Method for producing ruthenium complex, and method for producing ruthenium complex and diamine using the same

Abstract

To provide a ruthenium complex that facilitates separation recovery through the extraction separation technique and a method for producing the same.SOLUTION: A method for producing a ruthenium complex includes the steps of preparing a compound represented by the formula (3) from a compound represented by the formula (2) by an aromatic electrophilic substitution reaction under an acidic condition, preparing a compound represented by the formula (4) from the compound represented by the formula (3) by a nucleophilic substitution reaction, and preparing a ruthenium complex represented by the formula (1) from the compound represented by the formula (4). (R is a C1-18 hydrocarbon optionally including a heteroatom in the main chain; R1 and R2 independently represent a substituted / unsubstituted C1-4 alkyl group or a substituted / unsubstituted C3-8 cycloalkyl group; X independently represent F, Cl, Br, I, a triflate group, or a tosyl group).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a ruthenium complex, and a method for producing a ruthenium complex and a diamine using the same. [Background technology]

[0002] Diamines, which have two amino groups in their molecule, are one of the key substances in the chemical industry. In particular, hexamethylenediamine is a very useful monomer as a raw material for nylon, and one of the main methods for producing it is the amination reaction of 1,6-hexanediol. To efficiently produce hexamethylenediamine, catalysts have been developed to promote this amination reaction.

[0003] For example, Patent Documents 1 and 2 disclose the chemical structure and production method of a ruthenium-PNP-pincer catalyst that selectively promotes the amination reaction of 1,6-hexanediol. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 8,889,865 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-27052 Summary of the Invention [Problem to be solved by the invention]

[0005] However, homogeneous catalysts are difficult to recover from the reaction solution after the reaction is complete because the catalyst itself dissolves in the reaction substrate or solvent. The ruthenium complexes disclosed in Patent Documents 1 and 2 are known to be catalysts that produce hexamethylenediamine in high yield in the presence of a solvent, but Patent Documents 1 and 2 do not mention separation and recovery. Furthermore, as a catalyst separation method, it is preferable to be able to recover the catalyst by an extraction operation, which is more energy efficient than distillation.

[0006] Therefore, an object of the present invention is to provide a ruthenium complex that can be easily separated and recovered by extraction and a method for producing the same. [Means for solving the problem]

[0007] As a result of extensive research aimed at solving the above problems, the present inventors have found that a predetermined ruthenium complex can be easily separated and recovered by extraction and separation, and that such a ruthenium complex can be produced by a predetermined method, thereby completing the present invention.

[0008] That is, the present invention includes the following embodiments. [1] obtaining a compound represented by general formula (3) from a compound represented by general formula (2) by an aromatic electrophilic substitution reaction under acidic conditions; obtaining a compound represented by general formula (4) from a compound represented by general formula (3) by a nucleophilic substitution reaction; obtaining a compound represented by general formula (1) from a compound represented by general formula (4); A method for producing a ruthenium complex represented by general formula (1), comprising: [ka] (In the general formula (1), R is a hydrocarbon having 1 to 18 carbon atoms which may contain a heteroatom in the main chain and which is monosubstituted at least in one of the a, b, c, d, e, f, and g positions of the acridinyl group, and R 1 and R 2 are each independently an alkyl group having 1 to 4 carbon atoms which may have a substituent or a cycloalkyl group having 3 to 8 carbon atoms which may have a substituent. [ka] (In general formula (2), X is any one of a fluoro group, a chloro group, a bromo group, an iodo group, a triflate group, and a tosyl group, which is monosubstituted at least one of the a, b, c, d, e, f, and g positions of the acridinyl group.) [ka] (In general formula (3), X's are each independently any one of a fluoro group, a chloro group, a bromo group, an iodo group, a triflate group, and a tosyl group, and X's bonded to the acridine skeleton are monosubstituted with at least one of the a, b, c, d, e, f, and g moieties.) [ka] (In the general formula (4), X is any one of a fluoro group, a chloro group, a bromo group, an iodo group, a triflate group, and a tosyl group, which is monosubstituted at least in one of the a, b, c, d, e, f, and g positions of the acridinyl group, and R 1 and R 2 are each independently an alkyl group having 1 to 4 carbon atoms which may have a substituent or a cycloalkyl group having 3 to 8 carbon atoms which may have a substituent. [2] The step of obtaining the compound represented by the general formula (1) obtaining a compound represented by general formula (5) from a compound represented by general formula (4) by a ligand exchange reaction; obtaining a compound represented by general formula (1) from a compound represented by general formula (5) by a cross-coupling reaction using a transition metal catalyst containing at least one transition metal of Groups 3 to 11; The method for producing a ruthenium complex according to [1], comprising: [ka] (In the general formula (5), X is any one of a fluoro group, a chloro group, a bromo group, an iodo group, a triflate group, and a tosyl group, which is monosubstituted at least in one of the a, b, c, d, e, f, and g positions of the acridinyl group, and R 1 and R 2 are each independently an alkyl group having 1 to 4 carbon atoms which may have a substituent or a cycloalkyl group having 3 to 8 carbon atoms which may have a substituent. [3] The step of obtaining the compound represented by the general formula (1) obtaining a compound represented by general formula (6) from a compound represented by general formula (4) by a cross-coupling reaction using a transition metal catalyst containing at least one transition metal of Groups 3 to 11; obtaining a compound represented by general formula (1) from a compound represented by general formula (6) by a ligand exchange reaction; The method for producing a ruthenium complex according to [1], comprising: [ka] (In the general formula (6), R is a hydrocarbon having 1 to 18 carbon atoms, which may contain a heteroatom in the main chain and is monosubstituted at least in one of the a, b, c, d, e, f, and g positions of the acridinyl group; R 1 and R 2 are each independently an alkyl group having 1 to 4 carbon atoms which may have a substituent or a cycloalkyl group having 3 to 8 carbon atoms which may have a substituent. [4] A ruthenium complex represented by general formula (1) having an HLB value of 12.335 or less according to the Griffin method. [ka] (In the general formula (1), R is a hydrocarbon having 1 to 18 carbon atoms which may contain a heteroatom in the main chain and which is monosubstituted at least in one of the a, b, c, d, e, f, and g positions of the acridinyl group, and R 1 and R 2 are each independently an alkyl group having 1 to 4 carbon atoms which may have a substituent or a cycloalkyl group having 3 to 8 carbon atoms which may have a substituent. [5] The ruthenium complex according to [4], having an HLB value of 9.473 or less according to the Griffin method. [6] The ruthenium complex according to [4], having an HLB value according to the Griffin method of 8.715 or less. [7] A method for producing a diamine, comprising a step of reacting a diol with ammonia in the presence of the ruthenium complex according to any one of [4] to [6]. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a ruthenium complex that can be easily separated and recovered by extraction separation, a method for producing the same, and the like. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below. Note that the present invention is not limited to the following embodiments (present embodiments) and can be practiced in various modifications within the scope of the gist. The configurations of chemical formulae described in this specification and claims represent relative configurations unless otherwise specified.

