Method for producing nitrogen-containing compound

Abstract

The present invention provides a method for producing a nitrogen-containing compound, which comprises a step for synthesizing a nitrogen-containing compound from nitrogen and a proton source in the presence of a nitrogen activation catalyst having a structure represented by any one of formulae (I-1)-(I-4). (In the formula, R1 to R5), n1, n2, m1, m2, m3, m4, and Z are as defined in the description. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a method for producing a nitrogen-containing compound. Background Art

[0002] Ammonia is an important chemical raw material that can be used as a basic material for fertilizers and chemical products. In recent years, its application as a co-firing agent in coal-fired power generation and as an energy carrier has also attracted attention.

[0003] Conventionally, ammonia has been produced using the Haber-Bosch process, which is a method for producing ammonia by reacting nitrogen and hydrogen in the presence of an iron-based catalyst.

[0004] However, the Haber-Bosch process, which synthesizes ammonia at high temperatures and high pressures, consumes a lot of energy and requires large equipment made of specialized materials. Furthermore, obtaining hydrogen from natural gas, which primarily contains methane (CH4), also raises the issue of large amounts of carbon dioxide, a greenhouse gas, being emitted.

[0005] Therefore, it is desirable to develop a method for producing ammonia from nitrogen and water under mild reaction conditions.

[0006] Patent Document 1 discloses, as an invention for producing ammonia from nitrogen molecules at low cost, a method for producing ammonia from nitrogen molecules in the presence of a catalyst, a reducing agent, and a proton source using a specific molybdenum complex.

[0007] Patent Document 2 discloses a method for producing a nitrogen-containing compound as an invention for further increasing the production of ammonia, the method comprising the steps of synthesizing a nitrogen-containing compound from nitrogen and a proton source in the presence of a nitrogen-activating catalyst and a reducing agent, and simultaneously reducing the reducing agent oxidized by the synthesis reaction of the nitrogen-containing compound by electrolysis.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: International Publication No. 2019 / 168093

[0011] Patent Document 2: International Publication No. 2022 / 230898 Summary of the Invention

[0012] Problems to be solved by the invention

[0013] The present invention aims to provide a method for producing a nitrogen-containing compound with further improved productivity of the nitrogen-containing compound. In this specification, "productivity" refers to the amount of the nitrogen-containing compound produced by the method for producing a nitrogen-containing compound.

[0014] Means for solving problems

[0015] The present inventors have conducted intensive studies to solve the above-mentioned problems and have found that the productivity of nitrogen-containing compounds can be improved by using a catalyst having a specific structure.

[0016] The present invention includes the following aspects.

[0017] [1] A method for producing a nitrogen-containing compound, comprising the following steps:

[0018] A nitrogen-containing compound is synthesized from nitrogen and a proton source in the presence of a nitrogen-activating catalyst having a structure represented by any one of the following formulae (I-1) to (I-4).

[0019] [Chemistry 1]

[0020]

[0021] [Where R 1 ~R 4 Each independently represents an alkyl group having 1 to 10 carbon atoms.

[0022] R 5 It represents a phenyl group or a naphthyl group which may have one or more substituents selected from an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, a halogen atom, and a perfluoromethyl group (-CF3).

[0023] n1 and n2 each independently represent an integer of 1 to 3.

[0024] m1 means 1 or 2.

[0025] m2 represents an integer from 1 to 4.

[0026] m3 and m4 represent integers of 1 to 6.

[0027] Z represents a structure represented by the following formula (i) or (ii).

[0028] [Chemistry 2]

[0029]

[0030] {wherein, X represents a halogen atom.

[0031] Wavy lines indicate bonds to adjacent atoms.

[0032] [2] The manufacturing method according to [1], wherein R 5 It is a phenyl group or a naphthyl group which may have one or more substituents selected from a halogen atom and a perfluoromethyl group (-CF3).

[0033] [3] The production method according to [1] or [2], wherein the nitrogen activation catalyst is a nitrogen activation catalyst having a structure represented by the above formula (I-1) or (I-2).

[0034] [4] The production method according to any one of [1] to [3], wherein the nitrogen-containing compound is ammonia.

[0035] [5] The production method according to any one of [1] to [4], wherein the nitrogen-containing compound is synthesized in the presence of a reducing agent.

