JPS609741B2 - Method for producing 4,4'-diaminodiphenyl ether - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 4,4'-diaminodiphenyl ether.

4,4'-Diaminodiphenyl ether is used as a bifunctional monomer for producing condensation polymers used for heat-resistant resin molded products, electrical insulation films, etc., and as a quality agent for polymers in general. It is an important intermediate raw material, and conventionally, 4
・Produced by Bechamp reduction of 4'-dinitrodiphenyl ether.

However, according to such a method, iron and iron ions are inevitably mixed into the reduction product, and it is difficult to remove them. As mentioned above, the main use of 4,4-diaminodiphenyl ether is the production of heat-resistant and electrically insulating polymers, so if iron or iron ions are mixed into this compound, the resulting polymer Not only will the above performance of the coalescence be significantly impaired, but the polymer may become colored over time.

Furthermore, the production method using Bechamp reduction has a low yield. However, until now, there has been almost no literature on improving the production method of 4,4'-diaminodiphenyl ether, and the only one proposed is British Patent No. 1228738, which proposes a production method by catalytic hydrogen reduction of 4,4-dinitrodiphenyl ether. It's nothing more than that.

This method uses dimethylformamide as a solvent and Raney nickel as a catalyst, preferably 10
It reduces 414-dinito diphenyl ether at a temperature of 70 to 13,000 °C under a hydrogen pressure of ~50 k9/s. Although it is said that 414-diaminodiphenyl ether can be obtained in high yield by this method, there are still some points that need to be improved before it can be carried out industrially. That is, in the above method, the reaction conditions are still severe, the cost of incidental equipment is expensive, and the solvent used is also expensive. The present invention has been made in view of the above-mentioned problems, and it is possible to produce high-yield, high-purity 4,4-diaminodiphenyl ether under mild reaction conditions using an inexpensive solvent. The purpose is to provide a method suitable for industrial implementation.

The method for producing 4,4-diaminodiphenyl ether according to the present invention uses the general formula AO-(CH2CH20)n-B (where "A represents an alkyl group having 1 to 4 carbon atoms, and R is hydrogen or ~4 alkyl group, n is 1 or 2
It is.

) (may contain up to 5% by weight of water).

) is characterized by catalytic hydrogen reduction of 4,4-dinitrodiphenyl ether in the presence of tranney nickel.In general, in catalytic hydrogen reduction using a solvent, whether the reaction proceeds smoothly or not is a matter of doubt. This is related to the selection of solvents.
Moreover, in order to conduct the reaction on an industrial scale, it is necessary to use 4,4'-dinitrodiphenyl ether and 41
A solvent that can dissolve 4'-diaminodiphenyl ether well is desirable, but on the other hand, a solvent that dissolves these aromatic nitro compounds and amino compounds well does not necessarily allow the catalytic hydrogen reduction reaction to proceed smoothly.

Therefore, it is not easy to select a solvent for catalytic hydrogen reduction of 4,4-dinitrodiphenyl ether to give the corresponding diamino compound, and as mentioned above, only dimethylformamide has been disclosed. It's just that. However, as a result of intensive research into solvents suitable for the above reaction, the present inventors unexpectedly found that monoalkyl ethers and dialkylenes of ethylene glycol and diethylene glycol form 414-dinitrodiphenyl ether. It dissolves relatively well and allows the catalytic hydrogen reduction reaction to proceed extremely smoothly under mild conditions.
The present invention was achieved by discovering that 4,4-diaminodiphenyl ether can be obtained in high yield and with high purity.

The alkyl group in the alkyl ether of ethylene glycol and diethylene glycol used in the present invention preferably has 1 to 4 carbon atoms, and therefore, specific examples include methyl cellosolve, ethyl cellosolve, and fluoride.

Lopyl cellosolve, butyl cellosolve, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether (includes ethylene glycol dibutyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, diethylene glycol dimethyl ether, etc.) be able to.
Particularly preferably used solvents are monoalkyl ethers of ethylene glycol. In the method of the present invention,
It is not necessary that the 414-dinitrodiphenyl ether be completely dissolved in the solvent, and depending on the solvent, it may not dissolve in the solvent under the reaction conditions.

However, in any case, the reaction proceeds smoothly. Additionally, in the present invention, the solvent may contain up to about 5 weight percent water.

