JP2002030045A - Method for continuous production of diarylamine and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for the continuous production of a diarylamine from an arylamine in liquid phase under pressure using a solid acid catalyst with a simple procedure in high conversion to the objective reaction product compared with conventional methods. SOLUTION: A diarylamine is continuously produced without heating a reactor from exterior heat source by supplying an arylamine heated to the reaction temperature from the top of a heat-insulated fixed bed reactor packed with a solid acid catalyst, carrying out the reaction in liquid phase under pressure and discharging the reaction product from the bottom of the reactor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for continuously producing a diarylamine under a pressurized liquid phase using a solid acid catalyst starting from an arylamine.

[0002]

2. Description of the Related Art Diarylamines are industrially important compounds as raw materials for organic synthesis of rubber chemicals, pharmaceuticals and dyes. Conventionally, as a method for producing diphenylamine using aniline as a starting material, HCl, P ₂ O ₅ , PCl
₃ , a pressurized liquid phase method using an acid catalyst such as AlCl ₃ , BF ₃ and NH ₄ BF ₄ (JP-A-51-138628 and JP-A-5-138628).
3-40697) and a fixed-bed gas phase method using acid-treated γ-alumina (Japanese Patent Laid-Open No. 61-10385).
7 gazette and Japanese Patent Publication No. 3-16943). JP-B-52-15585 and JP-A-54-135728 disclose a fixed-bed pressurized liquid phase method using a silica-alumina-based synthetic solid acid catalyst.

In the above-mentioned pressurized liquid phase method, there are difficulties in the corrosiveness of the apparatus by an acid catalyst and in separation and recovery of the catalyst, and in the fixed bed gas phase method, the apparatus becomes large and tar-like by-products are formed during the reaction. There is a disadvantage that the substance adheres to the catalyst surface and the catalytic activity is significantly reduced.

In the fixed-bed pressurized liquid phase method, the conversion rate of the solid acid catalyst disclosed in the above publication, which is considered to have high reaction activity, is not sufficient, and a large amount of raw material is recovered and recycled. There is a need. Further, in the continuous production method of diarylamines by the fixed-bed pressurized liquid phase method, since ammonia gas is by-produced, the reaction raw material is conventionally supplied from the lower part of the reactor for the purpose of facilitating degassing, and the product is produced. A reaction method based on an upflow method derived from the upper part of the reactor is employed. The following are presumed to be reasons why a sufficient conversion rate from the starting arylamine to the desired diarylamine cannot be obtained by this method. The conversion refers to the ratio of the amount of the raw material consumed at the reactor outlet to the amount of the raw material supplied from the reactor inlet per unit time, and is expressed by the following equation. Conversion rate (%) = consumed raw material amount (kg / hr) / feed raw material amount (kg / hr)

Since the reaction for converting arylamines into diarylamines is an endothermic reaction, when the reaction proceeds under adiabatic conditions, the starting arylamines rise up the catalyst layer from the raw material supply port at the bottom of the reactor. As it progresses,
The temperature of the reaction solution gradually decreases. That is, the temperature becomes lower in the upper part of the reaction layer, and the density of the reaction solution becomes higher in the upper part of the reaction layer, so that a density difference occurs in the reaction system and a circulating flow is generated. When a circulating flow is generated, the unreacted raw material is short-passed to the reactor outlet by the circulating flow, which causes a reduction in the conversion. In addition, the reaction product moves to the raw material supply side due to the circulating flow to lower the raw material concentration in the lower part of the reaction layer, and the suppression of the reaction itself also causes a reduction in the conversion. By the way, Japanese Patent Application Laid-Open No. H11-11605 discloses a technique in which a production method using an upflow method is advantageous for improving the conversion.
No. 310554 proposes. However, in this method, a reactor with a heating furnace is used in the examples and apparatus diagrams, and the raw material arylamines are heated in the reactor. it is conceivable that.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a simple apparatus that does not require external heating of the reactor.
An object of the present invention is to provide a method for continuously producing diarylamines having a high conversion.

