JPS6028956A - Production of aromatic amine - Google Patents

Abstract

PURPOSE:The reaction between an aromatic halide and ammonia is carried out in the presence of an alcohol and a catalyst containing water and a copper compound to achieve high-yield and low-cost production of an aromatic amine at a high reaction rate. CONSTITUTION:In the reaction between an aromatic halide such as dichlorobenzene, chloroaniline, or trichlorobenzene and ammonia in aqueous solvent in the presence of a catalyst containing a copper compound such as cuprous oxide, cuprous halide, or cupric hydroxide, a C3-6 aliphatic alcohol such as propyl alcohol or alicyclic alcohol such as cyclohexanol is allowed to coexist in the reaction system and the reaction temperature is kept at 170-250, preferably 200-240 deg.C for 2-40hr to give the objective compound. The amount of alcohol used is 0.01-15pts.wt. per 100pts.wt. of ammonia.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing aromatic amines, and an object thereof is to provide an excellent method for producing aromatic amines that has high reaction efficiency and can use inexpensive raw materials.

Conventionally, as a method for producing aromatic amines, a method is known in which an aromatic halide and ammonia are reacted in the presence of water using a copper compound as a catalyst. It is known that copper oxides, hydrated oxides, copper halides, and the like are preferable as the copper compounds used as catalysts in this reaction. Furthermore, according to the literature (JI'J,; TR Rochutzoff, translated by Yoshio Nagai et al., "Fine Aromatics Intermediates, Their Chemistry and Synthesis" Gihodo, 1973, pp. 675-376), in the synthesis of aniline from chlorobenzene, It is reported that addition of hydrocarbon compounds and calcium compounds in addition to copper compounds is effective. However, the reason for its addition is to prevent the copper content of the catalyst from depositing on the reactor wall during the reaction, and is not to increase the reaction rate.

Furthermore, in JP-A-50-100028, when producing an aromatic amine by substituting the halogen of an aromatic halide with an amine group, the reaction rate is increased by allowing an alkali compound catalyst to coexist in addition to a copper compound catalyst. Although it has been described that the conversion rate to aromatic amines is improved, it cannot be said that the conversion rate to aromatic amines is still sufficiently high.

Furthermore, in producing aromatic amines from aromatic halides and ammonia, it is not enough to simply improve reaction efficiency; the reaction process requires separation, recovery, and recovery of aromatic amines.
It must be well integrated with all other steps, such as purification and catalyst reuse steps, and in this respect these potentially advantageous reaction methods have not yet been implemented.

As a result of intensive study in view of these points, the present inventors found that
The IC of the present invention was achieved by discovering that the reaction efficiency is significantly improved by adding alcohol to the reaction system and that this reaction step can be advantageously combined with subsequent steps.

That is, the present invention is characterized in that when an aromatic halide and ammonia are reacted in the presence of water using a catalyst containing a copper compound to produce an aromatic amine, the reaction is carried out in the presence of an alcohol. This is a method for producing aromatic amines.

Examples of aromatic halides in the present invention include evadichlorobenzene, trichlorobenzene, chloraniline, dichloroaniline, chlornitrobenzene, and dichloronitrobenzene, and preferred aromatic halides include evadichlorobenzene, trichlorobenzene, chloraniline, dichloroaniline, and dichloronitrobenzene. ,
Mention may be made of trichlorobenzene. These aromatic halides can be used in combination.

The amount of ammonia used is preferably from 2 to 1 gram atom of halogen requiring amination of aromatic halide.
25 mol, particularly preferably 4 to 20 mol.

The amount of water used is preferably 30-70%, particularly preferably 45-6%, based on the weighted sum of both ammonia and water.
The amount of the copper compound used as a catalyst is preferably 0.01 to 0.4 gram atom, particularly preferably 0.02 to 0.2 gram atom, per mol of aromatic halide. It is. Examples of copper compounds include steel oxides, hydrated oxides, and/or copper halides.
Specifically, cuprous oxide, cupric oxide, cupric hydroxide, cupric halide, cupric halide, etc. are preferable, and mixed hydroxides and mixed oxides of copper and alkaline earth metals. ,
Mixed halides are also preferred catalysts. When the catalyst contains an alkaline earth metal such as calcium, the content is preferably 10 gram atoms or less, particularly preferably 0.1 to 5 gram atoms, per 1 gram atom of copper.

