JPS6094946A - Production of aromatic amine - Google Patents

Abstract

PURPOSE:To obtain the titled compound, by reacting an aromatic halide with ammonia in the presence of water and a copper compound catalyst, adding an alkali metallic hydroxide to resultant reaction solution, extracting the resultant aromatic amine, adding the above-mentioned hydroxide to the remaining aqueous solution after the extraction to deposit and separate the copper catalyst. CONSTITUTION:An aromatic halide, e.g. chlorobenzene, is reacted with ammonia in the presence of water and a catalyst consisting essentially of a copper compound, e.g. cuprous oxide, and 0.05-1g equivalent, based on 1g halogen ion contained in the reaction product solution, alkali metallic hydroxide, e.g. NaOH, or alkaline earth metallic hydroxide, e.g. Ca(OH)2, or both are added to the reaction product solution. The resultant aromatic amine in the reaction product is then extracted with an extractant, e.g. propanol, and the extracted solution is separated from the remaining aqueous solution. The above-mentioned hydroxide is then added to the remaining aqueous solution to deposit and separate the copper compound. The deposited copper compound is reutilizable as the catalyst, and the resultant filtrate after the separation is easily subjected to waste water treatment due to a very small amount of copper ions left therein.

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.

However, a particular problem with this method is the separation of the copper compound catalyst after the reaction.The problem of separation of the copper compound catalyst from 0 is solved, and the recovered copper compound is reused as a catalyst. For example, Japanese Patent Publications No. 55-33707 and No. 55-3'37
In these methods, first, an alkali metal hydroxide is added to the reaction product liquid to precipitate and separate the copper component of the catalyst as a copper oxide, and then The target substance is separated by distillation or extraction.The steel oxide recovered by this method is effective as a catalyst and can be reused.However, in these methods, the precipitated copper Since the oxide is in the form of a colloid, it has the disadvantage of being very difficult to separate, and furthermore, a considerable amount of copper ions that do not form a precipitate remain in the reaction product solution. In the disposal of the residual liquid after separating the precipitates such as copper oxides and the target substance, there are problems such as the need for a further treatment step to remove copper ions.

Furthermore, in JP-A-51-59824, rather than separating the copper component of the catalyst by precipitation, a portion of ammonium chloride, which is a by-product present in the raffinate aqueous solution after extracting the aromatic amine, is removed. A method has been proposed in which the catalyst is crystallized and separated, and the residual liquid containing the catalyst is reused as it is.

However, this method has the drawback that the reused residual liquid contains a large amount of ammonium chloride, which reduces the reaction rate of the desired reaction and reduces the selectivity. In addition, the separated ammonium chloride contains a small amount of copper component, and it is difficult to completely remove this copper component even by using recrystallization power. Ammonium chloride cannot be used for this purpose, and there is a problem in that it is not easy to dispose of ammonium chloride.

As described above, although the method for producing aromatic amines from aromatic halides and ammonia is easy to obtain raw materials and can obtain the target substance in a small number of steps, it is difficult to use the method described above. Problems remain, and it has not yet been industrialized.

The present invention was made against the above-mentioned background, and its purpose is to facilitate the recovery of the catalyst.
An object of the present invention is to provide an efficient method for producing aromatic amines without problems in waste disposal.

That is, the present invention provides a method for producing an aromatic amine from an aromatic halide and ammonia, which includes the following (a) to (a).
The present invention provides a method for producing an aromatic amine, which includes the step (d).

(a) A first step in which aromatic halide and ammonia are reacted in the presence of water using a catalyst mainly consisting of a copper compound.

(b) Add 6.0% of alkali metal hydroxide and/or alkaline earth metal hydroxide to the reaction product solution obtained in the first step per 1 gram of halogen ions contained in the solution. o Second step of adding 5-1 gram equivalent.

(c) A sixth step of extracting the aromatic amine in the reaction product solution after the second step with an extractant and separating it into an extract solution and a raffinate aqueous solution.

(d) A fourth step of adding an alkali metal hydroxide and/or an alkaline earth metal hydroxide to the raffinate aqueous solution obtained in the sixth step to precipitate and separate a copper compound.

