Method for catalyzing N-formylation of organic amine and carbon dioxide by MIL-68 (In) loaded Ag nanoparticle material

Abstract

The invention provides a method for catalyzing N-formylation of organic amine and carbon dioxide by using an MIL-68 (In) loaded Ag nanoparticle material, and belongs to the field of catalytic chemistry. According to the method, carbon dioxide and organic amine serve as reaction raw materials, Ag-coated MIL-68 (In) serves as a catalyst, phenylsilane serves as a reducing agent, and the formamide compound is synthesized. The method is mild in condition and environment-friendly, provides a recyclable, green and efficient way for high value-added conversion of CO2, and has potential value in the aspect of industrial application. In addition, the novel catalyst provided by the invention is easy to separate from a reaction system, and has excellent recycling performance.

Description

Technical Field

[0001] The present invention belongs to the field of catalytic chemistry, and particularly relates to a method for catalytic N-formylation of organic amines and carbon dioxide by using an MIL-68(In) supported Ag nanoparticle material. Background Art

[0002] The use of fossil fuels in industrial processes has greatly promoted the emission of greenhouse gases. The greenhouse effect not only causes environmental and climate deterioration, but also has important negative impacts on society and the economy. The main solutions proposed currently are to allow energy to continue to be generated by burning fossil fuels while carrying out carbon capture and storage (CCS), that is, separating, purifying, pressurizing and transporting CO2 underground or to the seabed for long-term storage, so as to stabilize the global atmospheric CO2 level.

[0003] Nowadays, CO2 has been used as a C1 raw material with rich sources, low cost, non-toxicity and renewability in a variety of organic reactions. Compared with carbon capture and storage (CCS) technology, developing advanced catalytic technologies to chemically convert CO2 into value-added fine chemicals and fuels, that is, developing carbon dioxide capture and utilization (CCU) technology, is a very promising strategy for reducing carbon emissions. Among them, synthesizing N-formamide compounds by reacting CO2 with organic amines provides a simple, highly atom-economic and convenient method for the efficient utilization of CO2, which has attracted wide attention.

[0004] N - formamide compounds are a very important class of organic intermediates and have extensive applications in the fields such as the preparation of N,N - diethylformamide and N,N - dimethylacetamide, adhesives, agrochemicals, and pharmaceutical manufacturing. The traditional synthetic method of N - formamide compounds is to use CO or phosgene as the C1 source for synthesis. However, this synthetic route is highly toxic and the production process is complex. Therefore, people have shifted their attention to the abundant CO2 resource. Constructing the C - N bond through the N - formylation reaction of CO2 with amines is of great significance in the synthesis of N - formamides and their derivatives. It is reported that the synthetic route using CO2 as the raw material requires the use of reducing agents such as hydrogen, hydrosilanes, and hydroboranes. Although using H2 as the reducing agent has good economy and environmental friendliness, this method requires relatively harsh reaction conditions (high temperature, high pressure). For example, CN118047691A discloses a method for the N - formylation of amine compounds with carbon dioxide catalyzed by a heteropolyacid ionic liquid system, which uses hydrogen as the reducing agent and the reaction requires a relatively high reaction pressure to proceed. The reaction conditions are harsh and there are certain risks. The Si - H bond in hydrosilanes and the B - H bond in hydroboranes have weaker polarity compared with the H - H bond. Therefore, using hydrosilanes and hydroboranes as reducing agents requires milder conditions for the N - formylation reaction. Due to the high thermodynamic stability and kinetic inertness of CO2, the activation of CO2 still poses challenges. Therefore, it is particularly crucial to develop an efficient catalytic system that is easy to capture and activate CO2 and reactants.

[0005] Currently, for the N - formylation reaction of CO2 with organic amines, many metal - based (such as Pt, Ru, Rh, Ir, and Pd) homogeneous catalysts have been reported. However, these catalysts have disadvantages such as high cost, difficult separation and recycling, and harsh reaction conditions. Compared with homogeneous catalysts, heterogeneous catalysts have the inherent advantages of easy separation and recycling of the catalyst and reaction products, and have better stability and sustainability. Therefore, they have always been the preferred catalysts in industrial production. MOF - based catalysts have attracted much attention due to their high specific surface area, excellent CO2 capture and activation performance, uniformly distributed active sites, easy separation and recovery, etc. However, the comprehensive performance of the currently reported MOF - based catalysts still has certain deficiencies in terms of preparation process and cost, catalytic activity, and structural stability. Therefore, designing and developing a new type of MOF - based catalytic system that is cheap and easily available, and has both excellent catalytic activity and structural stability, and realizing high - efficiency and high - selectivity reactions of CO2 with organic amines under mild conditions is still an urgent need at present. Based on this, we have proposed the technology of the present invention. Summary of the Invention

[0006] The object of the present invention is to solve the problem that the comprehensive performance of existing MOF-based catalysts in terms of preparation process, cost, catalytic activity, and structural stability still has certain deficiencies, and to provide a method for the N-formylation of organic amines and carbon dioxide using an Ag nanoparticle-loaded MIL-68(In) material as a catalyst.

