Method for producing aminomethyl aromatics

Abstract

A method for producing aminomethyl aromatics by hydrogenating aromatic nitrites in a mixed solvent containing a hydrocarbon solvent and a polar organic solvent having a solubility parameter (SP value) of 10 or more in the presence of a quaternary ammonium compound and a hydrogenation catalyst.

Description

Technical Field

[0001] The invention relates to a process for producing aminomethyl aromatics by hydrogenating aromatic nitriles. Background Art

[0002] Aminomethyl aromatics are useful as raw materials or intermediates for pharmaceuticals, pesticides, resins, curing agents, etc. In particular, xylylenediamine having two aminomethyl groups is a very useful compound as a raw material for polyamide resins, curing agents, etc., and an intermediate for isocyanates.

[0003] As a method for producing aminomethyl aromatics, a method of hydrogenating aromatic nitrile is carried out.

[0004] In the hydrogenation of aromatic nitriles, a method using liquid ammonia as a solvent is known. However, due to environmental considerations, liquid ammonia needs to be recovered after the hydrogenation reaction without releasing it to the outside, which places a heavy burden on production. Various studies have been conducted on production methods that do not use liquid ammonia.

[0005] For example, Patent Document 1 discloses a method for hydrogenating a nitrile in a mixed solvent of a lower alcohol and a cyclic hydrocarbon in the presence of an alkali or alkaline earth metal hydroxide or alkoxide and a Raney nickel or Raney cobalt catalyst in order to obtain primary amines, including aminomethyl aromatics, in high yield.

[0006] In addition, for the purpose of obtaining cyanamidomethyl aromatics, which are one type of aminomethyl aromatics, in high yield, Patent Document 2 discloses a method for producing cyanamidomethyl aromatics by hydrogenating aromatic nitrile using a palladium catalyst in the presence of an alcohol and tetraalkylammonium hydroxide.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 54-41804

[0010] Patent Document 2: Japanese Patent Application Publication No. 2002-205980 Summary of the invention

[0011] Problem that the invention aims to solve

[0012] In order to use aminomethyl aromatics as raw materials for polyamide resins, curing agents, etc., or as intermediates for isocyanates, very high-purity aminomethyl aromatics are required, and a method for obtaining aminomethyl aromatics at a high yield in a production method that does not use liquid ammonia is required.

[0013] In addition, as in Patent Document 1, attempts have been made to obtain aminomethyl aromatics by adding a base without using liquid ammonia. However, when an alkali metal or the like is used, the catalyst is easily degraded, which causes a problem of deterioration in productivity.

[0014] Therefore, there is a need for a synthesis method that can achieve high yield while suppressing catalyst degradation and improving productivity.

[0015] Therefore, an object of the present invention is to provide a production method which can obtain aminomethyl aromatics at a high yield without substantially using liquid ammonia and can suppress the deterioration of the catalyst.

[0016] Solutions for solving problems

[0017] The present inventors have conducted intensive studies and have found that the above-mentioned problems can be solved by hydrogenating an aromatic nitrile in a specific mixed solvent in the presence of a quaternary ammonium compound and a catalyst.

[0018] That is, the present invention is a method for producing aminomethyl aromatics by hydrogenating aromatic nitrites in a mixed solvent containing a hydrocarbon solvent and a polar organic solvent having a solubility parameter (SP value) of 10 or more in the presence of a quaternary ammonium compound and a hydrogenation catalyst.

[0019] Effects of the Invention

[0020] According to the production method of the present invention, aminomethyl aromatics can be obtained at a high yield without substantially using liquid ammonia, and degradation of the catalyst can be suppressed. DETAILED DESCRIPTION

[0021] In the method for producing aminomethyl aromatics of the present invention, aromatic nitrile is hydrogenated in a mixed solvent containing a hydrocarbon solvent and a polar organic solvent having a solubility parameter (SP value) of 10 or more in the presence of a quaternary ammonium compound and a hydrogenation catalyst.

[0022] The production method of the present invention is described in detail below.

