JPH0635425B2 - Method for producing high-purity 3,4'-diaminodiphenyl ether - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing highly pure 3,4′-diaminodiphenyl ether.

More specifically, crude 3,4'-diaminodiphenyl ether prepared by reduction of 3,4'-dinitrodiphenyl ether or 3-amino-4'-nitrodiphenyl ether was prepared by adding an inert organic solvent having a boiling range of 240 to 350 ° C. The present invention relates to a method for producing 3,4'-diaminodiphenyl ether, which is characterized in that it is purified by distillation.

Although 3,4'-diaminodiphenyl ether is an important raw material for aromatic polyamide, polyimide, etc., it is a high-strength, high-modulus aramid fiber composed of three components of p-phenylenediamine and terephthalic acid chloride (Japanese Patent Publication No.
-39719.53-32838) important as a raw material.

(Prior Art) 3,4′-diaminodiphenyl ether has been
A method using dinitrodiphenyl ether as an intermediate or a method using 3-amino-4′-nitrodiphenyl ether as an intermediate is known. For example, the former intermediate is 3
-Bromonitrobenzene and 4-nitrophenol potassium salt were produced by a condensation reaction with a yield of 33% (Ikawa et al., Pharmaceutical Journal, 79 275 (1959)) to produce 4-chloronitrobenzene and 3-nitrophenol potassium salt in N, N. -Reacted in dimethylformamide to obtain 73% yield (JJ
Randall et al., J. Org Chem., 27 4098-4101 (1962)).

The latter intermediate is produced from 4-chloronitrobenzene and 3-aminophenol in a yield of 95.4% (Mushiaki et al., JP-B-47-18101).

Any of these intermediates can be introduced into the desired product, 3,4'-diaminodiphenyl ether, by a conventional reducing means.

(Problems to be Solved by the Invention) Among these known methods, the method using 3-bromonitrobenzene as a raw material has a low yield and is not economical.

All of the methods using 4-chloronitrobenzene give intermediates in good yield and can be said to be suitable for the industrial production method of 3,4'-diaminodiphenyl ether.

However, in order to use 3,4'-diaminodiphenyl ether as a raw material for aramid fiber, extremely high purity is required, and as a measure of this purity, 99.95% or more is desired.

Therefore, in order to obtain a high-purity target product by the above-mentioned industrial production method, it is necessary to recrystallize and refine the diamine after the intermediate stage or after reduction many times. For this reason, there are disadvantages that the yield is drastically reduced and the operation becomes complicated.

In addition, as a quality of this 3,4'-diaminodiphenyl ether, it is important to take measures against deterioration over time. That is, examples of deterioration with time include coloring by an atmosphere such as light and oxygen. The deterioration with time such as coloring also causes a decrease in the polycondensation degree. This deterioration over time is generally due to the impurities contained rather than the 3,4'-diaminodiphenyl ether itself.

That is, in the crude 3,4'-diaminodiphenyl ether produced by the known method using 4-chloronitrobenzene as a raw material, a trace amount to a small amount of an azoxy compound, 3-aminophenol derived from an unreacted raw material, 4- It contains chloroaniline, aniline, etc., and these are the causative substances such as coloring.

In addition, N, which is the most general-purpose aprotic polar solvent,
When N-dimethylformamide is used, it is well known that N, N-dimethylformamide by-produces an N, N-dimethylaniline compound by reaction with an active chlorine atom (ND Heinclel et al., Chemical Communications 38 (196
9)). That is, N, N-dimethylaminonitrobenzene is by-produced from 4-chloronitrobenzene by a condensation reaction,
Reduction produces N, N-dimethylaminoaniline.

This is a typical causative substance that induces deterioration such as coloration in 3,4'-diaminodiphenyl ether.

On the other hand, in the case of industrially producing 3,4′-diaminodiphenyl ether, the starting material, 4-chloronitrobenzene, was mixed with 0.
From 2-chloronitrobenzene containing about 3 to 3% 2,
3'-diaminodiphenyl ether and 2,4'-diaminodiphenyl ether are by-produced. This isomer compound is not only difficult to remove by recrystallization refining, but is also the most important factor for reducing the polycondensation degree of the aramid fiber.

Therefore, the method by distillation purification is suitable for obtaining the target product in high yield except for this isomer compound. However, when the impurities are present, they are decomposed by heating at the time of distillation, etc. The most unfavorable hydrochloride salt of the aniline derivative coagulates and adheres to the distillate portion, which makes it difficult to obtain a target product of high quality by distillation purification as shown in Comparative Examples below.