Next, the present invention will be explained in detail.

In the present invention, first, an aromatic halide and ammonia are reacted in the presence of water using a catalyst mainly composed of a copper compound (first step).

Examples of aromatic halides include chlorobenzene, dichlorobenzene, trichlorobenzene, chloraniline, dichloroaniline, chlornitrobenzene, and dichloronitrobenzene.
Examples of the 1-ride include chlorobenzene, dichlorobenzene, chloroaniline, and trichlorobenzene. These aromatic rides can be used in combination.

The amount of ammonia used is preferably from 2 to 25 mol, particularly preferably from 4 to 20 mol, per gram-atom of the rhodan required for amination of the aromatic halide.

The amount of water used is preferably 60 to 70% by weight, particularly preferably 45 to 6% by weight, based on the weight sum of both ammonia and water.
It is 5% by weight.

The amount of copper compound to be used is preferably 0.01 to 0.4 gram-atom as copper atom per mole of aromatic halide;
Particularly preferred is 0.02 to 0.2 gram-atom.

Examples of the copper compound used as a catalyst include copper oxides, hydroxides and/or copper halides, and in particular cuprous oxide, ferric oxide, ferric hydroxide, etc.
jffJ, cupric halides, and cupric halides are preferred, and mixed compounds, mixed oxides, or mixed halides of copper and alkaline earth metals are also preferred catalysts.

When the copper compound 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.

The reaction temperature of the aromatic halide and ammonia in the present invention is preferably 170 to 250'C, particularly preferably 200 to 240'C, and the reaction time is usually 2 to 40'C.
It's time. When carrying out the reaction continuously, it is preferable to connect two or more reactors in series so that the residence time of the reaction solution in the reactor becomes the desired reaction time.

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

After the reaction is completed, the reaction product solution obtained is preferably 20 to 8
The reaction product liquid (E) is cooled to 0°C, particularly preferably 60 to 70°C, and if necessary, the reaction system is returned to normal pressure.
It is possible to remove the ammonia as a gas to reduce the pressure during the operation of the following steps, but it is not necessary to remove the ammonia in the reaction product liquid at normal pressure.

Next, to the reaction product liquid obtained in the first step, an alkali metal hydroxide and/or alkaline earth metal hydroxide is added in an amount of 0.05 to 1 per gram of halogen ions contained in the liquid. The third by adding gram equivalent
The extraction operation during the process is facilitated and the distribution ratio of aromatic amine to the extractant is improved (second step).

If the amount of alkali metal hydroxide and/or alkaline earth metal hydroxide added to the reaction product solution is less than 0.05 gram equivalent per gram of halogen ion, the effect of improving the aromatic amine distribution ratio will be small; On the other hand, if the amount exceeds 1 gram equivalent, precipitation of the copper component in the reaction product solution will begin as in the 4th step described later, which will hinder the smooth operation of the subsequent 6th to 4th steps. Depending on the operating conditions of the extraction operation in the step, alkali metal halides and/or alkaline earth metal halides, which are by-products, may precipitate and clog the extractor.

Examples of the alkali metal hydroxide and alkaline earth metal hydroxide include sodium hydroxide, potassium hydroxide, calcium hydroxide, and hydroxide. These alkali metal hydroxides and/or alkaline earth metal hydroxides are usually added as an aqueous solution or suspension with a concentration of about 5 to 60% by weight, preferably 6% by weight.
React with the reaction product liquid at 0 to 80°C.

The solubility of ammonia in the reaction product liquid decreases and the pressure of the system increases due to the operations in the second step described above, so if necessary, the ammonia gas is released through gas-liquid separation and the pressure of the system is increased again. It can also be lowered.

It is also possible to carry out the step of adding an alkali metal hydroxide and/or alkaline earth metal hydroxide and the step of separating ammonia gas into gas and liquid at the same time.

Next, the reaction product liquid that has passed through the second step is extracted with an extractant and separated into an extract containing aromatic amines and a raffinate aqueous solution (sixth step).
).

