Catalytic hydrogenation reactions and use of manganese-based catalysts

Abstract

The present invention relates to catalytic hydrogenation and the use of manganese-based catalysts, in particular to the catalytic hydrogenation of urea or its derivatives, or carbamates using manganese-based polydentate ligand compounds. The use of manganese-based polydentate ligand compounds for the above reactions is proposed for the first time.

Description

Technical Field

[0001] This invention belongs to the field of fine chemicals and relates to a method for preparing amide compounds by catalytic hydrogenation, particularly a method for synthesizing the amide compounds by catalytic hydrogenation using a manganese-based catalyst, and also relates to a new application of the manganese-based catalyst. Background Technology

[0002] The excessive consumption of fossil fuels leads to excessive carbon dioxide (CO2) emissions, resulting in serious environmental problems. Therefore, CO2 emissions and utilization have received widespread attention. To date, only a few processes that use CO2 as a building block of C1 have been industrialized, and these are mainly used for the production of urea (Bosch-Meiser process) and carbamates.

[0003] However, compared to the global annual emissions of over 30 billion tons, the chemical utilization of CO2 remains very limited. It has been reported that further hydrogenating urea and its derivatives to produce high-value-added chemicals is a feasible way to indirectly expand the resource utilization of CO2.

[0004] Furthermore, formamide compounds are a class of chemicals with wide industrial applications; they serve as solvents and raw materials for the synthesis of other chemicals.

[0005] Traditionally, the synthesis of N-formamide involves the use of stoichiometric coupling agents such as chloral, formic acid, formaldehyde, or formate, generating significant waste and resulting in poor atom economy. Industrially, formamide is produced in methanol by reacting amines with toxic and flammable CO, catalyzed by NaOCH3. This process suffers from harsh reaction conditions and high energy consumption, making it unsuitable for green chemistry.

[0006] Furthermore, the direct catalytic synthesis of N-formamides from amines and carbon dioxide in the presence of a catalyst has become a very interesting field due to its high atom efficiency and environmental friendliness. However, one of the most challenging aspects of directly using carbon dioxide as a carbonyl source is its thermodynamic and kinetic stability. Therefore, a certain amount of energy must be provided or a highly reactive reagent must be used to activate CO2. Amines can coordinate with CO2 to form CN bonds to generate urea derivatives, lowering the activation energy of CO2 reduction. Therefore, the hydrogenation of urea derivatives to formamides is an attractive indirect and mild method for utilizing CO2.

[0007] Furthermore, the research teams of Klankermayer and Leitner (cited in reference 1) and the research group of the inventors of this application (cited in reference 2) have successively reported the reaction of urea derivatives to formamide by hydrogenation using ruthenium-based catalysts.

[0008] Furthermore, it is known that many transition metal catalysts have emerged in the field of homogeneous catalytic hydrogenation of esters (cited in reference 3), including noble metal catalysts such as ruthenium, osmium, and iridium, as well as abundant metal catalysts such as iron, cobalt, and manganese. The ligands in metal catalysts have also been greatly expanded, with the emergence of a series of tridentate pincer-shaped ligands with frameworks such as diethylamine and pyridine, tetradentate ligands with bipyridine and pyridine frameworks, and bidentate ligands of the types such as diamines, aminophosphines, pyridinamines, and aminocarbenes. As a result, the efficiency of homogeneous catalytic hydrogenation of esters has been significantly improved.

[0009] References:

[0010] Cited literature 1: vom Stein, T.; Meuresch, M.; Limper, D.; Schmitz, M.; Holscher, M.; Coetzee, J.; Cole-Hamilton, DJ; Klankermayer, J.; Leitner, W. Highly versatile catalytic hydrogenation of carboxylic and carbonic acid derivatives using aRu-triphos complex:molecular control over selectivity and substratescope.J.Am.Chem.Soc.2014,136(38),13217-13225.

[0011] Cited literature 2: Zhu, J.; Zhang, Y.; Wen, Z.; Ma, Q.; Wang, Y.; Yao, J.;

[0012] Reference 3: "Research progress on homogeneous catalytic hydrogenation of esters", Gu Xuesong et al., Acta Chimica Sinica, 2019, Vol.77, pp598-612. Summary of the Invention

[0013] The problem the invention aims to solve

[0014] In actual production processes, such as the hydrogenation reaction of urea derivatives, it has been found that formamide products are more easily hydrogenated than urea derivatives due to the additional resonance stability of the second nitrogen atom, making the half-hydrogenation reaction of urea derivatives challenging. Furthermore, there is currently limited research on this issue. Although some progress has been made in this reaction, it has primarily used the noble metal ruthenium as the catalytically active metal, as mentioned in references 1 and 2 above. However, noble metal catalysts suffer from high cost and limited availability. Additionally, while reference 3 explored more metal catalysts with ligands, this was only for the homogeneous catalytic hydrogenation of ester compounds, and there are no reports of its application in the hydrogenation of urea derivatives.

[0015] Due to the significant interest in developing catalysts based on abundant non-precious metals, manganese, being the third most abundant transition metal in the Earth's crust after iron and titanium, is a catalyst for hydrogenation catalysis using abundant manganese metal complexes. This reaction, carried out in the presence of a manganese-based polydentate ligand compound as a catalyst, not only reduces catalyst cost compared to conventional precious metal materials but also exhibits excellent catalytic selectivity and efficiency.

