COF-based heterogeneous iodobenzene catalyst and its preparation method and application

Abstract

The invention discloses a COF-based heterogeneous iodobenzene catalyst and its preparation method and application, belonging to the field of catalyst preparation technology. The COF-based heterogeneous iodobenzene catalyst is obtained by polymerizing a hydrazide monomer containing an iodophenyl group unit and 1,3,5-tris(4-formylphenyl)triazine; the structural formula of the hydrazide monomer containing an iodophenyl group unit is: The COF-based heterogeneous iodobenzene catalyst can be used as a catalyst for the chlorination reaction of anisole, catalyzing the chlorination reaction of anisole, achieving heterogeneous catalysis, and using a small amount, easy to recover, improving the utilization rate of the catalyst, and reducing the cost of anisole chlorination.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst preparation, and particularly relates to a COF-based heterogeneous iodobenzene catalyst and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Halogen bond catalysis, especially iodine derivative catalysis, is different from traditional metal and enzyme catalysts in that it is relatively cheap, stable, environmentally friendly, easy to operate, and has good catalytic activity. However, there is still room for improvement in catalytic activity and work efficiency. Therefore, there is an urgent need to develop halogen bond catalysts with high catalytic activity. In addition, common stoichiometric hypervalent iodine reagents produce non-recoverable reduced iodine products (such as PhI) as waste after each reaction. Polymer-supported reagents and recyclable non-polymer hypervalent iodine reagents can effectively overcome this shortcoming.

[0004] Covalent organic frameworks (COFs) are advanced crystalline porous materials with advantages such as high porosity, good thermal and chemical stability, large specific surface area, adjustable structure, and abundant active sites. Due to their versatile structure, COFs can contain different active sites for catalytic processes. According to the nature of the active sites, the structure and composition of COFs can be divided into two major parts: (1) organic active sites, which may exist in the form of COF skeletons or pendants; (2) metal active sites, which may exist in the form of COF skeletons or guests. The synthesis strategy of COFs with specific active sites can also be divided into three parts: (1) in situ formation during the network process and regarded as the backbone or link of COFs; (2) pre-designed network structure with building blocks of catalytic active sites; (3) incorporation of desired active sites into COFs through post-synthetic strategies. Patent CN117264152A discloses a covalent organic framework synthesized based on the Mannich reaction, which uses imine and triazine to link to obtain a catalyst with catalytic activity for hydroxylation of phenylboronic acid. Patent CN114716631A discloses a pyrrolidone covalent organic framework material, which uses imine and triazine to form a catalyst with Claisen-Schmidt reaction activity. However, there are no reports of the catalytic introduction of iodobenzene into COFs.

[0005] Therefore, it is of great significance to develop COFs with high catalytic activity and recyclable iodine phenyl groups and to explore new COF catalytic pendant sites. Summary of the Invention

[0006] In order to address the deficiencies of the prior art, the present invention aims to provide a COF-based heterogeneous iodine benzene catalyst and its preparation method and application. The COF-based heterogeneous iodine benzene catalyst provided by the present invention has high utilization rate, mild reaction conditions, and can effectively reduce catalytic costs.

[0007] In order to achieve the above object, the technical solution of the present invention is:

[0008] In a first aspect of the present invention, a COF-based heterogeneous iodine benzene catalyst is provided, wherein the COF-based heterogeneous iodine benzene catalyst is obtained by polymerizing a hydrazide monomer containing an iodine phenyl group unit and 1,3,5-tris(4-formylphenyl)triazine;

[0009] The structural formula of the hydrazide monomer containing iodophenyl group unit is as follows:

[0010]

[0011] In some embodiments of the present invention, the structural unit of the COF-based heterogeneous iodobenzene catalyst is as follows:

[0012]

[0013] The second aspect of the present invention provides a method for preparing the COF-based heterogeneous iodobenzene catalyst, comprising the following steps:

[0014] A hydrazide monomer containing an iodine phenyl group unit and 1,3,5-tris(4-formylphenyl)triazine are dissolved in a solvent, and acetic acid is added to carry out a solvent thermal reaction. After the reaction is completed, a COF-based heterogeneous iodine benzene catalyst is obtained.

[0015] It should be noted that the present invention utilizes a solvent-thermal synthesis method to synthesize a COF-based heterogeneous iodobenzene catalyst by a Schiff base condensation reaction of a hydrazide monomer containing an iodophenyl group unit and 1,3,5-tris(4-formylphenyl)triazine (TFPT).

