Bisadamantyl-containing porous aromatic framework, preparation method and application thereof in small molecule hydrocarbon adsorption

Abstract

The application relates to a porous aromatic framework material containing adamantane, a preparation method and application of the material in small-molecule hydrocarbon adsorption, and belongs to the technical field of porous organic material preparation. The porous aromatic framework material containing adamantane is prepared by taking bis-(1,5-cyclooctadiene) nickel, 2,2'-dipyridyl and 1,5-cyclooctadiene as a catalyst, and taking hexa(4-bromophenyl) 1,1'-adamantane as a monomer, and by changing reaction conditions. Nitrogen adsorption and desorption tests show that PAF-300s has good porous properties, the BET specific surface area of PAF-300-1 is 3543 m 2 g ‑1 , the BET specific surface area of PAF-300-2 is 2749 m 2 g ‑1 , and the BET specific surface area of PAF-300-3 is 2576 m 2 g ‑1 . At 273K and 298K, the PAF-300s has good adsorption effects on acetylene and propane.

Description

Technical Field

[0001] This invention belongs to the field of porous organic material preparation technology, specifically relating to a porous aromatic framework material (PAF-300s, PAF: porous aromatic framework) with a framework containing bis(4-bromobenzene)1,1'-bisadamantane as monomer and bis-(1,5-cyclooctadiene)nickel as catalyst, prepared by adjusting the synthesis conditions, the preparation method, and its application in the adsorption of small molecule hydrocarbons. Background Technology

[0002] Porous materials are a class of materials containing nanoscale pores, and they are widely used in fields such as gas adsorption, gas separation, catalysis, and energy storage. According to their composition, porous materials can be divided into: (1) molecular sieves and activated carbon constructed from inorganic components; (2) metal organic frameworks (MOFs) constructed from inorganic and organic components; and (3) porous organic frameworks (POFs) constructed from organic components. In the synthesis of POFs, the key lies in the organic building blocks. On the one hand, their configuration affects the pore structure of POFs, and on the other hand, their functional groups determine the type of polymerization reaction used in the synthesis. At present, dozens of polymerization reactions have been developed for the preparation of POFs, such as base-catalyzed polymerization, acid-catalyzed polymerization, catalyst-free polymerization, and noble metal-catalyzed polymerization. Among them, the bis-(1,5-cyclooctadiene)nickel-catalyzed Yamamoto-type Ullmann coupling reaction has high reactivity and is beneficial for the preparation of POFs with high specific surface area. In this application, hexa(4-bromobenzene)1,1'-diadamantane was used as a monomer (the compound shown in Formula 1). On the one hand, it can serve as a type of dimer-type building block, and on the other hand, diadamantane can be introduced into the skeleton after polymerization. PAF-300s with a skeleton containing diadamantane was prepared by adjusting the reaction temperature during synthesis under the catalysis of bis-(1,5-cyclooctadiene)nickel.

[0003] (1) Summary of the Invention

[0005] The purpose of this invention is to provide a porous aromatic framework material with a skeleton containing bisadamantane, its preparation method, and its application in the adsorption of small molecule hydrocarbons.

[0006] The monomer of this invention is hexa(4-bromobenzene)1,1'-diadamantane, the polymerization reaction type is Ullmann coupling reaction, the specific catalyst system is bis-(1,5-cyclooctadiene)nickel, 2,2'-bipyridine and 1,5-cyclooctadiene, and the reaction solvent is N,N'-dimethylformamide and tetrahydrofuran.

[0007] The present invention discloses a method for preparing a porous aromatic framework material containing bisadamantane, the steps of which are as follows:

[0008] (1) Under anhydrous and oxygen-free conditions, equal amounts of bis-(1,5-cyclooctadiene)nickel, 2,2'-bipyridine and 1,5-cyclooctadiene were added to tetrahydrofuran and activated at 20~80℃ for 0.5~2 hours to obtain an activated catalyst solution; the concentration of bis-(1,5-cyclooctadiene)nickel in tetrahydrofuran was 0.05 M~0.5 M;

[0009] (2) Add hexa(4-bromobenzene)1,1'-diadamantane monomer to N,N'-dimethylformamide and stir at 20~80 °C for 0.5~2 hours; the concentration of hexa(4-bromobenzene)1,1'-diadamantane monomer in N,N'-dimethylformamide is 0.001 M~0.05 M;

[0010] (3) The solution obtained in step (2) is slowly added to the catalyst solution activated in step (1), and the reaction is carried out at 20~100 °C for 1~48 hours. The molar ratio of hexa(4-bromobenzene)1,1'-diadamantane monomer to bis-(1,5-cyclooctadiene)nickel is 0.10~0.20:1.