Thus, in the present invention, an alcohol, preferably an aliphatic or alicyclic alcohol having 3 to 6 carbon atoms, is allowed to coexist in a reaction system comprising a catalyst containing such an aromatic halide, ammonia, water, and a copper compound, and the reaction is carried out. If the number of carbon atoms in the aliphatic alcohol is 2 or less, there will be no problem in the reaction system, but liquid-liquid extraction cannot be performed using the same alcohol after the reaction. Therefore, the effect of process simplification is lost, and the advantage of improving the reaction rate is not realized.

On the other hand, if the aliphatic or alicyclic algol coexisting in the reaction system has 7 or more carbon atoms, it will be less effective in the reaction system, and it is difficult to perform liquid-liquid extraction using the same alcohol after the reaction, so it is not suitable. Not. This is because higher alcohols have a low distribution rate with respect to amines such as phenylenediamine.

The particularly preferred number of carbon atoms in the alcohol coexisting in the reaction system is 6 to 4 for monoaliphatic alcohols, and 6 for alicyclic alcohols.

Examples of such alcohols include aliphatic alcohols such as propyl alcohol, inglobil alcohol, butyl alcohol, 5ec-butyl alcohol, tert-butyl alcohol, n-amyl alcohol, and oyohyisoamyl alcohol, and alicyclic alcohols such as cyclohexanol. I can give an example.

The amount of alcohol used is preferably 0.01 to 15 parts by weight, particularly preferably 0.5 to 10 parts by weight, and less than 0.01 parts by weight, based on 100 parts by weight of ammonia.
It makes little contribution to improving the reaction rate, and on the other hand, even if it exceeds 15 parts by weight, the reaction rate does not increase proportionally and is unnecessary.

The reaction temperature of the aromatic halide and ammonia in the present invention is preferably 170 to 250°C, particularly preferably 2
The reaction time at 00 to 240°C is usually 2 to 40 hours.

Examples of aromatic amines produced in this manner include chloraniline, phenylenediamine, chlorphenylenediamine, and triaminobenzene.

As described above, as in the present invention, when alcohol coexists in the reaction system, the conversion rate and reaction rate increase.

After the reaction is completed, the obtained reaction product liquid is preferably poured into 20 to 8
The reaction system is cooled to 0°C, preferably 60 to 70°C, and the ammonia in the reaction product liquid is removed as a gas by returning the reaction system to normal pressure as necessary prior to the extraction operation described later. Although the pressure can be reduced, there is no need to further remove ammonia in the reaction product liquid at normal pressure. In addition, the removed ammonia is preferably recovered by compression, cooling and/or gas absorption operation. In the present invention, aromatic halide and ammonia are combined with a catalyst containing a copper compound in the presence of water. This process is referred to as step (1), and the following steps (5) to (5) are also carried out. Extractive separation of aromatic amines, separation and recovery of catalysts containing copper compounds,
Extractant recovery and ammonia recovery can be performed rationally.

Step (2) A step of liquid-liquid extraction of the aromatic amine in the reaction product liquid obtained in step (1) using an aliphatic or alicyclic alcohol having 3 to 6 carbon atoms as an oil agent.

Step (3): Add an alkali metal hydroxide and/or alkaline earth metal hydroxide to the residual aqueous solution after the extraction operation obtained in step (21) to form a copper compound or a mixed compound of copper and alkaline earth metal. Step 5: Precipitate and separate.

Step (4) A step of treating the extract obtained in step (2) with a distillation operation to recover an extractant.

Step (5): Treat the ammonia gas discharged from step (1), step (3) and/or step (4) by compressing, cooling and/or gas absorption to reduce the number of carbon atoms contained from 6 to 6. The process of recovering ammonia as raw material for reuse while still containing aliphatic or alicyclic alcohol.

In the above step (2), aromatic amines are extracted from the reaction product liquid obtained in step (1) using an extractant whose main component is an aliphatic or alicyclic alcohol having 6 to 6 carbon atoms. .

