JPH0557258B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing aromatic amines using a novel extractant. Conventionally, methods for producing aromatic amines include reduction methods that reduce aromatic nitroamines, and reactions between aromatic halides such as aromatic dihalides and ammonia in the presence of water using catalysts mainly consisting of copper compounds. Amination methods and the like are known. However, particularly in the case of the amination method, the reaction product liquid containing the aromatic amine obtained in this way is In addition to the target substance phenylenediamine, the produced liquid contains dichlorobenzene,
An aqueous solution containing unreacted substances such as ammonia, intermediate products such as chloroaniline, by-products such as chlorobenzene, aniline, phenol, ammonium chloride, heavy substances, copper complex compounds resulting from the copper compound used as a catalyst, etc. It becomes an aqueous suspension. Furthermore, before separating the aromatic amine from the reaction product liquid, in order to separate the catalyst consisting of a copper compound, an alkali metal hydroxide or an alkaline earth metal hydroxide is added to precipitate the copper compound, The reaction product liquid becomes an aqueous solution or aqueous suspension having an extremely complex composition, containing in addition to the above-mentioned alkali metal halides, alkaline earth metal halides, and the like. Extraction is a common method for separating the target substance, aromatic amine, from these complex reaction product liquids. However, aromatic amines only dissolve in highly polar solvents, and such solvents also have a high solubility in water, so they are often unsuitable as extractants, and various studies are required to select an extractant. be. As a result of these studies, for example,
No. 59824 discloses a method of extracting and separating phenylenediamine using an aromatic amine such as aniline, o-chloroaniline, or o-toluidine as an extractant in a reaction product liquid. However, aniline and o-toluidine have specific gravity similar to water, and it takes time to separate them into extract and raffinate.
On the other hand, o-chloroaniline is an intermediate of o-phenylenediamine and is suitable for the production of o-phenylenediamine, but it is preferable to use it as an extractant when producing m,p-phenylenediamine. do not have. Furthermore, Japanese Patent Publication No. 55-330707, No. 55-33708, and No. 55-33709 disclose a method of extracting phenylenediamine from a reaction product liquid with an aliphatic alcohol having 3 to 4 carbon atoms. Although this method does not have the above-mentioned drawbacks, the distribution ratio [aromatic amine concentration in the extract (wt%)/aromatic amine concentration in the raffinate (wt%)] is still sufficiently high. In addition, the distillation process for recovering the extractant from the extract solution results in an increase in heavy substances, and when phenylenediamine is recovered by rectification after removing the extractant from the extract solution, the recovered phenylenediamine It has the problem of turning black in the air. Furthermore, U.S. Patent No. 4,193,938 describes a method of liquid-liquid extraction using a chlorinated carbon solvent having one carbon such as methylene chloride, chloroform, and carbon tetrachloride to recover phenylenediamine from the reaction product solution. Although this method has a relatively high distribution rate in the case of methylene chloride, it involves a decomposition reaction in the process of distilling the extract extracted using these solvents to remove the extractant, and it causes unidentified problems. May produce numerous by-products. This is probably because methylene chloride is hydrolyzed in this step, and the product causes a secondary reaction. The present invention has been made against the above background, and is a novel method that has a high distribution ratio to aromatic amines and is easy to recover the extractant when extracting aromatic amines from the reaction product liquid. The object of the present invention is to provide a method for producing aromatic amines using an extractant. That is, the present invention provides a method for producing an aromatic amine from an aromatic halide and ammonia, which is characterized by comprising the following steps (a) to (c). be. (a) A step in which an aromatic halide and ammonia are reacted in the presence of water using a catalyst mainly containing copper oxide, copper hydroxide and/or copper halide. (b) A step of extracting and separating the aromatic amine in the reaction product liquid obtained in step (a) in the presence of ammonia and/or an electrolyte using an extractant mainly composed of tetrahydrofuran. (c) A step of adding an alkali metal hydroxide and/or an alkaline earth metal hydroxide to the raffinate after the extraction operation obtained in step (b) to precipitate and separate a copper compound. The extraction material used in the extraction method of the present invention is an aqueous solution or suspension containing an aromatic amine. For example, as described above, an aromatic halide and ammonia are mixed in the presence of water with a catalyst mainly containing a copper compound. It can be obtained by an amination method using Examples of aromatic halides used in this amination method include chlorobenzene, dichlorobenzene, trichlorobenzene, chloroaniline, dichloroaniline, chlornitrobenzene, and dichloronitrobenzene. Mention may be made of benzene, dichlorobenzene, chloroaniline and trichlorobenzene. These aromatic halides can be used in combination. The amount of ammonia used is preferably 2 to 25 mol, particularly preferably 4 to 25 mol, per 1 gram atom of halogen that requires amination of aromatic halide.
