JPS6328416B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to diaminodiphenyl ether (hereinafter abbreviated as DADPE), particularly 3,4'-diaminodiphenyl ether (hereinafter 3,4'- DADPE
) and 4,4'-diaminodiphenyl ether (hereinafter abbreviated as 4,4'-DADPE)
The present invention relates to a new manufacturing method.

3,4'-DADPE is used as a raw material for aromatic polyamide fibers with excellent heat resistance and chemical resistance.
4,4'-DADPE is attracting attention as a raw material for aromatic polyimide resin, which has excellent heat resistance, wear resistance, and chemical resistance. others,
DADPE has useful applications as a fine chemical intermediate.

(Prior Art) As a general method for producing diphenyl ethers, a method using the Ullman reaction is known.
That is, this is a method in which an aryl oxide and an aryl halide are reacted in the presence of copper or a copper salt. Bromide is generally used as the aryl halide, and if the aromatic ring is activated by the presence of an electron-withdrawing group such as a nitro group or carbonyl group, the reaction becomes easier (edited by the Chemical Society of Japan).
New Experimental Chemistry Course 14, Synthesis and Reactions of Organic Compounds [], p571 (1977), Maruzen Co., Ltd.). for example,
3,4'-DADPE is produced by coupling m-aminophenol and p-chloronitrobenzene in a dimethyl sulfoxide solvent in the presence of potassium hydroxide and a copper catalyst to produce 3-nitro-
A method has been proposed to obtain 4′-aminodiphenyl ether followed by hydrogenation under palladium catalyst (YEN-CHEN YEN, LIN CHAIO HSU,
“Process Economics Program Report No.
167”, p153 (1983), SRI International).
A method for producing 4,4'-diaminodiphenyl ether is to couple the potassium salt or sodium salt of p-nitrophenol with p-chloronitrobenzene in a dimethyl sulfoxide solvent to produce 4,4'-dinitrodiphenyl ether. A method has been proposed to obtain the enyl ether (USP 3032594) followed by hydrogenation.

In addition, methods other than general manufacturing methods are also known. For example, the manufacturing method for 3,4′-DADPE is as follows:
Potassium salt of 2,4-dichlorophenol and 3,
4-dichloronitrobenzene in a dimethyl sulfoxide solvent to form 2,4,
2′-trichloro-4′-nitrodiphenyl ether is obtained, which is then nitrated to obtain 2,4,2′-trichloro-5,4′-dinitrodiphenyl ether,
Next, a method has been proposed in which hydrogenation of the nitro group and hydrogenation dechlorination of the nuclear substituted chlorine are carried out in the presence of a palladium catalyst (Japanese Patent Application Laid-Open No. 157749/1983). 4,
As a method for producing 4'-DADPE, a method has been proposed in which p-chloronitrobenzene is coupled in the presence of sodium nitrite to obtain 4,4'-dinitrodiphenyl ether, and then hydrogenated under a palladium catalyst. (Unexamined Japanese Patent Publication No. 54-66633, 88228,
106439, 56−32439, 158740, 161354).

(Problems to be Solved by the Invention) In all of the conventionally proposed methods, diphenyl ether having a nitro group is first produced;
This is followed by hydrogenation. That is, it is considered that the halogenated aryl having a nitro group capable of activating an aromatic ring is used in order to facilitate the coupling reaction. Therefore, a hydrogenation step is inevitably required. In addition, chloralkali will be produced as a by-product, but this by-product will be discarded.

In contrast to the above-mentioned conventional technology, by coupling an aryl halide with an amino group and an aminophenol, DADPE can be produced at once without a hydrogenation step.
It is conceivable that this could be a new manufacturing method that can produce . However, when an aryl halide having an amino group is used in the Ullman reaction, since the amino group is an electron-donating group, the aromatic ring is inactivated, making the coupling reaction difficult.
For example, as shown in the comparative example, in the coupling reaction of p-chloroaniline and p-aminophenol, the amount of 4,4'-DADPE produced is extremely small, which proves that this coupling reaction is difficult. .