[0016] Furthermore, this invention also proposes for the first time a new use for the above-mentioned manganese-based polydentate ligand compounds, namely, as a catalyst for the catalytic hydrogenation reaction of compounds of general formula (1).

[0017] Based on the above, this invention also proposes a new approach to the recycling of carbon dioxide.

[0018] Solution for solving the problem

[0019] Long-term research has revealed that the above-mentioned technical problems can be solved by implementing the following technical solutions:

[0020] [1]. The present invention primarily provides a method for catalytic hydrogenation, wherein the method includes:

[0021] The step of contacting a compound of general formula (1) with hydrogen in the presence of a catalyst and a solvent,

[0022] and,

[0023] The compound of general formula (1) has the following structure:

[0024]

[0025] In this context, R1, R2, and R3 may appear the same or different each time they appear, representing monovalent organic groups independently. Furthermore, R1 and R2 can be linked to form a ring; X represents a nitrogen atom or an oxygen atom; and n represents 1 or 2.

[0026] The catalyst is a manganese-based polydentate ligand compound.

[0027] The manganese-based polydentate ligand compounds are derived from the combination of at least a manganese-based compound and a compound having a ligand structure of the following general formula (2):

[0028] (R4)2Y-LQLY(R4)2 (2)

[0030] Wherein, Q represents an organic group containing nitrogen or phosphorus atoms, and the sum of the number of nitrogen and phosphorus atoms in Q is 1 or 2;

[0031] The L may appear the same or different each time, and the independent L indicates a single bond or a divalent connecting group;

[0032] Y may appear the same or different each time it appears, and each of them independently represents a phosphorus atom or a nitrogen atom.

[0033] R4 may appear the same or different each time, and each independent R4 represents a monovalent organic group.

[0034] [2]. According to the method of [1], wherein the manganese-based compound comprises one or more manganese compounds containing carbonyl and / or halogen; and the solvent is selected from one or more organic solvents sufficient to dissolve the catalyst.

[0035] [3]. According to the method of [1] or [2], wherein R1, R2 and R3 in the general formula (1) are each independently selected from hydrogen, straight chain, branched chain or hydrocarbon group having a cyclic structure, and optionally the hydrocarbon group has an aromatic structure.

[0036] [4]. The method according to any one of [1] to [3], wherein X in the general formula (1) is an oxygen atom and R3 is not hydrogen.

[0037] [5]. The method according to any one of [1] to [4], wherein the manganese-based compound is one or more of polycarbonyl manganese bromide or polycarbonyl manganese chloride.

[0038] [6]. The method according to any one of [1] to [5], wherein the ligand structure of the general formula (2) includes one or more of the following general formula (2-1), general formula (2-2) or general formula (2-3):

[0039] 3-t (R5-)N(-LY(R4)2) t

[0040] (2-1)

[0041]

[0042] 3-t (R5-)P(-LY(R4)2) t

[0043] (2-3)

[0044] Where t represents 2 or 3; R5 represents a monovalent organic group;

[0045] In general formula (2-1), N represents a nitrogen atom;

[0046] In general formula (2-2), the ring structure A represents a ring with an aromatic structure, N represents a nitrogen atom, and all three covalent bonds of the nitrogen atom are connected to the ring structure;

[0047] In general formula (2-3), P represents a phosphorus atom.

[0048] [7]. According to the method described in [6], the ring structure A in the general formula (2-2) has more than one ring, which are connected by single bonds or share at least one carbon atom.

[0049] [8]. The method according to any one of [1] to [7], wherein L in the general formula (2) is a hydrocarbon group having 1 to 6 carbon atoms.

[0050] [9]. The method according to any one of [1] to [8], wherein Y in the general formula (2) is a phosphorus atom and R4 is a hydrocarbon group with a straight chain, branched chain or aromatic structure having 1 to 12 carbon atoms.

[0051]

[10] . The method according to any one of [1] to [9], wherein the compound of general formula (1) reacts with the hydrogen gas at a temperature of 80 to 160°C and at a pressure of less than 100 bar.

[0052]

[11] . According to any one of [1] to

[10] , the amount of the catalyst used, in terms of the number of moles of manganese, is less than 30 mol% of the number of moles of the compound of general formula (1).

[0053]

[12] . Use of a catalyst for catalytic hydrogenation, wherein the catalytic hydrogenation is the catalytic hydrogenation of a compound of general formula (1) in any of the methods described in any of [1] to

[11] above, characterized in that the catalyst is a manganese-based polydentate ligand compound, and the manganese-based polydentate ligand compound satisfies the definition of a manganese-based polydentate ligand compound in any of the methods described in any of [1] to

[11] above.

[0054]

[13] . A method for utilizing carbon dioxide, wherein the method comprises:

[0055] Carbon dioxide was used to synthesize compounds with the following general formula (1-1):

[0056]

[0057] Among them, R1, R2 and R3 may be the same or different each time they appear, and they represent monovalent organic groups independently;

[0058] Furthermore, the compound of the general formula (1-1) structure is further reacted with hydrogen using a method in which X is a nitrogen atom, according to any one of [1] to

[11] .

[0059]

[14] . The method according to

[13] , wherein the carbon dioxide is recycled carbon dioxide.

