JP2000016972A - Production of diarylamines - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conveniently obtain a diarylamine useful as a raw material for rubber chemicals, medicines, dyes, etc., and having a remarkably improved degree of conversion by reacting arylamines in the presence of a zeolite in a liquid phase under pressure. SOLUTION: Arylamines as a raw material preferably shown by formula I and II [R1-R10 are each H, a 1-12C alkyl, a 1-12C alkoxy or the like] are reacted in the presence of a zeolite as a solid acid catalyst (preferably at least a zeolite selected from β-type, Y-type and USY-type) in a liquid phase under pressure, for example in the case of aniline as a raw material under 10-40 kg/cm2G pressure, at preferably 330-360 deg.C. The unconverted arylamines are distilled off from the reaction product and a high boiling by-product as a residue is separated to give the objective compound, preferably a compound of formula III. Water content of the arylamines is <0.9 wt.% preferably <0.7 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing diarylamines, which are raw materials for rubber drugs, medicines, dyes and the like. More specifically, the present invention relates to a method for producing diarylamines using an arylamine such as aniline as a starting material in the presence of a solid acid catalyst under a pressurized liquid phase.

[0002]

2. Description of the Related Art Conventionally, as a method for producing diphenylamine using aniline as a starting material, hydrochloric acid, P ₂ O ₅ ,
Pressurized liquid phase method (for example, JP-A-51-138628, JP-A-53-40697) using a catalyst such as PCl ₃ , AlCl ₃ , BF ₃ , NH ₄ BF _4, etc. Fixed bed gas phase method using γ-alumina (for example, JP-A-61-103857, JP-B-3-1694)
No. 3). In addition, Japanese Patent Publication 52-15
No. 585 discloses a fixed bed pressurized liquid phase method using a silica-alumina synthetic solid acid catalyst. Furthermore,
Japanese Patent Application Laid-Open No. 54-135728 discloses that in a fixed bed pressurized liquid phase method using a silica-alumina synthetic solid acid catalyst, the aniline conversion is significantly increased by coexisting a predetermined amount of water in the raw material aniline. It is disclosed to improve.

[0003]

However, the pressurized liquid phase method has disadvantages in that a highly corrosion-resistant container is required due to the corrosiveness of the catalyst, and there is a difficulty in separating and recovering the catalyst. . Further, the fixed bed gas phase method has disadvantages in that the size of the reaction apparatus becomes large and the catalytic activity is significantly reduced due to the adhesion of the tar by-product generated during the reaction to the catalyst surface. On the other hand, in the fixed bed pressurized liquid phase method, even in the case of a solid acid catalyst conventionally disclosed in the above patents and the like, for example, a silica-alumina-based catalyst having a high reaction activity,
The conversion is not enough, so the productivity is low,
It had drawbacks such as the need to collect and recycle a large amount of raw aniline.

[0004] Under such circumstances, the present inventors have conducted intensive studies on a pressurized liquid phase method using a solid acid catalyst in order to find a production method with a high conversion of arylamines to diarylamines. As a result, it was found that when the zeolite catalyst was used as the solid acid catalyst and the water content in the raw material arylamines was adjusted to a specific amount or less and used, the above object could be achieved. The invention has been completed.

[0005]

That is, the present invention relates to a method for producing a diarylamine from an arylamine as a raw material under a pressurized liquid phase in the presence of a solid acid catalyst, zeolite. The water content is 0.
An object of the present invention is to provide a method for producing diarylamines, which is less than 9% by weight.

Further, in the present invention, when diarylamines are produced from an arylamine as a raw material under a pressurized liquid phase in the presence of zeolite as a solid acid catalyst, the amount of water contained in the raw material is lower than that of the starting arylamine. It is another object of the present invention to provide a method for producing diarylamines, wherein an arylamine having a water content of less than 0.9% by weight is used as a raw material after removing water so as to have a water content of less than 9% by weight.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The method of the present invention will be specifically described below. In carrying out the method of the present invention, it is essential to use a zeolite catalyst as a solid acid catalyst. Various zeolites are known. For example, as typical examples, β type, Y type, USY type, L type, MFI type,
Although SAPO type, mordenite type and the like are known, in the method of the present invention, use of at least one zeolite selected from β type, Y type and USY type is recommended.

Although zeolite has acid sites as a solid acid catalyst, H-type and NH4-type are preferred as these acid sites. Of course, as long as the applicable zeolite is in a range having a function as a solid acid catalyst, it may contain Na type and K type. In addition, as long as the conversion of the solid acid catalyst is not remarkably reduced, the zeolite component Al
Alternatively, it is of course possible to use a zeolite catalyst in which a part of Si or the like is substituted by other various metals.