[0011] (4) After the reaction solution from step (3) has cooled to room temperature, add 30-35% concentrated hydrochloric acid and stir for 0.5-2 hours to remove excess bis-(1,5-cyclooctadiene) nickel.

[0012] (5) The reaction solution from step (4) was filtered to obtain a pale white solid product. The product was washed with water and tetrahydrofuran to remove inorganic salts and soluble organic matter. Finally, the product was vacuum dried at 80~150 °C for 4~40 hours to obtain the porous aromatic skeleton material PAF-300s described in this invention.

[0013] The structural formula of a porous aromatic framework material containing bisadamantane according to the present invention is shown in formula (2):

[0014] (2)

[0016] n represents the degree of aggregation, which is an integer greater than 1.

[0017] The structural formulas of the products obtained in Examples 1-3 are all shown in (2). X-ray powder diffraction showed that the products obtained in Examples 1-3 were all amorphous materials. Nitrogen adsorption-desorption showed that the porous properties of the products obtained in Examples 1-3 were different.

[0018] This porous aromatic framework material containing bisadamantane can be applied to the adsorption of small molecule hydrocarbons, specifically acetylene and propane.

[0019] This method uses hexa(4-bromobenzene)1,1'-diadamantane containing bisadamantane as the monomer, and controls the reaction temperature during synthesis to prepare PAF-300s under bis-(1,5-cyclooctadiene)nickel catalysis. Nitrogen adsorption and desorption tests show that PAF-300s have good porous properties, and the BET specific surface area of ​​PAF-300-1 is 3543 m². 2 g -1 The BET specific surface area of ​​PAF-300-2 is 2749 m². 2 g -1 The BET specific surface area of ​​PAF-300-3 is 2576 m². 2 g -1 Furthermore, the adsorption properties of PAF-300s for acetylene and propane were investigated at 273 K and 298 K. Attached Figure Description

[0020] Figure 1 Infrared spectra of the reactant monomer (curve 1) and the synthesized PAF-300-1 (curve 2) of this invention;

[0021] Figure 2 Infrared spectra of the reactant monomer (curve 1) and the synthesized PAF-300-2 (curve 2) of this invention;

[0022] Figure 3 Infrared spectra of the reactant monomer (curve 1) and the synthesized PAF-300-3 (curve 2) of this invention;

[0023] Figure 4 The PAF-300-1 synthesized in this invention 13 C NMR spectrum;

[0024] Figure 5 The PAF-300-2 synthesized in this invention 13 C NMR spectrum;

[0025] Figure 6 The PAF-300-3 synthesized in this invention 13 C NMR spectrum;

[0026] Figure 7X-ray powder diffraction pattern of PAF-300-1 synthesized in this invention;

[0027] Figure 8 X-ray powder diffraction pattern of PAF-300-2 synthesized in this invention;

[0028] Figure 9 X-ray powder diffraction pattern of PAF-300-3 synthesized in this invention;

[0029] Figure 10 Scanning electron microscope image of PAF-300-1 synthesized in this invention;

[0030] Figure 11 Scanning electron microscope image of PAF-300-2 synthesized in this invention;

[0031] Figure 12 Scanning electron microscope image of PAF-300-3 synthesized in this invention;

[0032] Figure 13 The N2 adsorption-desorption isotherms of PAF-300-1 synthesized in this invention (solid lines represent adsorption curves, hollow lines represent desorption curves);

[0033] Figure 14 The N2 adsorption-desorption isotherms of PAF-300-2 synthesized in this invention (solid lines represent adsorption curves, hollow lines represent desorption curves);