[0007]

According to the present invention, there are provided a step of supplying an arylamine as a raw material, a step of heating the supplied arylamine to a reaction temperature, and a step of converting the heated arylamine into a solid acid. The catalyst is filled and supplied from a raw material supply port located at the top of an adiabatic fixed bed reactor that extends up and down, comes into contact with the solid acid catalyst, reacts under a pressurized liquid phase, and converts the reaction product into a reactor. And continuously deriving the diarylamines from the bottom.

According to the present invention, the reaction is carried out by employing a down-flow system in which the raw material arylamines heated to a certain temperature are supplied from the upper part of the adiabatic fixed-bed reactor and the reaction solution is discharged from the lower part of the reactor. It is possible to prevent the reaction liquid from circulating in the system and moving the product to the raw material supply side. This provides a continuous production method of diarylamines having a high conversion rate from a raw material to a product using a simple reaction device without an external heating device. Here, the adiabatic fixed bed reactor refers to a fixed bed reactor having no external heating device. In contrast, in the upflow method in which the raw material arylamines are supplied from the lower part of the reactor and the reaction solution is drawn out from the upper part of the reactor, when the reaction proceeds under adiabatic conditions,
As the raw material arylamine rises up the catalyst layer from the raw material supply port at the bottom of the reactor and proceeds, the temperature of the reaction solution gradually decreases. In other words, the temperature becomes lower toward the upper part of the reaction layer,
Conversely, the density of the reaction solution becomes higher toward the upper part of the reaction layer, and a density difference occurs in the reaction system to generate a circulating flow. It is considered that the reaction product is moved to the raw material supply side by the circulating flow, the raw material concentration in the lower part of the reaction layer is reduced, and the reaction itself is suppressed, so that the conversion is reduced. Therefore, in order to prevent the generation of a circulating flow in the reaction system, it is necessary to install an external heating device in the reactor, and keep the reaction temperature at a constant temperature by heating the entire reactor from the outside.

In the present invention, the temperature of the arylamine in the raw material supply port is about 300 ° C. to about 380 ° C., and the reaction pressure is at least the saturated vapor pressure of the arylamine in the fixed bed reactor outlet composition. The reaction is performed under the above pressure.

According to the present invention, gasification of ammonia by-produced during the reaction can be prevented. That is, diarylamines can be efficiently and continuously produced without degassing the reaction system.

The present invention further provides a diaryl compound represented by the following general formula (3) by reacting an arylamine represented by the following general formula (1) with an arylamine represented by the following general formula (2). It is characterized by producing an amine.

[0012]

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[0013]

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[0014]

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(Wherein R1 to R10 are the same or different and each represents hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a phenyl group, a hydroxy group, an amino group, a nitro group, Or 1 to 12 carbon atoms
Represents an alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group, a phenyl group or a hydroxy group)

The present invention also provides a raw material supply means for supplying arylamines as a raw material, a heating means for heating the arylamines from the raw material supply means to a reaction temperature, and a method for heating the arylamines in an adiabatic pressurized liquid phase. An adiabatic fixed-bed reactor in which the arylamines that extend vertically and are filled with a solid acid catalyst and heated by heating means are supplied from above, and the reaction products are discharged from below. An apparatus for continuously producing diarylamines, comprising: an adiabatic fixed-bed reactor; and a cooling means for cooling a reaction solution drawn out from a lower part of the adiabatic fixed-bed reactor.

According to the present invention, there is provided an apparatus for continuously producing diarylamines having a high conversion rate by a downflow method.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for continuously producing diarylamines according to one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic view showing an example of a production apparatus for carrying out a continuous production method of diarylamines according to the present embodiment. The production apparatus includes a raw material feed pump 1 for supplying a raw material arylamine, a heater 2 for heating the arylamine to a reaction temperature, an adiabatic fixed bed reactor 3 for reacting the arylamine to produce a diarylamine, a reaction pressure. , A cooler 5 for cooling the reaction product, and a pressure regulating valve 6 for adjusting the reaction pressure.