[0007] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0008] A method for the N-formylation of organic amines and carbon dioxide using an Ag nanoparticle-loaded MIL-68(In) material as a catalyst, which uses carbon dioxide and organic amines as reaction raw materials, Ag@MIL-68(In) as a catalyst, and phenylsilane as a reducing agent to react organic amines with carbon dioxide to synthesize formamide compounds.

[0009] Preferably, the preparation method of the Ag@MIL-68(In) includes the following steps:

[0010] S1: Uniformly disperse MIL-68(In) in a solvent to obtain suspension A; add silver nitrate to distilled water and stir until completely dissolved to obtain solution B; slowly add solution B to suspension A and perform ultrasonic treatment on the resulting mixture;

[0011] S2: Transfer the above ultrasonically treated mixture to a reaction kettle, statically heat it to 50°C - 90°C and react for 4 - 8 hours, filter, wash, and vacuum dry the resulting solid to obtain a composite material of Ag nanoparticle-loaded MIL-68(In), labeled as Ag@MIL-68(In).

[0012] Preferably, the loading amount of Ag in the Ag@MIL-68(In) is 1.0 - 4.5 mmol / g.

[0013] Preferably, the mass ratio of silver nitrate to MIL-68(In) in step S1 is (0.6 - 1.8):1.

[0014] Preferably, the ultrasonic treatment time of the mixture in step S1 is 0.5 - 2 hours.

[0015] Preferably, the solvent in step S1 is N,N-dimethylformamide.

[0016] Preferably, in S2, it is statically heated to 60°C and reacted for 6 hours.

[0017] Preferably, the structural formula of the organic amine is as follows:

[0018]

[0019] Preferably, the molar ratio of the organic amine, phenylsilane, and Ag in the Ag@MIL-68(In) catalyst is 1:(1.2 - 3):(0.03 - 0.08).

[0020] Preferably, the N-formylation reaction temperature is 50 - 90 °C, the reaction pressure is 0.5 - 1.5 MPa, and the reaction time is 4 - 8 hours.

[0021] Advantages of the present invention

[0022] 1. The method provided by the present invention uses the Ag@MIL-68(In) composite material as a catalyst, which has ultra-high porosity and ordered open channels, facilitating the adsorption and activation of carbon dioxide on the catalyst surface; the anchored Ag nanoparticles are uniformly distributed and their content can be regulated, enabling efficient activation of the Si-H bond in phenylsilane and the organic amine, thus synergistically promoting the N-formylation reaction with CO2.

[0023] 2. Compared with the reported heterogeneous catalysts, the Ag@MIL-68(In) composite material catalyst used in the present invention is simple to prepare, low in cost, stable in structure, and has mild catalytic reaction conditions, providing an environmentally friendly and efficient new approach for the high-value conversion of CO2 to synthesize formamide compounds.

[0024] 3. The method provided by the present invention has substrate universality and can catalyze the N-formylation reaction between a series of different organic amines and CO2, all showing excellent catalytic effects. The catalyst structure is stable, easy to separate and recycle, showing potential industrial application prospects. Description of the drawings

[0025] Figure 1 is the preparation schematic diagram of the Ag@MIL-68(In) composite material prepared by the present invention;

[0026] Figure 2 is the powder X-ray diffraction pattern of MIL-68(In) prepared in Example 1 of the present invention, 0.6Ag@MIL-68(In) prepared in Example 2, and 1.2Ag@MIL-68(In) composite material prepared in Example 3;

[0027] Figure 3 is the structural characterization comparison diagram of MIL-68(In) prepared in Example 1 of the present invention, 0.6Ag@MIL-68(In) prepared in Example 2, and 1.2Ag@MIL-68(In) composite material prepared in Example 3. (a) is the nitrogen adsorption-desorption isotherm, and (b) is the pore size distribution diagram;