When using an aliphatic or alicyclic alcohol having 6 to 6 carbon atoms as an extraction agent, the distribution ratio of the aromatic amine to the alcohol should be good, and the separation from the amine should be easy in the distillation process [step (4)]. It has the following advantages: it has no reactivity with the amine, it is easy to handle, the extraction process is stable, and it is easily available.

Specific examples of such aliphatic or alicyclic alcohols having 6 to 6 carbon atoms are the same as the alcohols coexisting in the reaction system, and considering the simplification of the process, the same alcohols as the alcohols used in the reaction system are used. preferable.

Furthermore, although the extract obtained in step (2) mainly consists of extractants and aromatic amines, ammonium chloride, which constituted the reaction product liquid, remains in the extract. If left as is, it may lead to blockage in the distillation column due to ammonium chloride during the distillation process, or the formation of aromatic amine hydrochloride due to decomposition of ammonium chloride.
Furthermore, it is preferable to further reduce the ammonium chloride concentration in the extract by washing the extract with water.

In this case, a separate process method, such as a continuous batch tank method, in which the first reaction product solution is first extracted liquid-by-liquid with an extraction agent and then the extract is washed with water to remove ammonium chloride from the extract, may be used, but industrially For this purpose, a countercurrent liquid-liquid extraction column is used, and the reaction product liquid is supplied from the middle stage, the extractant is supplied from the bottom of the tower, and water is supplied from the top of the tower, so that extractant extraction and water washing are performed simultaneously. And the water supply ratio is 1:0 by weight.
5-5: 0.05-0.6 is preferred.

Next, in step (3), the residual aqueous solution after the extraction operation is usually heated to remove the extractant, unextracted aromatic compounds, etc. by a method such as azeotropic distillation or steam distillation, and then sodium hydroxide is added. , an alkali metal hydroxide such as potassium hydroxide and/or an alkaline earth metal hydroxide such as calcium hydroxide or magnesium hydroxide are added and heated to convert the copper component in the remaining aqueous solution into an oxide and/or hydroxide. Precipitate as a substance. During this step, when removing the extracting agent from the remaining aqueous solution, ammonia dissolved in the remaining aqueous solution is discharged as a gas. Such ammonia is recovered as a liquid by compression, cooling and/or gas absorption operations (step (5)). In this case, the recovered liquid ammonia or ammonia water contains an extractant with a carbon number of 6
Although some of the aliphatic or alicyclic alcohols No. 6 to 6 are accompanied, the alcohol can be supplied to the reaction system as it is, so no special operation for separating ammonia and the alcohol is required.

In addition, in the step of depositing a copper compound, when using an alkali metal hydroxide or a combination of an alkali metal hydroxide and an alkaline earth hydroxide, these should be sufficiently stirred after addition, and the pH should preferably be 10 or more, especially Preferably, by making the solution basic with a pH of 12 or more, most of the copper compounds precipitate as copper oxides, and at the same time, ammonium chloride contained in the solution decomposes to generate ammonia and precipitated copper. The compound is separated and recovered by filtration or the like. The recovered copper compound has substantially the same catalytic activity as copper oxide, hydrated oxide, and copper halide, and can be reused as a catalyst as it is.

In the copper compound precipitation step, when alkaline earth metal hydroxides are mainly used, simply adding these and heating and stirring may not result in sufficient precipitation of the copper compound.

In this case, the precipitation of the copper compound is promoted by passing air, nitrogen gas, or other non-reactive, non-condensable gas into the liquid. In this case, the copper compound co-precipitates with the alkaline earth metal hydroxide, making it impossible to obtain a highly pure copper compound. However, it does not matter that some alkaline earth metals are contained in the catalyst, and if the content is within the preferred range, it is better to reuse the recovered copper compound as a catalyst. The reaction rate may be increased.

Further, ammonia generated during precipitation of the copper compound can be recovered by compression, cooling and/or gas absorption operations in the same manner as described above (step (5)).

Since the F solution after separating the precipitated copper compounds contains only a very small amount of copper ions, it can be easily treated by ordinary wastewater treatment, such as activated sludge treatment or activated carbon treatment.

Furthermore, in step (4), the extract obtained in the extraction step of step d) is subjected to multiple distillation operations to recover the extractant and obtain the desired aromatic amine.