The arylamines as raw materials continuously supplied by the raw material feed pump 1 are heated to a predetermined reaction temperature by a heater 2 and then heated at a predetermined temperature above an adiabatic fixed bed reactor 3 filled with a solid acid catalyst. It is supplied from the raw material supply port, and arrow 11
Flows in the direction of. In the adiabatic fixed-bed reactor 3, the raw material arylamines come into contact with the solid acid catalyst and the reaction proceeds under a pressurized liquid phase. A reaction solution comprising diarylamines as reaction products and unreacted arylamines is continuously discharged from the lower part of the adiabatic fixed-bed reactor 3 and cooled by the cooler 5 to convert the diarylamines. Manufacture continuously.

As the adiabatic fixed bed reactor 3, a pressure-resistant reactor used in the technical field may be used as long as it has a raw material supply port at the upper part of the reactor and a reaction liquid outlet at the lower part. can do. It is not necessary to heat the reactor itself from the outside, but it is preferable that the outside of the reactor is kept warm with a heat insulating material or the like in order to prevent the reaction temperature from dropping too much and to suppress the progress of the reaction.

The solid acid catalyst to be filled in the adiabatic fixed bed reactor 3 includes a single oxide selected from silica, alumina, titania, zirconia and the like, a composite oxide containing at least two kinds as main components, and β Type, Y type, USY
Examples include zeolite catalysts such as type, L type, MFI type, SAPO type and mordenite type. Among them, silica alumina, β type zeolite, Y type zeolite and USY type zeolite are preferred. In addition, zeolite catalysts include Na type and
K-type may be contained. Further, as long as the conversion is not significantly reduced as a solid acid catalyst, a zeolite catalyst in which a part of zeolite component such as Al or Si is substituted by another kind of metal can be used.

The single oxide catalyst, composite oxide catalyst and zeolite catalyst may be those obtained by a conventionally known production method, and the production method is not particularly limited. It can also be appropriately selected from commercially available single oxides, composite oxides and zeolites.

The shape of the solid acid catalyst is not particularly limited, and it can be used in various shapes such as powder, granules and tablets. In terms of ease of handling,
Granules or tablets are recommended.

The arylamines used in the embodiment are represented by the following general formulas (1) and (2):
R1 to R10 are the same or different and are each hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a phenyl group, a hydroxy group, an amino group,
A nitro group, or an alkoxy group having 1 to 12 carbon atoms, a phenyl group or a hydroxy group,
2 represents an alkyl group). By reacting these starting arylamines in the presence of the above-mentioned zeolite catalyst or the like, diarylamines represented by the following general formula (3) [the symbols in the formulas are the same as those of the above general formulas (1) and (2)] are obtained. be able to.

[0026]

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[0027]

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[0028]

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The above-mentioned general formulas (1) and (2)
Specific examples of the arylamine represented by are aniline, toluidine, ethylaniline, cumidine, xylidine, butylaniline, and anisidine. Particularly, aniline, toluidine, cumidine and xylidine are preferred. In the reaction, the compounds of the general formulas (1) and (2) as the reaction raw materials may be the same compound, for example, both aniline or different compounds.

In carrying out the method for continuously producing diarylamines according to one embodiment of the present invention, first, the arylamines as raw materials are heated to a constant reaction temperature by the heater 2, and then the adiabatic fixed bed reactor is used. The raw material is continuously introduced into the adiabatic fixed-bed reactor 3 from the raw material supply port at the upper part of the reactor 3 and subjected to the reaction. The temperature at the time of introducing the raw material is about 300 to about 400 ° C.
Is preferable, and about 320 to about 360 ° C is more preferable. When the introduction temperature is lower than 300 ° C., the progress of the reaction becomes slow. In addition, when the introduction temperature exceeds 400 ° C., generation of by-products increases, and when a low-boiling compound such as aniline is used as a raw material, a high pressure is required to maintain the reaction solution as a liquid. It is not preferable because it becomes necessary.