[0028] Figure 4(a-c) are scanning electron microscope images of MIL-68(In) prepared in Example 1 of the present invention, and (d-f) are scanning electron microscope images of 1.2Ag@MIL-68(In) prepared in Example 3 of the present invention;

[0029] Figure 5 is a comparative diagram of the structural characterization of the 1.2Ag@MIL-68(In) composite material after fresh and 5 cycles in Example 15 of the present invention. (a) is an infrared spectrum, (b) is a CO2 cyclic adsorption isotherm; (c) is a powder X-ray diffraction pattern. Detailed implementation manners

[0030] A method for the catalytic N-formylation of organic amines and carbon dioxide by an Ag nanoparticle-loaded MIL-68(In) material. In this method, carbon dioxide and an organic amine are used as reaction raw materials, Ag@MIL-68(In) is used as a catalyst, and phenylsilane is used as a reducing agent to react the organic amine with carbon dioxide to synthesize formamide compounds. The temperature of the N-formylation reaction is preferably 50-90 °C, more preferably 80 °C, the reaction pressure is preferably 0.5-1.5 MPa, more preferably 1.0 MPa, and the reaction time is preferably 4-8 hours, more preferably 6 hours. The molar ratio of the organic amine, phenylsilane, and Ag in the Ag@MIL-68(In) catalyst is preferably 1:(1.2-3):(0.03-0.08); more preferably 1:2:0.05.

[0031] According to the present invention, the structural formula of the organic amine is preferably as follows:

[0032]

[0033] According to the present invention, the preparation method of Ag@MIL-68(In) is as Figure 1 shown, and includes the following steps:

[0034] S1: Uniformly disperse MIL-68(In) in a solvent. The solvent is preferably N,N-dimethylformamide to obtain suspension A; add silver nitrate to distilled water, preferably stir at room temperature until completely dissolved to obtain solution B; slowly add solution B to suspension A and perform ultrasonic treatment on the obtained mixture; the time of the ultrasonic treatment is preferably 0.5-2 hours. The mass ratio of silver nitrate to MIL-68(In) is preferably (0.6-1.8):1, more preferably 1.2:1.

[0035] S2: Transfer the above ultrasonic-treated mixture to a reaction kettle, statically heat it to 50 °C - 90 °C for reaction for 4 - 8 hours, preferably heat it to 60 °C for reaction for 6 hours, filter, wash, and vacuum-dry the obtained solid to obtain a composite material of Ag nanoparticles loaded on MIL-68(In), denoted as Ag@MIL-68(In). The loading amount of Ag in the Ag@MIL-68(In) is preferably 1.0 - 4.5 mmol / g, more preferably 1.39 - 4.25 mmol / g.

[0036] According to the present invention, the preparation method of the MIL-68(In) preferably includes: mixing indium nitrate hydrate and terephthalic acid with N,N-dimethylformamide solvent, stirring the mixture until it is clear and transparent at room temperature, and then putting it into an oil bath for heating, preferably heating to 125 °C for reaction for 3 hours. After the mixture is cooled to room temperature, centrifuge, wash, and vacuum-dry to obtain MIL-68(In). The mass ratio of the indium nitrate hydrate and terephthalic acid is preferably 1:1.

[0037] To make the purpose, technical solution, and advantages of the present invention clearer, the invention will be clearly and completely described below in conjunction with specific embodiments.

[0038] Example 1 Preparation of MIL-68(In)

[0039] Mix 0.30 g of indium nitrate hydrate and 0.30 g of terephthalic acid with 150 mL of N,N-dimethylformamide solvent, stir the mixture until it is clear and transparent at room temperature, and then put it into an oil bath for heating to 125 °C for reaction for 3 hours. After the mixture is cooled to room temperature, centrifuge to obtain a white solid, wash it three times with N,N-dimethylformamide and absolute ethanol respectively, and vacuum-dry it at 80 °C for 12 hours to obtain MIL-68(In). The X-ray diffraction pattern of the MIL-68(In) obtained in Example 1 is as Figure 2 shown.

[0040] Figure 4 (a - c) in [Figure number] is the scanning electron microscope image of the MIL-68(In) prepared in Example 1 of the present invention. It can be seen that the MIL-68(In) material presents a prismatic structure, proving its original crystal morphology.

