A heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst and its preparation and application

Abstract

The present invention discloses a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst and its preparation and application. The method comprises: placing a brominated nitrogen-containing ligand, an organoboron reagent, and a supported ruthenium catalyst in an organic solvent in the presence of an alkaline substance and a palladium catalyst, and subjecting the brominated nitrogen-containing ligand and the organoboron reagent to a Suzuki coupling reaction on the surface of the supported ruthenium catalyst at 80 to 150°C under inert gas conditions to obtain the heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst. The present invention solves the problems of low activity and poor stability of existing heterogeneous catalysts. The present invention precisely adjusts the electron cloud density and steric hindrance of the ruthenium center through heterogeneous nitrogen-containing ligands, thereby improving the activity and selectivity of the ruthenium catalyst; the coordination effect between the heterogeneous nitrogen-containing ligand and the active component ruthenium avoids the loss of the active component and improves the stability of the catalyst. Compared with the existing technology, the method of the present invention is simple and effective, with strong controllability and practicality, and is suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to a supported ruthenium catalyst, in particular to a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst and its preparation and application. Background Art

[0002] Carbon dioxide is a major component of the atmosphere and the final oxidation / combustion product of carbon and carbon-containing compounds. With the rapid development of human society and the extensive use of fossil energy, the current atmospheric CO2 concentration is 147% higher than pre-industrial levels, triggering a series of major environmental issues such as global warming, sea level rise, and ocean acidification. The greenhouse effect has attracted widespread attention worldwide, and CO2 is the primary culprit. Furthermore, CO2 is an important C1 resource, offering advantages such as safety, non-toxicity, low cost, and high availability, as well as being renewable. Therefore, converting CO2 into high-value-added chemical products, such as alkanes, alkenes, alcohols, acids, epoxides, and formamide, has practical significance for mitigating global warming and reducing dependence on fossil fuels.

[0003] Among the numerous pathways for high-value carbon dioxide utilization, N-formamides are a key class of compounds, widely used in the synthesis of natural products, pharmaceuticals, and pesticides. N,N-dimethylformamide (DMF), a key platform compound with an annual production of approximately 1 million tons, serves as a vital chemical raw material, a versatile reaction solvent, and an excellent chemical intermediate. Given that hydrogen (H2) is the cleanest reducing agent, the direct reaction of CO2 and H2 with amines to prepare various N-formamides is undoubtedly a green and environmentally friendly approach. While homogeneous N-formylation reactions offer high activity, high selectivity, and mild reaction conditions, homogeneous catalysts are difficult to separate and reuse, and ligand synthesis is challenging. In contrast, catalysts in heterogeneous N-formylation reactions are easily separated and recyclable. Recently, existing document 1 (Chem. Commun., 2014, 50, 189) discloses a heterogeneous Al2O3 nanorod (Al2O3-NR) loaded Pd catalyst, document 2 (Chinese J. Catal., 2019, 40, 1141.) discloses a palladium catalyst Pd / PAL loaded on a attapulgite (PAL), document 3 (Chem. Commun., 2014, 50, 9138.) TiO2 loaded Ir catalyst, and document 4 (Chem. Commun., 2010, 46, 5770) discloses a method for preparing formamide compounds by hydrogenation of carbon dioxide catalyzed by Cu / ZnO. The activity of these heterogeneous catalysts is relatively low, and the stability of the catalyst needs to be further improved. Therefore, for the purpose of industrial application, there is a strong demand for the development of highly active, highly selective, and highly stable heterogeneous carbon dioxide hydrogenation catalysts for preparing N-formamide compounds. Summary of the Invention

[0004] The purpose of the present invention is to provide a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst and its preparation and application, which solves the problems of low activity and poor stability of existing heterogeneous catalysts.