As the water content in the solvent increases, 4,4-dinitrodiphenyl ether becomes less soluble in the solvent, and therefore,
Although the catalytic reduction reaction is carried out in a heterogeneous phase, the reaction results are the same as when using anhydrous solvents, giving high yields and high purity 4,4'-diaminodiphenyl ether. Furthermore, in the method of the present invention, the solvent may contain water, so the solvent can be used repeatedly without being particularly purified. That is, although water is produced as a by-product in the catalytic reduction of 414-dinitrodiphenyl ether, the solvent can be used repeatedly without particularly removing this water. The solvent is usually used in an amount of 2 to 1 part by weight per 1 part by weight of 4,4'-dinitrodiphenyl ether.

In the present invention, a Raney nickel catalyst is used as the catalyst. There is no particular limit to its usage, but usually
It is about 0.1 to 5% by weight (in terms of aqueous paste alloy) of 4,4-dinitrodiphenyl ether. The reaction is usually
The feeding is carried out under a water pressure of about 1 to 1 pressure, at a temperature of about 50 to 150 qo, preferably about 70 to 10,000 qo, for about 30 minutes to 1 feeding time. In preferred cases, the reaction is complete in 1 to 2 hours. After the reaction is complete, add a solvent to the reaction mixture and heat it.
The catalyst is removed by passing through a heat furnace, and the mixture is cooled and 4,4-diaminodiphenyl ether is recovered from the furnace.

The solvent may be distilled off. According to the method of the present invention, the crude yield of 4,4-diaminodiphenyl ether in the reaction product is usually 90% or more, preferably almost quantitative, and the purity is usually 99% or more. .5% or more. Analysis of the crude product by gas chromatography revealed that the impurity content was about 0.1 to 0.5% at most, and this was a partially reduced product, 4-amino-4' nitrodiphenyl ether. In order to purify the product by removing such impurities, it is preferable to perform recrystallization using the above-mentioned solvent according to the present invention.

That is, 4-amino-4' nitrodiphenyl ether has higher solubility in the above solvent than 4,4-diaminodiphenyl ether, and the partially reduced product can be completely removed by recrystallizing the target product from these solvents. It is possible. As the recrystallization solvent, any of the above solvents can be used, but ethyl cellosolve and butyl cellosolve are particularly preferred. Also preferably used are ethylene glycol, diethylene glycol, ethyl cellosolve acetate, butyl cellosolve acetate, and the like. Therefore, according to the present invention, after the completion of the reaction, a high purity amino diphenyl ether can be obtained by a simple method of adding a solvent to the reaction mixture, removing the catalyst in a hot oven, and recrystallizing it. can. If desired, the solvent after recrystallization can be used repeatedly for recrystallization. Moreover, if desired, the solvent after recrystallization may be used as the reaction solvent. As described above, the method of the present invention
In the method of catalytic hydrogen reduction of -dinitrodiphenyl ether in the presence of a Raney-nickel catalyst, high-density reduction can be achieved in a short time under mild conditions by using a solvent whose main component is an organic solvent represented by the above general formula. 4 with high purity in yield
- It gives 4'-diaminodiphenyl ether, and the solvent used is safe to handle and inexpensive. Therefore, the method of the present invention is suitable for industrial implementation, and the resulting 4,4-diaminodiphenyl ether is particularly suitable for applications requiring high purity. Furthermore,
In the method of the present invention, the reaction solvent can be used repeatedly in reactions without being purified, and the recrystallization solvent can also be used repeatedly in recrystallization, which is more industrially and economically advantageous. The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 4,4'-dinitrodiphenyl ether 24.0 ml, butyl cellosolve 100 ml and Raney nickel catalyst aqueous paste 650 ml were charged into an autoclave with a capacity of 200 ml, and the air in the autoclave was replaced with hydrogen. , 5
The k9' gauge was pressurized.

Next, the contents were heated slowly while stirring, and when the temperature of the contents reached 70oC, the internal pressure was increased to 8k9/kg, and the heating was vigorously heated to start the reaction. After 30 minutes,
The reaction temperature was raised to 90°C and hydrogen was replenished.

