JPH035384B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 3,4'-diaminodiphenyl ether (hereinafter abbreviated as 3,4'-DADPE). More specifically, 4- substituted with chlorine
Nitrodiphenyl ether is nitrated to produce 3,4'-dinitrodiphenyl ether or 5,4'-dinitrodiphenyl ether (hereinafter abbreviated as 3,4'-DNDPE-Cl) having a nuclear chlorine substituent.
The present invention relates to a method for producing 3,4'-DADPE through amination by reduction of nitro groups and dechlorination through a hydrogenation reaction.

3,4'-DADPE is attracting attention as an intermediate for pharmaceuticals and as a raw material for aromatic polyamide fibers with excellent heat and chemical resistance. However, when used as a polymeric monomer, it needs to be highly pure and inexpensive.

As a general method for producing diphenyl ethers, a method using the Ullmann reaction is known. That is, this is a method in which phenoxide anion is reacted with an aromatic halogen compound in the presence of a catalyst such as copper or an inorganic copper salt using a nucleophilic reagent. 3,4′−DADPE
In this case, m-nitrophenol or m-aminophenol is condensed with p-nitrohalogenobenzene or p-aminohalogenobenzene, and if the substituent has a nitro group, the desired product is obtained by further reduction. It will be done. Although this method is relatively simple and has a good yield, it causes a decrease in purity due to the contamination of isomers of phenols and nitrohalogenobenzenes, and currently m-nitrophenol or m-aminophenol is considerably reduced. Expensive raw material, cheap 3,4'-
It is an industrially unsuitable method for producing DADPE. In addition, from the viewpoint of inexpensive raw materials, p-nitrophenol or p-aminophenol is condensed with m-nitrohalogenobenzene or m-aminohalogenobenzene, and those containing a nitro group as a substituent are further reduced. A method for producing a desired product is also known. However, this process has a low condensation yield of about 50% and, like the above-mentioned method, has problems with purity due to the contamination of isomers, and therefore cannot be used as an industrial method.

The present inventors have discovered a highly pure and inexpensive 3,4'-
We conducted extensive research on the production method of DADPE, added chlorine to diphenyl ether in advance, or obtained diphenyl ether derivatives having a mononitro group and a polychlorine group, and nitrated these to 3,4'-
We have found a method for producing 3,4'-DADPE that achieves the above objectives by reducing the nitro group and dechlorinating it by hydrogenation reaction after producing DADPE-Cl. According to the method of the present invention, by adding chlorine to an appropriate position of diphenyl ether,
Since it is possible to prevent nitro groups from being substituted at positions other than 3,4' during nitration, it is possible to selectively introduce nitro groups only at 3,4' positions. 3,4′−DADPE−
A high purity target product can be obtained by converting a high purity product of Cl into 3,4'-DADPE through subsequent hydrogenation and dechlorination reactions.

In the method of the present invention, as for the synthetic route of 3,4'-DADPE-Cl, for example, as an industrially advantageous method, 2,4-dichlorophenol and 3,4'
- When dichloronitrobenzene is condensed and then nitrated, the 5-position is selectively substituted with a nitro group,
2,4,2'-trichloro-5,4'-dinitrodiphenyl ether can be obtained in high yield and with high purity. 2,4-dichlorophenol can be easily obtained by chlorinating p-chlorophenol, and 3,4-dichloronitrobenzene can also be easily obtained by chlorinating p-nitrochlorobenzene. I can do it. Any combination in which 2,4,6-trichlorophenol is used instead of 2,4-dichlorophenol and 3,4,6-trichloronitrobenzene is used instead of 3,4-dichloronitrobenzene as the condensation raw material can also be used for condensation, By nitration, the corresponding 3,4'-DADPE-Cl in which the 3 position is selectively substituted with a nitro group can be obtained. In this case, 2,4,6-trichlorophenol can be easily obtained in high purity by chlorination of phenol, and 3,4,6-trichloronitrobenzene is a chlorinated product of the aforementioned 3,4-dichloronitrobenzene. All of them are easily available industrially at low cost.

