A covalent organic framework material based on cyclopentadienyl cobalt, preparation method and application thereof

Abstract

A covalent organic framework material based on cyclopentadiene cobalt, a preparation method and its application in light hydrocarbon adsorption and separation, belong to the technical field of polymer organic porous materials. The present invention first prepares an aldehyde monomer based on cyclopentadiene cobalt covalent organic framework material, then disperses it and p-phenylenediamine in a mixed solvent of mesitylene and dioxane to obtain a dispersion, then adds acetic acid aqueous solution as a catalyst and mixes; react under reflux conditions, so as to obtain the covalent organic framework material (TAPC-COF) based on cyclopentadiene cobalt. The covalent organic framework material based on cyclopentadiene cobalt prepared by the present invention can be used for preparing adsorption material, antibacterial material, catalytic material, photoelectromagnetic material and drug carrier material, is a composite functional porous material with great potential, can be applied to the field of light hydrocarbon gas separation, so that the function of the covalent organic framework material based on cyclopentadiene cobalt is more comprehensive.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer organic porous materials, and specifically relates to a covalent organic framework material based on cyclopentadienyl cobalt, a preparation method and application thereof in the adsorption and separation of light hydrocarbons. Background Art

[0002] Covalent organic framework (COF) is a crystalline organic porous material formed by discrete organic molecular connection units through reversible covalent bonds. Since the constituent elements of covalent organic framework materials are lightweight elements such as C, O, N, B, the connection bonds are covalent bonds with relatively high bond energy and the structure is long-range ordered, it not only has the advantages of high specific surface area, more active sites, easy functional modification, but also has the advantages of low skeleton density, no metal, high thermal stability and chemical stability, which makes this type of material a research hotspot in the field of chemistry and materials, so that COF has great application prospects in many fields such as gas adsorption, fluorescent probes, and drug sustained release. In addition, COF can be modified by chemical methods to change the structure and properties of the material, and designed and synthesized at the molecular level. It is a class of composite functional porous materials with great potential. At present, there are two main methods for constructing covalent organic framework materials: "bottom-up" and "top-down". Through reasonable design, molecules with specific functions can be introduced into the polymer skeleton while maintaining the extension of the conjugated skeleton, thereby realizing the functionalization of covalent organic framework materials. At present, many covalent organic framework materials have been successfully constructed through a "bottom-up" strategy, and have outstanding performance in gas separation and heterogeneous catalysis.

[0003] (Tetraphenylcyclobutadiene)cyclopentadiene cobalt is a thermally stable structural unit that is chemically resistant to a range of reagents. The cyclobutadiene and cyclopentadiene rings are parallel, with the cyclobutadiene ring being square, and if suitable functionalization can be introduced into the para position, the four cross-formed side groups of phenyl will be very suitable as rigid arms capable of linear coupling. At the same time, the cyclopentadiene ring is electron-rich, ensuring the reactivity required to connect a sufficient number of side groups. Therefore, the (tetraphenylcyclobutadiene)cyclopentadiene cobalt structure provides a promising template for the envisioned monomer module. There are currently no reports of covalent organic framework materials based on cyclopentadiene cobalt. Summary of the invention

[0004] In order to solve the technical problems in the above-mentioned background technology, the present invention provides a covalent organic framework material based on cyclopentadienyl cobalt, a preparation method and its application in the adsorption and separation of light hydrocarbons.

[0005] The first object of the present invention is to provide an aldehyde monomer based on cyclopentadienyl cobalt covalent organic framework material, whose chemical name is [tetrakis (4-formylphenyl) cyclobutadiene] cyclopentadienyl cobalt (TAPC for short), and whose structure is shown in Formula II:

[0006]

[0007] A second object of the present invention is to provide a method for preparing the above-mentioned [tetrakis (4-formylphenyl) cyclobutadiene] cyclopentadiene cobalt formyl monomer, the steps of which are as follows:

[0008] A. Synthesis of 4,4'-(acetylene-1,2-diyl)benzaldehyde (I): 4-iodobenzaldehyde and 4-alkynylbenzaldehyde are added to an anhydrous triethylamine solution, and 4,4'-(acetylene-1,2-diyl)benzaldehyde (I) is obtained by Sonogashira coupling reaction catalyzed by triphenylphosphine, cuprous iodide and palladium catalyst;