(Means for Solving the Problem) The present inventors have made a high-purity 3,4′-containing the above-mentioned drawbacks.
The method for producing diaminodiphenyl ether was thoroughly studied. As a result, crude 3,4'-diaminodiphenyl ether produced by reduction was distilled and refined by adding a small amount of a high-boiling point solvent. The present invention has been completed by finding that high-purity 3,4'-diaminodiphenyl ether can be obtained in a high yield.

That is, the present invention is a crude 3,4'-diaminodiphenyl ether produced by reduction of 3,4'-dinitrodiphenyl ether or 3-amino-4'-nitrodiphenyl ether, using an inert organic solvent having a boiling point range of 240 to 350 ° C. In addition, it is a method for producing high-purity 3,4'-diaminodiphenyl ether, which is characterized in that it is purified by distillation.

The 3,4'-diaminodiphenyl ether can be produced by the above-mentioned known method. That is, 3,4'-dinitrodiphenyl ether was produced as an intermediate from 4-chloronitrobenzene and 3-nitrophenol, and 3-amino-4'-nitrodiphenyl ether was produced as an intermediate from 4-chloronitrobenzene and 3-aminophenol. Then, it is manufactured by reducing these.

The crude 3,4'-diaminodiphenyl ether used as a raw material for distillation can be obtained by reducing the intermediate produced by the condensation reaction in an organic solvent and concentrating it or diluting it with water or the like.

This 3,4'-diaminodiphenyl ether needs to be purified because it has low purity regardless of whether the intermediate before reduction is recrystallized or purified. The method of the present invention is characterized by performing distillation purification using a selected solvent to efficiently remove various impurities.

The solvent used in the method of the present invention, alcohols, esters, phenols, glycols, glycol ethers, aprotic solvents and those having a boiling range of 240 ~ 350 ℃ selected from other groups, For example, dodecyl alcohol, butyl benzoate, isopentyl benzoate, dimethyl phthalate, diethyl phthalate, 4-sec-
Butylphenol, 4-tert-amylphenol, 2,4
-Ditert-butylphenol, 2,6-ditert-butyl-
4-cresol, diethylene glycol, triethylene glycol, tetraethylene glycol, tripropylene glycol, glycerin, 1,5-pentanediol,
1,2,3-butanetriol, 2,3,4-pentanetriol, 2-butyl-2-ethylbutane-1,3-diol,
Ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol dibutyl ether, diethylene glycol monobutyl ether acetate, triethylene glycol monomethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, dimethyl sulfone, sulfolane, diphenyl sulfide,
Diphenyl sulfone, biphenyl, diphenyl ether, dibenzyl ether, dipentylbenzene, cyclohexylbenzene, and the like. Among these, glycols because of being liquid at room temperature, easy to obtain, inexpensive, and the like. Glycol ethers are particularly preferably used. The amount of these solvents to be used is not particularly limited and may be about 1 to 50% by weight, preferably 3 to 20% by weight, based on the raw material to be distilled, in consideration of economical efficiency.

In the distillation purification of crude 3,4'-diaminodiphenyl ether, these solvents are charged together with the raw materials and distilled under vacuum to be distilled off as a forerunner with the above trace amount to a small amount of impurities.

That is, it is a characteristic that these solvents have the same or higher boiling point for impurities and the like.

Here, the range of similar to high boiling point is 24
The boiling point is in the range of 0 to 350 ° C. Below this range, the solvent is distilled off before impurities and the effect is lost. Further, when the content is more than this range, the boiling point of the target 3,4′-diaminodiphenyl ether is equal to or higher than the boiling point of the target, so that it is not preferable because the effect of mixing into the target and improvement of the effect of separation from impurities cannot be expected.

(Action and Effect) According to the method of the present invention, an isomer compound that inhibits polycondensation and various impurities can be efficiently removed. Therefore, the desired product, 3,4'-diaminodiphenyl ether, can be produced with high purity in high yield.

In contrast to the method of the present invention, repeating complicated recrystallization purification with an intermediate and a target as conventionally performed not only results in an extremely low yield, but also causes recovery of a recrystallization solvent. Economic burden including labor is large.

The method of the present invention is suitable as a method for industrially producing highly pure 3,4′-diaminodiphenyl ether.

