JPH09100260A - Production of 4,4'-di(n-alkylaniline) compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a 4,4'-di(N-alkylaniline) which is important as an curing agent for epoxy resins with industrial advantage in high yield, in high purity under mild reaction conditions by reductive alkylation of a 4,4'-dianiline with an aldehyde or ketone. SOLUTION: A compound of formula I (X is an alkylene; R2 and R3 are independently from each other H, a lower alkyl), for example, 4,4'- methylenedianiline is allowed to react with an aldehyde or ketone such as methyl ethyl ketone in the presence of a metallic catalyst under a hydrogen pressure to give a 4,4'-di(N-alkylaniline) of formula II (R1 is a lower alkyl), for example, 4,4'-methylenedi(N-sec-butylaniline).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an intermediate, and more particularly to a method for producing 4,4′-di (N-alkylaniline) s.

[0002]

2. Description of the Related Art 4,4'-di (N-alkylaniline)
Classes are important compounds as curing agents for epoxy resins, crosslinking agents for urethane resins, and urethane elastomer materials. Polyurethane elastomer with improved mechanical strength,
It is useful as a material for rigid polyurethane foams.
The following methods are available as methods for producing 4,4′-di (N-alkylaniline) s, but they have the following problems. (1) A method for producing 4,4′-methylenedi (N-alkylaniline) s by condensing N-alkylaniline with formaldehyde in an aqueous medium in the presence of a strong acid such as hydrochloric acid or sulfuric acid. Published patent gazette: Sho 58-83
656, German Patent; 2307864. In these methods, there are many by-products such as 2,4-bis (p-N-alkylaminobenzyl) N-alkylaniline, which requires a great deal of cost for purification, and there is a large amount of waste liquid, resulting in high treatment cost. There is. (2) A method of reacting 4,4′-dianilines with a halogenoalkyl such as alkyl iodide in an organic solvent. For example, there are Japanese Patent Laid-Open Publication No. 1-252627. This method is not industrially advantageous because the raw materials are expensive and there are many by-products such as 4,4'-di (N-dialkylaniline) and the purification is very expensive. (3) 4,4'-di (p-halogenobenzene) s and N-
A method of reacting an alkylamine in an organic solvent. Co
ll. Czech. Chem. Commun. Vol.
38, 3280, (1973). In this report, 4,4'-dichlorodiphenyl sulfone and methylamine were reacted at 220 ° C for 24 hours, and the yield of purified product was 62%.
It's just Not only the severe reaction conditions are required and the yield is low, but there is a problem that the types of the main raw material 4,4'-di (p-halogenobenzene) which are industrially available are very limited.

[0003]

The conventional method for producing 4,4'-di (N-alkylaniline) s requires expensive raw materials, has a large amount of by-products, has a large amount of waste liquid, and requires a large amount of treatment cost. There are problems such as severe reaction conditions.

[0004]

As a result of intensive studies to solve the above problems, the present inventor has found that 4,4'-dianilines and aldehydes or ketones under hydrogen pressure and a metal catalyst are used. Then reductive alkylation yields 4,4 '
The present invention has been completed by finding a method for industrially advantageous production of -di (N-alkylaniline) s with high yield, high purity and mild reaction conditions.

That is, (1) 4,4'-di (N) is characterized by reacting 4,4'-dianilines with aldehydes or ketones in the presence of a metal catalyst under hydrogen pressure. -Alkylaniline) production method (2) 4,4'-dianiline is a compound represented by the formula (1),

Embedded image (In the formula, X represents alkylene, substituted alkylene, oxy, thio, sulfonyl, imino, carbonyl or carboimino, R ₂ and R ₃ represent hydrogen atom, lower alkyl group, lower alkoxy group or halogen atom, and R ₂
And R ₃ may be the same or different. ) 4,4'-di (N-alkylaniline) s have the formula (2)
The production method according to (1) above, which is a compound represented by

Embedded image (In the formula, X, R ₂ and R ₃ have the same meanings as in formula (1), and R ₁ represents lower alkyl.) (3) 4,4′-di (N-alkylaniline) s The production method according to the above item (1), which is 4,4′-methylenedi (N-alkylaniline) represented by the formula (3).