The temperature of the reaction liquid outlet at the lower part of the adiabatic fixed bed reactor 3 depends on the feed rate of the raw material, but is preferably about 5 to about 40 ° C. lower than the temperature of the raw material feed port.
A temperature as low as about 30 ° C. is more preferable.

The reaction pressure may be any pressure which can prevent ammonia generated by the reaction from being bubbled and can maintain the reaction system in a liquid state under the reaction temperature conditions.
When ammonia by-produced in the reaction system foams,
The rising of the generated bubbles causes disturbance of the liquid flow and mixing of the reaction solutions. At the same time, the contact between the solid acid catalyst and the raw material arylamines is hindered, which suppresses the reaction and causes a reduction in the conversion rate. . Since the reaction pressure increases in proportion to the reaction temperature, it may be equivalent to the saturated vapor pressure of the arylamine at the reaction temperature. For example, in the case of aniline, the reaction temperature ranges from 2 to 6 MPa.

The feed rate (LHSV) of the raw material arylamine to the adiabatic fixed bed reactor 3, that is, the feed rate of arylamine (ml / hr) / the charged amount of catalyst (ml) is about 0.01.
From about 10 to about 10, more preferably from about 0.1 to about 1.
As this value increases, the residence time of the raw material arylamines in the adiabatic fixed bed reactor 3 becomes shorter, and the contact time with the solid acid catalyst also becomes shorter, so that the conversion from the raw material to the product tends to decrease. Can be seen.

The reaction liquid drawn out from the lower part of the adiabatic fixed-bed reactor 3 is cooled by the cooler 5 and then, by distillation treatment or the like, first, unreacted arylamines are recovered, and then high-boiling by-products are removed. To separate. By such fractionation, the desired diarylamines can be easily obtained.

In the down flow method using the production apparatus as shown in FIG. 1, arylamines as raw materials are heated to a certain reaction temperature and then supplied from a raw material supply port at the top of the adiabatic fixed bed reactor. Further, the reactor is an adiabatic type, to which heat is not supplied from the outside and the reaction itself is an endothermic reaction, so that the temperature decreases as the reaction proceeds. That is, since the temperature is higher in the upper part of the reaction phase and lower in the lower part, the density of the reaction solution is conversely lower at the upper part of the reaction phase and higher at the lower part, thereby preventing generation of a circulating flow in the reaction system. In addition, since the reaction is performed under a pressurized condition in which by-product ammonia does not evaporate, disturbance of the liquid flow due to the rising ammonia gas is also prevented.

In the down flow method employed in the manufacturing apparatus according to the embodiment, the disturbance of the liquid flow in the reaction system is prevented, and a steady laminar flow (plug flow) is realized. A high reaction conversion is achieved.

However, even in the downflow method, an external heating method is employed in which the raw material arylamines are supplied at room temperature and the reactor is heated from the outside in order to heat the reactor to a certain reaction temperature. In this case, the starting arylamines are supplied at room temperature and heated to a certain reaction temperature in the reactor, so that a low-temperature and high-density reaction solution flows in the initial stage of the reaction. As a result, a circulating flow is generated in the reaction system, and the reaction proceeds in a state close to a completely mixed state.
The conversion is lower than in the upflow method.

Hereinafter, the present invention will be specifically described with reference to a simulation relating to a circulating flow of a reaction solution.

FIG. 2 is a diagram showing the result of a simulation on the circulating flow of the reaction solution in the adiabatic fixed-bed reactor 3 of FIG. The simulation of the flow state of the reaction solution is performed by the flow analysis software FLUENT from FLUENT.
(Product name) was performed for each of the downflow method and the upflow method. The analysis conditions were as follows: the adiabatic fixed-bed reactor had a diameter of 2 m, a height of 8 m, and a catalyst filling section of 6 m.
The raw material inlet flow rate is 3.132 m / hr, and the raw material inlet temperature is 3
40 ° C, outlet temperature 320 ° C, pressure 1.01325 ×
10 ⁵ Pa and the working solution was aniline, a mixture of ammonia and diphenylamine.