[0011] [1] Ruthenium complex The ruthenium complex of this embodiment has a structure represented by general formula (1). From the viewpoint of improving the ease of separation and recovery by extraction separation from a hydrophilic solution, the HLB value (Griffin method) of the ruthenium complex is preferably 12.335 or less, more preferably 9.473 or less, even more preferably 8.715 or less, and even more preferably 7.343 or less. When the HLB value is within the above range, the ruthenium complex tends to have excellent separation performance from a hydrophilic solution. In this specification, the HLB value (Griffin method) is calculated using the following formula. HLB value = 20 x (total atomic weight of heteroatoms (including metal atoms) ÷ molecular weight (excluding the molecular weight of the substituent bonded to the phosphine)).

[0012] [ka]

[0013] In general formula (1), R represents a hydrocarbon having 1 to 18 carbon atoms, which is monosubstituted at at least one of the a, b, c, d, e, f, and g moieties of the acridinyl group and may contain a heteroatom in the main chain. From the viewpoint of improving the ease of separation and recovery by extraction separation, the number of carbon atoms in R is preferably 3 to 18, more preferably 8 to 18, and even more preferably 11 to 18. The heteroatom that may be contained in R is contained in the main chain of the hydrocarbon. Examples of heteroatoms that may be contained in R include a nitrogen atom, a sulfur atom, an oxygen atom, and a phosphorus atom. These heteroatoms may exist as a tertiary amine, an ether bond, a thioether bond, and a tertiary phosphine, respectively. When R contains a heteroatom, including it in the main chain improves the ease of separation and recovery of the ruthenium complex by extraction separation from a hydrophilic solution. The number of heteroatoms contained in R is preferably 0 to 3, more preferably 0 or 1, and even more preferably 0. From the viewpoint of improving the ease of separation and recovery by extraction separation, R is preferably an alkyl group having 3 to 18 carbon atoms, more preferably an alkyl group having 8 to 18 carbon atoms, and even more preferably an alkyl group having 11 to 18 carbon atoms. In this specification, the a, b, c, d, e, f, and g sites of the acridinyl group refer to the sites shown as a, b, c, d, e, f, and g in the following formula, respectively. The binding site of R may be, for example, the d site.

[0014] [ka]

[0015] In general formula (1), R 1 and R 2 are each independently an alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms, and are preferably selected from the group consisting of an isopropyl group and a cyclohexyl group, and more preferably a cyclohexyl group. 1 and R 2 may have a substituent, but preferably has no substituent. 1 and R 2The substituents which may be substituted include a fluoro group, a chloro group, a bromo group, a hydroxy group, a cyano group, and an amino group, and preferably a chloro group or a bromo group.

[0016] [2] Method for producing ruthenium complexes The method for producing a ruthenium complex of this embodiment is a method for producing a ruthenium complex represented by general formula (1), comprising the steps of obtaining a compound represented by general formula (3) from a compound represented by general formula (2) by an aromatic electrophilic substitution reaction under acidic conditions, obtaining a compound represented by general formula (4) from the compound represented by general formula (3) by a nucleophilic substitution reaction, and obtaining a compound represented by general formula (1) from the compound represented by general formula (4). The above production method may include other steps as necessary. These other steps may be carried out between the above steps, before the step of obtaining the compound represented by general formula (3), or after the step of obtaining the compound represented by general formula (1). Each of the above steps may be a one-step process or a multi-step process. The reaction scheme of the production method of this embodiment is shown in formula (7). [ka]

[0017] [Step of obtaining a compound represented by general formula (3) from a compound represented by general formula (2)] The method for producing a ruthenium complex of this embodiment includes a step of carrying out a reaction represented by formula (8) to obtain a compound represented by general formula (3) from a compound represented by general formula (2) by an aromatic electrophilic substitution reaction under acidic conditions. [ka]

[0018] In general formula (2), X is any one of a fluoro group, a chloro group, a bromo group, an iodo group, a triflate group (OTf), and a tosyl group, which is monosubstituted at at least one of the a, b, c, d, e, f, and g positions of the acridinyl group. X is preferably a chloro group, a bromo group, an iodo group, a triflate group, or a tosyl group, more preferably a bromo group, an iodo group, or a triflate group, and even more preferably an iodo group or a bromo group. The binding position of X may be, for example, the d position.