Although any conventional method can be used for this distillation operation, it is preferable to first distill the extract under normal pressure (bottom temperature 200°C or less, preferably 120-180°C, top pressure 1-2 atm). After distilling off part of the extractant and mixed water, one bottom solution is distilled under reduced pressure (bottom temperature 200°C or less, preferably 120-180°C, tower top pressure 10-100To
rr) to distill off the extractant. In this way, if the distillation operation in step (4) is carried out in two steps: atmospheric distillation and reduced pressure distillation, it is possible to avoid increasing the processing temperature of aromatic amines, thereby reducing the yield of aromatic amines. This method has the advantage of being able to prevent problems, such as being able to prevent problems, and having fewer troubles caused by pressure loss within the distillation column.

In addition, the ammonia dissolved during the extractant distillation operation is
Although gasified and discharged, these gases can be recovered as a liquid by compression, cooling and/or gas absorption operations (step (5)).

In this case, a portion of the alcohol as an extraction agent accompanies the recovered liquid ammonia or aqueous ammonia, but since this can be supplied to the reaction system as it is, no special operation is required to separate ammonia and alcohol.

As described above, according to the present invention, (a) the conversion rate and reaction rate can be improved by mixing an alcohol, preferably an aliphatic or alicyclic alcohol having 6 to 2 carbon atoms, into the reaction system. . Furthermore, by combining steps (b) to (5) with the present invention, (b) when recovering unreacted ammonia, there is no need for equipment to increase the purity of recovered ammonia, which is advantageous in terms of equipment. be.

(c) In the separation and recovery process of the copper compound catalyst, since the particle size and apparent specific gravity of the precipitated copper compound are large, the separation operation can be carried out smoothly and in a short time, making it efficient.

(d) In the separation and recovery process of copper compound catalysts.

The recovery rate of copper compounds is high, and the recovered copper compounds can be effectively reused as catalysts.

(e) Since the amount of copper remaining in the wastewater is small, subsequent wastewater treatment is easy.

(f) In order to separate the target aromatic amines and other aromatic compounds before proceeding to the copper compound catalyst recovery process, these useful substances are subjected to various operations performed in the subsequent catalyst recovery process. It is advantageous because it does not undergo deterioration or loss.

It has many advantages such as:

Hereinafter, the present invention will be explained by examples.

Example-1 In a stainless steel pressure-resistant reaction tube with an internal volume of 65 CC, p-dichloroberene 10F and 4oliJi% ammonia water 35
P, n-butanol 0.5Ji, cupric chloride hydrate 17
The mixture was filled with a stirrer and placed in an oil bath at 220"C to react for 6 hours. The reaction results are shown in Table 1.

Comparative Example-1 An experiment was conducted in the same manner as in Example-1 except that n-butanol was not included. The reaction results are shown in Table-1.

The conversion rate and the yield of p-phenylenediamine were lower than in Example-1.

Example 2 An experiment was conducted in the same manner as in Example 1, except that 0.50 II of calcium chloride aquarium salt was further added. The reaction results are shown in Table-1.

Examples 3 and 4 An experiment was conducted in the same manner as in Example 1, except that the amount of n-butanol added was changed. The results are shown in Table-2.

Example-5: P-dichlorobenzene 150F, 40% was placed in a stainless steel autoclave with an internal volume of 1 ton equipped with an electromagnetic rotary stirrer.
It was filled with 525F of ammonia water and 7.5Y of cupric oxide, 7ysn-butanol, heated to 220°C, and reacted for 4 hours. After the reaction, the autoclave was cooled to 40° C., and the pulp was opened little by little while stirring to release excess ammonia gas. The released gas was recovered as liquid ammonia using a dry ice trap.

After lowering the pressure to normal pressure, the reaction product solution in the autoclave was transferred to another container and stored. Reaction rate is 97.8%, yield is p
- Phenylenediamine was 74.2%, p-chloroaniline was 22.3 tlb, and aniline was 0.61%. The reaction was performed 10 times and the resulting reaction product liquids were mixed.

Next, using a vertically vibrating countercurrent liquid-liquid extractor having an inner diameter of 151II+ and an effective height of 2.0 m, 1 Kf of the reaction product liquid was extracted using 1 grade of n-butanol as an extractant. The extraction rate of p-phenylenediamine was 98%.