Examples of extractants include organic solvents whose main components are aliphatic or alicyclic alcohols having 3 to 3 carbon atoms, aniline or aniline derivatives, methylene chloride, etc. Examples of such alcohols include propatool, etc. , butanol, pentanol, hexanol, etc.

Note that other organic solvents such as propyl ether, butyl ether, etc. can be added to the solvent used for extraction in order to reduce the solubility of water and by-product ammonium chloride in the solvent. In addition, these extractants may contain water, ammonia, etc. in a saturated amount. By performing the second step, the distribution ratio of aromatic amines to the extractant can be adjusted without performing the second step. significantly improved than in the case of Here, the distribution ratio is defined based on the following formula.

It is not clear why the addition of an alkali metal hydroxide and/or an alkaline earth metal hydroxide improves the distribution ratio to the extractant, but the ammonium halide produced as a by-product in the reaction in the first step is alkali. Substances that react with metal hydroxides and/or alkaline earth metal hydroxides and reduce the content of ammonium halide in the reaction product solution, thereby reducing the solubility of aromatic amines in the aqueous layer of the reaction product solution. It is thought that.

From the extract obtained in the extraction process, the extractant: the desired aromatic amine is separated and recovered by distillation, crystallization, or other means. When extracts are processed by distillation, crystallization, etc., a small amount of ammonium halide dissolved in the extract may cause trouble during the process. For example, when attempting to recover the extractant from the extract by distillation, heating causes mL of ammonium halide to react with coexisting aromatic amines, forming ammonia and hydrogen halide salts of aromatic amines. Hydrogen halide salts of aromatic amines tend to adhere to the walls of the distiller due to heating and cause blockage in the distiller.

The amount of ammonium halide contained in the extract varies depending on the type of extractant, but as long as a hydrophilic extractant is used, it cannot be completely eliminated.

For this reason, before separating the aromatic amines from the extract obtained in the sixth step by means such as distillation, it is necessary to wash the extract with an aqueous solution of alkali metal hydroxide (for example, about 1 to 50% by weight) (hereinafter referred to as The amount of ammonium halide in the extract may be greatly reduced or substantially eliminated by washing with water (hereinafter referred to as "alkaline washing") or water (hereinafter referred to as "water washing"), or a combination thereof.

In the case of alkaline washing, ammonium halogenide in the extract is converted to alkali metal halogenide, but this alkali metal halide causes the above-mentioned troubles in the distillation process compared to ammonium chloride 710. There are far fewer. Also, in the case of washing with water, the concentration of ammonium halide in the extract can be made extremely low (about 0.01 to 0.2% by weight). The most preferred method is to carry out alkali washing followed by water washing to substantially eliminate ammonium halides and generated alkali metal halides in the extract.

To give a specific example of alkaline washing or water washing, for example, when combined with a countercurrent liquid-liquid extraction column, the reaction product liquid is placed in the middle stage, the extractant is placed at the bottom of the column, water is placed at the top of the column, and the alkaline aqueous solution is placed at the top of the column (top of the column). and the middle stage), and the reaction product liquid,
The supply ratio of extraction agent, alkaline aqueous solution and water is approximately 1 by weight.
:0.5~5: O, CI5~1:0.05~0.3
shall be.

In this case, the alkaline cleaning can also serve as the second step.

Next, an alkali metal hydroxide and/or alkali metal hydroxide gold is added to the raffinate aqueous solution obtained in the sixth step to precipitate a copper compound mainly consisting of a copper plate and/or a prepared hydroxide. 5 separation (4th step).

The raffinate aqueous solution after the extraction operation contains, in addition to copper ions, ammonium halides, alkali metal halides and/or alkaline earth metal halides, ammonia, and dissolved extractant, and further contains the extracting agent that remains after extraction. Contains small amounts of aromatic amines and unreacted raw materials. Therefore, extractants, aromatic amines, unreacted raw materials, etc. are removed by azeotropic distillation, steam distillation, or other methods as necessary. Afterwards, the raffinate aqueous solution is mixed with an alkali metal hydroxide such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide and/or an alkaline earth metal hydroxide such as calcium hydroxide, preferably. Adds an alkali metal hydroxide to cause copper ions in the raffinate aqueous solution to precipitate as a copper compound mainly consisting of copper oxide and/or hydroxide.