[0016] In some embodiments of the present invention, 2,5-dibromotoluene is used as a raw material, and organic synthesis reactions such as coupling, bromination, synthesis, ion exchange, and hydrazinolysis are performed to obtain a hydrazide monomer containing an iodine phenyl group unit. Specifically, the preparation method of the hydrazide monomer containing an iodine phenyl group unit comprises the following steps:

[0017] 2,5-Dibromotoluene reacts with p-methoxycarbonylphenylboronic acid to obtain intermediate A;

[0018] Intermediate A is converted into intermediate B;

[0019] Intermediate B reacts with imidazole to obtain intermediate C;

[0020] Intermediate C reacts with 4-iodobenzyl bromide to obtain intermediate D;

[0021] Intermediate D reacts with sodium hexafluorophosphate to obtain intermediate E;

[0022] Intermediate E is converted into a hydrazide monomer containing an iodine phenyl group unit;

[0023]

[0024] In some embodiments of the present invention, the molar ratio of the hydrazide monomer containing an iodine phenyl group unit to 1,3,5-tris(4-formylphenyl)triazine is (1-3):(2-4), preferably 2:3, to improve the reaction efficiency and yield.

[0025] In some embodiments of the present invention, the solvent is at least one of o-dichlorobenzene, methanol, and 1,3,5-mesitylene.

[0026] Preferably, the solvent is a mixed solution of o-dichlorobenzene and 1,3,5-mesitylene in a volume ratio of (0.9-1.1):(0.9-1.1).

[0027] More preferably, the amount of the solvent used is 1.9 to 2.1 mL, which is sufficient to effectively dissolve the amine compound and 1,3,5-tris(4-formylphenyl)triazine.

[0028] In some embodiments of the present invention, the solvent thermal reaction has a reaction temperature of 100-130° C. and a reaction time of 3-5 days.

[0029] Preferably, the reaction temperature is 120° C. and the reaction time is 3 days.

[0030] It should be noted that the present invention does not impose any requirements on the pressure of the solvent thermal reaction. As long as the reaction temperature is ensured to be the set temperature, the reaction can be carried out in different seasons and regions.

[0031] The third aspect of the present invention provides a use of the COF-based heterogeneous iodobenzene catalyst in the chlorination reaction of aromatic compounds;

[0032] The application is to use the COF-based heterogeneous iodobenzene catalyst as a catalyst to catalyze the chlorination reaction of aromatic compounds.

[0033] A fourth aspect of the present invention provides a method for chlorinating an aromatic compound, comprising the steps of:

[0034] Aromatic compounds, heterogeneous catalysts, m-chloroperbenzoic acid (mCPBA), 4-methylbenzenesulfonic acid (TsOH) and lithium chloride are dissolved in an organic solvent and reacted at room temperature to obtain p-chloroanisole;

[0035] The heterogeneous catalyst is the COF-based heterogeneous iodobenzene catalyst.

[0036] In some embodiments of the present invention, after the reaction is completed, the heterogeneous catalyst is removed by centrifugation to obtain the corresponding product.

[0037] In some embodiments of the present invention, the molar ratio of the aromatic compound, the heterogeneous catalyst, m-chloroperbenzoic acid, 4-methylbenzenesulfonic acid and lithium chloride is (0.9-1.1):(0.02-0.04):(0.9-1.1):(0.9-1.1):(0.9-1.1); preferably 1:0.03:1:1:1.

[0038] The organic solvent is dichloromethane;

[0039] React at room temperature for 40 to 60 minutes.

[0040] In some embodiments of the present invention, the aromatic compound comprises:

[0041]

[0042] Taking anisole as an example, the catalytic principle is clarified. The reaction route of anisole chlorination is as follows:

[0043]

[0044] In the anisole chlorination process, the catalytic principle of the COF-based heterogeneous iodobenzene catalyst is as follows:

[0045]

[0046] First, the iodophenyl group in the COF-based heterogeneous iodobenzene catalyst is oxidized by mCPBA in the presence of TsOH to a hypervalent iodine(III) reagent. This is then converted into another active hypervalent iodine intermediate, COF-I(OTs)Cl, which undergoes electrophilic substitution with anisole to form a chlorinated product. The reduced byproduct is then oxidized by mCPBA to a hypervalent iodine reagent, continuing the reaction cycle.