[0036] [6] The production method according to any one of [1] to [4], wherein the nitrogen-containing compound is synthesized by an electrochemical reduction reaction.

[0037] [7] The production method according to any one of [1] to [6], wherein the nitrogen activation catalyst is a nitrogen activation catalyst having a structure represented by any one of the following formulae.

[0038] [Chemistry 3]

[0039]

[0040] [In the formula, Z is the same as described above. tBu represents a tert-butyl group.]

[0041] [8] An apparatus comprising the aforementioned nitrogen activation catalyst, for producing a nitrogen-containing compound using the production method described in any one of [1] to [7].

[0042] Effects of the Invention

[0043] According to the present invention, a method for producing a nitrogen-containing compound with further improved productivity of the nitrogen-containing compound can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] [ Figure 1 ] Figure 1 It is a schematic diagram showing an example of an electrolysis cell. DETAILED DESCRIPTION

[0045] [Method for producing nitrogen-containing compound]

[0046] The method for producing a nitrogen-containing compound of the present invention comprises synthesizing a nitrogen-containing compound from nitrogen and a proton source in the presence of a nitrogen-activating catalyst having a structure represented by any one of the following formulae (I-1) to (I-4).

[0047] [Chemistry 4]

[0048]

[0049] [Where R 1 ~R 4Each independently represents an alkyl group having 1 to 10 carbon atoms.

[0050] R 5 It represents a phenyl group or a naphthyl group which may have one or more substituents selected from an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, a halogen atom, and a perfluoromethyl group (-CF3).

[0051] n1 and n2 each independently represent an integer of 1 to 3.

[0052] m1 means 1 or 2.

[0053] m2 represents an integer from 1 to 4.

[0054] m3 and m4 represent integers of 1 to 6.

[0055] Z represents a structure represented by the following formula (i) or (ii).

[0056] [Chemistry 5]

[0057]

[0058] {wherein, X represents a halogen atom.

[0059] Wavy lines indicate bonds to adjacent atoms.

[0060] <Nitrogen-containing compounds>

[0061] Examples of the nitrogen-containing compound produced by the method for producing a nitrogen-containing compound of the present invention include ammonia and hydrazine, and ammonia is preferred.

[0062] <Synthesis of Nitrogen-Containing Compounds>

[0063] The method for producing a nitrogen-containing compound of the present invention comprises the steps of synthesizing the nitrogen-containing compound from nitrogen and a proton source in the presence of a nitrogen-activating catalyst having a structure.

[0064] The synthesis of the nitrogen-containing compound is preferably carried out in the presence of a reducing agent described below or by an electrochemical reduction reaction.

[0065] The method for producing a nitrogen-containing compound of the present invention can carry out the synthesis reaction of the nitrogen-containing compound under mild reaction conditions, thereby reducing energy consumption and eliminating the need for large-scale equipment made of special materials, thereby achieving excellent industrial productivity.

[0066] Nitrogen

[0067] As nitrogen, nitrogen gas at normal pressure is preferably used. Nitrogen gas is inexpensive and can be used in a large excess relative to other reagents.

[0068] Proton Source

[0069] Examples of the proton source include alcohols such as water, methanol, ethanol, propanol, butanol, trifluoroethanol, phenol, and ethylene glycol, and hydrides of lutidine, picoline, and collidine. Water is preferred.

[0070] When water is used as a proton source, the process of obtaining hydrogen from natural gas mainly composed of methane (CH4) as in the conventional Haber-Bosch process can be omitted, and the emission of carbon dioxide, a greenhouse gas, can be significantly reduced.

[0071] <Nitrogen-activated catalyst>

[0072] The nitrogen activation catalyst in the method for producing a nitrogen-containing compound of the present invention has a structure represented by any one of the following formulae (I-1) to (I-4).

[0073] [Chemistry 6]

[0074]

[0075] [Where R 1 ~R 4 Each independently represents an alkyl group having 1 to 10 carbon atoms.

[0076] R 5 It represents a phenyl group or a naphthyl group which may have one or more substituents selected from an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, a halogen atom, and a perfluoromethyl group (-CF3).

[0077] n1 and n2 each independently represent an integer of 1 to 3.

[0078] m1 means 1 or 2.