[0005] In order to achieve the above object, the present invention provides a method for preparing a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst, the method comprising:

[0006] The brominated nitrogen-containing ligand, organic boron reagent and supported ruthenium catalyst are placed in an organic solvent under the action of an alkaline substance and a palladium catalyst, and the brominated nitrogen-containing ligand and the organic boron reagent undergo a Suzuki coupling reaction on the surface of the supported ruthenium catalyst at 80-150° C. under inert gas conditions to obtain the heterogeneous nitrogen-containing ligand modified supported ruthenium catalyst; the brominated nitrogen-containing ligand is 4,4'-dibromo-2,2'-bipyridine, 3,8-dibromo-1,10-phenanthroline, 5,5'-dibromo-1,10-phenanthroline, Any one of bromo-2,2'-bipyridine and 2,4,6-tris(4-bromophenyl)-1,3,5-triazine; the organic boron reagent is any one of 1,4-phenyldiboronic acid, 1,4-phenyldiboronic acid bis(pinacol) ester, 1,4-phenyldiboronic acid bis(neopentyl glycol) ester, 1,3,5-phenyltriboronic acid tris(pinacol) ester, anthracene-9,10-diboronic acid dipinacol ester, 4,4'-biphenyldiboronic acid, and 4,4'-biphenyldiboronic acid bis(pinacol) ester.

[0007] Preferably, the supported ruthenium catalyst is any one or more of SiO2, Al2O3, TiO2, CeO2, Fe2O3, activated carbon and MCM-41 molecular sieve carrier supported ruthenium catalyst; the palladium catalyst is any one of Pd(PPh3)2Cl2, Pd(PPh3)4, Pd(MeCN)2Cl2, Pd(dppf)Cl2, Pd(OAc)2, PdCl2, Pd(TFA)2, Pd(acac)2.

[0008] More preferably, the palladium catalyst is Pd(PPh3)2Cl2 or Pd(PPh3)4, Pd(MeCN)2Cl2; the organic boron reagent is 1,4-phenylenediboronic acid or 1,4-phenylenediboronic acid bis(pinacol) ester; and the supported ruthenium catalyst is SiO2 or Al2O3 supported ruthenium catalyst.

[0009] Preferably, the alkaline substance is any one or more of potassium carbonate, cesium carbonate, sodium hydroxide, and sodium carbonate; and the mass of the alkaline substance is 0.5 to 5 times the mass of the brominated nitrogen-containing ligand.

[0010] Preferably, the organic solvent is any one or two of dimethyl sulfoxide, N,N-dimethylformamide, dioxane, tetrahydrofuran, acetonitrile, and isopropanol; and the mass of the organic solvent is 2 to 20 times the mass of the supported ruthenium catalyst.

[0011] Preferably, the mass ratio of the supported ruthenium catalyst to the brominated nitrogen-containing ligand is 1:(0.10-1), and the molar ratio of the brominated nitrogen-containing ligand to the organoboron reagent is 1:(0.5-2). The ratio of the supported ruthenium catalyst to the brominated nitrogen-containing ligand and organoboron reagent affects the thickness of the heterogeneous ligand on the supported ruthenium catalyst. If the brominated nitrogen-containing ligand is too thick, it will completely cover the active sites, which is not conducive to its catalytic performance in the hydrogenation of carbon dioxide to formamide. On the other hand, if the brominated nitrogen-containing ligand is too thin, it will not be able to fully modify the supported ruthenium, which is also not conducive to its catalytic performance in the hydrogenation of carbon dioxide to formamide.

[0012] Preferably, the amount of the palladium catalyst is 0.5-10% of the amount of the brominated nitrogen-containing ligand. The amount of the palladium catalyst affects the polymerization reaction of the brominated nitrogen-containing ligand and the organoboron reagent. The more the amount of palladium catalyst, the better the polymerization effect.

[0013] The present invention provides a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst prepared by the method.

[0014] The present invention provides a use of the heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst in catalyzing the reaction of amines with carbon dioxide and hydrogen to prepare N-formamide compounds, wherein the amine has a structure as shown in formula (I):

[0015]

[0016] In formula (I), R 1 、R 2 are independently selected from hydrogen, substituted or unsubstituted C1-C 20 Alkyl, substituted or unsubstituted C4~C 10 Cycloalkyl, substituted or unsubstituted C6~C 24 Aryl or heteroaryl, substituted or unsubstituted C7~C 25 Arylalkyl or heteroarylalkyl, -(CH2) n -OR 3 and -(CH2) n0 -NR 4 R 5 Any one of, or R 1 、R 2 Ring; among them, R 1 、R 2 are not hydrogen at the same time; n and n0 are both integers from 1 to 8; R 3Selected from hydrogen, substituted or unsubstituted C1-C 20 Alkyl, substituted or unsubstituted C6~C 24 Aryl and substituted or unsubstituted C7~C 25 Any of arylalkyl or heteroaryl; R 4 、R 5 are independently selected from hydrogen, substituted or unsubstituted C1-C 20 Alkyl, substituted or unsubstituted C3~C 10 Cycloalkyl, substituted or unsubstituted C6~C 24 Aryl and substituted or unsubstituted C7~C 25 Any of arylalkyl or heteroaryl.