[0009] These zeolite catalysts may be those obtained by a generally known production method, and the production method is not particularly limited. Also, β type, Y type, USY type, L type, MFI
Since various types of zeolites are commercially available as a type, a SAPO type, a mordenite type and the like, it is sufficient to select and use from these. The shape of the zeolite catalyst at the time of use is not particularly limited, and it can be used in various shapes such as powder, granules, and tablets, but from the viewpoint of handling, granules or tablets are recommended. You. Further, at the time of molding, it is possible to use various materials as a binder, usually alumina, silica,
Diatomaceous earth or the like is used. Further, it is preferable to remove water adhering to the catalyst before use.

In the present invention, the arylamines used are represented by the following general formulas (1) and (2):
R10 may be the same or different, and each may be hydrogen, alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, phenyl, hydroxy, amino, nitro or alkoxy having 1 to 12 carbons, hydroxy Or selected from the group consisting of alkyl having 1 to 12 carbon atoms substituted with phenyl), and reacting these starting arylamines in the presence of the zeolite catalyst to obtain the following general formula (3) The symbols and conditions in the formula are the same as those in the above general formulas (1) and (2)].

[0011] Specific examples of the arylamine represented by the above general formulas (1) and (2) as raw materials include aniline, toluidine, ethylaniline, cumidine, xylidine, butylaniline, anisidine, fluoroaniline, bromoaniline, iodoaniline, and fluoroaniline. Although dimethylaniline and the like can be exemplified, aniline, toluidine, cumidine, and xylidine are preferable. In the reaction, general formulas (1) and (2) may of course be the same, for example, only aniline.

In carrying out the present reaction method, the starting arylamine has a water content of less than about 0.9% by weight, preferably 0.7% by weight.
It is necessary to carry out the reaction at less than the weight%. The amount of water in the starting arylamines is not unique, but if the content is more than 0.9% by weight, the water is removed in advance before the reaction. The removal of water from the starting arylamines may be performed by a known method, and the method is not particularly limited. For example, a method of purifying by distillation and the like can be mentioned. 1% by weight of water in the raw material arylamine
If the ratio exceeds 1, a remarkable improvement in the conversion cannot be expected.

This reaction is carried out at a temperature in the range of about 300 to 400 ° C., preferably about 330 to 360 ° C. When the temperature is lower than 300 ° C., the progress of the reaction is slow, and
When the temperature exceeds 00 ° C., a large amount of by-products is generated, and when a low-boiling material such as aniline is used as the material,
Requires high pressure to hold as a liquid.

The pressure in the practice of the present invention may be any pressure that can release the generated ammonia and maintain the liquid phase of the reaction phase at the above reaction temperature. This pressure increases in proportion to the reaction temperature and decreases as the mole fraction of arylamines in the reaction phase decreases as the reaction proceeds. In addition, this pressure may generally correspond to the saturated vapor pressure of the arylamine at the reaction temperature. For example, in the case of aniline, the pressure is generally in the range of about 10 to about 40 kg / cm ² G at the above-mentioned reaction temperature.

In the process of the present invention, after the reaction, unreacted arylamines are simply fractionated from the reaction product, and then high-boiling by-products are separated as residues to easily obtain the desired diarylamines. Can be. At this time, unreacted arylamines recovered have a water content of 0.
After adjusting to less than 9% by weight, it can be used again as a raw material.

The method of the present invention can be carried out by either a batch method or a continuous method. However, industrially, a continuous method of continuously supplying the starting arylamines and continuously extracting the reactants while controlling the pressure is advantageous in terms of work efficiency.

[0017]

According to the present invention described in detail above, zeolite is used as a solid acid catalyst, and the amount of water in an arylamine used as a raw material is adjusted to less than 0.9% by weight. It has been found that the conversion to diarylamine can be remarkably improved, and its industrial utility value is extremely large.

[0018]

EXAMPLES The present invention will be described below in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

EXAMPLE 1 50.1 g in a 500 ml stainless steel autoclave
H-β zeolite powder (Si / Al = 25.0, manufactured by JGC Universal Corporation, trade name BETA), 200.
1 g of aniline (water content: 0% by weight) was charged, and the air in the autoclave was replaced with nitrogen.
Heating was performed at ℃ for 3 hours. After cooling the reaction product, it was taken out of the autoclave, the catalyst was filtered, and the reaction solution was analyzed using a gas chromatograph. As a result, the diphenylamine concentration in the reaction solution was 36.8%.

Example 2 50.0 g in a 500 ml stainless steel autoclave
H-USY zeolite powder (Si / Al = 10.0,
N-Chem Cat Co., Ltd., trade name USY),
After adding 200.2 g of aniline (water content: 0% by weight) and replacing the air in the autoclave with nitrogen, the autoclave was heated at 350 ° C. for 3 hours in a sealed system. After cooling the reactants,
After removing from the autoclave and filtering the catalyst, the reaction solution was analyzed using a gas chromatograph. as a result,
The diphenylamine concentration in the reaction solution was 42.7%.