[0079] m2 represents an integer from 1 to 4.

[0080] m3 and m4 represent integers of 1 to 6.

[0081] Z represents a structure represented by the following formula (i) or (ii).

[0082] [Chemistry 7]

[0083]

[0084] {wherein, X represents a halogen atom.

[0085] Wavy lines indicate bonds to adjacent atoms.

[0086] In another embodiment of the present invention, the nitrogen activation catalyst has a structure represented by the following formula (I-5).

[0087] [Chemistry 8]

[0088]

[0089] [Where R 1 ~R 5 , Z, n1, n2 are the same as above.

[0090] m5 represents an integer from 1 to 8.]

[0091] The nitrogen activation catalyst having the structure represented by the above formulae (I-1) to (I-4) is an organometallic complex having molybdenum (Mo) as the central metal and a PCP-type pincer ligand.

[0092] The nitrogen activation catalyst has an activity capable of cutting the triple bond of the nitrogen molecule.

[0093] In the PCP-type pincer ligand, two phosphorus atoms located in the same plane and the carbon atom forming the carbene are tridentately coordinated to molybdenum.

[0094] When Z represents the structure represented by the above formula (i), three halogen atoms are bonded to Mo via σ bonds. In this case, a trivalent Mo complex is obtained.

[0095] When Z represents the structure represented by the above formula (ii), one halogen atom is bonded to Mo via a σ bond, and one nitrogen atom forms a triple bond with Mo. In this case, a tetravalent Mo complex is obtained.

[0096] R 1 ~R 4 Each independently represents an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group may be straight chain or branched. Specific examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, tert-hexyl (thexyl group, 2,3-dimethylbutan-2-yl), and adamantyl. 1 ~R 4 It is preferably a branched alkyl group with large steric hindrance, more preferably a tert-butyl group or a tert-hexyl group. 1 ~R 4 All are tert-butyl, or R 1 ~R 4 All are tert-hexyl groups.

[0097] The imidazole skeleton in the aforementioned formula (I-1) has m1 R bonded to it. 5 . m1 is 1 or 2.

[0098] The benzene skeleton in the aforementioned formula (I-2) has m2 R bonded to it. 5 . m2 is an integer from 1 to 4.

[0099] The naphthalene skeletons in the aforementioned formulas (I-3) and (I-4) have m3 and m4 R bonded to them, respectively.5 . m3 and m4 are integers ranging from 1 to 6 respectively.

[0100] In the above formula (I-5), m5 R5 are bonded to the anthracene skeleton. m5 is an integer of 1-8.

[0101] On the benzene skeleton in the aforementioned formula (I-2), the naphthalene skeletons in the aforementioned formulas (I-3) and (I-4), and the anthracene skeleton in the aforementioned formula (I-5), R 5 The location of the bonding is not restricted.

[0102] R 5 It is a phenyl group or a naphthyl group which may have one or more substituents selected from an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, a halogen atom, and a perfluoromethyl group (-CF3).

[0103] The C1-6 alkyl group is preferably a C1-3 alkyl group, more preferably a methyl group or an ethyl group. In the C1-6 alkoxy group, the alkyl moiety is the aforementioned C1-6 alkyl group, preferably a C1-3 alkoxy group, more preferably a methoxy group or an ethoxy group.

[0104] The halogen atom is a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br) or an iodine atom (I).

[0105] R 5 In the case of a phenyl group having a substituent, the number of substituents is 1 to 5, preferably 1 to 3, and more preferably 1 or 2. The position of the substituent is not limited.

[0106] R 5 When it is a naphthyl group which may have one or more substituents, the naphthyl group may be either 1-naphthyl or 2-naphthyl. 5 In the case of a naphthyl group having a substituent, the number of substituents is 1 to 7, preferably 1 to 4, and more preferably 1 or 2. The position of the substituent is not limited.

[0107] There are multiple R 5 When each R 5 It can be the same or different.

[0108] As R 5 Specific examples of include those represented by the following chemical formulas.

[0109] [Chemistry 9]

[0110]

[0111] [In the formula, Y represents a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, a halogen atom, and a perfluoromethyl group (-CF3). A plurality of Ys may be the same or different.]

[0112] p1 represents an integer from 1 to 5.