[0019] In general formula (3), X's are each independently any one of a fluoro group, a chloro group, a bromo group, an iodo group, a triflate group (OTf), and a tosyl group, and X's bonded to the acridine skeleton are monosubstituted with at least one of the a, b, c, d, e, f, and g moieties. X's are preferably a chloro group, a bromo group, an iodo group, a triflate group, and a tosyl group, more preferably a bromo group, an iodo group, and a triflate group, and even more preferably an iodo group and a bromo group. The three X's in general formula (3) are preferably the same. Furthermore, X's in general formula (2) and X's in general formula (3) are preferably the same. X's bonded to the acridine skeleton may be bonded to, for example, the d moiety.

[0020] The reaction represented by formula (8) can be carried out under various reaction conditions. For example, a reaction for converting a hydrogen atom of a compound represented by general formula (2) to a methyl halogen group can be carried out by the Friedel-Crafts reaction using a halogenated methyl alkyl ether (e.g., bromomethyl methyl ether) under acidic conditions. The use of a solvent in this step, and the type of solvent used, are not particularly limited and can be selected appropriately depending on the purpose. However, solvent-free conditions are preferred from the viewpoint of excellent reaction rate. Furthermore, the temperature and time are not particularly limited and can be selected appropriately depending on the purpose.

[0021] The reaction represented by formula (8) is carried out under acidic conditions. The acid used is not particularly limited and can be appropriately selected depending on the purpose. For example, sulfuric acid, hydrochloric acid, nitric acid, acetic acid, etc. can be used. Preferably, it is a strong acid (e.g., sulfuric acid, hydrochloric acid, nitric acid), more preferably sulfuric acid. The compound that serves as a precursor of the methyl halogen group used in this step is not particularly limited and can be appropriately selected depending on the purpose. For example, a halogenated methyl alkyl ether can be used. Preferably, it is selected from bromomethyl methyl ether, chloromethyl methyl ether, and iodomethyl methyl ether.

[0022] [Step of obtaining a compound represented by general formula (4) from a compound represented by general formula (3)] The method for producing a ruthenium complex of this embodiment includes a step of carrying out the reaction shown in formula (9) to obtain a compound represented by general formula (4) from a compound represented by general formula (3) by a nucleophilic substitution reaction. This step may be carried out directly after the reaction shown in formula (8) and appropriate treatment, or may be carried out after purifying and isolating the compound represented by general formula (3). [ka]

[0023] In general formula (4), X is any one of a fluoro group, a chloro group, a bromo group, an iodo group, a triflate group (OTf), and a tosyl group, which is monosubstituted at at least one of the a, b, c, d, e, f, and g positions of the acridinyl group. X is preferably a chloro group, a bromo group, an iodo group, a triflate group, or a tosyl group, more preferably a bromo group, an iodo group, or a triflate group, and even more preferably an iodo group or a bromo group. X in general formula (4) and X in general formula (3) are preferably the same. The binding position of X may be, for example, the d position.

[0024] In general formula (4), R 1 and R 2are each independently an alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms, and are preferably selected from the group consisting of an isopropyl group and a cyclohexyl group, and more preferably a cyclohexyl group. 1 and R 2 may have a substituent, but preferably has no substituent. 1 and R 2 The substituents which may be substituted include a fluoro group, a chloro group, a bromo group, a hydroxy group, a cyano group, and an amino group, and preferably a chloro group or a bromo group.

[0025] The reaction represented by formula (9) is not particularly limited, and reaction conditions and reagents can be selected appropriately depending on the purpose. Examples of such reactions include a reaction to convert a halogen group in a compound represented by general formula (3) to a phosphorus donor ligand. Examples of such reactions include a nucleophilic substitution reaction using a phosphine reagent such as a dialkylphosphine (e.g., dicyclohexylphosphine, diisopropylphosphine). The solvent used in the reaction is not particularly limited, and examples thereof include methanol. After the reaction, a base treatment may be performed. The base used is not particularly limited, and examples thereof include triethylamine, potassium carbonate, and cesium carbonate.

[0026] [Step of obtaining a compound represented by general formula (1) from a compound represented by general formula (4)] The method for producing a ruthenium complex of this embodiment includes a step of obtaining a compound represented by general formula (1) from a compound represented by general formula (4). This step can be carried out by various methods, but preferably includes a step of converting -X bonded to the acridine skeleton to -R and a step of coordinating ruthenium to the acridine skeleton. The step of obtaining a compound represented by general formula (1) more preferably includes a step of carrying out the reaction represented by formula (10) and a step of carrying out the reaction represented by formula (11), or a step of carrying out the reaction represented by formula (12) and a step of carrying out the reaction represented by formula (13), and even more preferably includes a step of carrying out the reaction represented by formula (10) and a step of carrying out the reaction represented by formula (11). This step may be carried out directly after the reaction represented by formula (9) and appropriate treatment, or may be carried out after purifying and isolating the compound represented by general formula (4).

[0027] [ka] [ka] [ka] [ka]

[0028] The step of carrying out the reaction represented by formula (10) is a step of obtaining a compound represented by general formula (5) from a compound represented by general formula (4), the step of carrying out the reaction represented by formula (11) is a step of obtaining a compound represented by general formula (1) from a compound represented by general formula (5), the step of carrying out the reaction represented by formula (12) is a step of obtaining a compound represented by general formula (6) from a compound represented by general formula (4), and the step of carrying out the reaction represented by formula (13) is a step of obtaining a compound represented by general formula (1) from a compound represented by general formula (6).

