrazolyl hydrogen-bonded organic framework material belongs to the orthorhombic system, the space group is Pbca, and the unit cell parameter is α=β=γ=90°.

3. A tetrazolyl hydrogen-bonded organic framework material according to claim 1 or 2, characterized in that: The tetrazolyl hydrogen-bonded organic framework material comprises a one-dimensional continuous channel, and the one-dimensional continuous channel extends along the [010] or [001] crystal plane direction; Preferably, the size of the one-dimensional continuous channel is p×m, wherein: Preferably, the porosity of the tetrazolyl hydrogen-bonded organic framework material is 16.1-32.5%.

4. A method for preparing a tetrazolyl hydrogen-bonded organic framework material according to any one of claims 1 to 3, characterized in that: The steps include: (1) dissolving tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane in an organic solvent and filtering to obtain a clear solution of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane; (2) The tetrakis(4-2H-tetrazolyl-5-phenyl)methane clarified solution and guest molecules are subjected to gas phase diffusion method or liquid phase diffusion method to obtain the tetrazolyl-based hydrogen bond organic framework material.

5. The preparation method according to claim 4, characterized in that: In step (1), the organic solvent is N,N'-dimethylformamide; And / or, the concentration of tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane in the organic solvent is 16-24 mg / mL.

6. The preparation method according to claim 4, characterized in that: In step (2), the volume ratio of the guest molecule to the organic solvent is ≥2.

7. The preparation method according to claim 4, characterized in that: In step (2), the vapor diffusion method is specifically as follows: placing the tetrakis(4-2H-tetrazolyl-5-phenyl)methane clarified solution in an uncovered device, and then placing the uncovered device in a covered device containing guest molecules, performing constant temperature diffusion crystallization to obtain the tetrazolyl hydrogen bonded organic framework material.

8. The preparation method according to claim 4, characterized in that: In step (2), the liquid phase diffusion method is specifically as follows: placing the tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane clear solution in a container, then slowly spreading the guest molecules on the surface of the tetrakis(4-2H-tetrazolyl-5-ylphenyl)methane clear solution, sealing the container, and diffusing and crystallizing at room temperature to obtain the tetrazolyl hydrogen bonded organic framework material.

9. An activated material for separating p-xylene, characterized in that: The activated material is prepared by the following method: removing guest molecules from the tetrazolyl hydrogen-bonded organic framework material described in any one of claims 1 to 3 or the tetrazolyl hydrogen-bonded organic framework material prepared by the method of any one of claims 4 to 8 by solvent exchange, and vacuum activating to obtain the activated material.

10. Use of the tetrazolyl hydrogen-bonded organic framework material according to any one of claims 1 to 3 or the tetrazolyl hydrogen-bonded organic framework material prepared by the method according to any one of claims 4 to 8 in the static adsorption of p-xylene or in the separation of p-xylene from a mixture, characterized in that: The application comprises the following steps: (a) removing guest molecules from a tetrazolyl hydrogen-bonded organic framework material by a solvent exchange method, and vacuum activating the material to obtain an activated material; (b) soaking the activated material in a C8 aromatic hydrocarbon mixture, centrifuging, removing the supernatant, washing, and drying to obtain a tetrazolyl hydrogen-bonded organic framework material that adsorbs p-xylene.

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