[0023] (Hydrocarbon Solvents)

[0024] The hydrocarbon solvent used in the present invention is one or more selected from aromatic hydrocarbon solvents and aliphatic hydrocarbon solvents, and an aromatic hydrocarbon solvent is preferred.

[0025] The solubility parameter (hereinafter also referred to as SP value) of the hydrocarbon solvent is preferably 9.5 or less, more preferably 9.0 or less. The lower limit is preferably 7.0 or more, more preferably 8.0 or more. When the hydrocarbon solvent is an aromatic hydrocarbon solvent, aromatic nitrile and hydrogen as raw materials are well dissolved, and hydrogenation reaction can be efficiently carried out. In addition, by SP value of 9.5 or less, aromatic nitrile and hydrogen as raw materials are well dissolved, and hydrogenation reaction can be efficiently carried out.

[0026] When the hydrocarbon solvent is an aromatic hydrocarbon solvent, the aromatic hydrocarbon solvent preferably has 7 to 12 carbon atoms, more preferably 7 to 9 carbon atoms, and even more preferably 8 to 9 carbon atoms.

[0027] Specific examples of aromatic hydrocarbon solvents include toluene, ethylbenzene, three isomers of xylene (o-xylene, m-xylene, p-xylene), monocyclic aromatic hydrocarbon compounds such as mesitylene and pseudocumene, and polycyclic aromatic hydrocarbon compounds such as naphthalene and methylnaphthalene. Monocyclic aromatic hydrocarbon compounds are preferred. From the perspective of easy industrial availability, xylene and mesitylene are more preferred, xylene (SP value 8.8) is further preferred, m-xylene and p-xylene are further preferred, and m-xylene is further preferred.

[0028] (Polar organic solvent with solubility parameter (SP value) of 10 or more)

[0029] The solubility parameter (SP value) of the polar organic solvent used in the present invention is 10 or more, preferably 11 or more, more preferably 12 or more, and further preferably 13 or more. The upper limit is preferably 20 or less, more preferably 17 or less, and further preferably 15 or less.

[0030] In addition, the SP value in the present invention is a value calculated|required by the following Hildebrand's solubility parameter formula.

[0031] Solubility parameter (SP value) = (ΔH A V -RT) 0.5 / V A 0.5

[0032] ΔH A V : Enthalpy of evaporation of liquid A (polar organic solvent)

[0033] R: Gas constant

[0034] T: Temperature

[0035] V A : Molar volume of liquid A

[0036] In the production method of the present invention, by using a polar organic solvent having an SP value of 10 or more, the aminomethyl aromatics as a product are distributed therein, so that the hydrogenation reaction can be efficiently carried out.

[0037] The polar organic solvent used in the present invention is at least one selected from alcohols, esters, amides, sulfoxides, ketones and amines, and alcohols are preferred.

[0038] Examples of the alcohol include monohydric alcohols and polyhydric alcohols, and monohydric alcohols are preferred. Examples of the monohydric alcohol include aliphatic alcohols and aromatic alcohols, and aliphatic alcohols are preferred.

[0039] The aliphatic alcohol preferably has 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms, from the viewpoint of easy industrial availability.

[0040] Specific examples of aliphatic alcohols include methanol (SP value 14.5), ethanol (SP value 12.7), n-propanol (SP value 11.9), isopropanol (SP value 11.5), n-butanol (SP value 11.4), sec-butanol (SP value 10.8), tert-butanol (SP value 10.6), pentanol, hexanol (SP value 10.7), heptanol (SP value 10.6), and n-octanol (SP value 10.3). Methanol and ethanol are preferred, and methanol is more preferred.

[0041] (Mixed solvents)

[0042] The mixed solvent in the present invention refers to the entire liquid compounds contained in the solution during the hydrogenation reaction, excluding the aromatic nitrile as a raw material and the aminomethyl aromatic as a product.

[0043] The mass ratio of the hydrocarbon solvent to the polar organic solvent in the mixed solvent (hydrocarbon solvent / polar organic solvent) is preferably 60 / 40 to 99 / 1, more preferably 70 / 30 to 99 / 1, more preferably 80 / 20 to 99 / 1, and still more preferably 82 / 18 to 99 / 1. By using a larger amount of hydrocarbon solvent than polar organic solvent, the concentration of nitriles dissolved in the hydrocarbon solvent is reduced, making it difficult to generate high boiling point substances on the catalyst.