~20 moles. Further, the amount of water used is preferably 30 to 70% by weight, particularly preferably 45 to 65% by weight, based on the total weight of both ammonia and water. Furthermore, the amount of copper compound to be used is preferably 0.01 to 0.01 to 0.01 to 0.01 as copper atoms per mole of aromatic halide.
0.4 gram-atom, particularly preferably 0.02-0.2 gram-atom. Copper compounds used as catalysts include copper oxides, copper hydroxides and/or copper halides, in particular cuprous oxide, cupric oxide, cupric hydroxide and cupric halides. Copper and cupric halides are preferred, and mixed hydroxides, 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 between aromatic halide and ammonia is
Preferably 170~250℃, particularly preferably 200~240℃
℃, and the reaction time is usually 2 to 40 hours.
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 chloroaniline, phenylenediamine, chlorophenylenediamine, and triaminobenzene. After the reaction is completed, the obtained reaction product liquid is preferably
The ammonia in the reaction product liquid is removed as a gas by cooling the reaction system to 20 to 80°C, particularly preferably 30 to 70°C, and returning the reaction system to normal pressure as necessary. Although the pressure can be reduced, it is not necessary to remove ammonia in the reaction product liquid at normal pressure. In the extraction method of the present invention, an aqueous solution or aqueous suspension containing an aromatic amine obtained by the above-mentioned amination method is used as an extraction material, and the aromatic amine is extracted using tetrahydrofuran as an extraction agent. During extraction, ammonia and/or
Alternatively, it is preferable that an electrolyte is present, which can improve the layer separation between the extraction liquid and the extraction agent. Such ammonia may be utilized by allowing unreacted ammonia present in the extraction material to exist as is, or by newly mixing ammonia.
Moreover, such an electrolyte is an electrolyte that is water-soluble and does not react with aromatic amines. Such electrolytes include ammonium halides such as ammonium chloride, which are by-produced in the reaction of the amination method, alkali metal halides such as sodium chloride, potassium chloride, sodium bromide, and potassium bromide, calcium chloride, and bromide. In addition to alkaline earth metal halides such as calcium, magnesium chloride, and magnesium bromide, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkali metal sulfates such as sodium sulfate, copper chloride,
Examples include water-soluble metal halide salts such as iron chloride, and water-soluble metal sulfates such as copper sulfate. If an electrolyte as a by-product of the reaction is present in the extracted material, there is no need to newly mix the electrolyte. The amount of ammonia and/or electrolyte in the extract is preferably 5 parts by weight or more, particularly 7 parts by weight or more and 50 parts by weight or less, based on 100 parts by weight of water in the extract. When the reaction product liquid obtained by the amination method is used as an extract, ammonia and/or electrolyte within this range is present in the extract even without adding ammonia and/or electrolyte. Tetrahydrofuran used as an extraction agent may contain water, but if water is contained in large amounts, it may be necessary to reduce the concentration of ammonia and/or electrolytes in the extraction agent, and also reduce the actual amount of extraction agent. The water content should be within a range that does not deteriorate the phase separation during extraction (usually 0 to 20% by weight as water content).
It is preferable that Tetrahydrofuran also contains alcohols with 3 to 6 carbon atoms in the main chain, such as propanol, butanol, pentanol, and hexanol, and other organic solvents, such as aniline, aniline derivatives, propyl ether, and butyl ether, at about 30% by weight or less. may have been done. The extraction agent/extractant ratio during extraction is changed as appropriate depending on the type and amount of aromatic amine, ammonia, electrolyte, etc. in the extract, but is usually 0.5 to 5 (weight ratio).