[0060] The effects of the invention

[0061] By implementing the above technical solution, the present invention can achieve the following technical effects:

[0062] 1) For compounds of general formula (1), the present invention provides a new method for catalytic hydrogenation, which uses a new (homogeneous) catalyst, which is a manganese-based polydentate ligand compound, and has improved production costs compared with the noble metal catalysts previously used in the catalytic hydrogenation of the above compounds.

[0063] 2) The catalytic hydrogenation method of the present invention has the advantages of high selectivity, mild reaction conditions, high atom economy, cheap and readily available catalytically active metal manganese, and environmental friendliness.

[0064] 3) This invention provides a novel catalytic application for a manganese-based polydentate ligand compound, expanding the industrial application scope of this catalyst.

[0065] 4) This invention also provides a cheaper and more feasible method for recycling carbon dioxide. Attached Figure Description

[0066] Figure 1 Example 1: MS-ESI spectrum of the catalytically active component detected in the reaction solution. Detailed Implementation

[0067] The present invention will now be described in detail. The descriptions of the technical features described below are based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0068] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0069] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0070] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0071] In this specification, the terms "optional" or "optional" are used to indicate the use or non-use of certain substances, components, procedures, application conditions, etc., and there are no restrictions on the manner of use.

[0072] In this specification, the term "unsaturated structure" refers to a structure formed by carbon-carbon double bonds, unless otherwise specified.

[0073] In this invention, the "monovalent organic group" includes a "hydrogen atom".

[0074] In this specification, the term "hydrocarbon group" is used to refer to an organic structure formed by carbon and hydrogen elements, and it can be an aromatic or non-aromatic group.

[0075] In this specification, the term "halogen" refers to fluorine, chlorine, bromine, or iodine. Fluorine, chlorine, or bromine are preferred, and bromine and chlorine are more preferred.

[0076] All unit names used in this manual are international standard unit names, and unless otherwise stated, the "%" used refers to weight or mass percentage content.

[0077] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0078] The present invention primarily provides a catalytic hydrogenation method for compounds with the following general formula (1), for example, the compound with the general formula (1) can be a urea (or a derivative thereof) or a carbamate compound. Furthermore, this type of compound undergoes a hydrogenation reaction with hydrogen under the catalysis of a manganese-based polydentate ligand compound, thereby enabling the economical and efficient production of products such as amide compounds.

[0079] This invention is mainly based on the following insights:

[0080] Although, for example, reference 3, metal compounds with polydentate ligands have been used for the homogeneous catalytic hydrogenation of esters to synthesize alcohols, while a wider variety of metal complexes can be used as catalysts, this involves the selective catalytic cleavage of the CO bond in -C-CO-O-. Therefore, there are no reports of using these catalysts for the hydrogenation of urea (or its derivatives) or carbamates, especially considering that the latter typically use limited noble metal catalysts and the resonance stabilization of the nitrogen atom adjacent to the carbonyl group.

[0081] It has been unexpectedly discovered that manganese-based polydentate ligands can exhibit good catalytic selectivity when used as catalysts to catalyze compounds of the general formula (1), thereby improving product yield and exhibiting good catalytic activity even under milder conditions, significantly reducing the cost of the catalytic process.

[0082] (Reaction raw materials)

[0083] The reaction raw materials or catalytic hydrogenation targets of the present invention are urea or its derivatives used in the art, or carbamate compounds.

[0084] In some specific embodiments of the present invention, the reactant compound can be one or more compounds having the following general formula (1).

[0085]

[0086] In this context, R1, R2, and R3 may appear the same or different each time they appear, and they represent monovalent organic groups independently. Furthermore, R1 and R2 can be linked together to form a ring.

[0087] There are no particular limitations on the monovalent organic groups mentioned above, and they can be selected based on the types of compounds already available in the art. In some specific embodiments, the monovalent organic group can be selected from hydrogen atoms, straight-chain or branched or cyclic hydrocarbon groups, or hydrocarbon groups with unsaturated (or aromatic) structures, and these hydrocarbon groups can optionally have substituents. Preferably, these substituents can be halogens or halogen-containing groups; or, the carbon atoms in the aforementioned hydrocarbon groups can be replaced by other N, O, or S atoms.

[0088] In some preferred embodiments, the monovalent organic group may be selected from hydrogen atoms, straight-chain, branched, cyclic saturated or unsaturated hydrocarbon groups having 1 to 25 carbon atoms (preferably 1 to 15), and these groups may optionally have halogenated substituents or may optionally have carbon aromatic or heteroaromatic structures.

[0089] In some preferred embodiments, the monovalent organic group may be selected from one or more of hydrogen atoms, alkyl groups (methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl), cycloalkyl (4-6 membered ring), phenyl, pyridyl, and imidazolyl, and these groups may optionally have alkyl groups or halogen-containing substituents, such as one or more chlorine atoms, fluorine atoms, trifluoromethyl, methyl, ethyl, isopropyl, tert-butyl, etc.

[0090] For X in the general formula (1), it can represent a nitrogen atom or an oxygen atom. When X represents a nitrogen atom, the compound with the general formula (1) can be urea or its derivatives, which has the structure of the following general formula (1-1); when X represents an oxygen atom, the compound with the general formula (1) can be a carbamate compound, which has the structure of the following general formula (1-2):

[0091]

[0092] The value of n can be chosen based on different cases of X; therefore, n can be 1 or 2.

[0093] In addition, in the case of general formula (1-2), preferably, R3 is not a hydrogen atom.