[0044] The total content of the hydrocarbon solvent and the polar organic solvent in the mixed solvent is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, and even more preferably 99 to 100% by mass.

[0045] The content of water in the mixed solvent is preferably 5% by mass or less, more preferably 2% by mass or less, and further preferably 1% by mass or less. By setting the content of water to 5% by mass or less, side reactions with the raw materials can be suppressed, thereby improving the yield of the product.

[0046] In addition, the mixed solvent of the present invention preferably does not contain liquid ammonia. By not containing liquid ammonia, the load during production consumed by the recovery of ammonia can be reduced.

[0047] The difference in SP value between the hydrocarbon solvent and the polar organic solvent in the mixed solvent is preferably 0.5 or more, more preferably 1.0 or more, further preferably 2.0 or more, and further preferably 4.0 or more. In addition, it is preferably 12 or less, more preferably 10 or less, further preferably 8 or less, and further preferably 6 or less.

[0048] As a combination of the hydrocarbon solvent and the polar organic solvent in the mixed solvent, a monocyclic aromatic hydrocarbon compound and an alcohol are preferred, xylene and an aliphatic alcohol having 1 or 2 carbon atoms are more preferred, and m-xylene and methanol are further preferred.

[0049] (Quaternary Ammonium Compounds)

[0050] Examples of the quaternary ammonium compound used in the present invention include tetraalkylammonium hydroxides and tetraalkylammonium organic acids. It is preferred to use one or more selected from these, and among these, tetraalkylammonium hydroxide is more preferred.

[0051] Since the quaternary ammonium compound is not a strong base like an alkali metal hydroxide, corrosion of a reaction vessel and the like, deterioration of a catalyst, and the like do not occur, and an aminomethyl aromatic compound can be obtained stably and in high yield.

[0052] Examples of the tetraalkylammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide and tetrabutylammonium hydroxide. Tetramethylammonium hydroxide and tetraethylammonium hydroxide are preferred. From the viewpoint of improving the yield and reducing impurities, tetraethylammonium hydroxide is preferred. From the viewpoint of availability, tetramethylammonium hydroxide is more preferred.

[0053] Examples of the tetraalkylammonium organic acid include tetraalkylammonium phenolates, tetraalkylammonium fatty acids, and tetraalkylammonium tetraphenylborate.

[0054] Examples of the tetraalkyl fatty acid ammonium include tetramethylammonium acetate.

[0055] The amount of the quaternary ammonium compound is preferably 0.1 to 10 mmol, more preferably 0.2 to 5 mmol, and further preferably 0.5 to 1 mmol relative to 1 g of the hydrogenation catalyst. In addition, it is preferably 1 to 20% by mass, more preferably 3 to 10% by mass, and further preferably 5 to 10% by mass relative to the hydrogenation catalyst. By using the quaternary ammonium compound of the aforementioned amount, even when the catalyst is repeatedly used, it will not deteriorate, and the reaction rate can be maintained, thereby the target aminomethyl aromatics can be obtained in high yield. In addition, when it is less than 20% by mass relative to the hydrogenation catalyst, even when the quaternary ammonium compound is used in the form of an aqueous solution, the amount of water brought in can be suppressed.

[0056] (Hydrogenation Catalyst)

[0057] As the hydrogenation catalyst used in the production method of the present invention, there is no restriction as long as it is a catalyst used in the hydrogenation of an organic compound, and a metal catalyst is preferred. As the metal, cobalt, nickel, palladium, and platinum can be cited, preferably one or more selected from cobalt and nickel, and more preferably cobalt. That is, preferably containing one or more metal catalysts selected from cobalt, nickel, palladium, and platinum, more preferably containing one or more metal catalysts selected from nickel and cobalt, and further preferably containing cobalt. By using a cobalt catalyst, the generation of high boiling point substances on the catalyst can be suppressed, the yield is improved, and the degradation of the catalyst can also be reduced.