[0047] The COF-based heterogeneous iodobenzene catalyst of the present invention is used to catalyze the chlorination reaction of aromatic compounds, thereby achieving heterogeneous catalysis, requiring less catalyst and being easy to recycle, thereby improving catalyst utilization and reducing costs.

[0048] The beneficial effects of the present invention are:

[0049] The present invention provides a novel covalent organic framework material (i.e., a COF-based heterogeneous iodobenzene catalyst). The present invention introduces an iodophenyl group as a synthetic monomer into a polymer framework, and forms a new imine bond COFs through hydrazide and aldehyde condensation. The iodophenyl group does not participate in the formation of the framework, and on the basis of the original stable framework, the catalytically active sites are increased. When the covalent organic framework material containing the iodophenyl group catalyzes the chlorination of aromatic compounds, the catalytic reaction temperature is low, the reaction effect is good, it has universality, reduces energy consumption, and the method is simple, low in cost, strong in practicality, and easy to promote. Specifically, as a heterogeneous catalyst, when catalyzing the chlorination reaction of anisole, heterogeneous catalysis is achieved, and the performance is stable. After five cycles of use, the product yield is still about 91%, the amount used is small, and it is easy to recycle, thereby improving the utilization rate of the catalyst and reducing the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0051] Figure 1 is the hydrogen spectrum of intermediate A prepared in Example 1 of the present invention;

[0052] Figure 2 is the carbon spectrum of intermediate A prepared in Example 1 of the present invention;

[0053] Figure 3 is the hydrogen spectrum of intermediate B prepared in Example 1 of the present invention;

[0054] Figure 4 is the carbon spectrum of intermediate B prepared in Example 1 of the present invention;

[0055] Figure 5 is the hydrogen spectrum of intermediate C prepared in Example 1 of the present invention;

[0056] Figure 6 is the carbon spectrum of intermediate C prepared in Example 1 of the present invention;

[0057] Figure 7 is the hydrogen spectrum of intermediate D prepared in Example 1 of the present invention;

[0058] Figure 8 is the carbon spectrum of intermediate D prepared in Example 1 of the present invention;

[0059] Figure 9 is the hydrogen spectrum of intermediate E prepared in Example 1 of the present invention;

[0060] Figure 10 is the carbon spectrum of intermediate E prepared in Example 1 of the present invention;

[0061] Figure 11is the hydrogen spectrum of the monomer LE prepared in Example 1 of the present invention;

[0062] Figure 12 is the carbon spectrum of monomer LE prepared in Example 1 of the present invention;

[0063] Figure 13 is an infrared spectrum of COF-1 and ligand prepared in Example 2 of the present invention;

[0064] Figure 14 is the PXRD pattern of COF-1 prepared in Example 2 of the present invention;

[0065] Figure 15 is the PXRD pattern of COF-1 in Example 3 of the present invention catalyzing the chlorination of anisole five times;

[0066] Figure 16 This is a statistical graph showing the yield of chlorinating anisole five times catalyzed by COF-1 in Example 3 of the present invention. DETAILED DESCRIPTION

[0067] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0068] Example 1: Preparation of hydrazide monomer containing iodophenyl group units

[0069]

[0070] Intermediate A: 2,5-Dibromotoluene (1.38 mL, 10 mmol), p-methoxycarbonylphenylboronic acid (4.34 g, 24 mmol), tetrakis(triphenylphosphine)palladium(0) (1.6 g, 5% mmol), and cesium fluoride (6.0 g, 40 mmol) were placed in a 250 mL three-necked flask. After evacuation and nitrogen purging three times, 1,4-dioxane (100 mL) was added. The reaction was stirred at 90°C and monitored by TLC. The reaction was complete after approximately 24 h. The product was purified by column chromatography (petroleum ether:dichloromethane = 3:1) to obtain 3.49 g of a white powdery solid, Intermediate A, in an 83% yield.

[0071]

[0072] Intermediate B: Intermediate A (2.5 g, 6.9 mmol) and azobisisobutyronitrile (0.114 g, 0.7 mmol) were placed in a 250 mL three-necked flask. After evacuation and nitrogen purging three times, carbon tetrachloride (100 mL) was added and the reaction was allowed to proceed under incandescent light for 0.5 h, at which point the reaction system turned from white to clear. N-bromosuccinimide (1.5 g, 8.3 mmol) was added and the reaction was stirred at 90°C. The reaction progress was monitored by TLC. The reaction was complete after approximately 24 h. The product was purified by column chromatography (petroleum ether:ethyl acetate = 10:1) to obtain 2.23 g of a white powdery solid, Intermediate B, in a 73.4% yield.

