JPS61259760A - Recovery of catalyst - Google Patents

Abstract

PURPOSE:To efficiently recover a reusable copper catalyst, by removing ammonia and an ammonia ion from the amination reaction solution at the time of the manufacturing of aromatic diamine before precipitating the copper catalyst in coexistence of alkali metal hydroxide and ethers. CONSTITUTION:Aromatic diamine is prepared by reacting an iodinated aromatic amino compound and ammonia in the presence of a copper catalyst, water and aromatic monoamine. In recovering the copper catalyst from the reaction product, ammonia and an ammonium ion are removed at first. Then, alkali metal hydroxide and ethers are allowed to coexist to lower not only the solubility of copper in an aqueous layer but also that of aromatic monoamine to efficiently recover the copper catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for recovering a copper catalyst when producing an aromatic diamine by reacting an iodinated aromatic amino compound with ammonia.

Aromatic diamines, particularly 72-2-diamine, have useful uses as synthetic intermediates for dyes, pigments, pharmaceuticals, aramid fibers, polyimide resins, and the like.

(Prior Art and Problems to be Solved by the Invention) 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 in this method is the separation of the reaction product and the copper catalyst after the reaction, and many proposals have been made in this regard.

For example, in the literature (edited by Kirk Othmer, Encise Clobbedea Opchemical Technology, Vol. 2, p. 661), after removing excess ammonia from the reaction product liquid, in addition to the sulfide, copper of the catalyst is removed. A method has been proposed in which the compound is precipitated as copper sulfide and then the aromatic amine is extracted, and also in West German Patent No. 654,39.
Specification No. 5 proposes a method in which sulfide is added together with sodium hydroxide to the reaction product solution to precipitate the copper compound of the catalyst as copper sulfide, and after this is filtered off, the aromatic amine is separated by crystallization. There is. These methods recover the copper component of the catalyst as sulfide. However, these methods have the problem that the recovered copper sulfide has low activity as a catalyst and cannot be reused, resulting in the need for a large amount of catalyst.

Also, Japanese Patent Publication No. 55-33,707, No. 55-55.
In Publication No. 70B and Publication No. 55-33,709, an alkali metal hydroxide is first added to the reaction product liquid to precipitate the copper component of the catalyst, and then the target substance is separated by distillation or extraction. Although the copper catalyst recovered by this method can be reused, it has the disadvantage that the precipitated copper catalyst is in the form of a fluid, making it difficult to separate. Since a large amount of copper ions that are not formed remain, there are problems such as the need for an additional treatment step to remove copper ions when disposing of the residual liquid after precipitation of the copper catalyst and separation of the target substance. have

After separating the target substances, a method is proposed in which an alkaline earth metal hydroxide or alkali metal hydroxide is added to the residual aqueous solution and a base treatment is performed to precipitate the copper catalyst and recover the catalyst. However, when applied to iodinated aromatic abanocompounds, the reaction solution contains aromatic monoamine, which is the starting material for iodinated aromatic amino compounds, as a reaction solvent, and also contains only a small amount of water. Therefore, when trying to extract the reaction product with K such as butanol, there is a problem that they mutually dissolve and the two layers do not separate, or even after one separation, only a very small amount of aqueous layer is obtained.

Moreover, in U.S. Patent No. 3,975,439,
After removing ammonia by adding an IJ cum aqueous solution to the reaction product solution and removing ammonia, the copper catalyst is precipitated and separated and recovered using a thickener, and then filtered and extracted to separate the target substance.

However, in this method, even after separating the precipitated copper catalyst, copper □ ions are dissolved in the organic layer K O at a concentration of 5 to 1% □.
However, it also has problems such as the need for a treatment step to remove copper ions.

(Problem to be solved by the invention) Even if conventional techniques are applied to the production of aromatic diamines by reacting iodinated aromatic amino compounds with ammonia, reusable catalysts cannot be recovered. However, even if a reusable catalyst can be recovered, the recovery is insufficient and may require extensive treatment to remove copper ions, or it may be difficult to recover the catalyst. 'It is not possible, etc., to be implemented industrially i:.

There was a problem with the case.
,,.

Therefore, in the present invention, the catalyst can be reused,
``It is an object of the present invention to provide a method for recovering a catalyst that can efficiently recover the catalyst through a simple process and almost completely recover reusable iodide.

(Means and effects for solving the problems) The present invention has the following features:
When separating and recovering a copper catalyst from a reaction solution obtained by reacting an iodinated aromatic amino compound with ammonia in the presence of a copper catalyst, water, and an aromatic monoamine, ammonia and ammonium ions are removed from the reaction solution, and then alkali metal This is a catalyst recovery method characterized by precipitating a copper catalyst in the coexistence of hydroxide and ethers.