[0058] Examples of the metal catalyst containing one or more metals selected from nickel and cobalt include metal-supported catalysts and sponge metal catalysts, and sponge metal catalysts are preferred.

[0059] Examples of metal-supported catalysts include catalysts in which one or more selected from nickel and cobalt are supported on Al2O3, SiO2, diatomaceous earth, SiO2-Al2O3, or ZrO2 by a precipitation method.

[0060] As a sponge metal catalyst, a catalyst prepared by dissolving a part of an alloy (nickel, cobalt, aluminum, iron, copper, etc.) of two or more components using an acid or an alkali can be cited, preferably a sponge cobalt catalyst and a sponge nickel catalyst, more preferably a sponge cobalt catalyst. The above catalyst can be used alone or in combination of two or more.

[0061] The amount of the catalyst is preferably 0.1 to 100 parts by mass, more preferably 1 to 50 parts by mass, and even more preferably 10 to 20 parts by mass based on 100 parts by mass of the aromatic nitrile. By using the above amount of catalyst, the yield of the obtained aminomethyl aromatic can be increased.

[0062] (Aromatic Nitrile)

[0063] The aromatic nitrile used as a raw material in the production method of the present invention has a nitrile group bonded to the aromatic ring (benzene ring), and the number of the nitrile groups is preferably 1 or 2, and more preferably 2.

[0064] Furthermore, other substituents may be bonded to the aromatic ring.

[0065] Specific examples of the aromatic nitrile include benzonitrile and dicyanobenzene, and dicyanobenzene is preferably used.

[0066] Dicyanobenzene has three isomers, namely, phthalonitrile (1,2-dicyanobenzene), isophthalonitrile (1,3-dicyanobenzene), and terephthalonitrile (1,4-dicyanobenzene). Among them, isophthalonitrile and terephthalonitrile are preferred, and terephthalonitrile is more preferred.

[0067] The concentration of the aromatic nitrile in the reaction solution during the hydrogenation reaction is preferably 2 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 7 to 20% by mass. The reaction solution does not contain a catalyst.

[0068] (Aminomethyl aromatic)

[0069] The aminomethyl aromatic group obtained by the production method of the present invention has an aminomethyl group bonded to the aromatic ring (benzene ring), and the number of the aminomethyl group is preferably 1 or 2, and more preferably 2.

[0070] Furthermore, other substituents may be bonded to the aromatic ring.

[0071] Specific examples of the aminomethyl aromatic group include benzylamine and xylylenediamine, and xylylenediamine is preferred.

[0072] Xylylenediamine exists in three isomers, namely, o-xylylenediamine, m-xylylenediamine, and p-xylylenediamine. Among them, m-xylylenediamine and p-xylylenediamine are preferred, and p-xylylenediamine is more preferred.

[0073] These isomers of xylylenediamine can be obtained by the production method of the present invention using the corresponding dicyanobenzene as a raw material.

[0074] (Method for producing aminomethyl aromatic compounds)

[0075] In the method for producing aminomethyl aromatics of the present invention, aromatic nitrile is hydrogenated in a mixed solvent containing a hydrocarbon solvent and a polar organic solvent having a solubility parameter (SP value) of 10 or more in the presence of a quaternary ammonium compound and a hydrogenation catalyst.

[0076] In the present production method, the order of mixing the raw materials and the like is not particularly limited, but it is preferred that the hydrocarbon solvent, the polar organic solvent, the quaternary ammonium compound, and the hydrogenation catalyst are placed in a pressure vessel and hydrogen is introduced.

[0077] In order to prevent the hydrogenation catalyst from containing gases other than hydrogen such as air and water, it is preferred that the catalyst be impregnated with water, then replaced with the aforementioned polar organic solvent, and added as a catalyst slurry.

[0078] The reaction in the present production method may be carried out by either a batch method or a flow method, but a batch method is preferred.