Embedded image (In the formula, R ₁ , R ₂ and R ₃ have the same meanings as in the formula (2).) (4) The above-mentioned item (1), wherein the metal catalyst is platinum or palladium,
(2) or the method for producing 4,4'-di (N-alkylaniline) s according to (3) (5) In the preceding paragraph (4), wherein the metal catalyst is a platinum catalyst supported on activated carbon and containing a sulfur compound. Process for producing 4,4′-di (N-alkylaniline) s described above (6) The above-mentioned item (1), wherein the metal catalyst is Raney-nickel,
(2) The method for producing 4,4'-di (N-alkylaniline) s according to (3) (7) The metal catalyst is Raney-Nickel treated with sulfite or acidic sulfite (6) 4,4'-
Method for producing di (N-alkylaniline) s (8) The above-mentioned item (1), wherein the reaction is carried out in the presence of an acidic catalyst,
(2), (3), (4), (5), (6) or (7)
4. Method for producing 4,4′-di (N-alkylaniline) s described in (9) The reaction is carried out in the presence of alcohols, (1),
(2), (3), (4), (5), (6), (7) or (8) method for producing 4,4'-di (N-alkylaniline) s according to (8) reaction The above item (1), in which the temperature is 10 to 150 ° C.,
(2), (3), (4), (5), (6), (7),
(8) or a method for producing 4,4′-di (N-alkylaniline) s according to (9) (11) The above-mentioned (1), wherein the reaction hydrogen pressure is 1 to 100 kg / cm ² (gauge pressure), (2), (3), (4),
(5), (6), (7), (8), (9) or (1
0) to 4,4'-di (N-alkylaniline) s.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The production method of the present invention will be described below in detail. 4,4 ′ represented by the formula (1) used in the present invention
-As the dianilines, 4,4'-methylenedianilines, 4,4'-isopropylidenedianilines, 2,
2'-bis (4-aminophenyl) -1,3-hexafluoropropanes, 4,4'-oxydianilines,
4,4'-thiodianilines, bis (4-aminophenyl) sulfones, 4,4'-diaminobenzophenones, 4,4'-diaminotriphenylamines, 4,
4'-diaminobenzanilides, 4,4'-diaminotriphenylmethanes and the like can be mentioned. R _{2 in} formula (1)
Alternatively, specific examples of the lower alkyl group represented by R ₃ include methyl, ethyl, n-propyl, isopropyl, n
-Butyl, isobutyl, tert-butyl, etc., and specific examples of the lower alkoxy group include methoxy,
Ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy and the like can be mentioned. Further, specific examples of the halogen atom include fluorine, chlorine, bromine, iodine and the like. If the specific example of a compound of Formula (1) is given,
4,4'-methylenedianiline (abbreviated as MDA),
2,2'-dimethyl MDA, 2,2'-diethyl MD
A, 2,2'-diisopropyl MDA, 2,2'-diisobutyl MDA, 2,2 ', 6,6'-tetramethyl M
DA, 2,2 ', 6,6'-tetraethyl MDA, 2,
2 ', 6,6'-Tetraisopropyl MDA, 2,2'
-Dimethyl-6,6'-diethyl MDA, 2,2'-dimethoxy MDA, 2,2'-difluoro MDA, 2,
2'-dichloro MDA, 2,2 ', 6,6'-tetrachloro MDA, 2,2'-dibromo MDA, 2,2',
6,6′-tetrabromo MDA, 3,3′-ditrifluoromethyl MDA, 4,4′-isopropylidenedianiline (abbreviated as PDA), 2,2′-dimethyl PDA,
2,2'-diethyl PDA, 2,2'-diisopropyl PDA, 2,2 ', 6,6'-tetramethyl PDA,
2,2 ', 6,6'-Tetraethyl PDA, 2,2'-
Dimethoxy PDA, 2,2'-difluoro PDA, 2,
2'-dichloro PDA, 2,2 ', 6,6'-tetrachloro PDA, 2,2'-dibromo PDA, 2,2'-bis (4-aminophenyl) -1,3-hexafluoropropane, 4 , 4'-oxydianiline (abbreviated as ODA), 2,2'-dimethyl ODA, 2,2'-diethyl ODA, 2,2'-dichloro ODA, 4,4'-thiodianiline, bis (4-aminophenyl) ) Sulfone, bis (4-amino-3-chlorophenyl) sulfone, 4,
4'-diaminobenzophenone, 4,4'-diamino-
3,3'-dichlorobenzophenone, 4,4'-diaminotriphenylamine, di (4-aminophenyl) -butylamine, 4,4'-diaminobenzanilide, 4,
4'-diaminotriphenylmethane, 4,4'-diamino-3,3'-dimethyltoluphenylmethane, 4,4 '
-Diamino-3,3'-diethyltriphenylmethane,
Examples thereof include 4,4′-diamino-3,3 ′, 5,5′-tetramethyltriphenylmethane, but are not limited thereto.