[0113] p2 represents an integer from 1 to 7.

[0114] Wavy lines indicate bonds to adjacent atoms.]

[0115] R 5 When it is a phenyl group having a substituent, R 5 It preferably has the following structure.

[0116] [Chemistry 10]

[0117]

[0118] [Wherein, Y is the same as above.]

[0119] In one preferred embodiment of the present invention, R 5 represents a phenyl group or a naphthyl group which may have one or more substituents selected from a halogen atom and a perfluoromethyl group (-CF3). That is, Y preferably represents a substituent selected from a halogen atom and a perfluoromethyl group (-CF3).

[0120] In one preferred embodiment of the present invention, the nitrogen-activated catalyst has a structure represented by the following formula (I-1) or (I-2).

[0121] [Chemistry 11]

[0122]

[0123] [Where R 1 ~R 4 Each independently represents an alkyl group having 1 to 10 carbon atoms.

[0124] R 5 It represents a phenyl group or a naphthyl group which may have one or more substituents selected from an alkyl group having 1 to 6 carbon atoms, a halogen atom, and a perfluoromethyl group (-CF3).

[0125] n1 and n2 each independently represent an integer of 1 to 3.

[0126] m1 means 1 or 2.

[0127] m2 represents an integer from 1 to 4.

[0128] Z represents a structure represented by the following formula (i) or (ii).

[0129] [Chemistry 12]

[0130]

[0131] {wherein, X represents a halogen atom.

[0132] Wavy lines indicate bonds to adjacent atoms.

[0133] The nitrogen-activated catalyst preferably has a structure represented by any of the following formulae.

[0134] [Chemistry 13]

[0135]

[0136] [Chemistry 14]

[0137]

[0138] [Chemistry 15]

[0139]

[0140] The nitrogen-activated catalyst more preferably has a structure represented by any of the following formulae.

[0141] [Chemistry 16]

[0142]

[0143] [Wherein, Z is the same as above.]

[0144] It should be noted that, in the above formula, tBu represents a tert-butyl group.

[0145] The reaction for synthesizing the nitrogen-containing compound from nitrogen and a proton source in the method for producing the nitrogen-containing compound of the present invention is presumed to proceed by the following mechanism.

[0146] The following describes the synthesis of ammonia using an iodine atom as an example, where X is an iodine atom and samarium (II) iodide is used as a reducing agent. Here, the pincer ligand in the nitrogen-activated catalyst is represented by L. It is assumed that the synthesis of ammonia proceeds according to Formulas <1> to <3>.

[0147] [Chemistry 17]

[0148] <1> LMoI3+2SmI2→LMoI+2SmI3

[0149] <2> 2LMoI+N2→LMoI…N≡N…IMoL→2LMo(I)≡N

[0150] <3> LMo(I)≡N+H + +e - →LMo(I)=NH

[0151] LMo(I)=NH+H + +e - →LMo(I)-NH2

[0152] LMo(I)-NH2+H ++e - →LMo(I)+NH3

[0153] Specifically, the central metal Mo of the nitrogen-activated catalyst is reduced from trivalent to monovalent (Formula <1> ).

[0154] Next, the nitrogen N 2 is activated by the reduced nitrogen activating catalyst (Formula 2).

[0155] Then, on the catalyst, the activated nitrogen, protons and reducing agent react in sequence to generate ammonia (Formula <3> ).

[0156] In this way, the nitrogen triple bond of nitrogen N2 is dissociated by the action of the nitrogen activation catalyst and is hydrogenated to generate ammonia.

[0157] <Reaction Conditions, etc.>

[0158] The method for producing a nitrogen-containing compound of the present invention enables synthesis of the nitrogen-containing compound under relatively mild conditions, for example, within a range of -80°C to 100°C and a pressure of 0.10 MPa to 0.20 MPa. The temperature is preferably -60°C to 70°C, and more preferably -40°C to 60°C.

[0159] In the method for producing a nitrogen-containing compound of the present invention, the production of the nitrogen-containing compound can be carried out in a solvent. The solvent is not particularly limited, and examples thereof include cyclic ether solvents, chain ether solvents, nitrile solvents, hydrocarbon solvents, and the like. Examples of cyclic ether solvents include tetrahydrofuran (hereinafter referred to as THF or THF) and dioxane. Examples of chain ether solvents include diethyl ether. Examples of nitrile solvents include acetonitrile and propionitrile. Examples of hydrocarbon solvents include aromatic hydrocarbons such as toluene and saturated hydrocarbons such as hexane.