[0079] In the present invention, the hydrogen used as the raw material for hydrogenation does not need to be particularly purified and can be of industrial grade. The hydrogen pressure during the reaction is preferably 2.0 to 20.0 MPa, more preferably 3.0 to 15.0 MPa, and further preferably 5.0 to 10.0 MPa. When the hydrogen pressure is within the above range, the yield of the product is sufficient, and a high-pressure pressure-resistant reactor is not required, thereby reducing costs, so it is preferred.

[0080] The reaction temperature is preferably 20 to 150° C., more preferably 50 to 130° C., and even more preferably 60 to 120° C. Within this range, the conversion rate of the aromatic dinitrile as a raw material is good, and the formation of by-products is suppressed, so that the yield is improved.

[0081] The reaction time varies depending on the reaction temperature, hydrogen pressure, etc., but is generally 0.1 to 100 hours, preferably 0.5 to 10 hours, under the above-mentioned conditions.

[0082] The obtained aminomethyl aromatics can be recovered by a known method. For example, it is preferred to separate the gaseous component and the liquid component from the reaction mixture at the end of the reaction, filter out the solid components such as the catalyst, and then distill the liquid component to recover it. In addition, it is also preferred to further distill the obtained aminomethyl aromatics to improve the purity.

[0083] Example

[0084] The present invention will be specifically described based on the following examples, but the present invention is not limited to these examples. In the following examples, gas chromatography was used for composition analysis.

[0085] <Gas chromatography (GC) analysis conditions>

[0086] Gas chromatography analysis was performed under the following conditions.

[0087] Instrument used: Gas chromatograph Nexis GC-2030 (manufactured by Shimadzu Corporation)

[0088] Column: DB-1 (length 30m, inner diameter 0.53mm, membrane thickness 1.5μm)

[0089] Detector: FID (H2 30mL / min, Air 300mL / min)

[0090] Carrier gas: He (constant flow: average linear velocity 38 cm / s)

[0091] Split ratio: 28.1

[0092] Inlet temperature: 300℃

[0093] Detector temperature: 300°C

[0094] Injection volume: 1.0 μL

[0095] Oven temperature: Raise the temperature from 50°C to 150°C at 5°C / min, then raise the temperature to 280°C at 10°C / min after reaching 150°C, and then keep it for 7 minutes. Then raise the temperature to 300°C at 10°C / min and keep it for 5 minutes.

[0096] <Conversion rate and yield>

[0097] The conversion rate of the raw material (terephthalonitrile) and the yield of the product (p-phenylenediamine) were determined by the internal standard method using the aforementioned gas chromatography and calculated based on the amount of the raw material and product in the reaction mixture. Diphenylmethane was used as the internal standard, so a standard curve was prepared in advance using terephthalonitrile and p-phenylenediamine solutions of known concentrations.

[0098] 0.5 g of diphenylmethane was added to 5.0 g of the reaction mixture to prepare a sample, and the gas chromatography was measured under the above-mentioned conditions to determine the conversion rate and yield according to the following formula.

[0099] Conversion rate (mol%) = [1-(amount of terephthalonitrile (mol) in the reaction mixture) / (amount of terephthalonitrile (mol) at the time of introduction)] × 100

[0100] Yield (mol%) = (amount of p-xylylenediamine in the reaction mixture [mol]) / (amount of terephthalonitrile at the time of introduction [mol]) × 100

[0101] <Reaction time after repeated hydrogenation reaction (catalyst degradation evaluation)>

[0102] The catalyst filtered off after the previous reaction was used to perform the same operation as in Example 1 described later. After hydrogen substitution, the time from when the hydrogen pressure was set to 8.0 MPa to when the hydrogen was completely consumed was taken as the reaction time after repeated hydrogenation. The shorter the reaction time after repeated hydrogenation, the more the degradation of the catalyst was suppressed.

[0103] <Aluminum Dissolution Amount after Repeated Hydrogenation Reaction (Catalyst Deterioration Evaluation)>

[0104] A sample for measuring the amount of aluminum dissolved was prepared from the reaction mixture after the reaction was completed according to the following sample preparation procedure, and aluminum was measured by ICP emission spectrophotometry. It is known that aluminum is contained in the Raney cobalt catalyst, and the catalyst deteriorates due to the dissolution of aluminum. Therefore, the less the amount of aluminum dissolved, the more the catalyst deterioration is suppressed.