[0073]

[0074] Intermediate C: A mixture of imidazole (0.14 g, 2 mmol) and sodium hydride (0.048 g, 2 mmol) was added to anhydrous tetrahydrofuran (15 mL) and refluxed at 67°C for 1 hour. Compound B (0.44 g, 1 mmol) was added and refluxed for an additional 24 hours (TLC monitoring). The product was purified on a silica gel column (dichloromethane:methanol = 50:1) to obtain 0.23 g of an off-white powdery solid, Intermediate C, in a 60% yield.

[0075]

[0076] Intermediate D: Intermediate C (0.44 g, 1 mmol) and 4-iodobenzyl bromide (0.59 g, 2 mmol) were placed in a 25 mL flask. After three evacuations and nitrogen flushing, acetonitrile (15 mL) was added and stirred at 70°C. The reaction progress was monitored by TLC. The reaction was complete after approximately 22 h. The product was purified by column chromatography (dichloromethane:methanol = 17:1) to obtain 0.55 g of a white crystalline solid, Intermediate D, in a 92% yield.

[0077]

[0078] Intermediate E: Intermediate D (0.36 g, 0.5 mmol) and sodium hexafluorophosphate (0.42 g, 2.5 mmol) were placed in a single-necked flask, and 20 mL of methanol solvent was added. The mixture was stirred at room temperature for 3 days. The reaction progress was monitored by TLC. After the reaction was completed, a small amount of methanol was used to rinse the product to obtain 0.4 g of a white powdery product, namely, Intermediate E, with a yield of 93%.

[0079]

[0080] Monomer LE: Intermediate E (1 mmol, 0.6 g), hydrazine hydrate (10 mmol, 0.6 mL) and 15 mL of tetrahydrofuran solvent were placed in a single-necked flask and refluxed at 67 ° C for 24 h. When white flocs were produced, a small amount of methanol was added to clarify them. The reaction progress was monitored by TLC. After the reaction was completed, the solvent was removed under reduced pressure and the product was washed with a small amount of methanol to obtain 0.34 g of white block product.

[0081] The yield of monomer LE (i.e., hydrazide monomer containing iodine phenyl group unit) was 56.7%.

[0082] Example 2: Synthesis of COF-based heterogeneous iodobenzene catalyst COF-1 having the structural unit shown in Formula I

[0083] The synthetic route is as follows:

[0084]

[0085]

[0086] Monomer LE (0.03 mmol, 19.3 mg) and 1,3,5-tris-(4-aminophenyl)triazine (0.02 mmol, 9.9 mg) were placed in a glass tube, and a mixed solution of 1,3,5-mesitylene / o-dichlorobenzene (1 mL / 1 mL) was added. After ultrasonic mixing, acetic acid (0.5 mL, 6 M) was added and heated at 120°C for three days. The solid was washed with THF, methanol, and ether, and vacuum dried to obtain 20.7 mg of a light yellow powder, namely COF-1.

[0087] The polymer was characterized by IR and PXRD. From the IR graph, it can be seen that the monomer LE is at 3287 cm -1 There is an obvious -NH2 absorption peak at 1693cm, which corresponds to the disappearance of the absorption peak in COF-1; 1,3,5-tris-(4-aminophenyl)triazine has a peak at 1693cm -1 The C=O characteristic absorption peak is clearly shown at 1609 cm-1, while the intensity of the band corresponding to C=O in COF-1 is significantly weakened. -1 The characteristic stretching vibration peak of imine C=N is shown, indicating the successful synthesis of COF-1. From the PXRD pattern, it can be seen that the generated COF-1 has excellent crystalline structural characteristics. The results are shown in Figure 2. Figure 13 、 14 .

[0088] Example 3: Chlorination of aromatic compounds

[0089] Anisole (0.3 mmol, 32 μL), TsOH·H2O (0.3 mmol, 57.1 mg), CH2Cl2 (4 mL), mCPBA (0.3 mmol, 69 mg), LiCl (0.36 mmol, 15.3 mg), and COF-1 (15 mg) were placed in a 25 mL round-bottom flask. The mixture was reacted at room temperature for 50 minutes, followed by centrifugation. The solution was taken for GC-MS yield testing and the product was obtained by chromatography (petroleum ether / ethyl acetate = 20 / 1).