Specific examples of preferred metal catalysts used in the present invention include noble metal catalysts (platinum, palladium, rhodium, etc.) and nickel catalysts (Raney-nickel, etc.). The platinum and palladium catalysts may be used by dispersing them on a carrier such as activated carbon, silica, alumina and barium sulfate, and palladium-carbon and platinum-carbon are preferred. The noble metal catalyst can also be used as an oxide, and specific examples of platinum oxide and palladium oxide can be used. Platinum-carbon catalysts containing sulfur compounds are especially preferred. The sulfur compound is preferably an inorganic sulfur compound, and specific examples of hydrogen sulfide, an inorganic sulfide such as sodium hydrogen sulfide, sulfur dioxide, a sulfite salt such as sodium sulfite, and a hydrogen sulfite salt such as potassium hydrogen sulfite can be used. I can name it. A catalyst in which platinum sulfide is dispersed on carbon can also be used. A platinum-carbon catalyst containing a sulfur compound can be produced, for example, by the method described below.
It is also commercially available from Car. A commercially available platinum-carbon catalyst is suspended in water, and a sulfur compound dissolved in water is added dropwise at room temperature while stirring. After stirring for a predetermined time, the catalyst is filtered and washed thoroughly with water. Content of sulfur compounds is 4,4
It varies depending on the type of ′ -dianiline, the type of aldehyde or ketone, the reaction temperature, and the like. The amount of the sulfur compound can be selected in the range of 0.1 to 5 parts by weight with respect to 100 parts of platinum. The Raney nickel catalyst is a nickel-aluminum alloy developed with Caseisoda, and is commercially available in the form of an aqueous paste. Raney-Nickel treated with sulfite or acidic sulfite is preferred. Specific examples of sulfite or acidic sulfite, sodium sulfite, potassium sulfite, ammonium sulfite,
Examples include acidic sodium sulfite and acidic potassium sulfite. The Raney nickel treatment can be performed, for example, as follows. The spread Raney-Nickel aqueous paste is suspended in water, an aqueous solution of sulfite or acidic sulfite is added dropwise at room temperature while stirring, and the mixture is stirred for a predetermined time. The concentration of the aqueous solution is usually 1 to 50% by weight. Usually, the treatment can be performed at a treatment temperature of 10 to 40 ° C. and a treatment time of several minutes to 3 hours. Then, the supernatant is removed, water is added and the mixture is stirred, and then the supernatant is removed. This washing operation is repeated several times. The amount of sulfite or acidic sulfite can be selected in the range of 1 to 30 parts based on 100 parts of Raney-nickel nickel metal. (Parts mean parts by weight in the following.) The amount of the catalyst used in the present invention is 4,4′-dianilines.
0.01 to 50 parts relative to 0 parts, more specifically, in the case of platinum or palladium, 0.01 to 5 parts, preferably 0.05 to 1 part, nickel 1 to 50 parts, preferably 5 in terms of metal. The range is from -25 parts.