[0034] Figure 15 The N2 adsorption-desorption isotherms of PAF-300-3 synthesized in this invention (solid lines represent adsorption curves, hollow lines represent desorption curves);

[0035] Figure 16 Pore ​​size distribution diagram of PAF-300-1 synthesized in this invention;

[0036] Figure 17 Pore ​​size distribution diagram of PAF-300-2 synthesized in this invention;

[0037] Figure 18 Pore ​​size distribution diagram of PAF-300-3 synthesized in this invention;

[0038] Figure 19 The acetylene adsorption isotherm of PAF-300s synthesized in this invention at 273 K;

[0039] Figure 20 The acetylene adsorption isotherm of PAF-300s synthesized in this invention at 298 K;

[0040] Figure 21The propane adsorption isotherm of PAF-300s synthesized in this invention at 273 K;

[0041] Figure 22 The propane adsorption isotherm of PAF-300s synthesized in this invention at 298 K.

[0042] Figure 1 The infrared spectra of the reactant monomer of this invention (curve 1) and the synthesized PAF-300-1 (curve 2) are shown, corresponding to Example 1. 1079 cm⁻¹ -1 The characteristic absorption peak of C-Br at the corresponding position disappeared significantly after the polymerization reaction, proving that the polymerization reaction was very complete.

[0043] Figure 2 The infrared spectra of the reactant monomer of this invention (curve 1) and the synthesized PAF-300-2 (curve 2) are shown, corresponding to Example 2. 1079 cm⁻¹ -1 The characteristic absorption peak of C-Br at the corresponding position disappeared significantly after the polymerization reaction, proving that the polymerization reaction was very complete.

[0044] Figure 3 The infrared spectra of the reactant monomer of this invention (curve 1) and the synthesized PAF-300-3 (curve 2) are shown in Example 3. (1079 cm⁻¹) -1 The characteristic absorption peak of C-Br at the corresponding position was significantly weakened after the polymerization reaction, proving that the polymerization reaction was relatively complete.

[0045] Figure 4 As shown, the PAF-300-1 synthesized in this invention... 13 C NMR spectrum, corresponding to Example 1. The peak at 39 ppm is attributed to the quaternary carbon of adamantane, the peak at 58 ppm is attributed to the secondary carbon of adamantane, and the peak at 120-150 ppm is attributed to the carbon of the benzene ring;

[0046] Figure 5 As shown, the PAF-300-2 synthesized in this invention... 13 C NMR spectrum, corresponding to Example 2. The peak at 39 ppm is attributed to the quaternary carbon of adamantane, the peak at 58 ppm is attributed to the secondary carbon of adamantane, and the peak at 120-150 ppm is attributed to the carbon of the benzene ring;

[0047] Figure 6 As shown, the PAF-300-3 synthesized in this invention... 13 C NMR spectrum, corresponding to Example 3. The peak at 39 ppm is attributed to the quaternary carbon of adamantane, the peak at 58 ppm is attributed to the secondary carbon of adamantane, and the peak at 120-150 ppm is attributed to the carbon of the benzene ring;

[0048] Figure 7 The X-ray powder diffraction pattern of PAF-300-1 synthesized in this invention is shown in Example 1. The absence of obvious diffraction peaks in the pattern indicates that PAF-300-1 does not possess a long-range ordered structure and is an amorphous material.

[0049] Figure 8 The X-ray powder diffraction pattern of PAF-300-2 synthesized in this invention is shown in Example 2. The absence of obvious diffraction peaks in the pattern indicates that PAF-300-2 does not possess a long-range ordered structure and is an amorphous material.

[0050] Figure 9 The X-ray powder diffraction pattern of PAF-300-3 synthesized in this invention is shown in Example 3. The absence of obvious diffraction peaks in the pattern indicates that PAF-300-3 does not possess a long-range ordered structure and is an amorphous material.

[0051] Figure 10 The image shown is a scanning electron microscope (SEM) image of PAF-300-1 synthesized in this invention, corresponding to Example 1. PAF-300-1 has a spherical morphology, and the spheres are of varying sizes, with a particle size of approximately 100-300 nm.