[0017] When R 1 、R 2 After ring formation, the amine is any one of the following structures:

[0018]

[0019] In formulae (II) to (V), n1, n2, n3, n4 and n5 are all integers of 1 to 10, and X is O or N.

[0020] Preferably, in formula (I), the R 1 、R 2 are independently selected from hydrogen, substituted or unsubstituted C1-C 16 Alkyl, substituted or unsubstituted C4~C8 cycloalkyl, substituted or unsubstituted C6~C 16 Aryl or heteroaryl, substituted or unsubstituted C7~C 16 Arylalkyl or heteroarylalkyl, -(CH2) n -OR 3 and -(CH2) n0 -NR 4 R 5 Any one of; said n, n0 are integers of 1 to 6; said R 3 Selected from hydrogen, substituted or unsubstituted C1-C 16 Alkyl, substituted or unsubstituted C6~C 16 Aryl and substituted or unsubstituted C7~C 16 Any one of arylalkyl or heteroaryl; said R 4 、R 5 are independently selected from hydrogen, substituted or unsubstituted C1-C 16 Alkyl, substituted or unsubstituted C3~C8 cycloalkyl, substituted or unsubstituted C6~C 16 Aryl and substituted or unsubstituted C7~C 16Any of arylalkyl or heteroaryl;

[0021] In formulae (II) to (III), n1 and n2 are integers of 1 to 6; in formulae (IV) to (V), n3, n4 and n5 are integers of 1 to 3.

[0022] More preferably, in formula (I), the R 1 、R 2 are independently selected from hydrogen, substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C4~C6 cycloalkyl, substituted or unsubstituted C6~C 12 Aryl or heteroaryl, substituted or unsubstituted C7~C 12 Arylalkyl or heteroarylalkyl, -(CH2) n -OR 3 and -(CH2) n0 -NR 4 R 5 Any one of; said n, n0 are integers of 1 to 4; said R 3 Selected from hydrogen, substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C6~C 10 Aryl and substituted or unsubstituted C7~C 10 Any one of arylalkyl or heteroaryl; said R 4 、R 5 are independently selected from hydrogen, substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C3~C6 cycloalkyl, substituted or unsubstituted C6~C 10 Aryl and substituted or unsubstituted C7~C 10 Any of arylalkyl or heteroaryl;

[0023] In formulae (II) to (III), n1 and n2 are both integers of 4; in formulae (IV) to (V), n3, n4 and n5 are all integers of 2.

[0024] The heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst of the present invention and its preparation and application solve the problems of low activity and poor stability of existing heterogeneous catalysts and have the following advantages:

[0025] 1. The present invention precisely adjusts the electron cloud density and steric hindrance of the ruthenium center through heterogeneous nitrogen-containing ligands, thereby improving the activity and selectivity of the ruthenium catalyst.

[0026] 2. The coordination effect between the heterogeneous nitrogen-containing ligand and the active component ruthenium avoids the loss of active components, improves the stability of the catalyst, and has good reusability.

[0027] 3. Compared with the existing technology, the method of the present invention is simple and effective, has strong controllability and practicality, and is suitable for industrial production. DETAILED DESCRIPTION

[0028] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0029] Example 1

[0030] A method for preparing a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst, the method comprising:

[0031] (1) Add 5 mL of methanol to 1.0 g of alumina and stir for 30 min. Add 1.0 mL of 5 mg / mL RuCl3 methanol solution, stir at room temperature for 24 h, dry at 80°C for 12 h, calcine at 500°C for 4 h, and reduce at 400°C in a hydrogen atmosphere for 3 h to obtain alumina-supported ruthenium catalyst Ru / Al2O3.