The reaction was allowed to run for 2 hours. After the reaction was completed, a solvent was added to the contents, heated, filtered in a thermal oven, and the solvent was evaporated to obtain 18.2% of 4,4'-diaminodiphenyl ether (yield: 9).
9.1%). This crude product was analyzed by gas chromatography and found to have a purity of 99.8%. Example 2 The same procedure as in Example 1 was carried out except that methyl cellosolve 80' was used instead of butyl cellosolve as the solvent. 2. An insect time reaction was performed.

After the reaction, add 80' of methyl cellosolve to the contents, heat it, heat it to remove the catalyst, cool it, and add 4.
13.2 hours of 4'-diaminodiphenyl ether was obtained. Analysis by gas chromatography revealed that the product contained no 4-amino-4'-nitrodiphenyl ether. Example 3 Using ethyl cellosolve 75' instead of butyl cellosolve as a solvent,
A reaction was carried out for 2.5 hours in the same manner as in Example 1 except that 450 ml of Raney nickel catalyst aqueous paste was used.

After the reaction is complete, add ethyl cellosolve 75' and heat.
The mixture was heated in a hot furnace and the solvent was distilled off to obtain 4,4-diaminodiphenyl ether with a yield of 98.8%. As a result of gas chromatography analysis, the purity was 99.5%.
Example 4 A reaction was carried out for 1.6 hours in the same manner as in Example 1, except that a mixed solvent of butyl cellosolve 40 and water 40 was used instead of butyl cellosolve.

After the reaction is completed, it is cooled, the solid content is taken out in an oven, 100% of ethyl cellosolve acetate is added thereto, heated, recrystallized in a heated oven, and 4,4-diaminodiphenyl ether containing no impurities is obtained. 14.3 pm. Example 6 Using a mixed solvent of 400 parts of methyl cellosolve and 120 parts of water instead of butyl cellosolve as a solvent, and using 1.84 parts of Raney nickel catalyst aqueous paste, the same machine as in Example 1 was prepared in an autoclave of 1 volume. The mixture was reacted for 2.2 hours.

After the reaction is completed, the contents are cooled, the solid content is taken out in an oven, 500 ml of ethyl cellosolve acetate is added, heated, filtered in a heat oven, and recrystallized to obtain 4,4-diaminodiphenyl containing no impurities. - Tel 15.7 pm was obtained. Example 6 A reaction was carried out in exactly the same manner as in Example 1 using butyl cellosolve 80' as a solvent.

After the reaction was completed, the contents were cooled, and the recovered solvent from which the solid content had been separated was used as a solvent, and the reaction was carried out again in the same manner. In this way, the recovered solvent was used repeatedly, and in the 8th reaction, 4,4-diaminodiphenyl ether was converted into 9
Obtained with a crude yield of 6.9%. When this crude product was recrystallized from butyl cellosolve acetate, 4,4'-diaminodiphenyl ether containing no impurities was obtained. Example 7 Example 1 except that ethylene glycol dimethyl ether 80 was used instead of butyl cellosolve as the solvent.
The reaction was carried out in the same manner as above for 3 hours.

After the reaction is complete, add 80% ethyl cellosolve acetate to the contents.
Add heat, heat, filter through a heat oven, distill off the solvent,
-Diamino diphenyl ether was obtained with a yield of 96.8%. As a result of gas chromatography analysis, the purity was 9.
It was 9.3%. Example 8 Dethylene glycol dimethyl ether 80 as solvent
3. Same as Example 1 except that a mixed solvent of 20 parts of water and 20 parts of water was used. A song time response was performed.

Claims (1)

[Claims] 1 General formula AO-(CH_2CH_2O)_n-B (wherein A represents an alkyl group having 1 to 4 carbon atoms, B represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and n is 1 or 2
It is. ) in the presence of a Raney-nickel catalyst in the presence of a Raney-nickel catalyst, 4. Method for producing 4'-diaminodiphenyl ether. 2 2 to 10 parts by weight of solvent and 0.001 to 0.0 parts by weight of catalyst per 1 part by weight of 4,4'-dinitrodiphenyl ether
4,4'-diaminodiphenyl according to claim 1, characterized in that the reaction is carried out using 5 parts by weight under the conditions of hydrogen pressure of 1 to 10 kg/cm^2 and temperature of 50 to 100°C. How to make ether. 3. The 4,4'-diaminodiphenium compound according to claim 1 or 2, characterized in that a solvent represented by the above general formula is added to the reaction mixture, heated, hot-filtered, and recrystallized. Method for producing enyl ether.