[0052] Figure 11 The image shown is a scanning electron microscope (SEM) image of PAF-300-2 synthesized in this invention, corresponding to Example 2. PAF-300-2 has a spherical morphology, and the spheres are of varying sizes, with a particle size of approximately 100-300 nm.

[0053] Figure 12 The image shown is a scanning electron microscope (SEM) image of PAF-300-3 synthesized in this invention, corresponding to Example 3. PAF-300-3 has a spherical morphology, and the spheres are of varying sizes, with a particle size of approximately 100-200 nm.

[0054] Figure 13 As shown, the N2 adsorption-desorption isotherms of PAF-300-1 synthesized in this invention (solid lines represent adsorption curves, hollow lines represent desorption curves) correspond to Example 1. The BET specific surface area of ​​PAF-300-1 is 3543 m². 2 g -1 It has porous properties;

[0055] Figure 14 As shown, the N2 adsorption-desorption isotherms of PAF-300-2 synthesized in this invention (solid lines represent adsorption curves, hollow lines represent desorption curves) correspond to Example 2. The BET specific surface area of ​​PAF-300-2 is 2749 m². 2 g -1 It has porous properties;

[0056] Figure 15 As shown, the N2 adsorption-desorption isotherms of PAF-300-3 synthesized in this invention (solid lines represent adsorption curves, hollow lines represent desorption curves) correspond to Example 3. The BET specific surface area of ​​PAF-300-3 is 2576 m². 2 g -1 It has porous properties;

[0057] Figure 16 The diagram shows the pore size distribution of PAF-300-1 synthesized in this invention, corresponding to Example 1. The main pore size of PAF-300-1 is 1.19 nm. When the pore size exceeds 2 nm, pores are distributed around 3 nm. The cumulative pore volume of pores smaller than 2 nm is 1.38 cm³. 3 g -1 When the pore size reaches 50 nm, the total cumulative pore volume is 2.12 cm³. 3 g -1 The cumulative pore volume smaller than 2 nm accounts for 65.09% of the total cumulative pore volume.

[0058] Figure 17 The diagram shows the pore size distribution of PAF-300-2 synthesized in this invention, corresponding to Example 2. The main pore size of PAF-300-2 is 1.10 nm, and when the pore size exceeds 2 nm, pores are distributed around 5 nm. The cumulative pore volume of pores smaller than 2 nm is 0.41 cm³. 3 g -1 When the pore size reaches 33 nm, the total cumulative pore volume is 2.81 cm³. 3 g -1 The cumulative pore volume smaller than 2 nm accounted for 14.59% of the total cumulative pore volume.

[0059] Figure 18 As shown in the diagram, the pore size distribution of PAF-300-3 synthesized in this invention corresponds to Example 3. The main pore size of PAF-300-3 is 1.05 nm. When the pore size exceeds 2 nm, pores are distributed at approximately 5 nm and 7 nm, respectively. The cumulative pore volume of pores with a pore size less than 2 nm is 0.52 cm³. 3 g -1 When the pore size reaches 33 nm, the total cumulative pore volume is 2.96 cm³. 3 g -1 The cumulative pore volume smaller than 2 nm accounts for 17.57% of the total cumulative pore volume.

[0060] Figure 19As shown, the acetylene adsorption isotherm of PAF-300s synthesized in this invention at 273 K shows that, at 1 bar, the acetylene adsorption capacities of PAF-300-1, PAF-300-2, and PAF-300-3 are 120.8, 119.2, and 135.9 cm⁻¹, respectively. 3 g -1 ;

[0061] Figure 20 As shown, the acetylene adsorption isotherm of the PAF-300s synthesized in this invention at 298 K shows that, at 1 bar, the acetylene adsorption capacities of PAF-300-1, PAF-300-2, and PAF-300-3 are 64.1, 67.1, and 71.4 cm⁻¹, respectively. 3 g -1 ;

[0062] Figure 21 As shown, the propane adsorption isotherm of PAF-300s synthesized in this invention at 273 K shows that, at 1 bar, the propane adsorption capacities of PAF-300-1, PAF-300-2, and PAF-300-3 are 305.8, 267.8, and 255.3 cm⁻¹, respectively. 3 g -1 ;