[0105] (Sample preparation steps)

[0106] After accurately weighing 5.0 g of the reaction mixture in a platinum crucible, heat it to remove the solvent. Then, perform an ashing treatment at 600°C for 3 hours. After cooling the sample and the container, add 10 mL of a 12% by mass hydrochloric acid aqueous solution and heat to dissolve it. Transfer the contents of the platinum crucible to a 25 mL volumetric flask and dilute it to 25 mL with pure water before performing ICP analysis.

[0107] <Preparation of Catalyst Slurry>

[0108] The following operation uses a 50mL beaker. 5.90g of Raney cobalt catalyst (sponge cobalt catalyst) (RANEY2724, W.R. Grace company) is placed in 30mL of water, and after the catalyst is allowed to settle, the supernatant is removed by decantation. Then, 30mL of methanol is added, and after stirring for 1 minute, the supernatant is removed in the same manner. The above-mentioned replacement with methanol is performed 5 times to prepare a methanol slurry of the catalyst.

[0109] <Example 1>

[0110] (Manufacture of p-phenylenediamine)

[0111] The methanol slurry of the catalyst (catalyst amount 5.90 g) was placed in a 500 mL autoclave container to adjust the total weight of methanol to 39.5 g. Then, 51.8 g of terephthalonitrile, 197.3 g of m-xylene, and 1.52 g of a 25% tetramethylammonium hydroxide aqueous solution (4.2 mmol, 0.38 g as tetramethylammonium hydroxide) were added.

[0112] The reactor was pressurized to 0.5 MPa with nitrogen and then returned to atmospheric pressure for nitrogen replacement. This nitrogen replacement was performed three times in total, and then hydrogen replacement was performed three times in total using hydrogen in the same manner.

[0113] The hydrogen pressure was set to 8.0 MPa, and the temperature was raised to 100°C while stirring at 1200 rpm, and hydrogen was supplied while reacting under the conditions of 8.0 MPa and 100°C. The reaction was terminated when the hydrogen was completely consumed. After the reaction was completed, the reaction mixture was cooled to 50°C and pressure filtered at a pressure of 0.4 MPa to filter out the catalyst, thereby obtaining a reaction mixture containing p-phenylenediamine as a reaction product. The conversion rate of terephthalonitrile was 100 mol%, and the yield of p-phenylenediamine was 94.8 mol%.

[0114] Furthermore, the above-mentioned hydrogenation reaction was performed 4 times using the filtered catalyst, and was performed 5 times in total. Table 2 shows the reaction time and the amount of aluminum dissolved in the 5th reaction.

[0115] <Examples 2 to 4>

[0116] The reaction was carried out in the same manner as in Example 1 except that the total amount of methanol and m-xylene was the same as in Example 1 and the mass ratio of methanol to m-xylene was adjusted to be the ratio shown in Table 1. The conversion rate of terephthalonitrile and the yield of p-xylylenediamine are shown in Table 1.

[0117] <Comparative Example 1>

[0118] The reaction was carried out by the same operation as in Example 1 except that the amount of m-xylene was 236.8 g and methanol was not used. It should be noted that the methanol slurry was replaced with m-xylene slurry as a catalyst. The conversion rate of terephthalonitrile and the yield of p-xylylenediamine are shown in Table 1.

[0119] <Comparative Example 2>

[0120] The reaction was carried out by the same operation as in Example 1 except that the amount of methanol was changed to 236.8 g and m-xylene was not used. Table 1 shows the conversion rate of terephthalonitrile and the yield of p-xylylenediamine.

[0121] [Table 1]

[0122] Table 1

[0123]

[0124] <Comparative Example 3>

[0125] The reaction was carried out by the same operation as in Example 1 except that the tetramethylammonium hydroxide aqueous solution was not used. Table 2 shows the conversion rate of terephthalonitrile and the yield of p-xylylenediamine.