[0094] Furthermore, as preferred reaction raw materials of the present invention, compounds with the following structures can be listed:

[0095]

[0096] (catalyst)

[0097] The catalyst of the present invention for the catalytic hydrogenation of compounds with the above-described general formula (1) can be one or more manganese-based polydentate ligand compounds. The manganese-based polydentate ligand compound can be derived from a combination of components comprising at least a manganese-based compound and a polydentate ligand compound.

[0098] In some specific embodiments of the present invention, the manganese-based compound includes one or more manganese compounds containing carbonyl groups and / or halogens. In some preferred embodiments, the manganese-based compound may be selected from manganese pentacarbonyl bromide (Mn(CO)5Br), manganese tricarbonylcyclopentadiene, 2-methylcyclopentadiene tricarbonyl manganese, MnCl2, preferably Mn(CO)5Br.

[0099] Furthermore, the polydentate ligand compound includes one or more compounds having a ligand structure of the following general formula (2):

[0100] (R4)3Y-LQLY(R4)3 (2)

[0102] Wherein, the compound of general formula (2) is a tridentate or more ligand, preferably a tridentate or tetradentate ligand. Q is an organic group containing a nitrogen atom or a phosphorus atom, and the total number of nitrogen atoms and phosphorus atoms is 1 or 2. Y may be the same or different each time it appears, and independently represents a phosphorus atom or a nitrogen atom, and preferably, all Y are phosphorus atoms.

[0103] The L mentioned above represents a single bond or a divalent linking group. In principle, there are no particular restrictions on the divalent linking groups that can be used for L. Commonly used linking groups in the art can be used. In some preferred embodiments, the divalent group can be a hydrocarbon group with 1 to 10 carbon atoms, more preferably 1 to 6.

[0104] R4 may be the same or different each time it appears, and each R4 independently represents a monovalent organic group. In some specific embodiments, each R4 independently represents a straight-chain, branched or aromatic hydrocarbon group with 1 to 20 carbon atoms, preferably 2 to 15 or 3 to 10.

[0105] In a further specific embodiment of the present invention, the ligand of the general formula (2) structure includes one or more of the following general formula (2-1), general formula (2-2), or general formula (2-3):

[0106] 3-t (R5-)N(-LY(R4)2) t

[0107] (2-1)

[0108]

[0109] 3-t (R5-)P(-LY(R4)2) t

[0110] (2-3)

[0111] In the general formula (2-1) structure, R5 represents a monovalent organic group. Preferably, R5 is the same or different each time it appears, representing a straight-chain, branched or aromatic hydrocarbon group with 1 to 20 hydrogen atoms or carbon atoms, preferably 2 to 15 or 3 to 10; t represents 2 or 3; N represents a nitrogen atom.

[0112] For the general formula (2-2) structure, where the above-mentioned cyclic structure A represents a ring with an aromatic structure, and all three bonds of the nitrogen atom represented by N are connected to the cyclic structure of the ring, preferably, the ring connected by N (the smallest unit ring) is an aromatic nitrogen heterocycle.

[0113] In other specific embodiments, the cyclic structure A has 4 to 20 rings, preferably 6 to 18 rings with carbon atoms on each ring. Such a cyclic structure can consist of one or more rings connected by single bonds or sharing at least one carbon atom, for example, by forming the cyclic structure A in a fused ring configuration. In a further preferred embodiment, the cyclic structure A can be a structure derived from pyridine, pyrrole, (poly)benzopyridine, or (poly)benzopyrrole, and these structures may optionally have substituents such as alkyl groups.

[0114] For the general formula (2-3) structure, R5 represents a monovalent organic group, which is defined in the same way as general formula (2-1). Preferably, R5 represents a hydrocarbon group with a straight chain, branched chain or aromatic structure having 1 to 20 hydrogen atoms or carbon atoms, preferably 2 to 15 or 3 to 10; t represents 2 or 3; and P represents a phosphorus atom.

[0115] From the perspective of improving the conversion rate of the catalyst hydrogenation reaction described below, the present invention preferably uses compounds with the general formula (2-2) as ligand compounds for forming the catalyst of the present invention.

[0116] (Catalyst formation)

[0117] The catalyst of the present invention can be obtained under alkaline conditions by reacting a manganese-based compound with a polydentate ligand compound having the structure of the above general formula (2). There are no particular limitations on the base that can be used; it can generally be an organic or inorganic base. In some preferred embodiments, the base may be selected from KO... t Bu, NaHBEt3, KOH, NaOH, Cs2CO3, Na2CO3, NaHCO3, more preferably KOH t Bu.

[0118] The main point is that, for the above catalyst, the catalyst can be added to the subsequent hydrogenation reaction system after the complete catalyst is formed, or the above manganese-based compound, the polydentate ligand compound with the above general formula (2) structure and the above base can be directly added to the reaction vessel, and then the hydrogenation reaction reactants can be added in situ in the vessel after the catalyst is formed.

[0119] In some specific embodiments, the molar ratio of the manganese-based compound, the ligand of the structure of the above general formula (2), and the base can be 1.0:(0.01-10):(0.01-10), preferably 1.0:(1-3):(1-3).

[0120] Additionally, if desired, the formation of the catalyst can be carried out in the presence of a solvent, which can be the same solvent used in the catalytic hydrogenation reaction described below.

[0121] (Catalytic hydrogenation reaction)

[0122] The catalytic hydrogenation reaction of the present invention involves the contact of a compound of general formula (1) with hydrogen gas in the presence of a solvent to undergo catalytic hydrogenation in order to obtain the desired product.