[0041] Example 2 Preparation of 0.6Ag@MIL-68(In) Composite Material

[0042] Take 0.10 g of MIL-68(In) prepared in Example 1 and disperse it evenly in 8 mL of N,N-dimethylformamide. Then take 0.06 g of silver nitrate and dissolve it in 4 mL of distilled water. Slowly add the silver nitrate solution to the N,N-dimethylformamide suspension containing MIL-68(In). Subsequently, ultrasonically treat the mixed solution for 1 hour. After the ultrasonic treatment is completed, transfer the mixed solution to a reaction kettle, react at 60 °C for 6 hours, then filter to obtain a black solid. Wash it three times with N,N-dimethylformamide and anhydrous ethanol respectively, and dry it in vacuo at 80 °C for 6 hours. The obtained solid product is labeled as 0.6Ag@MIL-68(In). Detect the silver loading amount by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer), and the silver loading amount is 1.39 mmol / g. The X-ray diffraction pattern of 0.6Ag@MIL-68(In) obtained in Example 2 is as Figure 2 shown, which proves the successful preparation of the material.

[0043] Example 3 Preparation of 1.2Ag@MIL-68(In) Composite Material

[0044] Take 0.10 g of MIL-68(In) prepared in Example 1 and disperse it evenly in 8 mL of N,N-dimethylformamide. Then take 0.12 g of silver nitrate and dissolve it in 4 mL of distilled water. Slowly add the silver nitrate solution to the N,N-dimethylformamide suspension containing MIL-68(In). Subsequently, ultrasonically treat the mixed solution for 1 hour. After the ultrasonic treatment is completed, transfer the mixed solution to a reaction kettle, react at 50 °C for 8 hours, then filter to obtain a black solid. Wash it three times with N,N-dimethylformamide and anhydrous ethanol respectively, and dry it in vacuo at 80 °C for 6 hours. The obtained solid product is labeled as 1.2Ag@MIL-68(In). Detect the silver loading amount by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer), and the silver loading amount is 2.85 mmol / g. The X-ray diffraction pattern of 1.2Ag@MIL-68(In) obtained in Example 3 is as Figure 1 shown.

[0045] Figure 3 is a comparative diagram of the structural characterization of MIL-68(In) prepared in Example 1 of the present invention, 0.6Ag@MIL-68(In) prepared in Example 2, and 1.2Ag@MIL-68(In) composite material prepared in Example 3, where Figure 3 (a) is the nitrogen adsorption-desorption isotherm, Figure 3 (b) is the pore size distribution diagram; it can be seen from the figure that the MIL-68(In) material has obvious microporous characteristics, and with the increase of the Ag loading amount, the specific surface area of the material decreases.

[0046] Figure 4(d-f) are the scanning electron microscope images of 1.2Ag@MIL-68(In) prepared in Example 3 of the present invention; it can be seen from the figure that Ag nanoparticles are uniformly loaded onto the MIL-68(In) support, and the original morphological structure of MIL-68(In) is retained.

[0047] Example 4 Preparation of 1.8Ag@MIL-68(In) Composite Material

[0048] Take 0.10 g of MIL-68(In) prepared in Example 1 and disperse it evenly in 8 mL of N,N-dimethylformamide. Then take 0.18 g of silver nitrate and dissolve it in 4 mL of distilled water, and slowly add the silver nitrate solution to the N,N-dimethylformamide suspension containing MIL-68(In). Subsequently, the mixed solution is ultrasonically treated for 1 hour. After the ultrasonic treatment is completed, the mixed solution is transferred to a reaction kettle and reacted at 90 °C for 4 hours, and then filtered to obtain a black solid, which is washed three times with N,N-dimethylformamide and absolute ethanol respectively, and vacuum dried at 80 °C for 6 hours. The obtained solid product is labeled as 1.8Ag@MIL-68(In), and the silver loading amount is detected by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer), and the silver loading amount is 4.26 mmol / g.

[0049] Example 5

[0050] Add 1 mmol of N-methylaniline, 2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and 0.6Ag@MIL-68(In) catalyst prepared in Example 2 to the high-pressure reaction kettle in sequence, where the molar ratio of the catalyst dosage (calculated according to Ag) to N-methylaniline is 3:100; after the feeding is completed, continuously purge with CO2 for 1 minute to remove the residual air in the reaction kettle; then seal the reaction kettle and fill it with CO2 until the pressure reaches 1 MPa, and react at 80 °C for 6 hours. After the reaction is completed, wait for the reaction kettle to cool naturally to room temperature, and slowly release the remaining CO2 in the kettle; the catalyst is recovered by centrifugation of the reaction solution, and the liquid-phase product is analyzed by gas chromatography-mass spectrometry, and the product yield is 89%, and the selectivity is ≥99%.