In the present invention, in order to prevent copper ions from forming stable copper/ammonium complex ions, ammonia and ammonium ions are removed from the reaction solution in advance, and then alkali metal hydroxide and ethers are allowed to coexist. Accordingly, alkali metal hydroxides reduce the solubility of copper in the aqueous layer, and ethers reduce the solubility of aromatic monoamines, so adding ether to the extraction solvent is necessary to efficiently recover the copper catalyst. Although there is a description that this is done to reduce the solubility of water and the by-product Ihiammonium salt in the solvent, there is no indication of the effect of the present invention.

The method for removing ammonia and ammonium ions from the reaction solution is to remove excess ammonia and then add an aqueous alkali metal hydroxide solution together with water, if the alkali metal hydroxide may be mixed in. Methods of removal by Ijt distillation or continuous or intermittent blowing of non-condensable gas can be applied. On the other hand, if contamination with alkali metal hydroxide is inconvenient, after releasing the excess ammonia, water is added to precipitate most of the copper catalyst, which is removed by filtration or other methods to separate the layers. A method in which ammonium ions are removed from the aqueous layer by water extraction or the like can be applied.

After ammonia and ammonium ions have been removed, the alkali metal hydroxide and ethers can be made to coexist, such as adding an aqueous alkali metal hydroxide solution and ethers sequentially or simultaneously, or An applicable method is to add ether, remove ammonia and ammonium ions, and then add ether. In addition, operations such as stirring are more effective in order to allow the alkali metal hydroxide and ether to coexist sufficiently and at the same time to efficiently precipitate the copper catalyst.

It is preferable to use sodium hydroxide or potassium hydroxide as the alkali metal hydroxide because they are industrially easily available and inexpensive. In particular, when aromatic monoamines are iodinated by electrolytic oxidation reaction to produce iodinated aromatic amino compounds, electrolysis is performed using a diaphragm method, and the alkali metal hydroxide produced in the catholyte can be effectively used. .

Alkali metal hydroxides are thought to have the following two effects. One is to reduce the solubility of copper in the water layer, and the other is to add it when removing ammonia and ammonium ions and convert the by-produced ammonium iodide into alkali metal iodide. . The latter can be returned as is as an iodide for electrolysis in the case of the diaphragm electrolysis method described above. In addition, in the case of the alkyl metal hydroxide mentioned above, which is added when it is disadvantageous if alkali metal is mixed in, only the former effect is utilized, and a method for removing ammonia and ammonium ions is devised.
The by-produced ammonium iodide can be recovered as is and returned to the previous process if necessary, and after removing ammonium ions, the alkali metal hydroxide and ethers are allowed to coexist to completely precipitate the copper catalyst. There is. The alkali metal hydroxide used here can be reused after recovering the aromatic diamine dissolved in it.
Iodide can be recovered without contamination with alkali metal hydroxide.

As the ether in the present invention, aliphatic ethers and aromatic ethers can be used, but aliphatic ethers are preferably used. More preferably, aliphatic ethers having 6 to 8 carbon atoms can be used. If the number of carbon atoms is less than 5, separation of the copper catalyst will be insufficient (but if the number of carbon atoms is more than 9, the copper catalyst can be recovered, but the boiling point will be high, making distillation separation difficult. Dibutyl ether and diisoglobyl ether, which are easily available, can be used.

Further, the ethers used in the present invention are separated into two layers after the copper catalyst is precipitated and separated into an upper layer. This upper layer is mainly composed of ethers and contains about 10 to 30% aromatic monoamines, but since it contains almost no aromatic diamines, it can be returned as ethers and reused.

In the present invention, the aromatic monoamine is a compound that is anily aromatic and corresponds to Noamici MK. Further, the aromatic diamine is a phenylene diamine having a substituent corresponding to p-phenylene diamine and an iodinated aromatic amino compound.

Copper compounds used as catalysts in the present invention include copper oxides such as cuprous oxide and cupric oxide, cuprous hydroxide, etc.
Examples include copper, copper hydroxides such as cupric hydroxide, and copper halides such as cuprous halides and cupric halides.Most preferably, copper iodide having the same anion is used. The copper catalyst mentioned in the present invention is the above-mentioned general term, and includes all catalysts including complexes with aromatic diamines that may be converted into copper compounds during processing.

The copper catalyst recovered by the method of the present invention exhibits high activity,
It exhibits activity and selectivity equivalent to those of the copper compounds mentioned above. The recovered copper catalyst can be used immediately as it is, but it can also be washed with water or the like.