This extract was mixed with an inner diameter of 45s11. Number of steps: 30 steps, step spacing: 60
It was supplied to the middle stage of Ryu's perforated plate distillation column. Distillation was carried out at normal pressure, and the temperature of the bottom liquid was adjusted to 160°C. Since the distillate was separated into two phases, the aqueous layer was extracted and stored, and 1/4 of the organic layer was extracted by refluxing the air to enhance the rectification effect. This organic layer liquid is n-butanol, an oil agent. At the top of the distillation columns, the ammonia gas expelled from the liquid was discharged and recovered from the gas vent. The bottoms were a crude aromatic amine liquid containing 22% n-butanol by weight.

On the other hand, 74 (approximately 1 t) of the residual aqueous solution obtained from the extraction device
was transferred to a 3t flask and distilled.

The distillate phase-separated into two layers, of which the aqueous layer was refluxed and the organic layer was extracted. Ammonia dissolved during this distillation became a gas and was released from the top of the column, liquefied by a dry ice trap, and recovered. When the distillate did not separate into two layers and only the aqueous phase remained, heating of the can was stopped and the distillation column was removed from the flask. and,
A KpH meter detector was installed inside the flask, and a gas release needle connected to the nitrogen supply line was installed at the bottom of the flask, and 3ooy of an aqueous slurry containing 160y of calcium hydroxide powder was added until the internal temperature reached 85-90. The flask was heated to ℃ and nitrogen gas was blown into the flask.

The pH value gradually decreased as ammonia was discharged from the liquid by blowing nitrogen gas, and eventually settled down. Furthermore, 10 y of 60% by weight calcium hydroxide slurry was added to raise the pH value, and nitrogen gas was blown in while heating until the I)H value settled down. This operation was repeated, and when the pH finally settled down to 6.2, the addition of calcium hydroxide was stopped. After blowing in nitrogen gas for another 10 minutes, the flask was allowed to cool, and the contents were filtered to recover a copper compound containing cupric hydroxide as a main component. When this offshore residue was washed with water and dried, it had a weight of 40.5 p. It was easy to cross the coast at this time. When a portion of the F solution was taken and the dissolved copper content was measured, the concentration was s, 0 ppm.

The amount of n-butanol contained in the ammonia recovered in each step was measured. That is, the liquid ammonia collected in each step is mixed, and 1 cc of it is passed through a syringe needle into distilled water IQ.
[After slow release and dissolution in lcc, the aqueous solution was analyzed by gas chromatography. As a result, the n-butanol contained in ammonia is 1.1
He was in charge of weight.

16.2 F (corresponding to cupric oxide 7.OF as the number of copper atoms), 150 F of p-dichlorobenzene, 230 y of recovered liquid ammonia (2.5 y of n-butanol and 2 oy of water) ), 300 y of water and 5 y of n-butanol were charged into the original autoclave, heated to 220'C, and reacted for 4 hours. As a result, the conversion rate was 99.0%, the yield was 85.2% for 1dp-phenylenediamine, 11.0% for p-chloroaniline, and 0.85% for aniline.

Examples 6 and 7 Propyl alcohol (propyl alcohol) was used as a substitute for n-butanol.
An experiment was conducted in the same manner as in Example 1, except that Example M (Example 6) and n-acyl alcohol (Example 7) were used. The results are shown in Table-6.

Table-6 Procedural amendment dated 2.2/r/1980 Mr. Commissioner of the Patent Office 1, Indication of the case, Patent Application No. 136765, 1988 2, Name of the invention Process for producing aromatic amines 3, Person making the amendment Case Relationship with Patent applicant: 2-11-24 Tsukiji, Chuo-ku, Tokyo (417) Japan Synthetic Rubber Co., Ltd. Representative: Hisashi Yoshimitsu 4, Agent: Ballet Royale Akasaka A1, 2-17-54 Akasaka, Minato-ku, Tokyo 107 Japan Room 3156. Contents of amendment 1) "40°C" on page 21, line 7 of the specification is corrected to "60°C".

Correct.

Claims (1)

[Claims] 1. An aromatic compound characterized by reacting an aromatic halide and ammonia in the presence of water in the presence of alcohol using a catalyst containing a copper compound to produce an aromatic amine in the presence of alcohol. Method for producing amines.