[0032] (2) 0.5 g of Ru / Al2O3, 3,8-dibromo-1,10-phenanthroline (34 mg, 0.1 mmol), 1,3,5-benzenetriboronic acid tripinacol ester (46 mg, 0.1 mmol), and Pd(PPh3)4 (12 mg, 0.01 mmol) were added to a 100 mL sealed tube, and then 10 mL of dioxane and 1 mL of 2 M K2CO3 solution were added. The tube was evacuated and filled with nitrogen for protection. The reaction was carried out in an oil bath at 100 °C for 24 h. After the reaction was completed, the obtained solid was filtered, repeatedly washed with DMF, water and methanol, and dried in vacuum at 60 °C for 12 h to obtain a nitrogen-containing ligand-modified supported ruthenium catalyst, which was recorded as catalyst A.

[0033] Example 2

[0034] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0035] In step (2), 3,8-dibromo-1,10-phenanthroline (34 mg, 0.1 mmol) was replaced with 5,5'-dibromo-2,2'-bipyridine (25 mg, 0.08 mmol);

[0036] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst B.

[0037] Example 3

[0038] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0039] In step (2), 3,8-dibromo-1,10-phenanthroline (34 mg, 0.1 mmol) was replaced with 4,4′-dibromo-2,2′-bipyridine (47 mg, 1.5 mmol);

[0040] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst C.

[0041] Example 4

[0042] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0043] In step (2), 1,3,5-phenyltriboronic acid tripinacol ester (46 mg, 0.1 mmol) was replaced with 1,4-phenyldiboronic acid (33 mg, 0.2 mmol);

[0044] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst D.

[0045] Example 5

[0046] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0047] In step (2), 1,3,5-benzenetriboronic acid tripinacol ester (46 mg, 0.1 mmol) was replaced with 1,4-phenyldiboronic acid bis(pinacol) ester (50 mg, 0.15 mmol);

[0048] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst E.

[0049] Example 6

[0050] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0051] In step (2), 1,3,5-phenyltriboronic acid trispinacol ester (46 mg, 0.1 mmol) was replaced with 4,4'-biphenyldiboronic acid bis(pinacol ester) (24 mg, 0.06 mmol);

[0052] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst F.

[0053] Example 7

[0054] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0055] In step (2), the catalyst Pd(PPh3)4 (12 mg, 0.01 mmol) was replaced with Pd(PPh3)2Cl2 (14 mg, 0.02 mmol);

[0056] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst G.

[0057] Example 8

[0058] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0059] In step (2), the catalyst Pd(PPh3)4 (12 mg, 0.01 mmol) was replaced with Pd(OAc)2 (11 mg, 0.05 mmol);

[0060] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst H.

[0061] Example 9

[0062] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0063] In step (2), the base 1 mL 2M K2CO3 was replaced with 1 mL 2M Cs2CO3;

[0064] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst I.

[0065] Example 10

[0066] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0067] In step (2), 1 mL of 2 M K2CO3 was replaced with 1 mL of 2 M KOH;

[0068] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst J.

[0069] Example 11

[0070] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0071] In step (2), 10 mL of dioxane was replaced with 5 mL of tetrahydrofuran;

[0072] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst K.

[0073] Example 12

[0074] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0075] In step (2), 10 mL of dioxane was replaced with 15 mL of acetonitrile;

[0076] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst L.

[0077] Example 13

[0078] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0079] In step (2), the reaction at 100°C for 24 h was replaced with the reaction at 80°C for 36 h;

[0080] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst M.

[0081] Example 14

[0082] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0083] In step (2), the reaction at 100°C for 24 h was replaced with the reaction at 130°C for 12 h;

[0084] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst N.

[0085] Example 15

[0086] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0087] In step (2), 1.0 g of alumina was replaced with 1.0 g of silica;

[0088] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst O.

[0089] Example 16

[0090] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0091] In step (2), 1.0 g of aluminum oxide was replaced with 1.0 g of titanium dioxide;

[0092] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst O.

[0093] Example 17

[0094] The preparation method of a heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst is basically the same as that in Example 1, except that:

[0095] In step (2), 1.0 g of alumina was replaced with 1.0 g of MCM-41 molecular sieve;

[0096] The same operation as in Example 1 was followed to prepare a nitrogen-containing ligand-modified supported ruthenium catalyst, which was designated as Catalyst O.