The amount of ether added is preferably 0.5 times to 5 times the amount of coexisting aromatic compounds and acacia.

If the amount is less than 0.5 times, the copper catalyst will not be sufficiently separated.

If the amount is more than 5 times, the amount of ethers circulating will be large.

In the amination reaction, since ammonia is recovered and used, it is very difficult to completely separate water. There is no problem if the water concentration in ammonia is less than 50% by weight.
If the amount is less than 20% by weight, it is more preferable since the amount of by-products will be reduced. The degree of amination temperature is also related to the type and amount of the catalyst used, but the reaction can proceed at room temperature or higher, but from the viewpoint of reaction rate, it is recommended to use 50°C.
The above temperature is preferable, and from the viewpoint of reaction pressure, 150° C. or lower is preferable. In addition, in the amination reaction, iodinated aromatic amide/
It is preferable to allow the compounds to react completely, and for this purpose it is preferable to carry out the reaction at a temperature of 70° C. or higher. The catalyst is 0.5 to iodinated aromatic amide/compound.
-50 molar mass can be used, but from the viewpoint of reaction rate, 2 to 20 molar mass is preferable.

(Effects of the Invention) As described above, according to the present invention, after removing ammonia and ammonium ions from the amination reaction solution, the alkali metal hydroxide and ether are combined to form a navy blue Copper catalyst can be efficiently recovered by wiping. Moreover, the catalyst can be reused and can be efficiently recovered simply by coexisting an alkali metal hydroxide and ether, so that aromatic sia i7 can be WIrR without increasing the number of steps. In addition, iodide can be almost completely recovered and reused in iodination reactions. In the above points, the method of the present invention is an extremely excellent method for recovering copper catalysts.

(Example) Next, the present invention will be explained in more detail with reference to Example 1.

Example 1 % p-iodoaniline (hereinafter abbreviated as P-A) 501. Aniline (hereinafter abbreviated as AN) 5511. 7.2 g of water, 3.5 II cuprous iodide,
65g of ammonia was added. The reaction was carried out at 75°C for 5 hours. The pressure was 9/cm2·G at 25'.

After the reaction was completed, excess ammonia was released. p-7 22-diamine (hereinafter abbreviated as PFD) in the residual liquid was 14
It was generated by JF. The response rate of P Work A was 100%. 45 g of a 15% aqueous sodium aqueous solution was added to the remaining liquid, and the mixture was heated at 80° GK under reduced pressure to flow out 15 g of water and at the same time remove ammonia. When measuring - of the water layer, m
=16°1, and excess sodium hydroxide remained. Next, 35 g of diptyl ether was added, and the precipitate was filtered to recover 5.5 g of copper catalyst. Filtration was very easy. The filtrate was separated into two layers. The upper layer was mainly composed of dibutyl ether, 1% I'FD, and 10 pTXn of steel. The lower layer was mainly composed of AN, water, and sodium iodide, and contained 13.6 g of PPD. The copper concentration is 20
It was ppm. The lower layer weighed 80 g.

Extraction was performed four times with 20 g of aniline. 99% of the aniline layer KPFD was extracted. Distill the aniline solution under reduced pressure to obtain P
FD 12.6N was obtained. Recovery rate of copper in copper catalyst is 9
It was 9%.

Comparative Example 1゜Reacted in the same manner as in Example 1 to release excess ammonia,
A residual liquid was obtained. 50 I of a 15% aqueous sodium hydroxide solution was added and heated to 80° C. under reduced pressure to drain out 18 g of water and simultaneously remove ammonia. - of the aqueous layer was 12.9. The precipitated copper catalyst was collected by vacuum filtration.

The deposited copper catalyst was so fine that it took time to filter it under reduced pressure. The upper layer was mainly composed of AN and PFD, and had a copper concentration of 5700 ppm.

The main components of the lower layer were water and sodium iodide, and the copper concentration was 120 ppm.

Comparative Example 2゜React in the same manner as in Example 1 to release excess ammonia. Add 15% sodium hydroxide aqueous solution 45F and filter the precipitated copper catalyst under reduced pressure without removing ammonia. The upper layer is AN, P,
FD was the main component, and the copper concentration was 5300 ppm. The main components of the lower layer were water, ammonium iodide, and sodium hydroxide, and the copper concentration was 500 ppm. The upper and lower layers were mixed, dibutyl ether 5811 was added, and the precipitate was filtered to separate the two layers. The upper layer contained diptyl ether as the main component and had a copper concentration of 20 ppm.

The main components of the lower layer are water, AN, and PFD, and the copper concentration is 5500.
It was ppm.