As the aldehydes or ketones used in the present invention, those used in ordinary reductive alkylation reaction can be used. Specific examples thereof include formaldehyde, acetaldehyde, propioaldehyde and n-.
Butyraldehyde, iso-butyraldehyde, hexyl aldehyde, octyl aldehyde, acrolein, crotonaldehyde, cinnamaldehyde, acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone,
2-hexanone, 3-hexanone, methyl isobutyl ketone, 4-heptanone, diisobutyl ketone, cyclohexanone, isophorone and the like can be mentioned. The amount of aldehydes or ketones used is 2 mol to 10 mol per 1 mol of 4,4'-dianiline, and it can also serve as a solvent.

In the production method of the present invention, a solvent can be used if necessary. As the solvent, lower aliphatic alcohol such as methanol, ethanol and isopropyl alcohol can be used, and methanol is industrially advantageous. The amount of the solvent used is 0.1 to 5 times by weight that of the aldehyde or ketone.

An acidic compound can be used as a catalyst for promoting the reductive alkylation reaction of 4,4'-dianilines with aldehydes or ketones. Specific examples of the acidic compound that can be used include acetic acid, propionic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, sulfuric acid and phosphoric acid. The amount used is 1 to 10 parts per 100 parts of 4,4'-dianiline.

As the method of operating the reaction according to the present invention, any of batch system, semi-batch system and continuous system can be adopted. The batch method means a method in which a metal catalyst, 4,4'-dianiline and aldehydes or ketones, and if necessary, a solvent and an acidic catalyst are charged and the reaction is performed under a predetermined reaction condition under hydrogen pressure. In the semi-batch method, a metal catalyst, 4,4′-dianiline, and, if necessary, a solvent and an acidic catalyst are charged in a reactor, and aldehydes or ketones are continuously charged under predetermined reaction conditions under hydrogen pressure. Charge the metal catalyst and solvent in the reactor,
It means a system in which 4,4'-dianilines and aldehydes or ketones and, if necessary, an acidic catalyst are continuously charged simultaneously under predetermined reaction conditions under hydrogen pressure and reacted.
In the continuous system, a metal catalyst, 4,4′-dianiline and aldehydes or ketones and, if necessary, a solvent and an acidic catalyst are continuously charged under predetermined reaction conditions under hydrogen pressure to prepare a reaction product, a metal catalyst, and a solvent. , A reaction system in which a reaction solution containing an acidic catalyst or the like is continuously withdrawn. Hydrogen is appropriately supplemented to complete the reaction. It is also possible to charge 4,4'-dianiline, an acidic catalyst and aldehydes or ketones in advance at room temperature or under heating to carry out a condensation reaction to charge the product. The reaction temperature is usually 10 to 150 ° C, preferably 30 to 120 ° C. If it exceeds 150 ° C, a large amount of by-products will occur, and if the temperature is lower than 10 ° C, the reaction rate will be low. The hydrogen pressure is 1 to 100 kg / cm ² (gauge pressure), preferably 5 to 50 kg / cm ² (gauge pressure). The reaction time varies depending on the amount of catalyst, reaction temperature, reaction pressure, etc., but is usually 30 minutes to 10 hours. After completion of the reaction, the catalyst is separated from the reaction solution by filtration or precipitation, and then the solvent and excess aldehyde or ketone are separated by a separation operation such as distillation to isolate 4,4'-di (N-alkylaniline). . If necessary, it can be further purified by a purification means such as distillation or recrystallization. The purity of the reaction product can be easily measured by liquid chromatography.