As a result of intensive research from the above viewpoint, the present inventors have found that by selecting iodine as a halogen among aryl halides having an amino group, p-iodoaniline (hereinafter referred to as
Abbreviated as PIA. ) was found to allow the coupling reaction to proceed successfully.
Furthermore, by combining the production of PIA with a process in which iodide is oxidatively reacted with aniline in an aqueous medium, alkali iodide, a by-product of the coupling reaction between PIA and aminophenol, can be removed. It has been discovered that it is possible to recycle and reuse the method in the production of PIA, and it is possible to assemble a closed system that does not generate any by-products as a whole.
The present invention is based on the above findings.

(Means and effects for solving the problems) The present invention is a method for producing DADPE, which is characterized by coupling PIA and aminophenol in a solvent in the presence of an alkali and a copper-based catalyst.

Furthermore, it is characterized in that PIA is obtained by oxidatively reacting iodide with aniline in an aqueous medium, and the PIA and p-aminophenol are coupled in a solvent in the presence of an alkali and a copper-based catalyst. This is a method for producing DADPE.

PIA in the present invention is produced by oxidatively reacting an iodide with aniline in an aqueous medium.
That is, possible methods include a method in which iodide is oxidized with a cupric compound or oxygen and reacted with aniline, and a method in which iodide is electrochemically oxidized and reacted with aniline.

The method using a cupric compound is unsatisfactory in that the cupric compound does not act as a catalyst and the reaction is stoichiometric. In addition, the method using oxygen oxidation is
If iodide can be oxidized in an aqueous medium containing a weak acid using panadium or a copper compound as a catalyst (Japanese Patent Application Laid-Open No. 59-29634, 73547), it may be an industrially advantageous method, but in this case, iodide is converted into ammonium iodide. It must be. In the case of the present invention, it is difficult to use ammonium iodide as the iodide if it is assumed that the alkali iodide by-produced during the coupling of PIA and aminophenol is recovered and used. On the other hand, the electrochemical oxidation method does not use a reagent as an oxidizing agent like cupric compounds, but uses electricity as an oxidizing agent. This is the most advantageous method industrially in that the alkali can be recovered and used directly as iodide.

The method for producing PIA by electrolytic oxidation will be specifically described below. By electrolytic oxidation in the present invention
A feature of the PIA manufacturing method is that phosphate is added to the electrolyte to maintain the pH of the aqueous layer between 5.5 and 6.9.

In the present invention, phosphate is added to the electrolyte to reduce PH changes, facilitate PH adjustment, and further improve current efficiency.

In the present invention, ammonium phosphate, sodium phosphate, and potassium phosphate are preferred as the phosphate. Industrially, sodium phosphate is particularly preferred. The phosphate concentration in the aqueous layer is preferably 1 to 20% by weight, and if it exceeds 20% by weight, the viscosity of the aqueous layer increases.

The pH of the aqueous layer is preferably 5.5 to 6.9. When the pH is higher than 6.9, the current efficiency of PIA decreases, and side reaction products such as 4-aminodiphenylamine are produced. Additionally, if the pH is lower than 5.5, what appears to be aniline phosphate will precipitate and adhere to the vessel wall, making it impossible to perform electrolysis normally.

In the present invention, iodide refers to an electrolyte that is soluble in water. Examples of iodides include ammonium iodide, alkali metal iodides, and quaternary ammonium iodide salts, and ammonium iodide, sodium iodide, and potassium iodide are preferably used. Preferably, the cation is the same as the cation of the phosphate described above.

The electrolytic reaction between an iodine compound and aniline can be carried out without any problem by either a diaphragm method or a diaphragmless method. In the case of the diaphragm method, hydrogen iodide is produced at the anode and the corresponding hydroxide is produced at the cathode.
If hydroxide is required, the diaphragm method is selected.
On the other hand, in the case of the non-diaphragm method, there is a high risk that the water layer becomes alkaline due to the hydroxide generated at the cathode and the current efficiency decreases. As is clear, PH changes are small and high current efficiency can be stably obtained. This method does not require a diaphragm, simplifies the structure of the container, and allows the electrode spacing to be narrowed, thereby improving the power consumption rate.

Anode materials include platinum, ruthenium, rhodium, and iridium alone or plated with titanium or tantalum, alloys and alloy platings, and oxides of platinum, ruthenium, rhodium, and iridium with bulk metals (titanium, tantalum, etc.). Examples include alloys and carbon.

The cathode material is preferably one with a low hydrogen overvoltage, but is not particularly limited, and examples include iron, nickel, stainless steel, and the like.

When using a diaphragm, a cation exchange membrane, an anion exchange membrane, etc. are used as necessary.