[0123] For the catalytic hydrogenation reaction of the present invention, depending on the different X in the compound of general formula (1), it can be carried out in the following manner:

[0124]

[0125] In method (a), formamide compounds and amine compounds can be obtained, and in method (b), in addition to formamide compounds, corresponding alcohols can also be obtained. In some preferred embodiments, the formamide compounds include p-halophenylformamide.

[0126] In addition, for method (a), since the reactants have symmetrical and asymmetrical structures, one or two different formamide compounds can be obtained.

[0127] There are no particular limitations on the solvents that can be used, as long as they are sufficient to dissolve the catalyst. In some specific embodiments, the solvent may include one or more of nitrogen heterocyclic solvents, oxygen heterocyclic solvents, benzene solvents, or sulfone solvents. More specifically, the solvent may be one or more of 1,4-dioxane, toluene, tetrahydrofuran, and dimethyl sulfoxide, with 1,4-dioxane being particularly preferred.

[0128] The reaction can be carried out under high pressure. In some specific embodiments, the reaction pressure is below 100 bar, preferably 20–90 bar, more preferably 40–80 bar, and most preferably 55–70 bar. Therefore, the hydrogenation reaction can be carried out in a high-pressure reactor.

[0129] In addition, there is no particular limitation on the reaction temperature in the hydrogenation reaction step. This may be related to the type of reactants. It can usually be below 160°C, preferably 80 to 140°C, and more preferably 105 to 120°C.

[0130] Furthermore, in the catalytic hydrogenation reaction, the amount of the catalyst, based on the molar amount of manganese therein, is less than 30 mol% of the molar amount of the compound of general formula (1), preferably 0.1 to 25 mol%, more preferably 0.5 to 15 mol%, and even more preferably 1 to 5 mol%.

[0131] In addition, there is no particular limitation on the reaction time, which is usually 8 to 60 hours, preferably 10 to 50 hours, and more preferably 10 to 20 hours.

[0132] In some preferred embodiments, the catalytic hydrogenation reaction of the present invention can have a yield of 28% by mass or more, preferably 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, and the conversion rate can preferably be 90% by mass or more, more preferably 95% by mass or more.

[0133] (Carbon dioxide recycling)

[0134] Furthermore, the present invention also provides a method for utilizing carbon dioxide, particularly wherein the carbon dioxide may be carbon dioxide recovered from the environment by means of adsorption or the like.

[0135] The method includes:

[0136] Using the carbon dioxide described above, compounds with the following general formula (1-1) structure can be synthesized:

[0137]

[0138] In this context, R1, R2, and R3 may appear the same or different each time they appear, and they represent monovalent organic groups that are independent of each other. The monovalent organic groups are defined in the same way as those in the general formula (1) above.

[0139] Furthermore, the compound with the general formula (1-1) structure is further reacted with hydrogen using the catalytic hydrogenation method described above.

[0140] Example

[0141] The embodiments of the present invention will be described in detail below with reference to the examples. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0142] Example 1

[0143] In a glove box under N2 atmosphere, 0.01 mmol of Mn(CO)5Br and 0.015 mmol of KO were added. tBu and 0.015 mmol of different ligands 2,6-bis[(diphenylphosphino)methyl]pyridine, 2,6-bis((di-tert-butylphosphino)methyl)pyridine, bis(2-(di-tert-butylphosphinoalkyl)ethyl)amine hydrochloride, ((phenylphosphinodiyl)bis(ethane-2,1-diyl))bis(diphenylphosphine), and tris(2-(diphenylphosphino)ethyl)phosphine were added to a 50 mL high-pressure reactor containing 2 mL of tetrahydrofuran solvent. After stirring for about 5 min, 1 mmol of 1,3-bis(4-chlorophenyl)urea was added.

[0144] Remove the sealed high-pressure reactor from the glove box and flush it with hydrogen 4-6 times (first pressurize to 50 bar, then release to about 2 bar, repeating this cycle 4-6 times). Finally, pressurize to 50 bar and heat at 140°C with stirring to carry out the hydrogenation reaction. After the reaction is complete, cool in an ice bath for about 30 minutes, then slowly release the gas to atmospheric pressure. Add the internal standard biphenyl and take samples for GC analysis. The conversion and yield are shown in Table 1.

[0145] The qualitative and quantitative methods for the products in this invention are based on gas chromatography-programmed temperature detection (Chem.Eur.J.2023,e202300106), and the instrument used is a GC-2010 (Shimadzu, Japan) with an HP-1 column.

[0146] Table 1. Conversion rate and formamide yield of 1,3-bis(4-chlorophenyl)urea with different ligands.

[0147]

[0148] As can be seen from the comparison of the results in Table 1, even without excessive optimization of the reaction conditions, the use of various ligands can demonstrate industrial usefulness.

[0149] Example 2

[0150] In a glove box under N2 atmosphere, 0.01 mmol of Mn(CO)5Br, 0.015 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand and 0.015 mmol of KO were added. tBu was added to a 50 mL high-pressure reactor containing 2 mL of tetrahydrofuran, toluene, and 1,4-dioxane solvent, respectively. After stirring for approximately 5 min, 1 mmol of 1,3-bis(4-chlorophenyl)urea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the reactor was pressurized to 50 bar and subjected to hydrogenation reaction at 140 °C with stirring. After the reaction was complete, the reactor was cooled in an ice bath for approximately 30 min, then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The conversion and yield are shown in Table 2.