[0051] Example 6

[0052] 1 mmol of N-methylaniline, 2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and 1.2 Ag@MIL-68(In) catalyst prepared in Example 3 were successively added into a high-pressure reactor, where the molar ratio of the catalyst dosage (calculated based on Ag) to N-methylaniline was 5:100; after the feeding was completed, CO2 was continuously purged for 1 minute to remove the residual air in the reactor; then the reactor was sealed and filled with CO2 until the pressure reached 1 MPa, and the reaction was carried out at 80 °C for 6 hours. After the reaction was completed, the reactor was allowed to cool naturally to room temperature, and the remaining CO2 in the reactor was slowly released; the catalyst was recovered by centrifugal separation of the reaction solution, and the liquid-phase product was analyzed by gas chromatography-mass spectrometry. The product yield was found to be 97%, and the selectivity was ≥99%.

[0053] Example 7

[0054] 1 mmol of N-methylaniline, 1.5 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and 1.8 Ag@MIL-68(In) catalyst prepared in Example 4 were successively added into a high-pressure reactor, where the molar ratio of the catalyst dosage (calculated based on Ag) to N-methylaniline was 4:100; after the feeding was completed, CO2 was continuously purged for 1 minute to remove the residual air in the reactor; then the reactor was sealed and filled with CO2 until the pressure reached 1 MPa, and the reaction was carried out at 80 °C for 6 hours. After the reaction was completed, the reactor was allowed to cool naturally to room temperature, and the remaining CO2 in the reactor was slowly released; the catalyst was recovered by centrifugal separation of the reaction solution, and the liquid-phase product was analyzed by gas chromatography-mass spectrometry. The product yield was found to be 92%, and the selectivity was ≥99%.

[0055] Example 8

[0056] 1 mmol of N-methylaniline, 2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and 1.2 Ag@MIL-68(In) catalyst prepared in Example 3 were successively added into a high-pressure reactor, where the molar ratio of the catalyst dosage (calculated based on Ag) to N-methylaniline was 5:100; after the feeding was completed, CO2 was continuously purged for 1 minute to remove the residual air in the reactor; then the reactor was sealed and filled with CO2 until the pressure reached 1 MPa, and the reaction was carried out at 90 °C for 4 hours. After the reaction was completed, the reactor was allowed to cool naturally to room temperature, and the remaining CO2 in the reactor was slowly released; the catalyst was recovered by centrifugal separation of the reaction solution, and the liquid-phase product was analyzed by gas chromatography-mass spectrometry. The product yield was found to be 96%, and the selectivity was ≥99%.

[0057] Example 9

[0058] 1 mmol of N-methylaniline, 2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and 1.2 Ag@MIL-68(In) catalyst prepared in Example 3 were successively added into a high-pressure reactor, where the molar ratio of the catalyst dosage (calculated based on Ag) to N-methylaniline was 5:100. After the addition was completed, CO2 was continuously purged for 1 minute to remove the residual air in the reactor. Subsequently, the reactor was sealed and filled with CO2 until the pressure reached 1 MPa, and the reaction was carried out at 50 °C for 8 hours. After the reaction was completed, the reactor was allowed to cool naturally to room temperature, and the remaining CO2 in the reactor was slowly released. The catalyst was recovered by centrifugation of the reaction solution, and the liquid-phase product was analyzed by gas chromatography-mass spectrometry. The product yield was found to be 83%, and the selectivity was ≥99%.

[0059] Example 10

[0060] 1 mmol of N-methylaniline, 2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and 1.2 Ag@MIL-68(In) catalyst prepared in Example 3 were successively added into a high-pressure reactor, where the molar ratio of the catalyst dosage (calculated based on Ag) to N-methylaniline was 5:100. After the addition was completed, CO2 was continuously purged for 1 minute to remove the residual air in the reactor. Subsequently, the reactor was sealed and filled with CO2 until the pressure reached 0.5 MPa, and the reaction was carried out at 80 °C for 7 hours. After the reaction was completed, the reactor was allowed to cool naturally to room temperature, and the remaining CO2 in the reactor was slowly released. The catalyst was recovered by centrifugation of the reaction solution, and the liquid-phase product was analyzed by gas chromatography-mass spectrometry. The product yield was found to be 87%, and the selectivity was ≥99%.