The diaphragm method will be described below. The description is generally applicable to the non-diaphragm method, so only examples are shown.

The electrolytic cell may be one commonly used in organic electrolytic reactions, as long as it is capable of passing an electrolytic solution between the two electrodes. For example, in an electrolytic cell, a cathode plate and an anode plate are opposed in parallel, and a polyethylene plate that defines the membrane-electrode distance, a diaphragm, and a polyethylene plate are placed in this order to form a cathode chamber and an anode chamber between the two electrodes. . An opening is provided in the center of each of these polyethylene plates to allow the electrolyte to pass therethrough. The current-carrying area of the electrode is determined by the size of the opening, and the distance between the electrode and the diaphragm is determined by the thickness of the polyethylene plate. The anolyte and catholyte enter the anode and cathode chambers from each tank through the supply ports provided in the electrolytic cell, and while passing through the chambers, a portion reacts and exits from the outlet, and is transferred to the anolyte tank. , return to the catholyte tank,
circulate between the tank and the chamber.

The current density is preferably 1 to 30A/ ^dm2 , and 30A/dm2.
Current densities higher than dm ² result in significantly higher voltages, and current densities lower than 1 A/dm ² result in poor productivity.

The electrolysis temperature is preferably 20 to 60°C. There is a correlation between the electrolysis temperature and the amount of by-product o-iodoaniline (hereinafter abbreviated as OIA), and the lower the temperature, the more
It is preferable because the p/o isomer ratio becomes large. However, the voltage increases and the power consumption rate worsens.

The flow rate of the electrolytic solution in the electrolytic cell is preferably 0.1 to 4 m/sec. A flow rate lower than 0.1 m/s will reduce the current efficiency, and a flow rate higher than 4 m/s will cause a significant pressure loss within the electrolytic cell.

The distance between the electrode and the diaphragm is usually preferably 0.5 to 3 mm.

The pH of the aqueous phase can be adjusted by adding a corresponding hydroxide or hydrogen iodide, if necessary.

The anolyte consists of an aqueous layer and an organic layer. The main components of the aqueous layer are water, phosphate, and iodine compounds, and the main components of the organic layer are aniline, PIA, and OIA. The concentration of PIA in the organic layer is preferably 1 to 60% by weight. The ratio of the organic layer in the anolyte is defined as the org capacity ratio, and the org capacity ratio is preferably 0.01 to 1. The catholyte is an aqueous solution of phosphate, an aqueous solution of iodine compound, and
Although both alkali hydroxide and aqueous ammonia solutions can be used, it is more preferable to use the corresponding alkali hydroxide product.

Details of the coupling reaction between PIA and aminophenol of the present invention will be described below.

As the solvent, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, aniline, tetrahydrofuran, benzene, toluene, etc. are used, and polar solvents are particularly preferred. These solvents may be used alone or in combination of two or more.

As catalyst copper or most copper compounds are used, but preferred are cuprous iodide, cuprous chloride, cuprous oxide, cuprous bromide, cuprous cyanide.
These include copper, copper sulfate, cupric chloride, cupric hydroxide, cupric oxide, cupric bromide, cupric phosphate, copper nitrate, copper carbonate, copper acetate, and the like. These compounds may be used alone or in combination of two or more. There is no particular restriction on the amount used, but it is preferably in the range of 0.1 mol% to 50 mol% based on the reactant PIA.

As the alkali, sodium hydroxide, potassium hydroxide, alcoholate, sodium hydride, sodium amide, sodium, potassium, etc. are used, but when considering the recovery of alkali iodide which is a by-product after the coupling reaction, sodium hydroxide or Preference is given to using potassium hydroxide. In other words, the recovered alkali iodide is
The iodine anion is recycled to the electrolytic process of PIA production, where it oxidatively reacts with aniline, and in the case of membrane electrolysis, alkali hydroxide is produced. This alkali hydroxide can be reused.

In the coupling reaction, PIA, aminophenol, alkali, catalyst, and solvent may be placed in a reactor all at once and reacted. Alternatively, the aminophenol alcoholate may be generated only with aminophenol, alkali, and solvent, and then You may add PIA and a catalyst to react. Reaction takes place from room temperature to 200℃
The reaction temperature can be selected depending on the relationship with the reaction time. Further, the reaction is preferably carried out under a nitrogen or argon stream.