[0097] Comparative Example 1

[0098] A method for preparing a supported ruthenium catalyst, the method comprising:

[0099] To 1.0 g of alumina, 5 mL of methanol was added and stirred for 30 min. 1.0 mL of 5 mg / mL RuCl3 methanol solution was added and stirred at room temperature for 24 h. The mixture was dried at 80°C for 12 h, calcined at 500°C for 4 h, and reduced under a hydrogen atmosphere at 400°C for 3 h to obtain an alumina-supported ruthenium catalyst Ru / Al2O3, which was designated as comparative catalyst A.

[0100] Comparative Example 2

[0101] The preparation method of a supported ruthenium catalyst is basically the same as that of Comparative Example 1, except that:

[0102] 1.0 g of aluminum oxide was replaced with 1.0 g of silicon dioxide; and the same operation as in Comparative Example 1 was performed to obtain a silicon oxide-supported ruthenium catalyst Ru / SiO2, which was designated as Comparative Catalyst B.

[0103] Experimental Example 1 Testing the performance of the catalyst

[0104] The catalysts prepared in Examples 1 to 15 and Comparative Examples 1 to 2 were used for N-formylation of dimethylamine with carbon dioxide and hydrogen, respectively, to test the catalytic performance of the catalysts. The specific testing process is as follows:

[0105] An experimental group and a control group were set up, wherein 15 experiments were set up in the experimental group in sequence, and in each experiment, 2.68 g (20 mmol, equivalent to 40 mmol dimethylamine) of dimethylammonium·dimethyl (DIMCARB), 4 mL of methanol and any one of the catalysts prepared in Examples 1 to 15 were added to a 100 mL high-pressure reactor equipped with a magnetic stirrer, and no repetition was performed. After the high-pressure reactor was sealed, it was replaced with carbon dioxide gas 3 times, and then 3 MPa of carbon dioxide was filled into the high-pressure reactor, and then 3 MPa of hydrogen was filled into the high-pressure reactor to a total pressure of 6 MPa, and then the reaction was carried out at 140° C. for 24 h; 2 experiments were set up in the control group in sequence, and the catalysts prepared in Comparative Examples 1 to 2 were added to each experiment, and the other experimental conditions were the same as those of the experimental group; after the reaction, the reactor was cooled to room temperature and the pressure was slowly released, 20 mL of methanol was added, and then trimethoxybenzene (336 mg, 2 mmol) was added to the reaction system as 1 The internal standard of H NMR analysis was used to determine the yield. The catalytic performance results of the catalysts are detailed in Table 1.

[0106] Table 1 Catalytic performance of the catalysts prepared in Examples 1-15 and Comparative Examples 1-2 in the N-formylation reaction of dimethylamine with CO2 / H2

[0107]

[0108] As shown in Table 1, the heterogeneous nitrogen-containing ligand-modified supported ruthenium catalysts prepared in different Examples exhibited moderate to excellent catalytic performance in the N-formylation reaction of amines with carbon dioxide and hydrogen. The brominated nitrogen-containing ligand, organoboron reagent, palladium catalyst, solvent, base, temperature, and pressure all had varying degrees of influence on catalyst performance. Changes in these conditions affected the polymerization reaction of the heterogeneous nitrogen-containing ligands on the surface of the supported ruthenium catalyst, forming heterogeneous nitrogen-containing ligands with different structures on the surface of the supported ruthenium catalyst. Therefore, these heterogeneous nitrogen-containing ligand-modified supported ruthenium catalysts exhibited different catalytic activities. The catalyst prepared in Example 8 showed lower catalytic results, possibly because Pd(OAc)2 did not perform as well as Pd(PPh3)4 in catalyzing the polymerization reaction of brominated nitrogen-containing ligands and organoboron reagents, affecting the modification of the nitrogen-containing ligands on the catalyst surface. Furthermore, compared with the comparative examples, the catalytic performance of the heterogeneous nitrogen-containing ligand-modified supported ruthenium catalysts prepared in the present invention in the N-formylation reaction of amines with carbon dioxide and hydrogen was significantly improved.