[0029] (Step of obtaining a compound represented by general formula (5) from a compound represented by general formula (4)) The step of obtaining the compound represented by general formula (1) may include a step of carrying out the reaction represented by formula (10) to obtain a compound represented by general formula (5) from a compound represented by general formula (4) by a ligand exchange reaction. [ka]

[0030] In general formula (5), X is any one of a fluoro group, a chloro group, a bromo group, an iodo group, a triflate group, and a tosyl group, which is monosubstituted at at least one of the a, b, c, d, e, f, and g positions of the acridinyl group. X is preferably a chloro group, a bromo group, an iodo group, a triflate group, or a tosyl group, more preferably a bromo group, an iodo group, or a triflate group, and even more preferably an iodo group or a bromo group. X in general formula (4) and X in general formula (5) are preferably the same. The binding position of X may be, for example, the d position.

[0031] In general formula (5), R 1 and R 2 are each independently an alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms, and are preferably selected from the group consisting of an isopropyl group and a cyclohexyl group, and more preferably a cyclohexyl group. 1 and R 2 may have a substituent, but preferably has no substituent. 1 and R 2 Examples of the substituent that may be present in R include a fluoro group, a chloro group, a bromo group, a hydroxy group, a cyano group, and an amino group, and a chloro group or a bromo group is preferred. 1 and R 2 and R in general formula (5) 1 and R 2 and are preferably the same.

[0032] The reaction represented by formula (10) is not particularly limited, and reaction conditions and reagents can be selected appropriately depending on the purpose. Examples of such reactions include a reaction in which a ruthenium central metal is coordinated to a compound represented by the general formula (4). Examples of such reactions include a ligand exchange reaction using a carbonylchlorohydridoruthenium(II) complex (e.g., carbonylchlorohydridotris(triphenylphosphine)ruthenium(II) chloride). The solvent used in the reaction in which the ruthenium central metal is coordinated is not particularly limited, and examples thereof include toluene. The temperature and time of the reaction treatment in which the ruthenium central metal is coordinated are not particularly limited, and can be selected appropriately depending on the purpose.

[0033] (Step of obtaining a compound represented by general formula (1) from a compound represented by general formula (5)) The step of obtaining a compound represented by general formula (1) from a compound represented by general formula (4) may include a step of carrying out a reaction represented by formula (11) in which a compound represented by general formula (5) is obtained from a compound represented by general formula (1) by a cross-coupling reaction using a transition metal catalyst containing at least one transition metal of Groups 3 to 11. This step may be carried out directly after the reaction represented by formula (10) and appropriate treatment, or may be carried out after purifying and isolating the compound represented by general formula (5). [ka]

[0034] The reaction represented by formula (11) is not particularly limited, and reaction conditions and reagents can be selected appropriately depending on the purpose. Examples of such reactions include a reaction in which a halogen group in a compound represented by general formula (5) is converted into an alkyl group, a cycloalkyl group, or a heterocyclyl group. Examples of such reactions include cross-coupling reactions using a catalyst selected from Group 3 to 11 transition metal catalysts, such as Suzuki-Miyaura coupling, Migita-Kosugi-Still coupling, and Kumada-Tamao-Colew coupling. The solvent used in this reaction is not particularly limited and can be appropriately selected depending on the purpose, such as tetrahydrofuran (THF). The catalyst used in this reaction is not particularly limited, and examples include solid catalysts used in coupling reactions and homogeneous catalysts (e.g., transition metal catalysts containing at least one Group 3 to 11 transition metal, such as palladium).

[0035] The precursor of an alkyl group, a cycloalkyl group, a heterocyclyl group, or the like used in the reaction is not particularly limited, and examples thereof include alkenes, cycloalkenes, heterocyclenes, and alkyl compounds, cycloalkyl compounds, and heterocyclyl compounds having a borane group.

[0036] (Step of obtaining a compound represented by general formula (6) from a compound represented by general formula (4)) The step of obtaining the compound represented by general formula (1) from the compound represented by general formula (4) may include a step of carrying out the reaction represented by formula (12) to obtain the compound represented by general formula (6) from the compound represented by general formula (4) by a cross-coupling reaction using a transition metal catalyst containing at least one transition metal of Groups 3 to 11. [ka]

[0037] In general formula (6), R represents a hydrocarbon having 1 to 18 carbon atoms, which is monosubstituted at least at one of the a, b, c, d, e, f, and g moieties of the acridinyl group and may contain a heteroatom in the main chain. From the viewpoint of improving the ease of separation and recovery by extraction and separation, the number of carbon atoms in R is preferably 3 to 18, more preferably 8 to 18, and even more preferably 11 to 18. The heteroatom that can be contained in R is contained in the main chain of the hydrocarbon. Examples of heteroatoms that can be contained in R include a nitrogen atom, a sulfur atom, an oxygen atom, and a phosphorus atom. These heteroatoms may exist as a tertiary amine, an ether bond, a thioether bond, and a tertiary phosphine, respectively. When R contains a heteroatom, including it in the main chain improves the ease of separation and recovery of the produced ruthenium complex by extraction and separation from a hydrophilic solution. The number of heteroatoms contained in R is preferably 0 to 3, more preferably 0 or 1, and even more preferably 0. R is preferably an alkyl group having 3 to 18 carbon atoms, more preferably an alkyl group having 8 to 18 carbon atoms, and even more preferably an alkyl group having 11 to 18 carbon atoms. The binding site of R may be, for example, the d site.

[0038] In general formula (6), R 1 and R 2 are each independently an alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms, and are preferably selected from the group consisting of an isopropyl group and a cyclohexyl group, and more preferably a cyclohexyl group. 1 and R 2 may have a substituent, but preferably has no substituent. 1 and R 2 Examples of the substituent that may be present in R include a fluoro group, a chloro group, a bromo group, a hydroxy group, a cyano group, and an amino group, and a chloro group or a bromo group is preferred. 1 and R 2 and R in general formula (6) 1 and R 2 and are preferably the same.