Comparative Example 1 50.1 g in a 500 ml stainless steel autoclave
H-β zeolite powder (Si / Al = 25.0, manufactured by JGC Universal Corporation, trade name BETA), 203.
7 g of aniline (water content 1.28% by weight)
After replacing the air in the autoclave with nitrogen, heating was performed at 350 ° C. for 3 hours in a sealed system. After cooling the reaction product, it was taken out of the autoclave, the catalyst was filtered, and the reaction solution was analyzed using a gas chromatograph. As a result, the diphenylamine concentration in the reaction solution was 27.1%.

Comparative Example 2 50.0 g in a 500 ml stainless steel autoclave
H-USY zeolite powder (Si / Al = 1.
0, manufactured by NE Chemcat Corporation, trade name: USY), 202.1 g of aniline (water content: 1.
After the air in the autoclave was replaced with nitrogen, the mixture was heated at 350 ° C. for 3 hours in a sealed system.
After cooling the reaction product, it was taken out of the autoclave, the catalyst was filtered, and the reaction solution was analyzed using a gas chromatograph. As a result, the diphenylamine concentration in the reaction solution was 3
It was 9.0%.

Examples 3 and 4 and Comparative Examples 3 and 4 In a 500 ml stainless steel autoclave, β zeolite powder (Si / Al = 25.0, manufactured by JGC Universal Co., Ltd., trade name: BETA) was added in the amount shown in Table 1. , Filling,
The aniline containing water shown in Table 1 was added in the amount shown in Table 1, and the air in the autoclave was replaced with nitrogen, and then heated at 350 ° C. for 3 hours in a sealed system. After cooling the reactants,
After removing from the autoclave and filtering the catalyst, the reaction solution was analyzed using a gas chromatograph. Table 1 shows the concentration of diphenylamine in the reaction solution.

[0024]

[Table 1] DPA in the table indicates diphenylamine, and the amount of aniline is an amount excluding the amount of water.

Example 5 A stainless steel reaction tube (diameter 28)
1.6 mm in diameter in a reactor equipped with a raw material charging port at the lower part of (mm × 400 mm) and a pressure gauge and a pressure regulating valve at the upper part.
m columnar H-β zeolite catalyst (Si / Al = 12.
5. Product name: H-Chem Cat Co., Ltd.
β) was charged to 183 ml, and aniline (water content: 0% by weight) was continuously supplied at a rate of 87.7 ml / Hr (LHSV = 0.48). At that time, the reaction was carried out while maintaining the temperature of the external heating furnace at 345 ° C. and the pressure at 20 kg / cm ² G, and the reaction liquid continuously withdrawn from the upper part of the reaction tube was cooled and collected. After 28 hours, the reaction solution was analyzed using a gas chromatograph. As a result, the diphenylamine concentration in the reaction solution was 16.7%. Table 2 shows the change over time of the diphenylamine concentration in the above continuous reaction evaluation.

Comparative Example 5 A stainless steel reaction tube (diameter 28)
1.6 mm in diameter in a reactor equipped with a raw material charging port at the lower part of (mm × 400 mm) and a pressure gauge and a pressure regulating valve at the upper part.
m columnar H-β zeolite catalyst (Si / Al = 12.
5. Product name: H-Chem Cat Co., Ltd.
β) was filled with 180 ml, and 1% by weight aqueous aniline was added in 8 ml.
It was fed continuously at a rate of 6.2 ml / Hr (LHSV = 0.48). At that time, the temperature of the external heating furnace was 345 ° C,
The reaction was carried out while maintaining the pressure at 20 kg / cm ² G, and the reaction solution continuously withdrawn from the upper part of the reaction tube was recovered after cooling. After 28 hours, the reaction solution was analyzed using a gas chromatograph. As a result, the diphenylamine concentration in the reaction solution was 16.0%. Table 2 shows the change over time of the diphenylamine concentration in the above continuous reaction evaluation.

[0027]

[Table 2]

Claims (4)

[Claims] When producing a diarylamine from an arylamine as a raw material in the presence of a solid acid catalyst zeolite and a pressurized liquid phase, the amount of water in the raw material arylamine is 0.9% by weight. A process for producing diarylamines. 2. The method for producing diarylamines according to claim 1, wherein the zeolite is at least one zeolite selected from β-type, Y-type and USY-type. 3. A diarylamine represented by the following general formula (3) is produced by reacting an arylamine represented by the following general formula (1) with an arylamine represented by the following general formula (2). The method for producing diarylamines according to claim 1, wherein (Wherein, R1 to R10 may be the same or different, and each represents hydrogen, alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, phenyl, hydroxy, amino, nitro or 1 carbon. 1 carbon atom substituted by alkoxy, hydroxy or phenyl
Selected from the group consisting of ~ 12 alkyls) 4. The amount of water in the raw material arylamine is 0.7.
The method for producing a diarylamine according to any one of claims 1 to 3, wherein the content is less than about 10% by weight.