[0160] <Reducing Agent>

[0161] In one preferred embodiment of the method for producing a nitrogen-containing compound of the present invention, the nitrogen-containing compound is synthesized from nitrogen and a proton source in the presence of a reducing agent.

[0162] The nitrogen-activated catalyst is reduced and activated by the action of the reducing agent, whereby the reaction of synthesizing the nitrogen-containing compound proceeds favorably.

[0163] Specific examples of reducing agents include at least one selected from lanthanide metal halides (II), decamethylcobaltocene, cobaltocene, and decamethylchromocene. Among these, lanthanide metal halides (II) are preferred, samarium (II) halides are more preferred, and samarium (II) iodide is further preferred. It should be noted that when the reduction reaction is performed by electrolytic reduction or the like, a reducing agent may not be used.

[0164] When a reducing agent is used, the amount of the reducing agent used is preferably 0.5 equivalents to 100,000 equivalents, more preferably 0.7 equivalents to 10,000 equivalents, and even more preferably 1 equivalent to 1,000 equivalents, relative to 1 mol of the central metal Mo of the nitrogen-activated catalyst.

[0165] Batch reaction

[0166] As a preferred embodiment of the method for producing the nitrogen-containing compound of the present invention, there is a batch reaction in which each component is charged into a container and reacted. Nitrogen is supplied from the gas phase by circulating nitrogen in the container, charging a solvent, and stirring. A gas trap filled with dilute sulfuric acid is provided at the nitrogen outlet to capture the nitrogen-containing compound in the gas generated. A nitrogen activator, a reducing agent, and a proton source are charged into the container. The nitrogen activator activates nitrogen, and the reducing agent reacts with protons from the proton source. The reduction reaction and the proton reaction can be carried out simultaneously or sequentially. The reduction of the nitrogen activator and the proton reaction are repeated to synthesize the nitrogen-containing compound. The nitrogen-containing compound is dissolved in the solvent and captured by the gas trap to be recovered.

[0167] <Electrochemical reduction reaction>

[0168] In another preferred embodiment of the method for producing a nitrogen-containing compound of the present invention, the nitrogen-containing compound is synthesized from nitrogen and a proton source by an electrochemical reduction reaction.

[0169] The electrochemical reduction reaction includes, for example, synthesizing a nitrogen-containing compound from nitrogen and a proton source in the presence of the nitrogen-activating catalyst and a reducing agent, and simultaneously reducing the reducing agent oxidized in the synthesis reaction of the nitrogen-containing compound by electrolysis.

[0170] Here, the term "simultaneously" means that the aforementioned steps are carried out in the same system. It is preferred that the time interval between the synthesis of the nitrogen-containing compound and the reduction of the oxidized reducing agent be short.

[0171] As an example, it can be implemented according to the description of International Publication No. 2022 / 230898.

[0172] Specifically, a nitrogen-activating catalyst is introduced into the cathode side of an electrolysis cell, where it reacts with nitrogen and, in addition, with protons supplied from the anode side, to produce nitrogen-containing compounds. It is presumed that when the proton source is water and a proton-coupled electron transfer mediator is used, nitrogen-containing compounds such as ammonia are continuously produced as nitrogen-containing compounds via the mechanisms shown in reaction equations (1) to (6) or reaction equations (7) to (12).

[0173] [Chemistry 18]

[0174] (1)Red+H2O→Red-H2O→Ox-OH+H + +e -

[0175] (2) Mo catalyst + N2 → (Mo≡N) compound

[0176] (3) (Mo≡N) compound + 3H + +3e - →Mo catalyst+NH3

[0177] (4) H2O (anode chamber) → 1 / 2O2 + 2H + +2e -

[0178] (5)H + (Anode chamber) → (Diaphragm) → H + (Anode chamber)

[0179] (6)Ox-OH+e - (electrode)+H + →Red-H2O

[0180] or

[0181] (7)Red+H2O→Red-H2O→Ox-OH+H + +e -

[0182] (8) Mo catalyst + N2 → (Mo≡N) compound

[0183] (9) (Mo≡N) compound + 3H + +3e - →Mo catalyst+NH3

[0184] (10)Ox-OH+e - (Electrode) → Red + OH -

[0185] (11)OH - →(diaphragm)→OH - (Anode chamber)

[0186] (12)4OH - →O2+2H2O+4e -

[0187] Here, Red represents a reducing agent, Ox represents an oxidized reducing agent, and Cat represents a nitrogen-activated catalyst.