[0151] Table 2. Conversion rate of 1,3-bis(4-chlorophenyl)urea and yield of formamide in different solvents.

[0152]

[0153] As can be seen from the comparison of the results in Table 2, although the yield of formamide fluctuates to some extent when carrying out the hydrogenation reaction of 1,3-bis(4-chlorophenyl)urea in different solvents, the overall results are still satisfactory.

[0154] Example 3

[0155] In a glove box under N2 atmosphere, 0.01 mmol of Mn(CO)5Br, 0.015 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand, and 0.015 mmol of KO were added. t Bu and 2 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 1 mmol of 1,3-bis(4-chlorophenyl)urea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 60 bar, and the hydrogenation reaction was carried out by stirring and heating at 140, 120, 110, and 100 °C, respectively. After the reaction was completed, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The conversion and yield are shown in Table 3.

[0156] Table 3. Conversion rate and formamide yield of 1,3-bis(4-chlorophenyl)urea at different reaction temperatures.

[0157]

[0158] Example 4

[0159] In a glove box under N2 atmosphere, 0.01 mmol of Mn(CO)5Br, 0.015 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand, and 0.015 mmol of KO were added. t Bu and 4 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 2 mmol of 1,3-bis(4-chlorophenyl)urea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 30, 40, and 50 bar respectively, and the hydrogenation reaction was carried out by stirring and heating at 110 °C. After the reaction was completed, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The conversion and yield are shown in Table 4.

[0160] Table 4. Conversion rate of 1,3-bis(4-chlorophenyl)urea and yield of formamide under different H2 pressures.

[0161]

[0162] As can be seen from the comparison of the results in Table 4, the influence of H2 pressure on the conversion efficiency of 1,3-bis(4-chlorophenyl)urea is the same as that when other catalysts are used in the prior art.

[0163] Example 5

[0164] In a glove box under N2 atmosphere, 0.01 mmol of Mn(CO)5Br, 0.015 mmol of 2,6-bis[(diphenylphosphino)methyl]pyridine ligand, and 0.015 mmol of different additives KOtBu, Cs2CO3, or NaHCO3 were added to a 50 mL high-pressure reactor containing 4 mL of 1,4-dioxane. After stirring for approximately 5 min, 2 mmol of 1,3-bis(4-chlorophenyl)urea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 60 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 50 bar, and the reactors were heated and stirred at 110 °C for hydrogenation. After the reaction was complete, the reactors were cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Internal standard biphenyl was added, and samples were taken for GC analysis. The conversion and yield are shown in Table 5.

[0165] Table 5 shows the conversion rate and formamide yield of 1,3-bis(4-chlorophenyl)urea under different base addition conditions.

[0166]

[0167] Example 6

[0168] In a glove box under N2 atmosphere, 0.01 mmol of Mn(CO)5Br, 0.015 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand, and 0.015 mmol of KO were added. t Bu and 4 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 2 mmol of 1,3-bis(4-fluorophenyl)urea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 60 bar, and the reaction was stirred and heated at 110 °C for 24 h. After the reaction was complete, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The yields are shown in Table 6.

[0169] Example 7

[0170] In a glove box under N2 atmosphere, 0.01 mmol of Mn(CO)5Br, 0.015 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand, and 0.015 mmol of KO were added. t Bu and 4 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 2 mmol of 1,3-bis(3,4-dichlorophenyl)urea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 60 bar, and the reaction was stirred and heated at 110 °C for 12 h. After the reaction was complete, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The yields are shown in Table 6.

[0171] Example 8

[0172] In a glove box under N2 atmosphere, 0.01 mmol of Mn(CO)5Br, 0.015 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand, and 0.015 mmol of KO were added. tBu and 4 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 2 mmol of 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 60 bar, and the reaction was stirred and heated at 110 °C for 12 h. After the reaction was complete, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The yields are shown in Table 6.

[0173] Example 9

[0174] In a glove box under N2 atmosphere, 0.02 mmol of Mn(CO)5Br, 0.03 mmol of 2,6-bis[(diphenylphosphino)methyl]pyridine ligand, 0.03 mmol of NaHBEt3, and 4 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 2 mmol of 1,3-bisphenylurea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 60 bar, and the reaction was stirred and heated at 110 °C for 48 h. After the reaction was complete, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The yields are shown in Table 6.

[0175] Example 10

[0176] In a glove box under N2 atmosphere, 0.02 mmol of Mn(CO)5Br, 0.03 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand, and 0.03 mmol of KO were added. t Bu and 4 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 2 mmol of 1,3-dipyridin-2-ylurea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 60 bar, and the reaction was stirred and heated at 110 °C for 48 h. After the reaction was complete, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The yields are shown in Table 6.

[0177] Example 11

[0178] In a glove box under N2 atmosphere, 0.03 mmol of Mn(CO)5Br, 0.045 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand, and 0.045 mmol of K2O were added. t Bu and 4 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 2 mmol of 1,3-bis(4-methylphenyl)urea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 60 bar, and the reaction was stirred and heated at 110 °C for 48 h. After the reaction was complete, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The yields are shown in Table 6.