[0109] Experimental Example 2 Testing the Reusability of Catalysts

[0110] The reusability of the catalyst prepared in Example 1 in catalyzing the N-formylation reaction of dimethylamine with CO2 / H2 was tested. The specific testing process is as follows:

[0111] In a 100 mL autoclave equipped with a magnetic stirrer, 2.68 g (20 mmol, equivalent to 40 mmol of dimethylamine) of dimethylammonium·dimethyl (DIMCARB), 4 mL of methanol, and 40 mg of the catalyst prepared in Example 1 were added. The autoclave was sealed and replaced with CO2 gas three times. 3 MPa of CO2 and 3 MPa of H2 were then introduced and reacted at 140°C for 24 h. After the reaction, the autoclave was cooled to room temperature and the pressure was slowly released. 20 mL of methanol was added to dilute the reaction mixture, and 336 mg (2 mmol) of mesitylene was added as a catalyst. 1 The yield was determined using an internal standard for H NMR analysis. The reaction solution was transferred to a centrifuge tube and centrifuged to obtain the catalyst. The catalyst was washed three times with 8 mL of methanol and once with 8 mL of acetone. After air-drying at room temperature, it was directly placed in an autoclave for reuse. The performance results of the reused catalyst are detailed in Table 2.

[0112] Table 2 Reusability of catalyst A in Example 1 in the N-formylation reaction of dimethylamine with CO2 / H2

[0113]

[0114] It can be seen from Table 2 that the catalyst A prepared in Example 1 of the present invention can be reused ten times, and during the repeated use, it still has the same catalytic activity as that of the initial use.

[0115] Experimental Example 3-15: Testing the Performance of Catalysts in N-Formylation of Different Amines with CO2 / H2

[0116] The experimental procedures for Example 3-15 were essentially the same as those for Example 1, except that 40 mmol of dimethylammonium dimethyl was replaced with 20 mmol of different amines (the specific names of the different amines are shown in Table 3), and the mass of Catalyst A was reduced from 40 mg to 20 mg. Specific reaction results are detailed in Table 3.

[0117] Table 3 Catalytic performance of catalyst A in the N-formylation reaction of different amines with CO2 / H2 Example 1

[0118]

[0119]

[0120] As can be seen from Table 3, the catalyst A prepared in Example 1 of the present invention can be applied to the N-formylation reaction of different amines with CO2 / H2, and exhibits high catalytic activity.

[0121] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst for catalyzing the reaction of amines with carbon dioxide and hydrogen to prepare N-formamide compounds, characterized in that: The amine has a structure as shown in formula (I): In formula (I), R 1 、R 2 are independently selected from hydrogen, substituted or unsubstituted C1-C 20 Alkyl, substituted or unsubstituted C4~C 10 Cycloalkyl, substituted or unsubstituted C6~C 24 Aryl or heteroaryl, substituted or unsubstituted C7~C 25 Arylalkyl or heteroarylalkyl, -(CH2) n -OR 3 and -(CH2)n0-NR 4 R 5 Any one of, or R 1 、R 2 Ring; among them, R 1 、R 2 Not simultaneously hydrogen; n and n0 are both integers from 1 to 8; R 3 Selected from hydrogen, substituted or unsubstituted C1-C 20 Alkyl, substituted or unsubstituted C6~C 24 Aryl and substituted or unsubstituted C7~C 25 Any of arylalkyl or heteroaryl; R 4 、R 5 are independently selected from hydrogen, substituted or unsubstituted C1-C 20 Alkyl, substituted or unsubstituted C3~C 10 Cycloalkyl, substituted or unsubstituted C6~C 24 Aryl and substituted or unsubstituted C7~C 25 Any of arylalkyl or heteroaryl; When R 1 、R 2 After ring formation, the amine is any one of the following structures: In formulas (II) to (V), n1, n2, n3, n4 and n5 are integers of 1 to 10, and X is O or N; The preparation method of the heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst comprises: The brominated nitrogen-containing ligand, the organoboron reagent and the supported ruthenium catalyst are placed in an organic solvent in the presence of an alkaline substance and a palladium catalyst, and the brominated nitrogen-containing ligand and the organoboron reagent undergo a Suzuki coupling reaction on the surface of the supported ruthenium catalyst at 80-150° C. under inert gas conditions to obtain the heterogeneous nitrogen-containing ligand-modified supported ruthenium catalyst; The brominated nitrogen-containing ligand is any one of 4,4'-dibromo-2,2'-bipyridine, 3,8-dibromo-1,10-phenanthroline, 5,5'-dibromo-2,2'-bipyridine, and 2,4,6-tris(4-bromophenyl)-1,3,5-triazine; The organic boron reagent is any one of 1,4-phenylenediboronic acid, 1,4-phenylenediboronic acid bis(pinacol) ester, 1,4-phenylenediboronic acid bis(neopentyl glycol) ester, 1,3,5-phenyltriboronic acid tripinacol ester, anthracene-9,10-diboronic acid dipinacol ester, 4,4'-biphenyldiboronic acid, and 4,4'-biphenyldiboronic acid bis(pinacol ester).