[0188] The proton H in the reactions (3) and (9) + The protons can be supplied from a proton source that has been added to the cathode chamber, or from the anode chamber through a diaphragm.

[0189] More specifically, in the method for producing a nitrogen-containing compound of the present invention, for example, when synthesizing ammonia (NH₃) using an electrolysis cell as the nitrogen-containing compound production apparatus, a molybdenum complex (hereinafter also referred to as "Mocat") as the nitrogen activation catalyst, samarium iodide (SmI₂) as the reducing agent, and water (H₂O) as the proton source, it is believed that ammonia is continuously synthesized through the reactions shown below (A) to (C). It should be noted that the reaction shown below (B) also includes the reaction shown below (A) that is carried out in conjunction with the NH₃ generation reaction.

[0190] [Chemistry 19]

[0191] (A) SmI2+H2O→SmI2(H2O)→SmI2(OH) + +e -

[0192] (B) NH3 formation reaction

[0193] N2+6SmI2+6H2O→(Proton-coupled electron transfer (PCET) reaction+Mocat)→2NH3+6SmI2(OH)

[0194] (C) Reduction reaction of samarium iodide (cathode reaction)

[0195] SmI2(OH)+e→SmI2+OH -

[0196] The nitrogen-containing compound can also be produced by reducing the reducing agent by electrolysis. In this case, the reaction apparatus, electrodes, and solvent used in the reaction can be freely selected.

[0197] For example, you can use Figure 1 The electrolysis cell shown.

[0198] Specifically, for example, a proton source such as water is used in the anode tank, titanium or a carbon-based material is used in the cathode electrode 1, and nickel or a carbon-based material is used in the anode electrode 2. A nitrogen-activated catalyst, a reducing agent, a proton source, and a solvent are added to the cathode chamber 4 to which a voltage is applied from a power supply 6. A proton supply source such as water is added to the anode chamber 5.

[0199] The nitrogen activation catalyst reacts with nitrogen molecules supplied to the cathode chamber 4, activating them and donating protons and electrons to the nitrogen, reducing the metal. This process is repeated to produce ammonia. When the reducing agent acts as an electron mediator, the oxidized reducing agent is reduced at the cathode electrode 1 and reused.

[0200] [Apparatus for producing nitrogen-containing compounds]

[0201] The present invention also provides an apparatus for producing nitrogen-containing compounds.

[0202] The apparatus for producing the nitrogen-containing compound of the present invention produces the nitrogen-containing compound by the above-mentioned method for producing the nitrogen-containing compound.

[0203] The specific structure is not limited as long as it includes the nitrogen activation catalyst and can carry out the method for producing the nitrogen-containing compound.

[0204] For example, the aforementioned Figure 1 The electrolysis cell shown.

[0205] Example

[0206] Hereinafter, the present disclosure will be further described in detail through examples, but the present disclosure is not limited to these examples.

[0207] Preparation Example 1 Synthesis of Complex (1)

[0208] In 100 mL of toluene, 2.0 g of 4-bromo-1,2-diaminobenzene and 1.6 g of phenylboronic acid were reacted at 85° C. for 48 hours in the presence of 0.15 mg of tetrakistriphenylphosphine palladium and 8.3 g of potassium carbonate to obtain 744 mg of 4-phenyl-1,2-diaminobenzene.

[0209] 510 mg of paraformaldehyde and 2.2 g of di-tert-butylphosphine were reacted at 60°C for 16 hours, and the resulting product was dissolved in 12 mL of dichloromethane. This was then added to 740 mg of the 4-phenyl-1,2-diaminobenzene obtained above, and the reaction was continued at 60°C for 96 hours. Subsequently, 69 mg of selenium was added, and the reaction was continued at room temperature for 1 hour. 12 mL of triethoxymethane and 150 mg of ammonium hexafluorophosphate were added to the product, and the reaction was continued at 120°C for 3 hours. 332 mg of tris(dimethylamino)phosphine and 10 mL of dichloromethane were added to the product, and the reaction was continued at room temperature for 1 hour.