[0009] B. Synthesis of [tetrakis(4-formylphenyl)cyclobutadiene]cyclopentadiene cobalt (II) aldehyde monomer: 4,4'-(ethynyl-1,2-diyl)benzaldehyde (I) and dicarbonylcyclopentadienyl cobalt are added to a xylene solution to obtain [tetrakis(4-formylphenyl)cyclobutadiene]cyclopentadiene cobalt aldehyde monomer (II) through a cycloaddition reaction;

[0010] The reaction formula is as follows:

[0011]

[0012] The third object of the present invention is to provide a covalent organic framework material based on cyclopentadienyl cobalt (TAPC-COF for short), the structure of which is shown in Formula III:

[0013]

[0014] The fourth object of the present invention is to provide a method for preparing the above-mentioned covalent organic framework material based on cyclopentadiene cobalt, which comprises dispersing [tetrakis (4-formylphenyl) cyclobutadiene] cyclopentadiene cobalt aldehyde monomer (II) and p-phenylenediamine in a mixed solvent of mesitylene and dioxane to obtain a dispersion, adding an acetic acid aqueous solution as a catalyst, and mixing; then reacting under reflux conditions to obtain a covalent organic framework material (TAPC-COF) based on cyclopentadiene cobalt; the ratio of [tetrakis (4-formylphenyl) cyclobutadiene] cyclopentadiene cobalt (II), p-phenylenediamine, mesitylene, dioxane and acetic acid is 0.2mmol: 0.4mmol: 5mL: 5mL: 1mL. The reaction formula is as follows:

[0015]

[0016] Another object of the present invention is to provide an application of the above-mentioned covalent organic framework material based on cyclopentadienyl cobalt in the adsorption and separation of low-carbon hydrocarbons. The covalent organic framework material can adsorb single components CO2, C2H2, C2H4 and C2H6 one by one to obtain differentiated adsorption amounts for adsorption and separation.

[0017] The invention has the beneficial effects of being simple in preparation method, being able to react quickly, being energy-saving and time-saving. The covalent organic framework product yield based on cyclopentadienyl cobalt of the invention is high, the amount of ligand used is small, and the cost is saved. Moreover, under the premise of suitable concentration and molar dosage, the obtained covalent organic framework material has better quality and the reaction is smoother. The covalent organic framework material based on cyclopentadienyl cobalt prepared by the invention can be used for preparing adsorption materials, antibacterial materials, catalytic materials, photoelectromagnetic materials and drug carrier materials, and is a composite functional porous material with great potential, which can be applied to the field of low-carbon hydrocarbon separation, so that the function of the covalent organic framework material based on cyclopentadienyl cobalt is more comprehensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the H NMR spectrum of the compound represented by formula I of the present invention;

[0019] Figure 2 is the H NMR spectrum of the compound represented by formula II of the present invention;

[0020] Figure 3 The powder X-ray diffraction pattern of the covalent organic framework material based on cyclopentadienyl cobalt represented by formula III of the present invention;

[0021] Figure 4 It is a thermogravimetric curve of the covalent organic framework material based on cyclopentadienyl cobalt represented by Formula III of the present invention, wherein the abscissa is the temperature and the ordinate is the weight loss percentage;

[0022] Figure 5 This is an infrared spectrum of the covalent organic framework material based on cyclopentadienyl cobalt represented by Formula III of the present invention, where the abscissa is the wave number and the ordinate is the transmittance;

[0023] Figure 6 This is a scanning electron microscope image of a covalent organic framework material based on cyclopentadienyl cobalt as shown in Formula III of the present invention;

[0024] Figure 7 It is the adsorption isotherm diagram of CO2, C2H2, C2H4 and C2H6 of the covalent organic framework material based on cyclopentadienyl cobalt represented by Formula III of the present invention at 273K, wherein the abscissa is the pressure and the ordinate is the adsorption amount;

[0025] Figure 8This is the adsorption isotherm diagram of CO2, C2H2, C2H4 and C2H6 of the covalent organic framework material based on cyclopentadienyl cobalt represented by Formula III of the present invention at 298K, wherein the abscissa is pressure and the ordinate is adsorption amount. DETAILED DESCRIPTION

[0026] The principles and features of the present invention are described in detail below in conjunction with implementation. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0027] Embodiment 1:

[0028] The preparation method of [tetrakis (4-formylphenyl) cyclobutadiene] cyclopentadiene cobalt specifically comprises the following steps:

[0029] A. Synthesis of 4,4'-(ethynyl-1,2-diyl)benzaldehyde (I)