In the present invention, as described above, 3,4'-DADPE-Cl can be obtained by condensing using industrially inexpensive raw materials and nitrating them under mild reaction conditions. That is, the condensation reaction can be carried out at 140 to 150°C using a polar solvent such as N-methylpyrrolidone or dimethyl sulfoxide with the addition of caustic alkali, but the reaction can be carried out at 200°C or lower even without a solvent. Although the following nitration reaction can be carried out without a solvent, it is preferable to use a solvent in consideration of removal after the reaction, separation of waste acid, etc. As the solvent, carbon tetrachloride, 1,2-dichloroethane, etc. are used in an amount equal to to 5 times the amount of the raw material. As a nitrating agent, a commonly used mixed acid of nitric acid and sulfuric acid is used. Nitric acid is used in an amount of 1 to 1.5 moles based on the raw materials, and sulfuric acid is used in a proportion of 2 to 10 moles, preferably 4 to 8 moles, based on the raw materials. The temperature is 10 to 100°C, preferably 20 to 60°C. In this way, particularly harsh conditions are not required, so high purity 3,4'-DADPE-Cl can be obtained in high yield without contamination with tar or by-products, and there is no need for purification of the product.

In the method of the present invention, in the production process of 3,4'-DADPE by the hydrogenation reaction of 3,4'-DADPE-Cl, raw materials are mixed into a solvent in a pressurized reaction vessel, and in addition to the metal catalyst, dechlorination For this purpose, caustic alkali is added, hydrogen is injected under pressure, and the mixture is stirred vigorously to cause a reaction.
In the case of no solvent, it is necessary to carry out the reaction at a high temperature higher than the melting point of the raw materials, and it is preferable to use a solvent in consideration of safety and complexity of removal after the reaction. As the solvent, water or aliphatic alcohol such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, etc., is used, which has relatively good solubility with the raw material or product and is easy to recover. The amount used should be at least 10 times the amount of the raw material. In addition, it is preferable to use a catalyst during the hydrogenation reaction, and examples of catalysts that are commonly used in hydrogenation reactions include Raney nickel, platinum,
Examples include carbon, palladium/carbon, and the like. These catalysts are used in an amount of 1 to 10% based on the raw material. The conversion reaction from 3,4'-DADPE-Cl to 3,4'-DADPE requires dechlorination as well as reduction of the nitro group, so caustic alkali is added after or during the hydrogenation reaction. , it is desirable to complete the dechlorination reaction. By selecting the above catalysts commonly used in hydrogenation reactions,
A certain degree of dechlorination reaction can also be carried out at the same time as the hydrogenation reaction. At this time, it is necessary to carry out the dechlorination reaction at a high temperature in order to complete it.
However, it can be carried out at low temperatures by adding caustic alkali. The caustic alkali may be either an aqueous solution or a solid, but considering the amount of water in the reaction system, it is better to use a caustic alkali of 40% or more, equivalent to the amount of chlorine added to the raw materials. The reaction temperature is 10 to 40°C for reduction of nitro groups, but higher temperature 40°C for dechlorination.
Requires ~120°C, preferably 50-100°C. Too high a temperature is undesirable because it promotes the formation of tar and byproducts.

In this way, the hydrogenation reaction and dechlorination reaction are carried out, and when the hydrogen pressure in the reaction vessel stops decreasing, the reaction is stopped and the reaction mass is taken out. After separation into the catalyst and reaction liquid, the reaction liquid is Distillation is performed to remove the solvent and water, followed by distillation under reduced pressure to obtain 3,4'-
DADPE is obtained.

Next, the present invention will be explained in more detail with reference to Examples. Note that % means weight %.

Example 1 2,4-dichlorophenol 13g (0.08mol)
After adding 4.5 g (0.08 mol) of solid potassium hydroxide to, 15 g of 3,4-dichloronitrobenzene
(0.08 mol) and 100 ml of dimethyl sulfoxide were added and reacted at 140°C for 3 hours. After the reaction is completed, the mixture is poured into water and extracted with benzene. Benzene was distilled off to obtain 24 g (0.075 mol) of 2,4,2'-trichloro-4'-nitrodiphenyl ether. 50 of this
g of 1,2-dichloroethane dissolved in 98% nitric acid
6.0g (0.094mol) and 45g (0.45mol) of 98% sulfuric acid
The mixture was mixed to form a mixed acid, which was added dropwise over 10 minutes, and then reacted at 60°C for 1 hour. After the reaction was completed, the organic phase and the waste acid phase were separated, and 1,2-dichloroethane was distilled off from the organic phase to obtain 26 g (0.072 mol) of 2,4,2'-trichloro-5,4'-dinitrodidiphenyl ether. ) was obtained. No impurities were observed in gas chromatography of this product. Next, 100 ml of methyl alcohol and 0.8 g of commercially available 5% palladium on carbon were charged into an autoclave, hydrogen was introduced under pressure, and the autoclave was vigorously stirred at 30°C. After 2 hours, when hydrogen absorption has stopped, add 10.4 ml of caustic soda.
g (0.26 mol, 1.2 times equivalent) and hydrogen was again pressurized, the temperature was raised to 90° C. and vigorous stirring was performed. 5
When hydrogen absorption stopped after some time, the reaction was stopped and the reaction mass was taken out. The reaction mass was immediately filtered, the catalyst was separated, and then distilled. After distilling off the solvent and water, vacuum distillation (260°C/10mmHg) was carried out.
g (0.07 mol) of white crystals were obtained. The analysis result of this substance by gas chromatography is 3,4'-
The purity of DADPE was 99.93%.