Next, the production of PIA, which is a raw material, and the production of DADPE, which is a target product, will be illustrated assuming the entire process.

Electrolysis is carried out using an electrolytic cell with a diaphragm, using a mixture of phosphate, alkali iodide, aniline, and water as the anolyte and 10% alkali hydroxide as the catholyte. After electrolysis, PIA is generated on the anode side,
Alkali hydroxide is generated on the cathode side. The anolyte is separated into two layers of oil and water in a decanter, and the aqueous layer is circulated to the electrolytic process and subjected to an electrolytic reaction. The oil layer is subjected to the next coupling reaction either as is or after PIA is isolated.

The coupling reaction step is carried out as follows.
Aminophenol and alkali hydroxide obtained by concentrating the catholyte in the electrolytic process are reacted in advance in dimethyl sulfoxide under a nitrogen stream to produce an alcoholate of aminophenol, and this solution is mixed with the alcoholate produced in the previous process. Add PIA or an aniline solution of PIA and a catalyst to react. After the reaction is completed, cool it down, add aniline and water to the reaction solution, and extract in two layers.
Separate crystals. DADPE was isolated from the oil layer,
The aqueous layer containing alkali iodide is circulated to the anolyte of the electrolysis process.

(Effects of the Invention) As described above, according to the present invention, an aryl halide can be used in the Ullman reaction for coupling an aryl halide and an aminophenol.
By selecting PIA, we provide a new manufacturing method that can produce DADPE all at once. Additionally, by adopting a process in which iodide is reacted with aniline through electrolytic oxidation for the production of PIA, alkali iodide, which is a by-product during the Ullman reaction, can be recovered and used as iodide during electrolytic oxidation. This makes it possible to assemble a closed system that is industrially extremely advantageous. Furthermore, PIA can be p
- It is possible to produce phenylenediamine, and it is also possible to assemble a process that co-produces it, which has important industrial implications.

Next, the present invention will be explained in more detail with reference to Examples.

[Manufacture of PIA]

Example 1 As the anolyte, 75 g of sodium dihydrogen phosphate,
75g disodium hydrogen phosphate, sodium iodide
A mixture of 150 g of aniline, 300 g of aniline, and 1200 g of water was used and placed in the anolyte tank. 5 in the catholyte tank
% aqueous sodium hydroxide solution was added. The electrolyte in both tanks was circulated to the next electrolytic cell.

The electrolytic cell consists of an anolyte and a cathode chamber separated by a diaphragm. The anode is a platinum-plated titanium plate, the cathode is an iron plate, and both electrodes have a current-carrying area of 1 cm x 100 cm. There is a current-carrying area between the electrodes. is 1cm×
Two 2 mm thick polyethylene plates with 100 cm openings and a perfluorocarbon cation exchange membrane placed in the center to form a cathode chamber and an anode chamber were used. The electrolytic cell has an electrolyte supply inlet and an outlet, and the electrolyte has a flow rate of 2m/
Electrolysis was carried out for 2 hours at a current density of 10 A/dm ² and an electrolysis temperature of 50°C. The pH of the anolyte aqueous layer was adjusted to 6.5 in advance, and during electrolysis, NaOH was added to raise the pH to 6.5.
I kept it.

The average voltage was 3.5V. After electrolysis, PIA in the electrolyte was analyzed by gas chromatography. As a result, the current efficiency was 94%. There were few PH changes during operation, and PH adjustment was easy. The p/o ratio of the iodoaniline produced was 24.

Note that the current efficiency and p/o (molar ratio) are expressed by the following formula.

Current efficiency (%) = Number of moles of PIA generated x 2 / Amount of current flow (Faraday units) x 100 p/o (mole ratio) = PIA generated / OIA generated Example 2 As an electrolyte, 70 g of potassium dihydrogen phosphate, Dipotassium hydrogen phosphate 70g, potassium iodide 150g,
A mixed solution of 250 g of aniline and 1210 g of water was used and placed in an electrolyte tank. The pH of the aqueous layer was 6.0.