[0061] Example 11

[0062] 1 mmol of N-methylaniline, 1.2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and 1.2 Ag@MIL-68(In) catalyst prepared in Example 3 were successively added into a high-pressure reactor, where the molar ratio of the catalyst dosage (calculated based on Ag) to N-methylaniline was 5:100. After the addition was completed, CO2 was continuously purged for 1 minute to remove the residual air in the reactor. Subsequently, the reactor was sealed and filled with CO2 until the pressure reached 1.5 MPa, and the reaction was carried out at 80 °C for 6 hours. After the reaction was completed, the reactor was allowed to cool naturally to room temperature, and the remaining CO2 in the reactor was slowly released. The catalyst was recovered by centrifugation of the reaction solution, and the liquid-phase product was analyzed by gas chromatography-mass spectrometry. The product yield was found to be 94%, and the selectivity was ≥99%.

[0063] Example 12

[0064] 1 mmol of N-methylaniline, 3 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and 1.2 g of Ag@MIL-68(In) catalyst prepared in Example 3 were successively added to a high-pressure reactor, where the molar ratio of the catalyst dosage (calculated as Ag) to N-methylaniline was 6:100. After feeding, CO2 was continuously purged for 1 minute to remove the residual air in the reactor. Subsequently, the reactor was sealed and filled with CO2 to a pressure of 1 MPa, and the reaction was carried out at 50 °C for 8 hours. After the reaction, the reactor was allowed to cool naturally to room temperature, and the remaining CO2 in the reactor was slowly released. The catalyst was recovered by centrifugation of the reaction solution, and the liquid-phase product was analyzed by gas chromatography-mass spectrometry. The product yield was 92%, and the selectivity was ≥99%.

[0065] Example 13

[0066] 1 mmol of N-methylaniline, 2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and 1.2 g of Ag@MIL-68(In) catalyst prepared in Example 3 were successively added to a high-pressure reactor, where the molar ratio of the catalyst dosage (calculated as Ag) to N-methylaniline was 8:100. After feeding, CO2 was continuously purged for 1 minute to remove the residual air in the reactor. Subsequently, the reactor was sealed and filled with CO2 to a pressure of 0.5 MPa, and the reaction was carried out at 60 °C for 8 hours. After the reaction, the reactor was allowed to cool naturally to room temperature, and the remaining CO2 in the reactor was slowly released. The catalyst was recovered by centrifugation of the reaction solution, and the liquid-phase product was analyzed by gas chromatography-mass spectrometry. The product yield was 93%, and the selectivity was ≥99%.

[0067] Example 14

[0068] The specific experimental procedures and detection methods were the same as those in Example 6, except that N-methylaniline was replaced with different organic amine substrates, and the reaction time and temperature were adjusted to carry out the N-formylation reaction with carbon dioxide respectively. The results are shown in Table 1.

[0069] Table 1 Investigation of the reactant scope of 1.2Ag@MIL-68(In) catalyst

[0070]

[0071] Example 15

[0072] The specific experimental conditions and procedures were the same as those in Example 6. After the reaction was completed, the catalyst 1.2Ag@MIL-68(In) was recovered by centrifugation. After washing with absolute ethanol and drying, the recovered catalyst was used to conduct 5-cycle experiments under the same conditions. The obtained results are shown in Table 2. The structural characterizations of the fresh 1.2Ag@MIL-68(In) composite material and the material after 5 cycles were compared. The comparison diagrams are as shown in the appended Figure 5 the specification, where Figure 5 (a) is the infrared spectrum diagram, Figure 5 (b) is the CO2 cyclic adsorption isotherm; Figure 5 (c) is the powder X-ray diffraction pattern. It is proved that the catalyst has good cyclic stability.

[0073] Table 2 Results of the catalyst reuse experiment

[0074]

[0075]

[0076] Preparation of 0.3Ag@MIL-68(In) composite material in Comparative Example 1

[0077] Take 0.10 g of MIL-68(In) and disperse it evenly in 8 mL of N,N-dimethylformamide. Then take 0.03 g of silver nitrate and dissolve it in 4 mL of distilled water. Slowly add the silver nitrate solution to the N,N-dimethylformamide suspension containing MIL-68(In). Subsequently, ultrasonically treat the mixed solution for 1 hour. After the ultrasonic treatment is completed, transfer the mixed solution to a reaction kettle, react at 60 °C for 6 hours, and then filter to obtain a black solid. Wash it three times with N,N-dimethylformamide and absolute ethanol respectively, and dry it in vacuum at 80 °C for 6 hours. The obtained solid product is labeled as 0.3Ag@MIL-68(In). The silver loading amount is detected by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer), and the silver loading amount is 0.64 mmol / g.