Example 2 15.8 g of 2,4,6-trichlorophenol was used instead of 13 g of 2,4-dichlorophenol in Example 1.
(0.08 mol), 3,4-dichloronitrobenzene 15
Condensation nitration was carried out in the same manner as in Example 1, using 18.1 g (0.08 mol) of 3,4,5-trichloronitrobenzene instead of 31.1 g (0.072 mol) of dinitrodidiphenyl ether was obtained. Next, a hydrogenation reaction was carried out in the same manner as in Example 1. However, 16 g (0.40 mol, 1.2 times equivalent) of caustic soda was used. As a result, 14 g (0.07 mol) of 3,4'-DADPE with a purity of 99.95%
I got it.

Example 3 15.8 g of 2,4,6-trichlorophenol instead of 2,4-dichlorophenol in Example 1
(0.08 mol) to potassium hydroxide 4.5g (0.08 mol)
was added to prepare a potassium salt of 2,4,6-trichlorophenol, and then 30 g (0.16 mol) of 3,4-dichloronitrobenzene was added and reacted at 170°C for 3 hours. After the reaction was completed, unreacted 3,4-dichloronitrobenzene was distilled off to obtain 26.5 g (0.075 mol) of 2,4,6-tetrachloro-4'-nitrodiphenyl ether. This was nitrated in the same manner as in Example 1 to obtain 28.7 g (0.072 mol) of 2,4,6-2'-tetrachloro-5,4'-dinitrodidiphenyl ether. Next, a hydrogenation reaction was carried out in the same manner as in Example 1. However, 12.9 g (0.32 mol, 1.2 times equivalent) of caustic soda was used. As a result, 3, with a purity of 99.94%,
14 g (0.07 mol) of 4'-DADPE was obtained.

Example 4 2,4,2',6'-tetrachloro-4'-nitrodidiphenyl ether 26.5 g (0.075 mol) was dissolved in 50 g of carbon tetrachloride and then 7.2 g (0.113 mol) of 98% nitric acid and 98% A mixed acid was prepared by mixing 67.5 g (0.675 mol) with sulfuric acid, which was added dropwise over 10 minutes, and then reacted at 40° C. for 1 hour. After this, the process was carried out in the same manner as in Example 1.
28.7 g (0.072 mol) of 4,2',6'-tetochloro-5,4'-dinitrodiphenyl ether was obtained. Next, instead of the 5% palladium/carbon in Example 1, 3 g of commercially available Raney nickel and 12.9 g of caustic soda were added.
The same procedure as in Example 1 was carried out except that 3, with a purity of 99.92%, was used, except that 3,
14 g (0.07 mol) of 4'-DADPE was obtained.

Claims (1)

[Claims] 1 The structural formula of general formula (A) is shown, and X is hydrogen or chlorine. A 3,4'-dinitrodiphenyl ether compound or 5,4'-dinitrodiphenyl having a corresponding nuclear chlorine substituent obtained by nitrating a certain nuclear chlorine-substituted 4-nitrodiphenyl ether compound A method for producing high-purity 3,4'-diaminodiphenyl ether, which is obtained from an ether compound by a hydrogenation reaction to convert a nitro group into a corresponding amino group and a dechlorination reaction of nuclear-substituted chlorine. 2. The method according to claim 1, wherein Raney nickel, platinum carbon, or paldium carbon is used as a catalyst for the hydrogenation reaction. 3. The method according to claim 1, wherein water or an aliphatic alcohol is used alone or as a mixture as a solvent for the hydrogenation reaction. 4. The method according to claim 1, in which caustic alkali is used in an amount equivalent to or more than chlorine in the dechlorination reaction. 5 Reaction temperature of hydrogenation reaction and dechlorination reaction
The method according to claim 1, which is carried out at a temperature of 10°C or higher and 120°C or lower.