It is. Further, for extraction, continuous countercurrent liquid-liquid extraction is preferably employed from the viewpoint of efficiency, but a batch extraction method may also be employed. When 5 parts by weight or more of ammonia and/or electrolyte are present in the extract, the extraction temperature is generally 10 to 100°C;
Or, when the amount of electrolyte is less than 5 parts by weight, the extraction temperature should be determined from the viewpoint of layer separation between the extract and raffinate.
50-100°C is preferred. In addition, when extracting aromatic amines using the reaction product liquid obtained by the amination method as an extraction material, prior to the extraction, the obtained reaction product liquid is added to 1 gram of halogen ions contained in the liquid. By adding 0.05 to 1 gram equivalent of alkali metal hydroxide and/or alkaline earth metal hydroxide to the above extraction, it is possible to facilitate the extraction operation and further improve the distribution ratio of aromatic amine to the extractant. . Alkali metal hydroxide and/or to the reaction product liquid
Alternatively, if the amount of alkaline earth metal hydroxide added is less than 0.05 gram equivalent per gram of halogen ions, the effect of improving the distribution ratio of aromatic amines will be small, while if it exceeds 1 gram equivalent, the reaction product solution will be The copper components in the extract begin to precipitate, impeding the smooth operation of subsequent extractions, and depending on the extraction conditions, by-product alkali metal halides and/or alkaline earth metal halides may precipitate, causing damage to the extractor. There is also a risk that it may become blocked. Examples of the alkali metal hydroxide and alkaline earth metal hydroxide include sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide. These alkali metal hydroxides and/or alkaline earth metal hydroxides are usually added as an aqueous solution or suspension at a concentration of about 5 to 60% by weight, and are reacted with the reaction product solution preferably at 30 to 80°C. let Note that this reaction reduces the solubility of ammonia in the reaction product liquid and increases the pressure of the system.
If necessary, the system pressure can be lowered again by performing gas-liquid separation to release ammonia gas. 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. The extractant and the target aromatic amine are separated and recovered from the extract obtained by extraction 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, the ammonium halide decomposes due to heating and reacts with the coexisting aromatic amine to form ammonia and the hydrogen halide salt of the aromatic amine. However, the hydrogen halide salt of the aromatic amine adheres to the walls of the distiller and solidifies due to heating, which tends to cause blockage in the distiller. For this reason, before separating aromatic amines from the extract obtained by extraction by means such as distillation,
Aqueous solutions of alkali metal hydroxides (e.g. approx. 1-50
ammonium halide in the extract by washing with aqueous alkali metal halide solution (hereinafter referred to as "alkali halide washing") or a combination thereof. The amount may be greatly reduced or virtually eliminated. In the case of alkaline washing, ammonium halide in the extract is converted to an alkali metal halide, but this alkali metal halide is much less likely to cause the above-mentioned troubles during distillation than ammonium halide. Furthermore, in the case of alkali halide washing, the concentration of ammonium halide in the extract can be made extremely low (approximately 0.01 to 0.2% by weight). To give a specific example of alkaline washing or halogenated alkali washing, for example, when combined with a counterfluid liquid-liquid extraction tower, the extractant is in the middle stage, the extractant is in the bottom part of the tower,
The aqueous alkali metal halide solution is supplied to the top of the column, and the aqueous alkali metal hydroxide solution is supplied to the top of the column (between the top and the middle stage), and the extracted material, extractant, aqueous alkali metal hydroxide solution, and aqueous alkali metal halide solution are supplied to the top of the column. The supply ratio is approximately 1:0.5 to 5: by weight.