Example 2 500dt-) Crepe VcP engineering A4[]p, Al16
0g, water 2011 ammonia 100g, 1st chloride @
3.2 f! I put it in. The reaction was carried out at 100°C for 3 hours.

The pressure is 30 kliF/CI+! It was 2. After repulsion and releasing excess ammonia, 70 g of 15% potassium hydroxide was added and heated to 80° C. under reduced pressure to distill out 30 g of water and remove ammonia at the same time. The - of the aqueous layer was measured and found to be 12.9, and since potassium hydroxide remained, 80 g of diisozorobyl ether was then added, the precipitated copper catalyst was filtered under reduced pressure, and the two layers were separated. The copper concentration in the upper layer was 23 ppm%, and the copper concentration in the lower layer was 30 ppm. The recovery rate of copper in the copper catalyst was 98.5%.

Example 3 A reaction was carried out using 5.1 g of the catalyst recovered in Example 1. PIA 29.9°AN4 in 500d autoclave
0g of water, 8g of water, 55g of ammonia, and a recovery reactor were added, and the mixture was reacted at 90°C for 6 hours. Pressure is 27kg/cII
It was L2・G. After the reaction was completed, excess ammonia was released. KPPD in the residual liquid is 15.5! i' was being generated. The reaction rate of PIA was 100%. After that, as in Example 1, 15% NaOH40F! , '□Add 36 g'l of diptyl ether and treat with copper catalyst '□5
．． 0g was collected. The copper concentrations in the two separated upper and lower layers were 15 ppm and 25 ppm. The recovery rate of copper catalyst medium steel was 98%.

Example 4 React in the same manner as in Example 1 and remove excess ammonia □
75 g of residual liquid was obtained. PPD is 14.2. i! i
'It was generating. The reaction rate of PIA was 100%.

Add 60g of water to the residual liquid, stir to precipitate most of the copper catalyst, and filter under reduced pressure to obtain 5.011% of the copper catalyst □
Recovered. After filtration, two layers were separated, and the upper layer was 40I.
i, and the copper content was 3500 ppmsa and the ammonium chloride content was 7%. The lower layer is 95! I and copper.

is 180ppms'=ammonium ytride is 18.1%
Met. Also, since the lower layer contained 7.0 g of PI'D, 35.0 g of aniline was contained. Extracted with F, 95% of PPD
was extracted. Mix the extracted aniline with the above-mentioned upper layer,
Extraction was performed with 40 g of water to extract 98% of ammonium iodide. The copper content in the PPD aniline solution thus obtained was 2000 ppm. To this solution, 15% water-solubilized sodium 5ON and diptyle ether 70F were simultaneously added and stirred to precipitate the copper catalyst, and the copper catalyst was removed by filtration.
, s g were collected. Then, the two layers are separated, and the upper layer is an organic layer mainly composed of diptyle ether and contains 20 ppm of copper.
Met. The lower layer is hydroxide) The main component is an IJium aqueous solution with 1s ppm of copper, and PPDikI Z! ! It contained.

This lower layer was extracted with aniline 60F and the PPD was 11.5.
g was collected. This aniline solution was distilled to a PPD of 10
．． I got 51. The recovery rate of copper in the copper catalyst was 97%.

Claims (1)

[Scope of Claims] 1. When separating and recovering a copper catalyst from a reaction solution obtained by reacting an iodinated aromatic amino compound with ammonia in the presence of a copper catalyst, water, and an aromatic monoamine, ammonia and ammonium are removed from the reaction solution. Catalyst recovery method 2 characterized in that after removing ions, a copper catalyst is precipitated by making an alkali metal hydroxide and ethers coexist. Method 6 according to Claim 1, wherein the copper catalyst is copper iodide, Method 4 according to Claim 2, wherein the alkali metal hydroxide is sodium hydroxide. or potassium hydroxide, method 5 according to claim 1, method 6 according to claim 1, wherein the ether is an aliphatic ether having 6 to 8 carbon atoms, the ether is dibutyl ether or Method 7 according to claim 5, which is diisopropyl ether, and the amount of ether added is 0.5 to 0.5 of the aromatic monoamine.
5 times the amount of the ammonium ions, and the method of removing ammonium ions is a method of removing excess ammonia by adding an alkali metal hydroxide after releasing the excess ammonia. Method 9 described in Item 1, a method for removing ammonium ions, releases excess ammonia, then adds water to precipitate and recover most of the copper catalyst, separates the two layers, and removes the ammonium ions in the organic layer with water. Method 10 according to claim 1, which is a method of removing into a layer, and the method according to claim 1, wherein the aromatic monoamine is aniline and the iodinated aromatic amino compound is iodoaniline.