[0210] The obtained product was then reacted with potassium hexamethyldisilazane and then with molybdenum chloride, and purified by recrystallization to obtain 209 mg of the Mo complex having a monophenylbenzimidazole-type ligand shown below, hereinafter referred to as PhPCPMoCl 3 .

[0211] In addition, tBu represents a tert-butyl group.

[0212] [Chemistry 20]

[0213]

[0214] Preparation Example 2 Synthesis of Complex (2)

[0215] The following Mo complex was obtained in the same manner as in Preparation Example 1 except that 3.36 g of 3,5-ditrifluoromethylphenylboric acid was used in place of 1.6 g of phenylboric acid.

[0216] [Chemistry 21]

[0217]

[0218] Preparation Example 3 Synthesis of Complex (3)

[0219] The following Mo complex was obtained in the same manner as in Preparation Example 1 except that 2.9 g of 4,5-dibromo-1,2-diaminobenzene was used in place of 2.0 g of 4-bromo-1,2-diaminobenzene.

[0220] [Chemistry 22]

[0221]

[0222] Preparation Example 4 Synthesis of Complex for Comparative Example (1)

[0223] The same operation as in Production Example 1 was carried out except that 430 mg of 1,2-diaminobenzene was used instead of 4-phenyl-1,2-diaminobenzene produced in Production Example 1 to obtain 190 mg of the Mo complex shown below.

[0224] [Chemistry 23]

[0225]

[0226] Preparation Example 5 Synthesis of Complex for Comparative Example (2)

[0227] The same procedures as in Preparation Example 1 were followed except that 80 mg of 4-SF5-1,2-diaminobenzene was used instead of 4-phenyl-1,2-diaminobenzene produced in Preparation Example 1 to obtain 190 mg of the Mo complex having a 4-SF5-benzimidazole-type ligand shown below. Hereinafter, this will be referred to as SF5-PCPMoCl3.

[0228] [Chemistry 24]

[0229]

[0230] Table 1 shows the NMR measurement results of the PCP ligands constituting the Mo complexes of Production Examples 1 to 3 and 5.

[0231] [Table 1]

[0232]

[0233] Example 1 Synthesis of Ammonia (Batch Method (1))

[0234] Under a nitrogen atmosphere, 25 nmol of the complex PhPCPMoCl3 obtained in Example 1, 720 μmol of SmI2, and 720 μmol of water were added to 6 mL of THF. The mixture was reacted for 15 minutes to synthesize ammonia. The reaction was then quenched with dilute sulfuric acid. KOH was added to the resulting solution, which was then distilled off under reduced pressure to obtain ammonia.

[0235] The obtained ammonia was quantified by ion chromatography, and it was confirmed that 5600 mol / mol of ammonia was generated per 1 mol of molybdenum in the complex.

[0236] Example 2 Synthesis of Ammonia (Batch Method (2))

[0237] Ammonia was synthesized in the same manner as in Example 1 except that 25 nmol of the complex 3,5-CF3PhPHPMoCl3 obtained in Preparation Example 2 was used.

[0238] The obtained ammonia was quantified by ion chromatography, and it was confirmed that 7230 mol of ammonia was generated per 1 mol of molybdenum in the complex.

[0239] Example 3 Synthesis of Ammonia (Batch Method (3))

[0240] Ammonia was synthesized in the same manner as in Example 1 except that 25 nmol of the complex Ph2PCPMoCl3 obtained in Preparation Example 3 was used.

[0241] The obtained ammonia was quantified by ion chromatography, and it was confirmed that 4910 mol of ammonia was generated per 1 mol of molybdenum in the complex.

[0242] Comparative Example 1 Synthesis of Ammonia (Batch Method (c1))

[0243] Ammonia was synthesized in the same manner as in Example 1 except that 25 nmol of the complex PCPMoCl 3 obtained in Production Example 4 was used.

[0244] The obtained ammonia was quantified by ion chromatography, and it was confirmed that 4190 mol of ammonia was generated per 1 mol of molybdenum in the complex.