FIG. 2A shows the result of the downflow method. The reaction liquid flows from the upper part of the reactor to the lower part of the reactor as indicated by arrow 21. The achromatic shades in FIG. 2 indicate that the higher the concentration, the higher the concentration of diphenylamine. As shown in FIG. 2A, a circulating flow does not occur in the downflow method, and the reaction solution has a steady laminar flow.

On the other hand, FIG. 2 (2) shows the result when the reaction was carried out using an adiabatic fixed-bed reactor 3, that is, by an up-flow method without externally heating the reactor.
The reaction liquid flows from the lower part of the reactor to the upper part of the reactor as shown by arrow 22. From FIG. 2 (2), it can be seen that a circulating flow of the reaction liquid occurs in the upflow method, and that the product, diphenylamine, is distributed also in the lower part of the reactor, that is, on the raw material supply side.

[0042]

As described above, according to the present invention, the raw material arylamines are supplied from the upper part of the adiabatic fixed bed reactor and the reaction product is derived from the lower part of the adiabatic fixed bed reactor by a simple method. In addition, diarylamines can be continuously produced in a high yield over a long period of time using a reactor without an external heating device.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a method for introducing a raw material into an adiabatic fixed-bed reactor 3 according to an embodiment of the present invention.

FIG. 2A is a simulation diagram showing a flow of a reaction solution in an adiabatic fixed-bed reactor 3 in a down-flow method. FIG. 2B is a simulation diagram showing a circulating flow of the reaction solution in the adiabatic fixed-bed reactor 3 in the upflow method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Feed pump 2 Heater 3 Insulated fixed bed reactor 5 Cooler

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toyohiro Kamada 5-1 Sokai-cho, Niihama-shi, Ehime F-term (reference) in Sumitomo Chemical Co., Ltd. 4G070 AA01 AB07 BB02 CA06 CA09 CA16 CA24 CA25 CB17 CC02 CC11 DA23 4H006 AA02 AA04 AC52 BA68 BA71 BC10 BC11 BC14 BD10 BD80 BD81 4H039 CA41 CD10 CD50

Claims (4)

[Claims] 1. A step of supplying a raw material of arylamines, a step of heating the supplied arylamines to a reaction temperature, and a step of filling the heated arylamines with a solid acid catalyst and extending up and down. Supplied from a raw material supply port located at the upper part of the adiabatic fixed bed reactor, brought into contact with the solid acid catalyst, reacted under a pressurized liquid phase, and withdrawing a reaction product from the lower part of the reactor. A method for continuously producing diarylamines. 2. The temperature of the arylamine at the raw material supply port is about 300 ° C. to about 380 ° C., and the reaction pressure is at least a saturated vapor pressure of the arylamine at the outlet composition of the fixed bed reactor. The method according to claim 1, wherein the reaction is carried out under the following conditions. 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 continuously producing diarylamines according to claim 1 or 2, wherein: Embedded image Embedded image Embedded image (Wherein, R1 to R10 are the same or different,
Each of hydrogen, an alkyl group having 1 to 12 carbon atoms, and 1 carbon atom
Represents an alkoxy group having 1 to 12 carbon atoms, a phenyl group, a hydroxy group, an amino group, a nitro group, or an alkyl group having 1 to 12 carbon atoms, which is substituted with an alkoxy group having 1 to 12 carbon atoms, a phenyl group or a hydroxy group) 4. A raw material supply means for supplying arylamines as a raw material, a heating means for heating the arylamines from the raw material supply means to a reaction temperature, and reacting the arylamines under an adiabatic pressurized liquid phase. An adiabatic fixed-bed reactor in which arylamines which are vertically extended, are filled with a solid acid catalyst, and are heated by a heating means are supplied from an upper portion, and reaction products are discharged from a lower portion. An apparatus for continuously producing diarylamines, comprising: a bed reactor; and cooling means for cooling a reaction solution drawn out from a lower part of the adiabatic fixed bed reactor.