[0126] <Comparative Examples 4 and 5>

[0127] The reaction was carried out by the same operation as in Example 1, using the basic compounds shown in Table 2 instead of the tetramethylammonium hydroxide aqueous solution in Example 1. Table 2 shows the conversion rate of terephthalonitrile and the yield of p-xylylenediamine.

[0128] <Comparative Example 6>

[0129] The reaction was carried out by using sodium hydroxide instead of the tetramethylammonium hydroxide aqueous solution in Example 1 in the same manner as in Example 1. Table 2 shows the conversion rate of terephthalonitrile and the yield of p-xylylenediamine.

[0130] Furthermore, the above-mentioned hydrogenation reaction was performed twice using the filtered catalyst, and was performed three times in total. Table 2 shows the reaction time and the amount of aluminum dissolved in the third reaction.

[0131] <Comparative Example 7>

[0132] The reaction was carried out by using potassium tert-butoxide instead of the tetramethylammonium hydroxide aqueous solution in Example 1 in the same manner as in Example 1. Table 2 shows the conversion rate of terephthalonitrile and the yield of p-xylylenediamine.

[0133] Furthermore, the above-mentioned hydrogenation reaction was performed 4 times using the filtered catalyst, and was performed 5 times in total. The reaction time in the 5th reaction is shown in Table 2.

[0134] [Table 2]

[0135] Table 2

[0136]

[0137] <Example 5>

[0138] The reaction was carried out by using a tetraethylammonium aqueous solution instead of the tetramethylammonium hydroxide aqueous solution of Example 1 in the same manner as in Example 1. Table 3 shows the conversion rate of terephthalonitrile and the yield of p-xylylenediamine.

[0139] [Table 3]

[0140] Table 3

[0141]

[0142] The results in Tables 1 to 3 show that when the production method of the Examples is used, p-xylylenediamine can be obtained at a high yield, and further, even when the reaction is repeated, the catalyst does not deteriorate, and the reaction can be performed in a short time.

Claims

1. A method for producing an aminomethyl aromatic, wherein: In a mixed solvent containing a hydrocarbon solvent and a polar organic solvent having a solubility parameter, i.e., an SP value of 10 or more, an aromatic nitrile is hydrogenated in the presence of a quaternary ammonium compound and a hydrogenation catalyst, wherein the quaternary ammonium compound is a tetraalkylammonium hydroxide, the hydrocarbon solvent is an aromatic hydrocarbon solvent, the polar organic solvent is an alcohol, the aminomethyl aromatic is benzylamine or xylenediamine, and the aromatic nitrile is benzonitrile or dicyanobenzene.

2. The method for producing aminomethyl aromatics according to claim 1, wherein The mass ratio of the hydrocarbon solvent to the polar organic solvent in the mixed solvent, that is, hydrocarbon solvent / polar organic solvent, is 60 / 40 to 99 / 1.

3. The method for producing aminomethyl aromatics according to claim 1 or 2, wherein: The total amount of the hydrocarbon solvent and the polar organic solvent in the mixed solvent is 90 to 100% by mass.

4. The method for producing aminomethyl aromatics according to claim 1 or 2, wherein The hydrogenation catalyst is a metal catalyst containing at least one selected from nickel and cobalt.

5. The method for producing aminomethyl aromatics according to claim 1 or 2, wherein The amount of the quaternary ammonium compound is 1 to 20% by mass relative to the hydrogenation catalyst.

6. The method for producing an aminomethyl aromatic according to claim 1 or 2, wherein: The mixed solvent does not contain liquid ammonia.

7. The method for producing an aminomethyl aromatic according to claim 1 or 2, wherein: The water content in the mixed solvent is 5 mass % or less.

8. The method for producing an aminomethyl aromatic according to claim 1 or 2, wherein: The aromatic nitrile is dicyanobenzene.

9. The method for producing aminomethyl aromatics according to claim 1 or 2, wherein The aromatic nitrile is terephthalonitrile.

10. The method for producing an aminomethyl aromatic compound according to claim 1 or 2, wherein: The aminomethyl aromatic is xylylenediamine.

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