[0090] The chlorination reaction was carried out by changing the molar ratio of different aromatic compounds and the above method. The products and yields of each reaction are shown in Table 1.

[0091] Table 1 Products and yields of chlorination reactions of aromatic compounds

[0092]

[0093]

[0094] As can be seen from Table 1, the catalyst prepared by the present invention has universal applicability in catalyzing the chlorination of aromatic compounds, and has high catalytic activity and high product yield.

[0095] In the reaction where the raw material is anisole, the filtered catalyst is added back into the anisole chlorination reaction, and repeated five times. After the anisole chlorination reaction is completed, the yield each time is as follows: Figure 16 As shown, the yield is still maintained at about 91%.

[0096] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A COF-based heterogeneous iodobenzene catalyst, characterized in that: The COF-based heterogeneous iodobenzene catalyst is obtained by polymerizing a hydrazide monomer containing an iodophenyl group unit and 1,3,5-tris(4-formylphenyl)triazine; The structural formula of the hydrazide monomer containing iodophenyl group unit is as follows: 。 2. The COF-based heterogeneous iodobenzene catalyst according to claim 1, wherein The structural unit of the COF-based heterogeneous iodobenzene catalyst is as follows: 。 3. A method for preparing a COF-based heterogeneous iodobenzene catalyst according to claim 1 or 2, characterized in that: The following steps are involved: A hydrazide monomer containing an iodine phenyl group unit and 1,3,5-tris(4-formylphenyl)triazine are dissolved in a solvent, and acetic acid is added to carry out a solvent thermal reaction. After the reaction is completed, a COF-based heterogeneous iodine benzene catalyst is obtained.

4. The preparation method according to claim 3, wherein The preparation method of the hydrazide monomer containing iodine phenyl group units comprises the following steps: 2,5-Dibromotoluene reacts with p-methoxycarbonylphenylboronic acid to obtain intermediate A; Intermediate A is converted into intermediate B; Intermediate B reacts with imidazole to obtain intermediate C; Intermediate C reacts with 4-iodobenzyl bromide to obtain intermediate D; Intermediate D reacts with sodium hexafluorophosphate to obtain intermediate E; Intermediate E is converted into a hydrazide monomer containing an iodine phenyl group unit; 。 5. The preparation method according to claim 3, wherein The molar ratio of the hydrazide monomer containing an iodine phenyl group unit to 1,3,5-tris(4-formylphenyl)triazine is (1-3):(2-4).

6. The preparation method according to claim 5, wherein The molar ratio of the hydrazide monomer containing iodine phenyl group units to 1,3,5-tris(4-formylphenyl)triazine is 2:

3.

7. The preparation method according to claim 3, wherein The solvent is at least one of o-dichlorobenzene, methanol, and 1,3,5-mesitylene.

8. The preparation method according to claim 7, wherein The solvent is a mixed liquid of o-dichlorobenzene and 1,3,5-mesitylene in a volume ratio of (0.9-1.1):(0.9-1.1).

9. The preparation method according to claim 3, wherein The solvent thermal reaction has a reaction temperature of 100-130° C. and a reaction time of 3-5 days.

10. Use of the COF-based heterogeneous iodobenzene catalyst according to claim 1 or 2 in the chlorination reaction of aromatic compounds; The application is to use the COF-based heterogeneous iodobenzene catalyst as a catalyst to catalyze the chlorination reaction of aromatic compounds.

11. A method for chlorinating an aromatic compound, characterized in that: The steps include: An aromatic compound, a heterogeneous catalyst, m-chloroperbenzoic acid, 4-methylbenzenesulfonic acid and lithium chloride are dissolved in an organic solvent and reacted at room temperature to obtain p-chloroanisole; The heterogeneous catalyst is the COF-based heterogeneous iodobenzene catalyst according to claim 1 or 2.

12. The method according to claim 11, wherein The molar ratio of the aromatic compound, the heterogeneous catalyst, m-chloroperbenzoic acid, 4-methylbenzenesulfonic acid and lithium chloride is (0.9-1.1):(0.02-0.04):(0.9-1.1):(0.9-1.1):(0.9-1.1); The organic solvent is dichloromethane; React at room temperature for 40-60 min; The aromatic compounds include: 、 、 、 、 、 、 、 、 or .

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