[0039] The reaction represented by formula (12) is not particularly limited, and reaction conditions and reagents can be selected appropriately depending on the purpose. Examples of such reactions include a reaction in which a halogen group in a compound represented by general formula (4) is converted into an alkyl group, a cycloalkyl group, or a heterocyclyl group. Examples of such reactions include cross-coupling reactions using a catalyst selected from Group 3 to 11 transition metal catalysts, such as Suzuki-Miyaura coupling, Migita-Kosugi-Still coupling, and Kumada-Tamao-Colew coupling. The solvent used in this reaction is not particularly limited and can be appropriately selected depending on the purpose, such as tetrahydrofuran (THF). The catalyst used in this reaction is not particularly limited, and examples include heterogeneous catalysts used in coupling reactions and homogeneous catalysts (e.g., transition metal catalysts containing at least one Group 3 to 11 transition metal, such as palladium).

[0040] The precursors of alkyl groups, cycloalkyl groups, heterocyclyl groups, etc. used in the reaction are not particularly limited, and examples thereof include alkenes, cycloalkenes, heterocyclenes, and alkyl compounds, cycloalkyl compounds, and heterocyclyl compounds having a borane group.

[0041] (Step of obtaining a compound represented by general formula (1) from a compound represented by general formula (6)) The step of obtaining a compound represented by general formula (1) from a compound represented by general formula (4) may include a step of carrying out a reaction represented by formula (13) to obtain a compound represented by general formula (1) from a compound represented by general formula (6) by a ligand exchange reaction. This step may be carried out directly after the reaction represented by formula (12) and appropriate treatment, or may be carried out after purifying and isolating the compound represented by general formula (6). [ka]

[0042] The reaction represented by formula (13) is not particularly limited, and reaction conditions and reagents can be selected appropriately depending on the purpose. Examples of such reactions include a reaction in which a ruthenium central metal is coordinated to a compound represented by the general formula (6). Examples of such reactions include a ligand exchange reaction using a carbonylchlorohydridoruthenium(II) complex (e.g., carbonylchlorohydridotris(triphenylphosphine)ruthenium(II) chloride). The solvent used in this reaction is not particularly limited, and examples include toluene. The temperature and time of this reaction are not particularly limited, and can be selected appropriately depending on the purpose.

[0043] [3] Method for producing diamine The ruthenium complex represented by general formula (1) of this embodiment is useful as a diamine production catalyst for producing diamines from diols, and can catalyze the reaction of a diol with ammonia. That is, this embodiment also includes a method for producing a diamine, which includes a step of reacting a diol with ammonia in the presence of the ruthenium complex of this embodiment. Examples of such diols include 1,4-butanediol, 1,5-pentanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol. However, 1,6-hexanediol is preferred from the viewpoint of the usefulness of the resulting diamine. In this embodiment, the step of reacting a diol with ammonia may be carried out under an inert gas atmosphere such as nitrogen or argon, or in the presence of an active gas such as hydrogen. This reaction step can be carried out by a conventional method, such as a batch process, a semi-batch process, or a continuous process.

[0044] The method for producing a diamine according to this embodiment may include a separation step of recovering the ruthenium complex according to this embodiment from the amination reaction solution after the reaction. Examples of methods used in the separation step include concentration, distillation, extraction, crystallization, recrystallization, and combinations thereof. However, from the viewpoint of excellent energy efficiency, extraction-based separation and recovery is preferred. The ruthenium complex according to this embodiment can be easily separated and recovered by extraction, and therefore can be efficiently recovered using extraction-based separation and recovery.

[0045] [4] Extraction of ruthenium complexes The ruthenium complex of this embodiment can be separated and recovered in high yield from a hydrophilic solution by extraction. In this specification, "hydrophilic" refers to the property of being easily soluble in or miscible with water. Examples of such hydrophilic solutions include a reaction solution for producing a diamine by amination of a diol, such as a reaction mixture obtained after the diamine is produced by the reaction of a diol with ammonia.

[0046] The extraction of the ruthenium complex is carried out by mixing an extraction solvent with a hydrophilic solution containing the ruthenium complex, allowing for phase separation, and then recovering the extraction solvent. The extraction solvent is preferably a non-polar solvent that dissolves little polar compounds (e.g., diamines and diols).

[0047] The extraction efficiency is expressed by the partition coefficient (= [complex concentration in the extracting solvent wt / wt%] / [complex concentration in the solution to be extracted wt / wt%]). When extracting the ruthenium complex of this embodiment, an appropriate extraction solvent can be selected, but from the viewpoint of excellent energy efficiency, it is preferable to use an extraction solvent with a partition coefficient of 1.35 or more. From the viewpoint of excellent separation performance from the hydrophilic mixed liquid, the extraction solvent preferably has a dielectric constant of 5 or less, more preferably 4 or less, and even more preferably 3 or less. Such solvents are not particularly limited, but include petroleum ether, pentane, hexane, heptane, octane, dodecane, cyclohexane, toluene, and benzene. [Example]

[0048] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited to these examples and comparative examples. Reactions in the following examples were carried out in anhydrous solvents under a nitrogen atmosphere unless otherwise specified.

[0049] In the examples, "Et" represents an "ethyl group," "MOMBr" represents "bromomethyl methyl ether," "Me" represents a "methyl group," "THF" represents "tetrahydrofuran," and "9-BBN" represents "9-borabicyclo[3.3.1]nonane."

[0050] In the following examples, various measurements were carried out under the following conditions. Nuclear magnetic resonance (NMR, 1H NMR at 400 MHz, 13C NMR at 100 MHz) spectra were measured using a Bruker AVANCE 400. Chemical shift values ​​(δ values) are reported in ppm using the solvent peak (δ = 7.24 ppm for 1H NMR and δ = 77.0 ppm for 13C NMR relative to CHCl3) as a reference. Silica gel (230-400 mesh) manufactured by Kanto Chemical Co., Inc. was used for column chromatography.