[0030] 5.05g of 4-iodobenzaldehyde, 5.0g of 4-alkynylbenzaldehyde, 0.5g of triphenylphosphine, 0.5g of cuprous iodide and 0.7g of bis(triphenylphosphine)palladium dichloride were placed in a 500mL two-necked round-bottom flask, and 300mL of deoxygenated anhydrous triethylamine was added after vacuuming and nitrogen filling three times. The resulting mixed solution was heated under reflux for 48 hours in an inert atmosphere. After the reaction was completed, it was cooled to room temperature, the reaction solution was evaporated to dryness and extracted three times with dichloromethane, and then the combined organic layer was washed three times with water, dried with anhydrous magnesium sulfate for 30 minutes, filtered, and the filtrate was collected. The filtrate was evaporated under reduced pressure to remove the volatile organic solvent, and the crude product was subjected to column chromatography using dichloromethane as an eluent. After vacuum drying, 4.1g (yield 80%) of yellow powder of 4,4'-(ethyne-1,2-diyl)dibenzaldehyde (I) was obtained;

[0031] B. Synthesis of [tetrakis(4-formylphenyl)cyclobutadiene]cyclopentadiene cobalt(II):

[0032] 2.57g of 4,4'-(acetylene-1,2-diyl)benzaldehyde (I) and 1.0g of dicarbonylcyclopentadienyl cobalt were placed in a 250mL two-necked round-bottom flask, and 150mL of deoxygenated xylene was added after vacuuming and filling with nitrogen three times. The resulting mixed solution was heated under reflux for 48 hours in an inert atmosphere. After the reaction was completed, it was cooled to room temperature, the reaction solution was evaporated to dryness and extracted with dichloromethane three times, and then the combined organic layer was washed with water three times, dried with anhydrous magnesium sulfate for 30 minutes, filtered, and the filtrate was collected. The filtrate was evaporated under reduced pressure to remove the volatile organic solvent, and the crude product was subjected to column chromatography using dichloromethane as an eluent. After vacuum drying, 1.2g (yield 34%) of [tetrakis (4-formylphenyl) cyclobutadiene] cyclopentadienyl cobalt (II) orange-red powder was obtained. The reaction formula is as follows:

[0033]

[0034] The H NMR spectra of 4,4'-(ethyne-1,2-diyl)benzaldehyde (I) and [tetrakis(4-formylphenyl)cyclobutadiene]cyclopentadienylcobalt (II) are shown in Figure 1 and Figure 2 As shown, the NMR integrated area at the corresponding chemical shift is consistent with the corresponding number of hydrogen atoms, indicating that the product of the target structure has been prepared.

[0035] Embodiment 2:

[0036] A method for preparing a covalent organic framework material based on cyclopentadienyl cobalt comprises the following steps:

[0037] 118.4 mg (0.2 mmol) of [tetrakis (4-formylphenyl) cyclobutadiene] cyclopentadiene cobalt (II) and 43.2 mg (0.4 mmol) of p-phenylenediamine were placed in a 25 mL Schlenk tube, 5 mL of mesitylene, 5 mL of dioxane, and 1 mL of acetic acid aqueous solution (6 mol / L) as a catalyst. The resulting mixture was degassed by freezing three times, sealed with a polytetrafluoroethylene valve at 77 K, and then placed in a 120 ° C oven for 7 days. After the reaction was completed, it was cooled to room temperature and filtered. The filter cake was washed three times with tetrahydrofuran, N, N-dimethylacetamide and acetone respectively, and the solid was collected and dried in vacuum to obtain 120.6 mg of yellow powder of covalent organic framework material TAPC-COF (III) (yield 81%). The reaction formula is as follows:

[0038]

[0039] like Figure 3 As shown, the covalent organic framework material based on cyclopentadienylcobalt is subjected to powder X-ray diffraction analysis, and the diffraction data within the 2θ angle range of 2 to 50° is collected using a PANalytical X'Pert PRO diffractometer. The diffraction peaks at 2θ angles of 4.68°, 7.58°, 9.43° and 10.57° prove that the covalent organic framework material based on cyclopentadienylcobalt of the present invention has good crystallinity.