0.05-1: 0.05-0.3. In this case, the alkali cleaning can also serve as a step of adding a small amount of alkali metal hydroxide to the reaction product liquid. By adding an alkali metal hydroxide and/or an alkaline earth metal hydroxide to the raffinate obtained from the extraction to precipitate a copper compound mainly consisting of copper oxide and/or copper hydroxide. , can be separated. The raffinate solution after extraction contains, in addition to copper ions, ammonium halides, alkali metal halides and/or alkaline earth metal halides, ammonia, and dissolved extractants, as well as aromas left after extraction. Contains small amounts of group amines and unreacted raw materials. Therefore, if necessary, extractants, aromatic amines, unreacted raw materials, etc. are removed by azeotropic distillation, steam distillation, or other methods. Thereafter, while thoroughly stirring this raffinate, 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 is added, preferably an alkaline metal hydroxide such as calcium hydroxide. An alkali metal hydroxide is added to cause copper ions in the raffinate to be precipitated as a copper compound mainly consisting of copper oxide and/or copper hydroxide. In this copper compound precipitation step, when using an alkali metal hydroxide or a combination of an alkali metal hydroxide and an alkaline earth metal hydroxide, these are thoroughly stirred after addition, preferably at a pH of 10 or higher, particularly preferably. By making the solution basic with a pH of 12 or higher and at a temperature of preferably 50°C or higher, particularly preferably boiling, most of the copper compound is precipitated as copper oxide, and at the same time the ammonium halide contained in the liquid is decomposed. Ammonia is generated. The precipitated copper compound can be easily separated and recovered by filtration or the like. The recovered copper compound has substantially the same catalytic activity as copper oxide, copper hydroxide, and copper halide, and can be reused as it is as a catalyst in the amination method. In the copper compound precipitation step, when alkaline earth metal hydroxides are mainly used, they are preferably added in an amount of 1 molar equivalent per gram of ammonium ions in the raffinate, and the pH is adjusted to 5.5 to 5.5.
9.5, particularly preferably 6.0 to 7.0. in this case,
Mere heating and stirring may not result in sufficient precipitation of the copper compound. At this time, ammonia in the raffinate is removed by passing air, nitrogen gas, or other non-reactive non-condensable gas into the liquid, or by distillation to promote the precipitation of copper compounds. .
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, there is absolutely 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 liquid 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. In addition, when the reaction product liquid obtained by the above-mentioned amination method is used as an extraction material, in order to recover the copper compound which is a catalyst present in the reaction product liquid, an alkali metal hydroxide and/or alkaline earth By adding a large amount of metal hydroxide, the copper compound can be precipitated and recovered by filtration. In this case, the liquid becomes an extract and an alkali metal halide and an alkaline earth metal halide are further present in the extract. However, this method has a problem in that the precipitated copper compound becomes colloidal and is difficult to separate due to excess. As described above, the extraction method of the present invention uses an aqueous solution or aqueous suspension containing aromatic amines as an extraction material and extracts with a new extractant mainly composed of tetrahydrofuran, thereby achieving excellent phase separation and extracting aromatic amines. It has a high distribution ratio to amines and is extremely effective as a method for extracting aromatic amines. Furthermore, this extraction method has the advantage that the extraction agent, tetrahydrofuran, can be recovered very easily by distillation with almost no generation of heavy substances after extraction. Furthermore, after tetrahydrofuran is distilled off from the extract obtained by the extraction method of the present invention, aromatic amines, especially phenylenediamine, obtained by rectification do not cause blackening or other problems even when stored in air. It has the characteristic of not being easily colored. Although the extraction material used in the extraction method of the present invention is mainly the reaction product liquid obtained by the amination method, it goes without saying that the material is not limited thereto. The present invention will be described in more detail below with reference to Examples. Reference examples 1 to 4 Aqueous solution containing sodium chloride, ammonium chloride, ammonia, etc. in a 200 c.c. Erlenmeyer flask 50
g and 50 g of tetrahydrofuran, 5 g of p-phenylenediamine was added thereto, and the mixture was heated to 50° C. and stirred to dissolve it. After dissolution, the solution was kept at 40°C and the distribution ratio of each component was measured. The results are shown in Table-1. The distribution rate follows the definition below. Distribution ratio = Component concentration (weight %) in the upper layer (extract liquid) / Component concentration (weight %) in the lower layer (extract liquid)

[Table] * Reference example for comparison without measurement 1 10.5 parts by weight of sodium chloride, ammonium chloride
2.6 parts by weight, 18.4 parts by weight of ammonia, and 100 parts by weight of water.