[0051] The reaction schemes in Examples 1 and 2 are shown below. [ka]

[0052] [Example 1] <Step 1: Synthesis of 9-bromo-4,5-bis(bromomethyl)acridine (15)> 9-Bromoacridine (5.0 g, 19.5 mmol, Sigma-Aldrich) was suspended in sulfuric acid (10 g) and stirred. Bromomethyl methyl ether (12.2 g, 97.3 mmol, Tokyo Chemical Industry Co., Ltd.) was added to the suspension to form a homogeneous solution, which was then stirred at 50°C for 7 days. Water (50 ml) was added to the resulting reaction solution, causing yellow crystals to precipitate. The reaction suspension containing the crystals was filtered, yielding 1.7 g (3.9 mmol, 20% yield) of the compound represented by formula (15) as yellow needles. H-NMR analysis of the resulting yellow needles revealed no impurities, so the resulting yellow needles were used in the next step without further purification. The appearance of a characteristic peak derived from methylene bromide (H-NMR chemical shift δ = 5.35 ppm) confirmed the synthesis of the target compound represented by formula (15). The reaction in this step is shown in formula (16).

[0053] [ka] [ka]

[0054] <Step 2: Synthesis of 9-bromo-4,5-bis((dicyclohexylphosphanyl)methyl)acridine (17)> In a glove box, 9-bromo-4,5-bis(bromomethyl)acridine (15) (10 g, 22.7 mmol) prepared in step 1 was dissolved in methanol (30 g) and stirred at room temperature. Dicyclohexylphosphine (9.0 g, 45.4 mmol, manufactured by Kanto Chemical Co., Ltd.) was added to the resulting solution, and the mixture was stirred at 50 °C for 2 days. After cooling to room temperature, triethylamine (4.6 g, 45.4 mmol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added and the mixture was stirred for 2 hours. The resulting reaction mixture was concentrated under reduced pressure using a rotary evaporator to obtain 10.8 g (15.9 mmol, 70% yield) of the compound represented by formula (17) as a colorless amorphous substance. H-NMR analysis of the resulting colorless amorphous substance revealed no impurities, and the resulting colorless amorphous substance was used in the next step without further purification. The disappearance of the characteristic peak derived from methylene bromide (H-NMR chemical shift δ = 5.35 ppm) confirmed the synthesis of the target compound represented by formula (17). The reaction in this step is shown in formula (18).

[0055] [ka] [ka]

[0056] <Step 3: Synthesis of ruthenium complex (19)> In a glove box, 9-bromo-4,5-bis((dicyclohexylphosphanyl)methyl)acridine (17) (10 g, 14.8 mmol) prepared in step 2 was dissolved in toluene (70 g), and carbonylchlorohydridotris(triphenylphosphine)ruthenium(II) chloride (14.1 g, 14.8 mmol, Fujifilm Wako Pure Chemical Industries, Ltd.) was added. The mixture was then stirred at 70 °C for 2 hours. After cooling, hexane (100 g, Fujifilm Wako Pure Chemical Industries, Ltd.) was added to the reaction mixture. The precipitated crystals were filtered to obtain 13.4 g (14.7 mmol, 99% yield) of the compound represented by formula (19) as a brown powder. The appearance of a characteristic peak (H-NMR chemical shift δ = -0.5 ppm) attributable to ruthenium hydride confirmed the synthesis of the target compound represented by formula (19). The reaction in this step is shown in formula (20).

[0057] [ka] [ka]

[0058] <Step 4: Synthesis of ruthenium complex (21)> In a glove box, 1-octene (0.66 g, 5.9 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was mixed with THF (20 g), and 0.5 mol / L 9-BBN (12 mL, 5.9 mmol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added at room temperature. The resulting mixture was stirred at 50 °C for 1 hour. To the resulting reaction solution, ruthenium complex (19) (5 g, 5.9 mmol) obtained in step 3 and dichloro(1,1'-bis(diphenylphosphino)ferrocene)palladium (43 mg, 0.06 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) were added in that order, and the mixture was stirred at 70 °C for 24 hours. The resulting reaction solution was concentrated under reduced pressure using a rotary evaporator (manufactured by Buchi), and then hexane (30 g, manufactured by Wako Pure Chemical Industries, Ltd.) was added. The hexane-soluble and insoluble materials were separated by filtration. The hexane solution was again concentrated under reduced pressure using a rotary evaporator (Buchi), yielding 1.6 g (1.8 mmol, 31% yield) of the compound represented by formula (21) as a brown oil. The appearance of a characteristic peak (H-NMR chemical shift δ = 3.70 ppm) derived from the octyl group confirmed that the target compound represented by formula (21) had been synthesized. The reaction in this step is shown in formula (22). The HLB value of the compound represented by formula (21) is 9.473 ((228.81871÷483.09029)×20).

[0059] [ka] [ka]

[0060] Next, a diamine was produced from a diol and ammonia using the ruthenium complex obtained in step 4 as a catalyst. <Preparation of hexamethylenediamine using ruthenium complex (21)> 15.0 g of 1,6-hexanediol, 4.62 equivalents of ammonia, and 50 mg of ruthenium-PNP-pincer complex (21) were added to a pressure-resistant reactor, which was then filled with nitrogen at room temperature at 1.0 MPa and reacted at 180 °C for 2 hours. As a result, 89 mol% of the raw materials were consumed, and 38 mol% of hexamethylenediamine, 38 mol% of aminohexanol, 2.60 mol% of hexamethyleneimine, and 3.3 mol% of hexamethylenediamine dimer were obtained. Subsequently, 25 g of cyclohexane was added to the resulting reaction mixture and stirred at 50 °C for 1 hour. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) of the cyclohexane and aqueous phases revealed that 44 mg of ruthenium complex (21) was dissolved in the cyclohexane phase. The partition coefficient was 1.563, and the recovery rate of complex (21) was 88%. From the above, it was found that the ruthenium complex (21) has catalytic activity in the reaction of diol with ammonia and can be easily extracted and separated from the reaction mixture after the reaction.