[0040] like Figure 4 As shown, the covalent organic framework material based on cyclopentadienyl cobalt was subjected to thermogravimetric analysis. The thermogravimetric test was conducted on a Mettler synchronous thermogravimetric analyzer, machine model RGA / DSC-1, the reaction gas and the protective gas were both nitrogen, the flow rate was 25 mL / min, the running time was 50 minutes, the heating rate was 10°C / min, and the test temperature range was 40-900°C. Figure 4From the thermogravimetric curve, we can know that the covalent organic framework material based on cyclopentadienylcobalt is stable to about 500° C., and the covalent organic framework material based on cyclopentadienylcobalt decomposes after 500° C. This shows that the covalent organic framework material based on cyclopentadienylcobalt of the present invention has good stability and can be decomposed at high temperature.

[0041] like Figure 5 As shown, the cyclopentadienyl cobalt-based covalent organic framework material was tested by infrared spectroscopy. The infrared test was performed by KBr tablet method, and the 4000-400 cm-1 wavelength was collected on a Nicolet 330 FTIR spectrometer. -1 Infrared spectrum in the region. Figure 5 It can be seen that the 1618cm -1 The nearby absorption peak can be attributed to the C=N stretching vibration peak, proving the occurrence of the amine-aldehyde condensation reaction, further illustrating the successful synthesis of covalent organic framework materials based on cyclopentadienylcobalt.

[0042] like Figure 6 As shown, the cyclopentadienylcobalt-based covalent organic framework material was characterized by scanning electron microscopy, and the electron microscope image was obtained by HITACHI Regulus 8100 instrument. The uniform morphology of the lamellar structure proved the good crystallinity of the cyclopentadienylcobalt-based covalent organic framework material of the present invention.

[0043] like Figure 7 and Figure 8 As shown in the figure, the covalent organic framework material based on cyclopentadienyl cobalt was tested by the ASAP2020 instrument of Mack Company in the United States. The covalent organic framework material based on cyclopentadienyl cobalt was tested for adsorption of single components CO2, C2H2, C2H4 and C2H6 one by one, and the adsorption isotherms shown in the figure were shown. The adsorption amounts of CO2, C2H2, C2H4 and C2H6 at 273K were 53.4 cm 3 / g, 108.4cm 3 / g, 63.6cm 3 / g and 76.0cm 3 / g, the adsorption capacities of CO2, CH4, C2H2, C2H4 and C2H6 at 298K were 45.5 cm 3 / g,89.8cm 3 / g,53.5cm 3 / g and 57.3cm 3 / g. Therefore, it can be known from the differentiated adsorption amounts in the figure that the covalent organic framework material based on cyclopentadienyl cobalt can be applied to the field of gas adsorption and separation.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A covalent organic framework material based on cyclopentadienyl cobalt, the structural formula of which is shown below:

2. The method for preparing a covalent organic framework material based on cyclopentadienyl cobalt according to claim 1, characterized in that: The method comprises dispersing [tetrakis (4-formylphenyl) cyclobutadiene] cyclopentadiene cobalt formyl monomer and p-phenylenediamine in a mixed solvent of mesitylene and dioxane to obtain a dispersion, then adding an acetic acid aqueous solution as a catalyst and mixing well; reacting under reflux conditions to obtain a covalent organic framework material based on cyclopentadiene cobalt.

3. A method for preparing a covalent organic framework material based on cyclopentadienyl cobalt as claimed in claim 2, characterized in that: The structural formula of the [tetrakis(4-formylphenyl)cyclobutadiene]cyclopentadiene cobalt formyl monomer is shown below:

4. A method for preparing a covalent organic framework material based on cyclopentadienyl cobalt as claimed in claim 3, characterized in that: [Tetrakis(4-formylphenyl)cyclobutadiene]cyclopentadiene cobalt formyl monomer is prepared by the following steps: A. Synthesis of 4,4'-(ethynyl-1,2-diyl)benzaldehyde: 4-iodobenzaldehyde and 4-alkynylbenzaldehyde are added to an anhydrous triethylamine solution, and 4,4'-(ethynyl-1,2-diyl)benzaldehyde (I) is obtained by a Sonogashira coupling reaction catalyzed by triphenylphosphine, cuprous iodide and a palladium catalyst; B. Synthesis of [tetrakis(4-formylphenyl)cyclobutadiene]cyclopentadienylcobalt: 4,4'-(ethynyl-1,2-diyl)benzaldehyde (I) and dicarbonylcyclopentadienylcobalt are added to a xylene solution to obtain [tetrakis(4-formylphenyl)cyclobutadiene]cyclopentadienylcobalt (II) through a cycloaddition reaction; the reaction formula is as follows:

5. Use of the covalent organic framework material based on cyclopentadienyl cobalt as claimed in claim 1 in the adsorption and separation of light hydrocarbons.

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