200g of an aqueous solution consisting of parts by weight and n-butanol
200g, and 50g of p-phenylenediamine
The mixture was sufficiently stirred to dissolve at 40°C and allowed to cool at 40°C. The distribution ratio of p-phenylenediamine was determined to be 0.90 by analyzing the upper and lower layers. It was significantly lower than that of Reference Example-3. The obtained upper layer liquid is distilled at normal pressure, and the temperature of the can part is
When the temperature reached 150℃, I switched to vacuum distillation (50Torr). A distilled p-phenylenediamine having a boiling point of around 175°C was obtained. However, when this p-phenylenediamine was left in dry air at room temperature, 3
It turned black in the sun. Moreover, many black heavy substances were present in the residue after p-phenylenediamine rectification. Reference Example 5 16.9 parts by weight of p-phenylenediamine, 0.7 parts by weight of p-chloroaniline, 0.1 parts by weight of aniline, 0.1 parts by weight of phenol, 0.3 parts by weight of p-dichlorobenzene, 3.5 parts by weight of ammonium chloride, 11.6 parts by weight of sodium chloride. , an aqueous solution containing 0.6 parts by weight of copper, 7.3 parts by weight of ammonia and 100 parts by weight of water was used as the extraction material, and tetrahydrofuran was used as the extraction agent.
Countercurrent liquid-liquid extraction was performed at a temperature of 45°C with an extraction ratio of 1.35 (weight ratio). The extraction tower used was a vertically vibrating countercurrent liquid-liquid extraction device with an inner diameter of 15 mm and an effective height of 2 m.
It was carried out at 50°C. The extraction rate of p-phenylenediamine was 98.0%, and the extraction rate of p-chloroaniline, aniline, phenol, and p-dichlorobenzene was 100%. Tetrahydrofuran was added to the obtained extract at 65°C.
The residue was rectified at 172° C./50 Torr to recover p-phenylenediamine. Even when the recovered p-phenylenediamine was left in the air at room temperature for 30 days, no discoloration occurred at all. In addition, there were almost no heavy substances in the residue after the p-phenylenediamine rectification. Example 1 O-dichlorobenzene was placed in a stainless steel autoclave with an internal volume of 1 equipped with an electromagnetic rotary stirrer.
150g, 40% by weight ammonia water 375g, cupric oxide
7.0 g was charged, heated to 220°C, and reacted for 12 hours. After the reaction, cool the autoclave to 60℃,
While stirring, the valve was opened little by little to release excess ammonia gas. After lowering the pressure to normal pressure, the reaction product solution in the autoclave was transferred to another container and stored. Reaction rate is 95%, selectivity is o-phenylenediamine 79%, o-chloroaniline 14.5%, aniline
It was 3.7%. This reaction was repeated 10 times and the resulting reaction product liquids were mixed. The content of o-phenylenediamine in the reaction product liquid was 17.3% by weight,
It also contained 19.5% by weight of ammonium chloride and 9.1% by weight of ammonia. Next, using a vertically vibrating countercurrent liquid-liquid extractor with an inner diameter of 15 mm and an effective height of 2.0 m, extraction was performed using 1.5 kg of tetrahydrofuran per 1 kg of the reaction product liquid. The extraction rate of o-phenylenediamine is 98
It was %. Tetrahydrofuran was added to the obtained extract at 65°C.
The residue was rectified at 150° C./50 Torr to recover o-phenylenediamine. Even when the recovered o-phenylenediamine was left in the air at room temperature for 30 days, no discoloration occurred at all. In addition, almost no heavy substances were present in the residue after the o-phenylenediamine rectification. Next, transfer the raffinate after the extraction operation to a flask,
It was distilled to remove tetrahydrofuran. Next, while refluxing the content liquid in the flask, 25% by weight was added from the upper part.