[0061] <Preparation of pentamethylenediamine using ruthenium complex (21)> A pressure-resistant reactor was charged with 15.0 g of 1,5-pentanediol, 4.50 equivalents of ammonia, and 50 mg of ruthenium-PNP-pincer complex (21). The reactor was then filled with nitrogen at room temperature at 1.0 MPa and reacted at 180°C for 2 hours. In this example, 95 mol% of the raw materials were consumed, and pentamethylenediamine was obtained in a yield of 55 mol%. Subsequently, cyclohexane (25 g) was added to the resulting reaction mixture, and the mixture was stirred at 50°C for 1 hour. ICP-AES analysis of the cyclohexane and aqueous phases revealed that 44 mg of ruthenium complex (21) was dissolved in the cyclohexane phase. The distribution coefficient was 1.563, and the recovery rate of complex (21) was 88%.

[0062] Next, we carried out an extraction and separation experiment of the ruthenium complex (21) from an aqueous diamine solution using an organic solvent. <Extraction and separation of ruthenium complex (21) from aqueous hexamethylenediamine solution containing the ruthenium complex (21)> Water (1.55 g), hexamethylenediamine (5 g), and ruthenium complex (21) (10 mg, HLB value 9.473) were added to a 200 ml test tube and stirred for 30 minutes. Then, cyclohexane (25 g) was added and stirred at 50 °C for 1 hour. ICP-AES measurements of the cyclohexane and aqueous phases revealed that 8.4 mg of ruthenium complex (21) was dissolved in the cyclohexane phase. The distribution coefficient was 1.375, and the recovery rate of ruthenium complex (21) was 84%.

[0063] <Extraction and separation of ruthenium complex (21) from an aqueous solution of octamethylenediamine containing the ruthenium complex (21)> Water (1.55 g), octamethylenediamine (5 g), and ruthenium complex (21) (10 mg, HLB value 9.473) were added to a 200 ml test tube and stirred for 30 minutes. Then, cyclohexane (25 g) was added and stirred at 50 °C for 1 hour. ICP-AES measurements of the cyclohexane and aqueous phases revealed that 8.5 mg of ruthenium complex (21) was dissolved in the cyclohexane phase. The distribution coefficient was 1.484, and the recovery rate of ruthenium complex (21) was 85%.

[0064] [Example 2] <Step 1: Synthesis of 4,5-bis((dicyclohexylphosphanyl)methyl)-9-octylacridine (23)> In a glove box, 1-octene (0.83 g, 7.4 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in THF (20 g), and 0.5 mol / L 9-BBN (15 ml, 7.4 mmol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added at room temperature. The mixture was then heated from room temperature to 50°C and stirred for 1 hour. To the resulting reaction solution, 9-bromo-4,5-bis((dicyclohexylphosphanyl)methyl)acridine (17) (5 g, 7.4 mmol) obtained in Step 2 of Example 1 and dichloro(1,1'-bis(diphenylphosphino)ferrocene)palladium (51 mg, 0.07 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) were added in that order, and the mixture was stirred at 70°C for 24 hours. The resulting reaction solution was concentrated under reduced pressure using a rotary evaporator, and then hexane (30 g, manufactured by Wako Pure Chemical Industries, Ltd.) was added. The hexane soluble and insoluble materials were separated by filtration. The hexane solution was again concentrated under reduced pressure using a rotary evaporator, yielding 2.6 g (3.7 mmol, 50% yield) of the compound represented by formula (23) as a colorless oil. The appearance of a characteristic peak (H-NMR chemical shift δ = 3.63 ppm) derived from the methylene (CH2) of the octyl group adjacent to the acridine skeleton confirmed that the target compound represented by formula (23) had been synthesized. The reaction in this step is shown in formula (24). [ka] [ka]

[0065] <Step 2: Synthesis of ruthenium complex (25)> In a glove box, 4,5-bis((dicyclohexylphosphanyl)methyl)-9-octylacridine (2.6 g, 3.7 mmol) (23) was dissolved in toluene (20 g), and carbonylchlorohydridotris(triphenylphosphine)ruthenium(II) chloride (3.5 g, 3.7 mmol, Fujifilm Wako Pure Chemical Industries, Ltd.) was added. The mixture was then stirred at 70 °C for 2 hours. To the resulting reaction solution, hexane (30 g, Fujifilm Wako Pure Chemical Industries, Ltd.) was added. The hexane-soluble and insoluble materials were separated by filtration, and the hexane solution was concentrated under reduced pressure using a rotary evaporator to obtain 2.6 g (3.0 mmol, 80% yield) of the compound represented by formula (25) as a brown oil. The appearance of a characteristic peak (H-NMR chemical shift δ = -0.5 ppm) attributable to ruthenium hydride confirmed the synthesis of the target compound represented by formula (25). The reaction in this step is shown in formula (26). The HLB value of the compound represented by formula (25) is 9.473 ((228.81871÷483.09029)×20).

[0066] [ka] [ka]

[0067] [Example 3] <Synthesis of ruthenium complex (27)> The synthesis was carried out in the same manner as in Example 1, except that 1-octadecene was used instead of 1-octene in step 4 of Example 1, to obtain 3.0 g of a ruthenium complex represented by formula (27). The synthesis of ruthenium complex (27) was confirmed by 1H-NMR. The reaction in this step is shown in formula (28). The HLB value of the compound represented by formula (27) is 7.343 ((228.81871 ÷ 623.24679) × 20).