(Example) Hereinafter, the method of the present invention will be described in more detail with reference to Examples.

Example 1 Industrial 4-chloronitrobenzene (manufactured by Mitsui Toatsu Chemicals; purity 99.3%) in a reactor equipped with a stirrer and a thermometer 165.
5g (1.05mol), 109g meta-aminophenol
(1.0 mol), 97 g (0.7 mol) of anhydrous potassium carbonate and 500 m of N, N-dimethylformamide were charged,
The reaction was carried out under stirring while passing nitrogen gas through. The reaction was completed by carrying out the reaction at a temperature of 130 to 135 ° C. for 15 hours. After completion of the reaction, the solvent was collected by concentration and then discharged into water 1. The precipitated yellow crystals were washed with 3-amino-
4'-Nitrodiphenyl ether was obtained.

Then, in a closed reduction reactor equipped with a stirrer and a thermometer, 5% of the above 3-amino-4'-nitrodiphenyl ether was added.
Palladium carbon catalyst 4.5g and methanol 500m
Was charged, and hydrogen gas was introduced with vigorous stirring.

When the reaction temperature was 25 to 35 ° C for 8 hours,
Absorbed hydrogen and no more absorption was observed, so the reaction was terminated. After the completion of the reaction, the catalyst palladium carbon was removed, and the mixture was concentrated under reduced pressure by an evaporator to deposit crude crystals of 3,4'-diaminodiphenyl ether. This was filtered, washed with water and dried to obtain 198.5 g.

The crude crystals were analyzed by gas chromatography and found to be as follows.

Next, 50 g of the above crude crystal was placed in a vacuum distillation apparatus equipped with a rectification column.
And triethylene glycol 5g are charged, and the pressure is 2-3mm.
When vacuum distillation was carried out with Hg, the forerunner had a boiling point range of 120.
At 215 ° C, 8.4 g was obtained, the main fraction was 44.7 g in the boiling range of 215 to 216 ° C (total yield from the condensation reaction was 88.6%), and 1.4 g of tar material remained as a residue. . This main fraction was obtained as white crystals and was analyzed by gas chromatography to find that it had a purity of 9% as 3,4'-diaminodiphenyl ether.
The melting point was 9.95% and the melting point was 74 to 74.5 ° C. Even when the crystals were stored in a white polyethylene container for 1 week, no change in appearance was observed.

Example 2 50 g of crude 3,4'-diaminodiphenyl ether obtained in Example 1 and 3 g of glycerin were used for distillation in the same manner as in Example 1 to obtain a purity of 9 by gas chromatography.
9.96% pure 3,4'-diaminodiphenyl ether 43.
8 g (total yield 86.8%) of white crystals were obtained. When this was stored for 1 week as in Example 1, no change in appearance was observed.

Comparative Example 1 50 g of the crude 3,4'-diaminodiphenyl ether obtained in Example 1 was vacuum distilled at a pressure of 2 to 3 mmHg without adding a solvent.

As a result, when the distilling started, white crystals adhered to the distilling portion and were mixed little by little in the receiver.

The front fraction obtained 7.6 g in the boiling range 180-214 ° C, the main fraction 31.5 g (total yield 62.4%) in the boiling range 214-215 ° C, and the residual tar material 9. 3 g remained. The main fraction gradually turned dark purple when exposed to air.

According to an analysis by gas chromatography, the purity as 3,4′-diaminodiphenyl ether was 98.15%,
Although there were no isomer compounds, multiple aniline derivatives and unknown components were confirmed. The white crystals adhering to the distillate were soluble in water, the aqueous solution was acidic, and when neutralized and analyzed by gas chromatography, chlorine ions were confirmed by flame reaction. It was presumed to be the derivative hydrochloride.

Comparative Example 2 To 30 g of the crude 3,4'-diaminodiphenyl ether obtained in Example 1, 1.5 g of anhydrous sodium carbonate was added and distillation was carried out in the same manner as in Comparative Example 1.

As a result, 3.2 g of a main distillate, 25.1 g of a main distillate (total yield: 82.9%) were obtained, and 2.5 g of tar substances and the like were obtained as a residue. White crystals did not adhere to the distilled portion, but the main fraction gradually changed to a dark purple color when exposed to air.

According to the analysis by gas chromatography, the purity was 9,982% as 3,4'-diaminodiphenyl ether, and no isomer compound was confirmed, but a plurality of aniline derivatives were detected.