[0179] Example 12

[0180] In a glove box under N2 atmosphere, 0.03 mmol of Mn(CO)5Br, 0.045 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand, and 0.045 mmol of K2O were added. t Bu and 4 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 2 mmol of 1,3-dicyclohexaneurea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 60 bar, and the reaction was stirred and heated at 110 °C for 48 h. After the reaction was complete, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The yields are shown in Table 6.

[0181] Example 13

[0182] In a glove box under N2 atmosphere, 0.04 mmol of Mn(CO)5Br, 0.06 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand, and 0.06 mmol of K2O were added. t Bu and 4 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 2 mmol of 1,3-dibutylurea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 60 bar, and the reaction was stirred and heated at 110 °C for 48 h. After the reaction was complete, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The yields are shown in Table 6.

[0183] Example 14

[0184] In a glove box under N2 atmosphere, 0.02 mmol of Mn(CO)5Br, 0.03 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand, and 0.03 mmol of KO were added. t Bu and 4 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 2 mmol of 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 60 bar, and the reaction was stirred and heated at 110 °C for 24 h. After the reaction was complete, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The yields are shown in Table 6.

[0185] Example 15

[0186] In a glove box under N2 atmosphere, 0.02 mmol of Mn(CO)5Br, 0.03 mmol of 2,6-bis[(diphenylphosphine)methyl]pyridine ligand, and 0.03 mmol of KO were added. t Bu and 4 mL of 1,4-dioxane solvent were added to a 50 mL high-pressure reactor. After stirring for approximately 5 min, 2 mmol of N-phenylcarbamate was added. The sealed high-pressure reactor was removed from the glove box and flushed with hydrogen 4-6 times (first pressurizing to 50 bar, then releasing to approximately 2 bar, repeating this cycle 4-6 times). Finally, the pressure was increased to 60 bar, and the reaction was stirred and heated at 110 °C for 16 h. After the reaction was complete, the reactor was cooled in an ice bath for approximately 30 min, and then slowly vented to atmospheric pressure. Biphenyl (internal standard) was added, and samples were taken for GC analysis. The yields are shown in Table 6.

[0187] Table 6: Reaction conditions and yields of Examples 6-15

[0188]

[0189] As shown in Table 6, the in-situ manganese-based catalyst system has a wide range of applications for the hydrogenation of urea derivatives and carbamates.

[0190] Example 16

[0191] In a glove box under N2 atmosphere, 0.01 mmol of Mn(CO)5Br and 0.015 mmol of KO were added. tBu and 0.015 mmol of the different ligands listed in Table 1 were added to a 50 mL high-pressure reactor containing 2 mL of tetrahydrofuran solvent. After stirring for about 5 min, 1 mmol of 1,3-bis(4-chlorophenyl)urea was added.

[0192] Remove the sealed high-pressure reactor from the glove box and flush it with hydrogen 4-6 times (first pressurize to 50 bar, then release to about 2 bar, repeating this cycle 4-6 times). Finally, pressurize to 60 bar and heat at 110°C with stirring to carry out the hydrogenation reaction. After the reaction is complete, cool in an ice bath for about 30 minutes, then slowly release the gas to atmospheric pressure. Add the internal standard biphenyl and take a sample for GC analysis. The conversion and yield are shown in Table 7.

[0193] The qualitative and quantitative methods for the products in this invention are based on gas chromatography-programmed temperature detection (Chem.Eur.J.2023,e202300106), and the instrument used is a GC-2010 (Shimadzu, Japan) with an HP-1 column.

[0194] Table 7 shows the conversion rate of 1,3-bis(4-chlorophenyl)urea and the yield of formamide when different ligands are used.

[0195]

[0196] Example 17

[0197] In a glove box under N2 atmosphere, 0.01 mmol of each of the eight manganese-based compounds and 0.015 mmol of KO were added. t Bu and 0.015 mmol of the ligand 2,6-bis[(diphenylphosphino)methyl]pyridine were added to a 50 mL high-pressure reactor containing 2 mL of tetrahydrofuran solvent. After stirring for about 5 min, 1 mmol of 1,3-bis(4-chlorophenyl)urea was added.

[0198] Remove the sealed high-pressure reactor from the glove box and flush it with hydrogen 4-6 times (first pressurize to 50 bar, then release to about 2 bar, repeating this cycle 4-6 times). Finally, pressurize to 60 bar and heat at 110°C with stirring to carry out the hydrogenation reaction. After the reaction is complete, cool in an ice bath for about 30 minutes, then slowly release the gas to atmospheric pressure. Add the internal standard biphenyl and take a sample for GC analysis. The conversion and yield are shown in Table 8.

[0199] The qualitative and quantitative methods for the products in this invention are based on gas chromatography-programmed temperature detection (Chem.Eur.J.2023,e202300106), and the instrument used is a GC-2010 (Shimadzu, Japan) with an HP-1 column.

[0200] Table 8 shows the conversion rate of 1,3-bis(4-chlorophenyl)urea and the yield of formamide when different ligands are used.

[0201]

[0202] Comparative Example

[0203] In a glove box under N2 atmosphere, 0.01 mmol of the metal precursor in Table 9 and 0.015 mmol of KO were added. t Bu and 0.015 mmol of the ligand 2,6-bis[(diphenylphosphino)methyl]pyridine were added to a 50 mL high-pressure reactor containing 2 mL of tetrahydrofuran solvent. After stirring for about 5 min, 1 mmol of 1,3-bis(4-chlorophenyl)urea was added.