640 ml of an aqueous sodium hydroxide solution was added dropwise. At this time, ammonia gas was generated. The contents became a black suspension. After continuing to reflux for another 15 minutes, the mixture was allowed to cool, and a black copper compound consisting mainly of cupric oxide precipitated. A small amount of the clear supernatant liquid was extracted and the dissolved copper content was measured, and the concentration was 50 ppm. Moreover, this liquid had a pH of 12.1. While the flask was heated again to reflux, air was bubbled through the contents for 1 hour. The flask was allowed to cool, and the contents were filtered to recover a copper compound mainly consisting of cupric oxide. The recovery rate was almost 100% based on the calculated metallic copper content. It was easy. When a portion of the liquid was taken and the dissolved copper content was measured, the concentration was 6 ppm. In addition, the recovered copper compounds were washed again with distilled water,
Dry. 7.0 g of this dried copper compound was taken, 150 g of o-dichlorobenzene and 375 g of 40% by weight aqueous ammonia were added, and the reaction was carried out at 220°C for 13 hours in the autoclave. 95.2%, selectivity o-phenylenediamine 79%, o-chloroaniline 14%, aniline 4
% was almost the same as the original one. Example 2 O-dichlorobenzene was placed in a stainless steel autoclave with an internal volume of 1 equipped with an electromagnetic rotary stirrer.
The flask was charged with 150 g of 40% by weight ammonia water, 375 g of aqueous ammonia, and 7 g of cupric oxide, heated to 220°C, and reacted for 6 hours. After the reaction, cool the autoclave to 60℃,
While stirring, the valve was opened little by little to release excess ammonia gas. After lowering the pressure to normal pressure, the reaction product solution in the autoclave was transferred to another container and stored. The conversion rate was 99.7%, and the selectivity was 92.3% for p-phenylenediamine, 4.8% for p-chloroaniline, and 0.9% for aniline. This reaction was repeated 10 times, and the resulting reaction product liquids were mixed. p in the reaction product solution
- The content of phenylenediamine was 20.7% by weight, and also contained 21.6% by weight of ammonium chloride and 8.2% by weight of ammonia. next,
Using a vertically vibrating countercurrent liquid-liquid extractor with an inner diameter of 15 mm and an effective height of 2.0 m, 1 kg of reaction product liquid was extracted with 1.5 kg of tetrahydrofuran.
The extraction rate of p-phenylenediamine was 98%. Tetrahydrofuran was added to the obtained extract at 65°C.
The residue was rectified at 172° C./50 Torr to recover p-phenylenediamine. Even when the recovered p-phenylenediamine was left in the air at room temperature for 30 days, no discoloration occurred at all. In addition, there were almost no heavy substances in the residue after the p-phenylenediamine rectification. Next, transfer the raffinate after the extraction operation to a flask,
It was distilled to remove tetrahydrofuran. Next, after installing a PH meter detector in this flask, add 100g of calcium hydroxide and water.
100 ml of the flask was added and heated so that the temperature inside the flask reached 90 to 95°C, and then nitrogen gas was blown into the liquid using a syringe needle to effect bubbling. When bubbling was continued for a while while maintaining the liquid temperature at 90 to 100°C, the pH value of the liquid gradually decreased and settled at a constant value. Next, a small amount of a 20% by weight suspension of calcium hydroxide was further added to increase the pH value, and bubbling was performed again until the pH value reached a constant value. After that, repeat this operation several times until the liquid is completely
Addition of calcium hydroxide was stopped when the pH value reached 6.2. At this time, the liquid was a pale blue suspension. After bubbling was continued for another 10 minutes, the flask was allowed to cool, and the precipitate (copper compound) was separated and collected by filtration. When the recovery rate was calculated assuming that the obtained precipitate was cupric hydroxide, the result was
It was 121%, which was excessive. This is thought to be due to the presence of calcium hydroxide in the precipitate.
The filtration can be easily carried out in a short period of time, and when a portion of the liquid was sampled and the concentration of copper components was measured, it was 3.5 ppm. In addition, the recovered copper compound was washed with distilled water and then dried. 10.4 g of the dried copper compound was collected and put into the autoclave described above together with 150 g of p-dichlorobenzene and 375 g of 40% by weight aqueous ammonia, and reacted at a temperature of 220° C. for 6 hours. The conversion rate in this reaction was 99.8%, and the selectivity was 95.1% for p-phenylenediamine, 2.2% for p-chloroaniline, and 0.8% for aniline. From this result, it can be said that the copper compound recovered by the calcium hydroxide addition treatment has higher activity as a catalyst than the original cupric oxide. Example 3 P-dichlorobenzene was placed in a stainless steel autoclave with an internal volume of 3 equipped with an electromagnetic rotary stirrer.