[0012]

EXAMPLES The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 F1901XRCSA / W3% Pt (trade name, 3% Pt-carbon catalyst, Degussa Japan Co., Ltd.) treated with a sulfur compound in a 300 cc autoclave equipped with a stirrer
1.5 g (dry basis), methyl ethyl ketone 58
g, 4,4'-methylenedianiline (40 g) and p-toluenesulfonic acid (1 g) were added, and the atmosphere was replaced with nitrogen and then with hydrogen. The temperature was raised and the hydrogen pressure was maintained at 10 kg / cm ² (gauge pressure) and the reaction temperature was kept at 80 ° C. for reaction. Hydrogen was continuously supplied during the reaction, and the required amount of hydrogen was absorbed in 3.5 hours, and the hydrogen absorption was almost stopped. After stirring for 15 minutes at the same temperature, the mixture was cooled and allowed to stand. The catalyst was filtered off to obtain a reaction solution. Excess methyl ethyl ketone and by-produced sec-butyl alcohol were distilled off from the reaction solution under reduced pressure to obtain an oil. The oil was washed with warm water, and the separated oil was heated under reduced pressure to distill off the water to obtain 61.3 g of 4,4′-methylenedi (N-sec-butylaniline). Yield 97.8%. Liquid chromatographic analysis value 97.6% (area%).

Example 2 Pt-used in Example 1 in a 300 cc autoclave
Carbon catalyst 1.5 g, methyl ethyl ketone 100 g,
50 g of bis (4-aminophenyl) sulfone and 1 g of p-toluenesulfonic acid were charged, and the hydrogen pressure was 10 kg / c.
The reaction was carried out at m ² and a reaction temperature of 90 ° C. Hydrogen absorption stopped after 5 hours. After the catalyst was filtered off from the reaction solution, the same post-treatment as in Example 1 was carried out to obtain 71.5 g of bis (4-N-sec-butylaminophenyl) sulfone. Yield 9
8.5%. Liquid chromatographic analysis value: 96.7%.

Example 3 Pt-used in Example 1 in a 300 cc autoclave
Carbon catalyst 1.5 g, methyl ethyl ketone 58 g,
40 g of 4,4′-oxydianiline and 1 g of p-toluenesulfonic acid were charged and reacted at a hydrogen pressure of 10 kg / cm ² and a reaction temperature of 80 ° C. Hydrogen absorption stopped in 4 hours.
After the catalyst was filtered off from the reaction solution, the same post-treatment as in Example 1 was carried out to obtain 60.6 g of 4,4′-oxydi (N-sec-butylaniline). Yield 97.0%. Liquid chromatographic analysis value 98.3%.

Example 4 Pt-used in Example 1 was added to a 500 cc autoclave.
A carbon catalyst (1.5 g), 4,4'-methylenedianiline (80 g) and methanol (150 cc) were charged and the temperature was raised. While maintaining the hydrogen pressure at 10 kg / cm ² and the reaction temperature at 80 ° C., 39 g of acetaldehyde was continuously injected for 3 hours for reaction. The hydrogen absorption stopped 15 minutes after the press-fitting was completed. After the catalyst was filtered off from the reaction solution, methanol and by-produced ethanol were distilled off to obtain an oil. The oil was washed with warm water and separated, and the oil obtained was heated under reduced pressure to distill off the water to give 4,4'-methylenedi (N-ethylaniline).
99.5 g was obtained. Yield 97.8%. Liquid chromatographic analysis value: 95.5%.