2. The use according to claim 1, characterized in that The loaded ruthenium catalyst is any one or more of SiO2, Al2O3, TiO2, CeO2, Fe2O3, activated carbon and MCM-41 molecular sieve carrier loaded ruthenium catalyst; the palladium catalyst is any one of Pd(PPh3)2Cl2, Pd(PPh3)4, Pd(MeCN)2Cl2, Pd(dppf)Cl2, Pd(OAc)2, PdCl2, Pd(TFA)2, Pd(acac)2.

3. The use according to claim 1, characterized in that The alkaline substance is any one or more of potassium carbonate, cesium carbonate, sodium hydroxide and sodium carbonate; the mass of the alkaline substance is 0.5 to 5 times the mass of the brominated nitrogen-containing ligand.

4. The use according to claim 1, characterized in that The organic solvent is any one or two of dimethyl sulfoxide, N,N-dimethylformamide, dioxane, tetrahydrofuran, acetonitrile, and isopropanol; and the mass of the organic solvent is 2 to 20 times the mass of the supported ruthenium catalyst.

5. The use according to claim 1, characterized in that The mass ratio of the supported ruthenium catalyst to the brominated nitrogen-containing ligand is 1:(0.10-1); the molar ratio of the amount of the brominated nitrogen-containing ligand to the amount of the organoboron reagent is 1:(0.5-2).

6. The use according to claim 1, characterized in that The amount of the palladium catalyst is 0.5 to 10% of the amount of the brominated nitrogen-containing ligand.

7. The use according to claim 1, characterized in that In formula (I), the R 1 、R 2 are independently selected from hydrogen, substituted or unsubstituted C1-C 16 Alkyl, substituted or unsubstituted C4~C8 cycloalkyl, substituted or unsubstituted C6~C 16 Aryl or heteroaryl, substituted or unsubstituted C7~C 16 Arylalkyl or heteroarylalkyl, -(CH2) n -OR 3 and -(CH2)n0-NR 4 R 5 Any of the following; Said n and n0 are both integers of 1 to 6; The R 3 Selected from hydrogen, substituted or unsubstituted C1-C 16 Alkyl, substituted or unsubstituted C6~C 16 Aryl and substituted or unsubstituted C7~C 16 Any of arylalkyl or heteroaryl; The R 4 、R 5 are independently selected from hydrogen, substituted or unsubstituted C1-C 16 Alkyl, substituted or unsubstituted C3~C8 cycloalkyl, substituted or unsubstituted C6~C 16 Aryl and substituted or unsubstituted C7~C 16 Any of arylalkyl or heteroaryl; In formulae (II) to (III), n1 and n2 are integers of 1 to 6; in formulae (IV) to (V), n3, n4 and n5 are integers of 1 to 3.

8. The use according to claim 1, characterized in that In formula (I), the R 1 、R 2 are independently selected from hydrogen, substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C4~C6 cycloalkyl, substituted or unsubstituted C6~C 12 Aryl or heteroaryl, substituted or unsubstituted C7~C 12 Arylalkyl or heteroarylalkyl, -(CH2) n -OR 3 and -(CH2)n0-NR 4 R 5 Any of the following; Said n and n0 are both integers of 1 to 4; The R 3 Selected from hydrogen, substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C6~C 10 Aryl and substituted or unsubstituted C7~C 10 Any of arylalkyl or heteroaryl; The R 4 、R 5 are independently selected from hydrogen, substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C3~C6 cycloalkyl, substituted or unsubstituted C6~C 10 Aryl and substituted or unsubstituted C7~C 10 Any of arylalkyl or heteroaryl; In formulae (II) to (III), n1 and n2 are both 4; in formulae (IV) to (V), n3, n4 and n5 are all 2.

Images