[0078] Preparation of 2.4Ag@MIL-68(In) composite material in Comparative Example 2

[0079] Take 0.10 g of MIL-68(In) and disperse it evenly in 8 mL of N,N-dimethylformamide. Then take 0.24 g of silver nitrate and dissolve it in 4 mL of distilled water. Slowly add the silver nitrate solution to the N,N-dimethylformamide suspension containing MIL-68(In). Subsequently, ultrasonically treat the mixed solution for 1 hour. After the ultrasonic treatment, transfer the mixed solution to a reaction kettle, react at 60 °C for 6 hours, then filter to obtain a black solid. Wash it three times with N,N-dimethylformamide and anhydrous ethanol respectively, and dry it under vacuum at 80 °C for 6 hours. The obtained solid product is labeled as 2.4Ag@MIL-68(In). Detect the silver loading amount by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer), and the silver loading amount is 5.75 mmol / g.

[0080] Comparative Example 3

[0081] Add 1 mmol of N-methylaniline, 2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and 0.3Ag@MIL-68(In) catalyst prepared in Comparative Example 1 to the autoclave in sequence. The molar ratio of the catalyst (calculated by Ag) to N-methylaniline is 5:100. After feeding, continuously purge with CO2 for 1 minute to remove the residual air in the autoclave. Then seal the autoclave and fill it with CO2 until the pressure reaches 1 MPa, and react at 80 °C for 6 hours. After the reaction, wait for the autoclave to cool naturally to room temperature, and slowly release the remaining CO2 in the autoclave. The catalyst is recovered by centrifugal separation of the reaction solution, and the liquid-phase product is analyzed by gas chromatography-mass spectrometry. The product yield is 62%, and the selectivity is ≥99%.

[0082] Comparative Example 4

[0083] Add 1 mmol of N-methylaniline, 2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and 2.4Ag@MIL-68(In) catalyst prepared in Comparative Example 2 to the autoclave in sequence. The molar ratio of the catalyst (calculated by Ag) to N-methylaniline is 5:100. After feeding, continuously purge with CO2 for 1 minute to remove the residual air in the autoclave. Then seal the autoclave and fill it with CO2 until the pressure reaches 1 MPa, and react at 80 °C for 6 hours. After the reaction, wait for the autoclave to cool naturally to room temperature, and slowly release the remaining CO2 in the autoclave. The catalyst is recovered by centrifugal separation of the reaction solution, and the liquid-phase product is analyzed by gas chromatography-mass spectrometry. The product yield is 71%, and the selectivity is ≥99%.

[0084] Comparative Example 5 (using MIL-68(In) alone)

[0085] 1 mmol of N-methylaniline, 2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and MIL-68(In) prepared in Example 1 were successively added to a high-pressure reactor, where the molar ratio of MIL-68(In) to N-methylaniline was 3:100 (calculated according to In, with the same In content as the catalyst used in Example 6); after the addition was completed, CO2 was continuously purged for 1 minute to remove the residual air in the reactor; then the reactor was sealed and filled with CO2 until the pressure reached 1 MPa, and the reaction was carried out at 80 °C for 6 hours. After the reaction was completed, the reactor was allowed to cool naturally to room temperature, and the remaining CO2 in the reactor was slowly released; the catalyst was recovered by centrifugation of the reaction solution, and the liquid-phase product was analyzed by gas chromatography-mass spectrometry. The product yield was 46%, and the selectivity was ≥99%.

[0086] Comparative Example 6 (using silver nanoparticles alone)

[0087] 1 mmol of N-methylaniline, 2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and silver nanoparticles were successively added to a high-pressure reactor, where the molar ratio of silver nanoparticles (calculated according to Ag) to N-methylaniline was 5:100; after the addition was completed, CO2 was continuously purged for 1 minute to remove the residual air in the reactor; then the reactor was sealed and filled with CO2 until the pressure reached 1 MPa, and the reaction was carried out at 80 °C for 6 hours. After the reaction was completed, the reactor was allowed to cool naturally to room temperature, and the remaining CO2 in the reactor was slowly released; the catalyst was recovered by centrifugation of the reaction solution, and the liquid-phase product was analyzed by gas chromatography-mass spectrometry. The product yield was 33%, and the selectivity was ≥99%.