Example 5 ND developed on a 1000 cc beaker containing a stirrer
T-90 (trade name, Raney-Nickel catalyst, manufactured by Kawaken Fine Chemicals Co., Ltd.) and 500 g of water were put in and stirred, and 100 g of an aqueous solution containing 10% sodium acid sulfite was dissolved in 15 minutes. Dropped. After stirring at room temperature for 30 minutes, the supernatant water was discarded and the mixture was washed with 500 cc of water to obtain the desired Raney-Nickel catalyst (treated catalyst). In a 500 cc autoclave equipped with a stirrer, 7 g of the treated catalyst prepared above, 58 g of methyl ethyl ketone, 4,
4'-Methylenedianiline (40 g), p-toluenesulfonic acid (1 g) and methanol (60 cc) were added and the atmosphere was replaced with nitrogen and then hydrogen. The pressure was raised and the hydrogen pressure was maintained at 10 kg / cm ² and the reaction temperature was 90 ° C., and the reaction was carried out. During the reaction, hydrogen was continuously supplied and the required amount of hydrogen was absorbed in 3 hours. The mixture is stirred at the same temperature for 15 minutes, cooled, and allowed to stand. After the catalyst was filtered off from the reaction solution, methanol, excess methyl ethyl ketone and sec-butyl alcohol by-produced were distilled off under reduced pressure. The obtained oil was washed with warm water, and the oil obtained by liquid separation was heated under reduced pressure to distill off the water to obtain 61.6 g of 4,4′-methylenedi (N-sec-butylaniline).
Yield 98.3%. Liquid chromatographic analysis value 98.0
%.

Example 6 A 300 cc autoclave was charged with 7 g of the treated catalyst obtained by the method of Example 5, 100 g of acetone, 40 g of 4,4'-methylenedianiline and 1 g of p-toluenesulfonic acid, and hydrogen pressure was applied. The reaction was carried out at 10 kg / cm ² and a reaction temperature of 80 ° C. The reaction time was 1 hour and 40 minutes. After the catalyst was filtered off from the reaction solution, acetone and by-produced iso-propanol were distilled off. The oil obtained was washed with warm water, and the oil obtained by liquid separation was heated under reduced pressure to distill off the water to obtain 4,4'-
Methylenedi (N-iso-propylaniline) 54.4
g was obtained. Yield 97.5%. Liquid chromatographic analysis value
99.3%.

Example 7 A 500 cc autoclave was charged with 3 g of the treated catalyst obtained by the method of Example 5, 80 g of 4,4'-methylenedianiline and 150 cc of methanol, and the temperature was raised. Hydrogen pressure 1
While maintaining the reaction temperature at 0 kg / cm ² and the reaction temperature at 80 ° C., 64 g of n-butyraldehyde was continuously injected for 2 hours for reaction. The hydrogen absorption stopped 15 minutes after the press fitting was completed. After the catalyst was filtered off from the reaction solution, methanol and n-butyl alcohol were distilled off. The oil obtained was washed with warm water, and the oil obtained by liquid separation was heated under reduced pressure to distill off the water to obtain 4,4 '.
123 g of methylenedi (Nn-butylaniline) was obtained. Yield 98.0%. Liquid chromatographic analysis value 96.3
%.

Example 8 A 500 cc autoclave was charged with 7 g of the treated catalyst obtained by the method of Example 5, 100 g of acetone, 51 g of 4,4'-methylenedi (2-ethylaniline) and 1 g of p-toluenesulfonic acid. Charge, hydrogen pressure 10 kg / cm ² , reaction temperature 9
The reaction was performed at 0 ° C. The reaction time was 2 hours and 45 minutes.
The catalyst was filtered off from the reaction solution, and post-treatment was carried out in the same manner as in Example 6 to obtain 72.4 g of 4,4'-methylenedi (2-ethyl-N-iso-propylaniline). Yield 98.5
%. Liquid chromatographic analysis value 98.0%.

Example 9 By the same operation as in Example 5, 10 g of the treated Raney-nickel catalyst treated with 10% by weight of ammonium sulfite based on the Raney-nickel catalyst, 70 g of methyl ethyl ketone,
MDA (40 g) and acetic acid (1 g) were charged in a 500 cc autoclave and reacted at a hydrogen pressure of 10 kg / cm ² and a reaction temperature of 110 ° C. The reaction time was 4 hours and 20 minutes. After the catalyst was filtered off from the reaction solution, methyl ethyl ketone and sec-butyl alcohol by-produced were distilled off. The obtained oil was washed with warm water, and the separated oil was heated under reduced pressure to distill off the water to give 4,4'-methylenedi (N-butylaniline) 6
1.3 g were obtained. Yield 97.8%. Liquid chromatographic analysis value: 97.7%.