[0204] Remove the sealed high-pressure reactor from the glove box and flush it with hydrogen 4-6 times (first pressurize to 50 bar, then release to about 2 bar, repeating this cycle 4-6 times). Finally, pressurize to 60 bar and heat at 110°C with stirring to carry out the hydrogenation reaction. After the reaction is complete, cool in an ice bath for about 30 minutes, then slowly release the gas to atmospheric pressure. Add the internal standard biphenyl and take a sample for GC analysis. The conversion and yield are shown in Table 9.

[0205] The qualitative and quantitative methods for the products in this invention are based on gas chromatography-programmed temperature detection (Chem.Eur.J.2023,e202300106), and the instrument used is a GC-2010 (Shimadzu, Japan) with an HP-1 column.

[0206] Table 9 shows the conversion rate of 1,3-bis(4-chlorophenyl)urea and the yield of formamide when other metal precursors are used.

[0207]

[0208] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0209] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing formamide compounds by catalytic hydrogenation, characterized in that, The method includes: The step of contacting a compound of general formula (1) with hydrogen in the presence of a catalyst and a solvent, and, The compound of general formula (1) has the following structure: （1） In this design, R1, R2, and R3 may appear the same or different each time they appear, and independently represent monovalent organic groups. These monovalent organic groups are selected from hydrogen atoms, straight-chain, branched, or cyclic saturated or unsaturated hydrocarbon groups with 1 to 25 carbon atoms, and the hydrocarbon groups may optionally have halogen-containing substituents. Furthermore, R1 and R2 can be linked to form a ring; X represents a nitrogen atom or an oxygen atom; and n represents 1 or 2. The catalyst is a manganese-based polydentate ligand compound, which is derived from a manganese-based compound and a combination of one or more ligand structures having the following general formula (2-1), general formula (2-2), or general formula (2-3): （2-1） （2-2） （2-3） Where t represents 2 or 3; R5 may appear the same or different each time, representing a straight-chain, branched or aromatic hydrocarbon group with 1 to 20 carbon atoms; R4 may appear the same or different each time, representing a straight-chain, branched or aromatic hydrocarbon group with 1 to 20 carbon atoms; L may appear the same or different each time, representing a single bond or a divalent hydrocarbon group with 1 to 10 carbon atoms. and, In general formula (2-1), N represents a nitrogen atom, and Y represents a phosphorus atom or a nitrogen atom; In general formula (2-2), the ring structure A represents an aromatic ring with 4-20 carbon atoms, N represents a nitrogen atom, and all three covalent bonds of the nitrogen atom are connected to the ring structure, and Y represents a phosphorus atom; In general formula (2-3), P represents a phosphorus atom, and Y represents a phosphorus atom or a nitrogen atom. The formamide compounds have the following structures: The definitions of R1 and R2 are the same as those in general formula (1).

2. The method according to claim 1, characterized in that, The manganese-based compound is selected from one or more manganese compounds containing a carbonyl group and / or a halogen; the solvent is selected from one or more organic solvents sufficient to dissolve the catalyst.

3. The method according to claim 1 or 2, characterized in that, The unsaturated hydrocarbon groups of R1, R2 and R3 in the general formula (1) have carbon aromatic structures.

4. The method according to claim 1 or 2, characterized in that, In the general formula (1), X is an oxygen atom and R3 is not hydrogen.

5. The method according to claim 1 or 2, characterized in that, The manganese-based compound is one or more of polycarbonyl manganese bromide or polycarbonyl manganese chloride.

6. The method according to claim 1, characterized in that, The ring structure A in the general formula (2-2) has more than one ring, which are connected by single bonds or share at least one carbon atom.

7. The method according to claim 1 or 2, characterized in that, In this context, L represents a hydrocarbon group with 1 to 6 carbon atoms.

8. The method according to claim 1 or 2, characterized in that, R4 is a hydrocarbon group with a straight chain, branched chain, or aromatic structure having 2 to 15 carbon atoms.

9. The method according to claim 1 or 2, characterized in that, The compound of general formula (1) reacts with hydrogen gas at a temperature of 80–160°C and at a pressure of less than 100 bar.

10. The method according to claim 1 or 2, wherein the amount of catalyst, in terms of the number of moles of manganese, is less than 30 mol% of the number of moles of the compound of general formula (1).

11. Use of a catalyst for catalytic hydrogenation to prepare formamide compounds, said catalytic hydrogenation being the catalytic hydrogenation of a compound of general formula (1) according to any one of claims 1 to 10, characterized in that, The catalyst is a manganese-based polydentate ligand compound, and the manganese-based polydentate ligand compound satisfies the definition of a manganese-based polydentate ligand compound in the method according to any one of claims 1 to 10. The catalytic hydrogenation is carried out in the presence of hydrogen gas, and the formamide compound has the following structure: The definitions of R1 and R2 are the same as those of general formula (1) in the method described in any one of claims 1 to 10.

12. A method for utilizing carbon dioxide, characterized in that, The method includes: Carbon dioxide was used to synthesize compounds with the following general formula (1-1): （1-1） Wherein, R1, R2 and R3 are the same as those defined in the method described in any one of claims 1 to 10; Furthermore, the compound of the general formula (1-1) structure is further reacted with hydrogen gas using the method in any one of claims 1 to 10, in which X is a nitrogen atom, to generate the formamide compound.

13. The method according to claim 12, characterized in that, The carbon dioxide mentioned is recycled carbon dioxide.

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