450g, 40% ammonia water 1125g, cupric oxide 21
g was charged, the temperature was raised to 210°C, and the reaction was carried out for 5 hours.
After the reaction, the autoclave was cooled to 60°C, and the valve was opened little by little while stirring 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 analyzed and the reaction rate was 99.8%, selectivity was 92.0% for p-phenylenediamine, 4.0% for p-chloroaniline,
Aniline was 0.8%. This reaction solution also contained 312 g of ammonium chloride.
(5.83 mol) was produced. Thereafter, the autoclave was allowed to cool to room temperature. Next, 326 g of an aqueous solution containing 163 g (4.08 mol) of sodium hydroxide was added to the autoclave with stirring. Thereafter, the temperature of the autoclave was raised again to 60°C, 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. p- in this reaction product liquid
The content of phenylenediamine was 16.9% by weight, and also contained 5.2% by weight of ammonium chloride, 13.2% by weight of sodium chloride, and 11.0% by weight of ammonia. Next, using a vertically vibrating countercurrent liquid-liquid extraction device with an inner diameter of 15 mm and an effective height of 2 m, 1 kg of tetrahydrofuran was supplied to 1 kg of the reaction product liquid for liquid-liquid extraction. The extraction rate was 99.5%. Tetrahydrofuran was added to the obtained extract at 65°C.
The residue was rectified at 172° C./50 Torr to recover p-phenylenediamine. Even when the recovered p-phenylenediamine was left in the air at room temperature for 30 days, no discoloration occurred at all. In addition, there were almost no heavy substances in the residue after the p-phenylenediamine rectification. Two of the raffinates were transferred to three flasks and distilled under atmospheric pressure to remove tetrahydrofuran. Next, a PH meter detector was installed inside the flask, a gas release needle connected to the nitrogen supply line was installed inside the flask, and a dropping funnel containing a 30% aqueous solution of sodium hydroxide was attached. Once the flask is heated again and reaches a reflux state, add approximately 65 c.c. of sodium hydroxide solution to bring the pH to 12.5.
And so. At this time, ammonia gas was generated and at the same time black cupric oxide precipitated. Therefore, the nitrogen supply line was opened, and bubbling was continued for about 30 minutes while controlling the temperature of the can at 90°C, after which it was allowed to cool. This raffinate treatment operation was repeated to process approximately 7.5 raffinates. When the treated solution was filtered, 104.0 g of cupric oxide was recovered. It was easy.
A portion of the liquid was taken and the dissolved copper content was measured.
The concentration was 6ppm. Reference example 6 50g of tetrahydrofuran in a 200c.c. pressure glass tube,
50 g of water, 5 g of p-phenylenediamine and a stirrer were added, the mixture was sealed, and the mixture was stirred to dissolve the p-phenylenediamine. At 30-40°C, the system was homogeneous, but as the temperature was raised further, it became non-uniform. After thorough stirring at 80°C, the mixture was allowed to stand still. Since the mixture was separated into upper and lower layers, each layer was analyzed and the distribution ratio of p-phenylenediamine was determined to be 2.3.

Claims (1)

[Claims] 1. A method for producing an aromatic amine from an aromatic halide and ammonia, comprising the following steps (a) to (c).
A method for producing an aromatic amine, the method comprising: (a) A step in which an aromatic halide and ammonia are reacted in the presence of water using a catalyst mainly containing copper oxide, copper hydroxide and/or copper halide. (b) A step of extracting and separating the aromatic amine in the reaction product liquid obtained in step (a) in the presence of ammonia and/or an electrolyte using an extractant mainly composed of tetrahydrofuran. (c) A step of adding an alkali metal hydroxide and/or an alkaline earth metal hydroxide to the raffinate after the extraction operation obtained in step (b) to precipitate and separate a copper compound.