Example 10 In 500 cc autoclave, 7 g of the treated catalyst obtained by the method of Example 5, 58 g of methyl ethyl ketone, 50 g of bis (4-aminophenyl sulfone), 1 g of p-toluenesulfonic acid, 100 cc of methanol. Charged, hydrogen pressure 10k
The reaction was carried out at g / cm ² and a reaction temperature of 100 ° C. The reaction time was 6 hours and 30 minutes. The catalyst was filtered off from the reaction solution, and post-treatment was carried out in the same manner as in Example 5 to obtain 71.0 g of bis (4-N-sec-butylaminophenyl) sulfone. yield
97.8%. Liquid chromatographic analysis value 96.0%.

[0023]

According to the present invention, 4,4'-di (N-alkylaniline) s can be obtained in a high yield by simple operation by reductive alkylation of 4,4'-dianilines with aldehydes or ketones. Can be manufactured with high purity.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C07C 213/02 C07C 213/02 217/90 217/90 315/04 315/04 317/36 7419- 4H 317/36 // C07B 61/00 300 C07B 61/00 300

Claims (11)

[Claims] 1. A 4,4′-di (N-alkylaniline) which is characterized by reacting 4,4′-dianiline with an aldehyde or a ketone in the presence of a metal catalyst under hydrogen pressure. Production method 2. A 4,4′-dianiline compound represented by the formula (1): (In the formula, X represents alkylene, substituted alkylene, oxy, thio, sulfonyl, imino, carbonyl or carboimino, R ₂ and R ₃ represent hydrogen atom, lower alkyl group, lower alkoxy group or halogen atom, and R ₂
And R ₃ may be the same or different. ) 4,4'-di (N-alkylaniline) s have the formula (2)
The production method according to claim 1, which is a compound represented by: (In the formula, X, R ₂ and R ₃ have the same meanings as in formula (1), and R ₁ represents lower alkyl.) 3. The process according to claim 1, wherein the 4,4′-di (N-alkylaniline) s are 4,4′-methylenedi (N-alkylaniline) s represented by the formula (3). Method [Chemical Formula 3] (In the formula, R ₁ , R ₂ and R ₃ have the same meanings as in the formula (2).) 4. The method for producing 4,4′-di (N-alkylaniline) s according to claim 1, 2 or 3, wherein the metal catalyst is platinum or palladium. 5. The 4,4'- according to claim 4, wherein the metal catalyst is a platinum catalyst supported on activated carbon and containing a sulfur compound.
Method for producing di (N-alkylaniline) s 6. The method for producing 4,4′-di (N-alkylaniline) s according to claim 1, 2 or 3, wherein the metal catalyst is Raney-nickel. 7. The method according to claim 6, wherein the metal catalyst is Raney-nickel treated with sulfite or acidic sulfite.
Process for producing 4'-di (N-alkylaniline) s 8. The method according to claim 1, wherein the reaction is carried out in the presence of an acidic catalyst.
4,4'-di (N according to 2, 3, 4, 5, 6 or 7
-Method for producing alkylaniline) 9. The 4,4 'according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the reaction is carried out in the presence of alcohols.
-Process for producing di (N-alkylaniline) s 10. The reaction temperature according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, which is 10 to 150 ° C.
Method for producing 4'-di (N-alkylaniline) s 11. The reaction hydrogen pressure is 1 to 100 kg / cm.
² (gage pressure), Claims 1, 2, 3, 4, 5, 6,
7,8,9 or 10 production method of 4,4'-di (N-alkylaniline) s