[0063] Figure 22 As shown, the propane adsorption isotherm of PAF-300s synthesized in this invention at 298 K shows that, at 1 bar, the propane adsorption capacities of PAF-300-1, PAF-300-2, and PAF-300-3 are 206.6, 198.8, and 176.1 cm⁻¹, respectively. 3 g -1 . Detailed Implementation

[0064] Example 1:

[0065] In a glove box (where bis-(1,5-cyclooctadiene)nickel needs to be used under anhydrous and oxygen-free conditions), weigh 0.142 g (0.9 mmol) of 2,2'-bipyridine and 0.25 g (0.9 mmol) of bis-(1,5-cyclooctadiene)nickel, and add them to a 100 mL double-necked flask. Then add 0.11 mL (0.9 mmol) of 1,5-cyclooctadiene and 10 mL of anhydrous tetrahydrofuran. Activate the catalyst solution in the double-necked flask by heating and stirring at 80 °C for 0.5 hours. Weigh 0.16 g (0.133 mmol) of hexa(4-bromobenzene)-1,1'-diadamantane and add it to a 100 mL single-necked flask. Then add 14 mL of anhydrous N,N'-dimethylformamide. Activate the monomer solution in the single-necked flask by heating and stirring at 80 °C. The mixture was heated at 80 °C for 0.5 hours. The monomer solution in the single-necked flask was slowly added dropwise to the double-necked flask, followed by heating and stirring at 80 °C for 24 hours. After the reaction temperature cooled to room temperature, 20 mL of 35% hydrochloric acid was slowly added to the double-necked flask. The solid was obtained by vacuum filtration, washed three times with distilled water and three times with tetrahydrofuran, and then dried under vacuum at 100 °C for 12 hours to obtain PAF-300-1 (87%), a porous aromatic framework material containing bisadamantane.

[0066] Example 2:

[0067] Weigh 0.142 g (0.9 mmol) of 2,2'-bipyridine and 0.25 g (0.9 mmol) of bis-(1,5-cyclooctadiene)nickel into a 100 mL double-necked flask, then add 0.11 mL (0.9 mmol) of 1,5-cyclooctadiene and 10 mL of anhydrous tetrahydrofuran. Activate the catalyst solution in the double-necked flask by stirring at 22 °C for 0.5 h. Weigh 0.16 g (0.133 mmol) of hexa(4-bromobenzene)-1,1'-diadamantane into a 100 mL single-necked flask, then add 14 mL of anhydrous N,N'-dimethylformamide. Stir the monomer solution in the single-necked flask at 22 °C for 0.5 h. Slowly add the monomer solution from the single-necked flask dropwise into the double-necked flask, and then continue stirring at 22 °C for 24 h. After the reaction was complete, 20 mL of 35% hydrochloric acid was slowly added to a two-necked flask. The solid was obtained by vacuum filtration, then washed three times with distilled water and three times with tetrahydrofuran. The product was then vacuum dried at 100 °C for 12 hours to obtain PAF-300-2 (87%), a porous aromatic framework material containing bisadamantane.

[0068] Example 3:

[0069] Weigh 0.142 g (0.9 mmol) of 2,2'-bipyridine and 0.25 g (0.9 mmol) of bis-(1,5-cyclooctadiene)nickel into a 100 mL two-necked flask, then add 0.11 mL (0.9 mmol) of 1,5-cyclooctadiene and 10 mL of anhydrous tetrahydrofuran. Activate the catalyst solution in the two-necked flask by stirring at 22 °C for 0.5 h. Weigh 0.16 g (0.133 mmol) of hexa(4-bromobenzene)-1,1'-diadamantane into a 100 mL one-necked flask, then add 14 mL of anhydrous N,N'-dimethylformamide. Heat the monomer solution in the one-necked flask at 80 °C for 0.5 h. Then slowly add it dropwise into the two-necked flask, and continue stirring at 22 °C for 24 h. After the reaction was completed, 20 mL of 35% hydrochloric acid was slowly added to a two-necked flask. The solid was obtained by vacuum filtration, then washed three times with distilled water and three times with tetrahydrofuran. The product was then vacuum dried at 100°C for 12 hours to obtain PAF-300-3 (89%), a porous aromatic framework material containing bisadamantane.