[0068] [ka] [ka]

[0069] Next, an extraction separation experiment of the obtained ruthenium complex (27) from an aqueous diamine solution using an organic solvent was carried out. <Extraction and separation of ruthenium complex (27) from aqueous hexamethylenediamine solution containing the ruthenium complex (27)> Water (1.55 g), hexamethylenediamine (5 g), and ruthenium complex (27) (10 mg, HLB value 7.343) were added to a 200 ml test tube and stirred for 30 minutes. Cyclohexane (25 g) was then added, and the mixture was stirred at 50°C for 1 hour. ICP-AES analysis of the cyclohexane and aqueous phases revealed that 9.9 mg of ruthenium complex (27) was dissolved in the cyclohexane phase. The distribution coefficient was 25.923, and the recovery rate of ruthenium complex (27) was 99%. The results of Examples 1 and 3 demonstrate that complexes with HLB values ​​of 12.335 or less, such as ruthenium complexes (21) and (27), can be efficiently separated from hydrophilic mixtures by extraction with a nonpolar solvent.

[0070] [Comparative Example 1] <Extraction and separation of ruthenium complex (29) from aqueous hexamethylenediamine solution containing the ruthenium complex (29)> A ruthenium complex represented by formula (29) was synthesized by the method described in Patent Document 1 (US Pat. No. 8,889,865). Water (1.55 g), hexamethylenediamine (5 g), and ruthenium complex (29) (10 mg, HLB value 12.336) were added to a 200 ml test tube and stirred for 30 minutes. Cyclohexane (25 g) was then added, and the mixture was stirred at 50°C for 1 hour. ICP-AES measurements of the cyclohexane and aqueous phases revealed that 3.8 mg of ruthenium complex (29) was dissolved in the cyclohexane phase. The distribution coefficient was 0.1607, and the recovery rate of ruthenium complex (29) was 38%. These findings demonstrate that the ruthenium complex (29) disclosed in Patent Document 1 (U.S. Pat. No. 8,889,865) is difficult to separate by extraction from a hydrophilic solution.

[0071] [ka]

Claims

1. a step of reacting the compound represented by general formula (2) with a bromomethyl alkyl ether by an aromatic electrophilic substitution reaction under acidic conditions to obtain a compound represented by general formula (3); a step of reacting the compound represented by general formula (3) with a dialkylphosphine by a nucleophilic substitution reaction to obtain a compound represented by general formula (4); a step of reacting the compound represented by general formula (4) with carbonylchlorohydridotris(triphenylphosphine)ruthenium(II) chloride by a ligand exchange reaction to obtain a compound represented by general formula (5); a step of reacting a compound represented by general formula (5) with an alkene by a cross-coupling reaction using a transition metal catalyst containing palladium to obtain a compound represented by general formula (1); A method for producing a ruthenium complex represented by general formula (1), comprising: 【Chemistry 1】 (In the general formula (1), R is an alkyl group having 8 to 18 carbon atoms, which is monosubstituted at the d position of the acridinyl group, and R 1 and R 2 are each independently a cycloalkyl group having 3 to 8 carbon atoms. 【Chemistry 2】 (In general formula (2), X is a bromo group monosubstituted at the d position of the acridinyl group.) 【Transformation 3】 (In general formula (3), X is a bromo group, and X bonded to the acridine skeleton is monosubstituted at the d position.) 【Chemistry 4】 (In the general formula (4), X is a bromo group monosubstituted at the d position of the acridinyl group, and R 1 and R 2 are each independently a cycloalkyl group having 3 to 8 carbon atoms. 【Transformation 5】 (In the general formula (5), X is a bromo group monosubstituted at the d position of the acridinyl group, and R 1 and R 2 are each independently a cycloalkyl group having 3 to 8 carbon atoms.

2. A process for obtaining a compound represented by general formula (3) by reacting a compound represented by general formula (2) with a bromomethyl alkyl ether through an aromatic electrophilic substitution reaction under acidic conditions; a step of reacting the compound represented by general formula (3) with a dialkylphosphine by a nucleophilic substitution reaction to obtain a compound represented by general formula (4); a step of reacting a compound represented by general formula (4) with an alkene by a cross-coupling reaction using a transition metal catalyst containing palladium to obtain a compound represented by general formula (6); a step of reacting the compound represented by general formula (6) with carbonylchlorohydridotris(triphenylphosphine)ruthenium(II) chloride by a ligand exchange reaction to obtain the compound represented by general formula (1); A method for producing a ruthenium complex represented by general formula (1), comprising: 【Transformation 6】 (In general formula (1), R is an alkyl group having 8 to 18 carbon atoms which is monosubstituted at the d position of the acridinyl group, and R 1 and R 2 are each independently a cycloalkyl group having 3 to 8 carbon atoms.) 【Transformation 7】 (In general formula (2), X is a bromo group monosubstituted at the d position of the acridinyl group.) 【Transformation 8】 (In general formula (3), X is a bromo group, and X bonded to the acridine skeleton is monosubstituted at the d position.) 【Chemistry 9】 (In general formula (4), X is a bromo group monosubstituted at the d position of the acridinyl group, and R 1 and R 2 each independently represent a cycloalkyl group having 3 to 8 carbon atoms.) 【Chemistry 10】 (In the general formula (6), R is an alkyl group having 8 to 18 carbon atoms, which is monosubstituted at the d position of the acridinyl group, and R 1 and R 2 are each independently a cycloalkyl group having 3 to 8 carbon atoms.

3. a step of producing the ruthenium complex by the production method according to claim 1 or 2; reacting a diol with ammonia in the presence of the ruthenium complex; A method for producing a diamine, comprising:

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