In this copper compound precipitation step, after adding an alkali, the alkali is sufficiently stirred to make it basic, preferably at a pH of 10 or higher, particularly preferably at a pH of 12 or higher, and at a temperature of preferably 50°C.
As mentioned above, most of the copper compound is preferably precipitated as copper oxide by boiling, and at the same time, the ammonium halide contained in the liquid is decomposed to generate ammonia.

The precipitated copper compounds are separated and recovered by filtration.

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.

When alkaline earth metal hydroxides are mainly used in the copper compound precipitation step, they are preferably added in an amount of 1 mol or more per gram of ammonium ions in the raffinate aqueous solution. In this case, heating and stirring alone may not result in sufficient precipitation of the copper compound. At this time, 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, since the copper compound co-precipitates with the alkaline earth metal hydroxide, it is not possible to obtain a highly pure copper compound. However, there is no problem with the inclusion of alkaline earth metals as a catalyst, and if the content is within the preferred range, it would be better to reuse the recovered copper compound as a catalyst. The reaction rate may be increased.

Note that even when an alkali metal hydroxide or an alkali metal hydroxide and an alkaline earth metal hydroxide are used together, a non-condensable gas may be passed in order to promote the precipitation of the copper compound.

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

The present invention will be explained in more detail below using the drawings.

FIG. 1 is an embodiment of the present invention, which is a process diagram for producing an aromatic amine.

In FIG. 1, raw materials supplied through an aromatic halide supply pipe 1a, an ammonia supply pipe 1b, and a catalyst-water supply pipe 1C react in a reactor 2, and a reaction product liquid is obtained.
The reaction product liquid enters a gas-liquid separator 4 through a pipe 3, and excess ammonia is discharged through a pipe 5, while the reaction product liquid is supplied through a pipe 6 to a countercurrent liquid-liquid extraction column 7. An extractant (d) is supplied from a pipe 10, an alkali metal hydroxide aqueous solution is supplied from a pipe 9, and water is supplied from a pipe 8.

The extract is sent to an extractant separation step 12 (distillation step) through a pipe 11, and the crude aromatic amine is discharged through a pipe 16. On the other hand, the raffinate aqueous solution is discharged from the pipe 14 and sent to the oil recovery step 15.

In step 15, the extractant is distilled and the recovered oil is returned to the tube 10 via a tube 16. The raffinate aqueous solution that has passed through step 15 is sent via pipe 17 to catalyst recovery step 18 . Also, process 1
An alkali metal hydroxide and/or an alkaline earth metal hydroxide is supplied to 8 from a pipe 19 and mixed with the raffinate aqueous solution to precipitate a copper compound. The precipitated copper compound is separated by filtration to obtain a recovered catalyst 20, and waste water is discharged into a pipe 21.

The one shown in FIG. 1 is one example in which the extraction column VC,1 is used to carry out the second to sixth steps, alkaline washing and water washing at the same time. In this way, it is shown that the process substantially includes each step, but also includes a streamlined form.

As described above, the method according to the present invention is particularly suitable as a method for producing phenylenediamine, since it can exhibit the same effects as the method when producing aromatic amines.

(1) Since the particle size and apparent specific gravity of the fiid compound precipitated during the separation and recovery of a catalyst consisting of a copper compound are large, the separation operation can be carried out smoothly and efficiently in a short time.

(II) Waste liquid (C) The residual copper component can be reduced to a trace amount, making subsequent wastewater treatment easy. (iii) It is possible to reduce the amount of ammonium halides, etc. contained in the extract. Furthermore, it is economical since the amount of extractant used is relatively small.

M Steps 2 to 6 can also be greatly simplified by devising extraction tower type equipment, and no complicated equipment is required.

Hereinafter, the present invention will be explained by examples.

Note that the percentages in the examples are based on weight.