Example 3 139.1 g (1.0 mol) of metanitrophenol, 58.3 g (1.0 mol) of 96% caustic potash, and dimethyl sulfoxide were placed in a reactor equipped with a stirrer, a thermometer, a reflux condenser and a water separator. 350 m and 50 m of toluene were charged, and water distilled under the refluxed state of toluene was taken out of the system by a water separator. Then, a solution of 165.5 g (1.05 mol) of industrial 4-chloronitrobenzene and 250 m of dimethyl sulfoxide was added dropwise over 30 minutes, and the temperature was adjusted to 130.
Keep at ~ 145 ° C. After reacting for 6 hours at the same temperature, the solvent was concentrated and discharged into water 1. The precipitated yellowish brown crystals were filtered to obtain 3,4'-dinitrodiphenyl ether.

This 3,4'-dinitrodiphenyl ether was catalytically reduced in the same manner as in Example 1 to obtain 194 g of crude 3,4'-diaminodiphenyl ether.

The crude crystals were analyzed by gas chromatography and found to be as follows.

Next, 50 g of this crude crystal was added with 3 g of tripropylene glycol monobutyl ether and distilled in the same manner as in Example 1.

As a result, the front fraction 6.4 g, the main fraction 43.2 g (total yield 8
3.7%) was obtained, and 2.3 g of a tar substance was obtained as a residue. The main fraction was obtained as white crystals and was analyzed by gas chromatography to find that it had a purity of 99.98% as 3,4'-diaminodiphenyl ether and a melting point of 74 to 74.5.
It was ℃. Even when the crystals were stored in a white polyethylene container for 1 week, no change in appearance was observed.

Example 4 Stable 3,4'-diaminodiphenyl ether 4 of white crystals was obtained by distillation in the same manner as in Example 3 except that sulfolane was used instead of tripropylene glycol monobutyl ether.
3.9 g (total yield 85.1%) was obtained. Purity is 99.96%
Met.

Comparative Example 3 When the crude 3,4′-diaminodiphenyl ether obtained in Example 3 was used and the same procedure as in Comparative Example 1 was performed, white crystals of the hydrochloride of the aniline derivative were precipitated in the distillate portion, and the main fraction was air. The color gradually changed when I touched. The yield of this main fraction is 6
As in Comparative Example 1, the residual tar substance increased at 9.9%.

Comparative Example 4 The crude 3,4′-diaminodiphenyl ether obtained in Example 3 was used in the same manner as in Comparative Example 2 to obtain a yield of 78.5% and a purity by gas chromatography of 99.-84% of 3,4 ′.
-Diaminodiphenyl ether was obtained. It contained multiple alinine derivatives and gradually discolored on exposure to air.

Comparative Example 5 Purity by gas chromatography after redistilling the 3,4'-diaminodiphenyl ether obtained in Comparative Example 9 9.
91% of white crystals were obtained. When it was stored in a white polyethylene container for 1 week, it turned a faint dark purple color.

Comparative Example 6 To 50 g of crude 3,4'-diaminodiphenyl ether obtained by the method of Example 3, 5 g of ethylene glycol dibutyl ether at bp 204 ° C was added, and distillation was carried out in the same manner as in Example 3.

As a result, diethylene glycol dibutyl ether was distilled out first, and combined with the previous fraction, 9.8 g was obtained, and the main fraction was 39.0 g.
Got The main fraction was analyzed by gas chromatography to find that it was 98.72 as 3,4'-diaminodiphenyl ether.
%, And multiple aniline derivatives were confirmed.

This main fraction gradually colored when exposed to air.

Comparative Example 7 The same procedure as in Comparative Example 6 was repeated except that dioctyl phthalate having a boiling point of 387 ° C. was used instead of diethylene glycol dibutyl ether.

As a result, a front distillate fraction of 8.5 g and a main distillate fraction of 43.2 g were obtained. When the Ichi-yu fraction was analyzed, it was 95.32% as 3,4'-diaminodiphenyl ether, and 4.51% of dioctyl phthalate was detected together with several aniline derivatives.

Claims (1)

[Claims] 1. A crude 3,4′-diaminodiphenyl ether produced by reduction of 3,4′-dinitrodiphenyl ether or 3-amino-4′-nitrodiphenyl ether is treated with an inert organic solvent having a boiling point range of 240 to 350 ° C. A method for producing high-purity 3,4'-diaminodiphenyl ether, which is characterized in that it is additionally purified by distillation.