[0070] In summary, this invention synthesizes PAF-300s using hexa(4-bromobenzene)-1,1'-bisadamantane as a monomer via an Ullmann coupling reaction. Powder diffraction patterns indicate that PAF-300s lacks a long-range ordered structure and is an amorphous material. Nitrogen adsorption-desorption isotherms demonstrate the excellent porosity of PAF-300s. The calculated BET specific surface area of ​​PAF-300-1 is 3543 m². 2 g -1 The BET specific surface area of ​​PAF-300-2 is 2749 m². 2 g -1 The BET specific surface area of ​​PAF-300-3 is 2576 m². 2 g -1 Furthermore, at 273 K and 1 bar, the acetylene adsorption capacities of PAF-300-1, PAF-300-2, and PAF-300-3 were 120.8, 119.2, and 135.9 cm⁻¹, respectively. 3 g -1 At 298 K and 1 bar, the acetylene adsorption capacities of PAF-300-1, PAF-300-2, and PAF-300-3 were 64.1, 67.1, and 71.4 cm⁻¹, respectively. 3 g -1 At 273 K and 1 bar, the propane adsorption capacities of PAF-300-1, PAF-300-2, and PAF-300-3 were 305.8, 267.8, and 255.3 cm⁻¹, respectively. 3 g -1At 298 K and 1 bar, the propane adsorption capacities of PAF-300-1, PAF-300-2, and PAF-300-3 were 206.6, 198.8, and 176.1 cm⁻¹, respectively. 3 g -1 .

[0071] As described above, those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts of this invention, and all such changes and modifications fall within the scope of protection claimed by this invention.

Claims

1. A porous aromatic framework material with a framework containing bisadamantane, the structural formula of which is shown below: n represents the degree of aggregation, which is an integer greater than 1; Furthermore, this porous aromatic framework material containing bisadamantane was prepared by the following steps: (1) Under anhydrous and oxygen-free conditions, equal amounts of bis-(1,5-cyclooctadiene)nickel, 2,2'-bipyridine and 1,5-cyclooctadiene were added to tetrahydrofuran and activated at 20~80 °C for 0.5~2 hours to obtain an activated catalyst solution; (2) Add hexa(4-bromobenzene)1,1'-bisadamantane monomer to N,N'-dimethylformamide and stir at 20~80 °C for 0.5~2 hours; (3) Slowly add the solution obtained in step (2) to the catalyst solution activated in step (1) and react at 20~100 °C for 1~48 hours; the molar ratio of hexa(4-bromobenzene)1,1'-diadamantane monomer to bis-(1,5-cyclooctadiene)nickel is 0.10~0.20:1; (4) After the reaction solution from step (3) has cooled to room temperature, add 30-35% concentrated hydrochloric acid and stir for 0.5-2 hours to remove excess bis-(1,5-cyclooctadiene) nickel. (5) The reaction solution from step (4) was filtered to obtain a pale white solid product. The product was washed with water and tetrahydrofuran to remove inorganic salts and soluble organic matter. Finally, the product was vacuum dried at 80-150 °C for 4-40 hours to obtain the porous aromatic framework material.

2. The porous aromatic framework material with a framework containing bisadamantane as described in claim 1, characterized in that: In step (1), the concentration of bis-(1,5-cyclooctadiene)nickel in tetrahydrofuran is 0.05 M to 0.5 M, and in step (2), the concentration of hexa(4-bromobenzene)1,1'-bisadamantane monomer in N,N'-dimethylformamide is 0.001 M to 0.05 M.

3. The application of the porous aromatic framework material containing bisadamantane as described in claim 1 or 2 in the adsorption of small molecule hydrocarbons.

4. The application of a porous aromatic framework material containing bisadamantane as described in claim 3 in the adsorption of small molecule hydrocarbons, characterized in that: Small molecule hydrocarbons include acetylene and propane.

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