The electrolytic cell consists of a titanium plate with platinum and titanium mixed, coated, and fired to form an oxide alloy as the anode, and an iron plate as the cathode, with a current-carrying area of 1 cm x 1 cm between the two electrodes.
An electrolytic chamber was formed by placing one 2 mm thick polyethylene plate with 100 cm openings. The electrolytic cell had an electrolytic solution inlet and an outlet, and the electrolytic solution was flowed at a flow rate of 2 m/sec, and electrolysis was performed for 2 hours at a current density of 10 A/dm ² and an electrolysis temperature of 50°C. No PH adjustment was performed during electrolysis. The pH of the aqueous layer after electrolysis was 6.5. The average voltage was 3.2V.
The current efficiency of PIA was 92%. The p/o ratio of the iodoaniline produced was 25.

Example 3 Ammonium dihydrogen phosphate 50 as electrolyte
A mixture of 50 g of ammonium hydrogen phosphate, 200 g of ammonium iodide, 300 g of aniline, and 1200 g of water was used and placed in an electrolyte tank. The pH of the water layer is 5.5
It was hot.

The same electrolytic cell as in Example 3 was used, the electrolytic solution was flowed at a flow rate of 1.5 m/sec, and electrolysis was carried out for 2 hours at a current density of 10 A/dm ² and an electrolysis temperature of 45°C. No PH adjustment was performed during electrolysis. The pH of the aqueous layer after electrolysis was 6.3. The average voltage was 3.2V. The current efficiency of PIA was 91%. p/o of produced phenylenediamine
The ratio was 25.3.

[Manufacture of DADPE]

Example 4 3.2 g (0.03 mol) of m-aminophenol, 2.0 g (0.03 mol) of potassium hydroxide, 10 g of dimethyl sulfoxide, and 10 g of toluene were placed in a 100 ml four-necked flask, and heated with toluene at 130°C for 3 hours under a nitrogen stream. was stirred while allowing it to flow out. The reaction solution was cooled to 100℃, and 0.4 g of copper iodide and PIA4.0 were added to a four-necked flask.
(0.02 mol) and 10 g of dimethyl sulfoxide were added thereto, and the mixture was stirred at 100°C for 3 hours under a nitrogen stream. After the reaction was completed, the reaction solution was analyzed by liquid chromatography, and the yield of 3,4′-DADPE was found to be based on PIA standards.
It was 50%.

Example 5 m-aminophenol 3.2g (0.03mol), sodium hydroxide 1.2g (0.03mol), aniline 10g,
10 g of monochlorobenzene was placed in a 100 ml four-necked flask, and the mixture was stirred at 150° C. for 3 hours while the monochlorobenzene was flowing out. reaction solution
Cool to 100℃ and add 0.4 cuprous oxide to a four-necked flask.
g, PIA 40 g (0.02 mol), and dimethyl sulfoxide 10 g were added, and the mixture was stirred at 100° C. for 3 hours under a nitrogen stream. After the reaction was completed, the reaction solution was analyzed by liquid chromatography, and the yield of 3,4'-DADPE was found to be
It was 30% according to PIA standards.

Example 6 The m-aminophenol in Example 4 was converted to p-
The reaction was carried out in exactly the same manner as in Example 4 except that aminophenol was used. The yield of 4,4'-DADPE was 35%.

Example 7 The m-aminophenol in Example 5 was converted to p-
The reaction was carried out in exactly the same manner as in Example 5 except that aminophenol was used. The yield of 4,4'-DADPE was 20%.

Comparative Example m-aminophenol in Example 4 was replaced with p-
The reaction was carried out in exactly the same manner as in Example 4, except that aminophenol was used and p-iodoaniline was replaced with p-chloroaniline. The yield of 4,4'-DADPE was 2%.

Claims (1)

[Claims] 1. A method for producing diaminodiphenyl ether, which comprises coupling p-iodoaniline and aminophenol in a solvent in the presence of an alkali and a copper-based catalyst. 2. Oxidatively reacting iodide to aniline in an aqueous medium to obtain p-iodoaniline, and coupling the p-iodoaniline and aminophenol in a solvent in the presence of an alkali and a copper-based catalyst. Characteristic method for producing diaminodiphenyl ether. 3. The method according to claim 2, wherein alkali iodide produced as a by-product during coupling of p-iodoaniline and aminophenol is recovered and used as an iodide for the reaction with aniline in the previous step. 4. The method according to claim 2, wherein iodide is electrolytically oxidized and reacted with aniline. 5. The method according to claim 4, wherein the electrolytic oxidation is carried out by adding a phosphate to the electrolytic solution and maintaining the pH of the aqueous layer at 5.5 to 6.9.