Example 450 y of p-dichlorobenzene, 40
The flask was filled with 1125% ammonia water and 21y oxide, heated to 210°C, and reacted for 5 hours. After the reaction, the autoclave was cooled to 6D°C, and while stirring, the valve was gradually opened to release excess ammonia gas. After lowering the internal pressure of the autoclave to around normal pressure, a portion of the reaction product liquid was taken and analyzed, and the reaction rate was 99.8%.
The selectivity was 92.0% for p-phenylenediamine, 4.0% for p-chloroaniline, and 70.8% for aniline. ■The octopus reaction solution contains ammonium chloride 312y (5,8
3 mol] was produced. Thereafter, the autoclave was allowed to cool to room temperature. Next, sodium hydroxide 163j' (
An aqueous solution 626F containing 4.08 mol) was added to the autoclave with stirring. Then autoclave at 60℃
The temperature was raised again to 100%, and the mixture was transferred to a separate container and stored.

The above operation was performed 5 times, and the reaction product liquids for the 5 times were mixed.

Next, using a vertically vibrating countercurrent liquid-liquid extractor having an inner diameter of 15 mm and an effective height of 2 m, the reaction product liquid 11 was subjected to liquid-liquid extraction by supplying 1°59 of water-saturated n-butanol. The extraction rate was 98%.

2 t of the raffinate aqueous solution was transferred to a 6 t flask and distilled under normal pressure. Distillate phase separates into two layers,
The aqueous layer was refluxed, and the organic layer was extracted. When the distillate did not separate into two layers and only an aqueous layer remained, heating of the can was stopped.

Next, attach a pH meter detector inside the flask (inside it),
A gas release needle connected to a nitrogen supply line was installed in the flask, and a dropping funnel containing a 30% aqueous solution of sodium hydroxide was attached to the flask. The flask was heated again, and when it reached Frank's condition, 65 cc of sodium hydroxide was added to adjust the pH to 12.5.At this time, ammonia gas was generated and at the same time black cupric oxide precipitated.Therefore, the nitrogen supply line was opened. , the temperature of the can part is 90°
Bubbling was continued for about 30 minutes while being controlled at C, and then allowed to cool. This treatment of the raffinate aqueous solution was repeated until approximately 7.
5 tons of raffinate aqueous solution was treated. When the treated solution was completely filtered and dried, 20.8 F of oxidized carbon dioxide was recovered.

Comparative Example The reaction was carried out in the same manner as in Example, and excess ammonia gas was released. This operation was performed 5 times, and the reaction product liquids for the 5 times were mixed. Next, using the same extraction equipment as in the example,
1.5 parts of water @ 1.5 parts of n-butanol per 19 parts of the reaction product solution
When 9 was supplied and liquid extraction was performed, the extraction rate only reached 65%, and in the end, the extraction rate did not reach 98% unless 2.51ψ of water-saturated n-butanol was supplied to 1 part of the reaction product liquid. I understand. A larger amount of extractant was required compared to the example.

[Brief explanation of the drawing]

FIG. 1 is a process diagram for producing an aromatic amine in one embodiment of the present invention. 2: Reactor 7: Countercurrent liquid-liquid extraction tower 12: Extractant separation process Patent applicant: Japan Synthetic Rubber Co., Ltd. Patent attorney: Takashi Shirai / Diagram

Claims (1)

[Scope of Claims] 1. A method for producing an aromatic amine, which comprises the following steps (a) to (d) in producing an aromatic amine from an aromatic halide and ammonia. (a) A first step in which aromatic halide and ammonia are reacted in the presence of water using a catalyst mainly consisting of a copper compound. (b) Add 0.05 to 1 gram of alkali metal hydroxide and/or alkaline earth metal hydroxide to the reaction product solution obtained in the first step per 1 gram of halogen ions contained in the solution. Second step of adding gram equivalent. (c) A sixth step of extracting the aromatic amine in the reaction product solution after the second step with an extractant and separating it into an extract solution and a raffinate aqueous solution. (d) A fourth step of adding an alkali metal hydroxide and/or an alkaline earth metal hydroxide to the raffinate aqueous solution obtained in the sixth step to precipitate and separate a copper compound.