[0245] Comparative Example 2 Synthesis of Ammonia (Batch Method (c2))

[0246] Ammonia was synthesized in the same manner as in Example 1 except that 25 nmol of the complex SF5-PCPMoCl3 obtained in Preparation Example 5 was used.

[0247] The obtained ammonia was quantified by ion chromatography, and it was confirmed that 1390 mol of ammonia was generated per 1 mol of molybdenum in the complex.

[0248] Example 4 Electrolytic synthesis of ammonia

[0249] Used Figure 1 The electrolysis cell shown (made of Pyrex glass, H-type cell) was used. The cell's diaphragm used an anion exchange membrane (manufactured by Astom Co., Ltd., product name: "Neosepta ASE-A-5142 membrane," thickness: 150 μm), the anode electrode used a nickel electrode (manufactured by Niraco Co., Ltd., product name: "100mesh" nickel), and the cathode electrode used a titanium electrode (manufactured by Taiyo Gold Mesh Co., Ltd., product name: "fine titanium fiber processed product").

[0250] Separately, 40 mL of a 0.2 mol / L potassium hydroxide aqueous solution was charged into the anode chamber of the aforementioned H-type cell, and in the cathode chamber, 0.01 mmol of the complex PhPCPMoCl3 and 0.06 mmol of SmI2 obtained in Preparation Example 1 were charged into 40 mL of dimethoxyethane (DME), and 200 mg of tetrabutylammonium trifluoromethanesulfonate (Bu4NSO3CF3) and 500 mg of lithium iodide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added as additives.

[0251] Next, a voltage of 3.5 V was applied between the anode and cathode electrodes of the electrolysis cell for 4 hours to allow for ammonia synthesis. The reaction was terminated by adding 10 mL of 0.02 mol / L sulfuric acid to the cathode chamber. The generated ammonia was quantified by ion chromatography, yielding a yield of 0.06 mmol.

[0252] Description of Reference Numerals

[0253] 1 cathode electrode

[0254] 2 Anode electrode

[0255] 3 Diaphragm

[0256] 4 Cathode chamber

[0257] 5 Anode chamber

[0258] 6 Power Supply

[0259] 10 Electrolysis cell

Claims

1. A method for producing a nitrogen-containing compound, comprising the following steps: A nitrogen-containing compound is synthesized from nitrogen and a proton source in the presence of a nitrogen-activated catalyst having a structure represented by any one of the following formulae (I-1) to (I-4), [Chemistry 1] Where R 1 ~R 4 each independently represents an alkyl group having 1 to 10 carbon atoms, R 5 represents a phenyl group or a naphthyl group which may have one or more substituents selected from an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, a halogen atom, and a perfluoromethyl group (-CF3), n1 and n2 each independently represent an integer of 1 to 3, m1 means 1 or 2, m2 represents an integer from 1 to 4, m3 and m4 represent integers from 1 to 6, Z represents a structure represented by the following formula (i) or (ii), [Chemistry 2] In the formula, X represents a halogen atom, Wavy lines represent bonds to adjacent atoms.

2. The manufacturing method according to claim 1, wherein R 5 It is a phenyl group or a naphthyl group which may have one or more substituents selected from a halogen atom and a perfluoromethyl group (-CF3).

3. The manufacturing method according to claim 1 or 2, wherein: The nitrogen activation catalyst is a nitrogen activation catalyst having a structure represented by the above formula (I-1) or (I-2).

4. The production method according to any one of claims 1 to 3, wherein The aforementioned nitrogen-containing compound is ammonia.

5. The production method according to any one of claims 1 to 4, wherein Nitrogen-containing compounds are also synthesized in the presence of a reducing agent.

6. The production method according to any one of claims 1 to 4, wherein Nitrogen-containing compounds are synthesized under electrochemical reduction reaction.

7. The production method according to any one of claims 1 to 6, wherein The nitrogen activated catalyst is a nitrogen activated catalyst having a structure represented by any one of the following formulae: [Chemistry 3] In the formula, Z is the same as described above, and tBu represents a tert-butyl group.

8. An apparatus comprising the nitrogen-activated catalyst, for producing a nitrogen-containing compound by the production method according to any one of claims 1 to 7.

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