[0088] Comparative Example 7 (physical mixture catalyst of MIL-68(In) and silver nanoparticles)

[0089] 0.05 mol of silver nanoparticles and 0.03 mol (calculated as In) of MIL-68(In) prepared in Example 1 were mixed evenly in 2 mL of N,N-dimethylformamide solvent.

[0090] 1 mmol of N-methylaniline, 2 mmol of phenylsilane, 2 mL of N,N-dimethylformamide solvent and a physical mixture catalyst of silver nanoparticles / MIL-68(In) were successively added into a high-pressure reactor, wherein the molar ratio of silver nanoparticles (calculated as Ag) to N-methylaniline was 5:100, and the molar ratio of MIL-68(In) (calculated as In) to N-methylaniline was 3:100; after the feeding was completed, CO2 was continuously purged for 1 minute to remove the residual air in the reactor; then the reactor was sealed and filled with CO2 until the pressure reached 1 MPa, and the reaction was carried out at 80 °C for 6 hours. After the reaction was completed, the reactor was allowed to cool naturally to room temperature, and the remaining CO2 in the reactor was slowly released; the catalyst was recovered by centrifugal separation of the reaction solution, and the liquid-phase product was analyzed by gas chromatography-mass spectrometry, and the product yield was 62%, and the selectivity was ≥99%.

[0091] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for catalyzing the N-formylation of organic amines and carbon dioxide using a MIL-68 (In)-loaded Ag nanoparticle material, characterized in that: The method uses carbon dioxide and organic amine as reaction raw materials, Ag@MIL-68(In) as a catalyst, and phenylsilane as a reducing agent to react the organic amine with carbon dioxide to synthesize formamide compounds.

2. The method for N-formylation of organic amines and carbon dioxide catalyzed by MIL-68 (In)-loaded Ag nanoparticle material according to claim 1, characterized in that: The preparation method of Ag@MIL-68(In) comprises the following steps: S1: Disperse MIL-68(In) uniformly in a solvent to obtain a suspension A; add silver nitrate to distilled water and stir until completely dissolved to obtain a solution B; slowly add the solution B to the suspension A and perform ultrasonic treatment on the obtained mixture; S2: The mixed solution after the ultrasonic treatment is transferred to a reactor, statically heated to 50°C-90°C for reaction for 4-8 hours, and the obtained solid is filtered, washed, and vacuum dried to obtain a composite material of MIL-68(In) loaded with Ag nanoparticles, marked as Ag@MIL-68(In).

3. The method for N-formylation of organic amines and carbon dioxide catalyzed by MIL-68 (In)-loaded Ag nanoparticle material according to claim 2, characterized in that: The loading amount of Ag in the Ag@MIL-68(In) is 1.0-4.5 mmol / g.

4. The method for N-formylation of organic amines and carbon dioxide catalyzed by MIL-68 (In)-loaded Ag nanoparticle material according to claim 2, characterized in that: In the step S1, the mass ratio of silver nitrate to MIL-68 (In) is (0.6-1.8):

1.

5. The method for N-formylation of organic amines and carbon dioxide catalyzed by MIL-68 (In)-loaded Ag nanoparticle material according to claim 2, characterized in that: The time for ultrasonic treatment of the mixed solution in step S1 is 0.5-2 hours.

6. The method for N-formylation of organic amines and carbon dioxide catalyzed by MIL-68 (In)-loaded Ag nanoparticle material according to claim 2, characterized in that: The solvent in step S1 is N,N-dimethylformamide.

7. The method for N-formylation of organic amines and carbon dioxide catalyzed by MIL-68 (In)-loaded Ag nanoparticle material according to claim 2, characterized in that: The S2 is statically heated to 60° C. for reaction for 6 hours.

8. The method for N-formylation of organic amines and carbon dioxide catalyzed by MIL-68 (In)-loaded Ag nanoparticle material according to claim 1, characterized in that: The structural formula of the organic amine is as follows:

9. The method for N-formylation of organic amines and carbon dioxide catalyzed by MIL-68 (In)-loaded Ag nanoparticle material according to claim 1, characterized in that: The molar ratio of the organic amine, phenylsilane and Ag in the Ag@MIL-68(In) catalyst is 1:(1.2-3):(0.03-0.08).

10. The method for N-formylation of organic amines and carbon dioxide catalyzed by MIL-68 (In)-loaded Ag nanoparticle material according to claim 2, characterized in that: The N-formylation reaction temperature is 50-90° C., the reaction pressure is 0.5-1.5 MPa, and the reaction time is 4-8 hours.

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