JPS6281358A - Production of aminodiphenyl ether - Google Patents

Abstract

PURPOSE:To readily obtain a compound useful as a raw material for medicines, agricultural chemicals, synthetic resins, etc., in high purity and yield, by condensing an aminophenol with a halonitrobenzene under specific conditions. CONSTITUTION:An aminophenol is condensed with a halonitrobenzene in a mixed solvent of N-methyl-2-pyrrolidone and water at 50-90 deg.C for 1-15hr while adding an alkali metal hydroxide, e.g. NaOH, thereto to afford the aimed substance. The reaction is carried out by using the halonitrobenzene in a molar amount of 0.5-3 times based on the aminophenol and the alkali metal hydroxide in a molar amount of 1-1.03 times based on the halonitrobenzene.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing aminodiphenyl ethers.

Aminodiphenyl ethers are extremely useful as raw materials for medicines, agricultural chemicals, synthetic resins, etc., and their production methods include (1) mixing an alkali metal salt of aminophenol and chloronitrobenzene in a solvent such as dimethylformamide at 50 to 110°C; (Special Publication No. 47-1)
(Japanese Patent Publication No. 8101), (21) A method of reacting aminophenol and halonitrobenzene under reflux using dimethylformamide or the like as a solvent (Japanese Patent Publication No. 55-40578), (3) Reacting aminophenol and halonitrobenzene with dimethylformamide or the like as a solvent. A method is known in which the reaction is carried out in the presence of an alkali metal carbonate at 130 to 150° C. while removing by-product water (Japanese Patent Laid-Open Publication No. 105649/1983).

However, in the case of these methods, for example in the case of method (1), the reaction temperature can be made relatively low;
The formation of by-products can also be suppressed, but there is a problem that the reaction rate is low, and in the case of methods (2+ and +31) there is a disadvantage that the reaction is carried out at high temperature, and in the case of (3) there is an additional However, there are operational and equipment disadvantages in that the reaction must be carried out while removing by-product water from the system.

Based on this, the present inventors reacted aminophenols tohalonitrobenzenes at a relatively low temperature and without removing by-product water during the reaction, and produced aminodiphenyl ethers in good yields and industrially. As a result of studies to produce the above, it was discovered that the above object could be achieved by carrying out the reaction in a specific reaction medium while adding a specific alkali compound to the reaction system, leading to the present invention.

That is, the present invention provides aminodiphenyl ethers characterized by subjecting aminophenols and halonitrobenzenes to a condensation reaction in a mixed solvent of N-methyl-2-pyrrolidone and water while adding an alkali metal hydroxide. It provides a manufacturing method.

The aminophenols used in the present invention include p-aminophenol, m-aminophenol, 0-aminophenol,
Examples include aminophenol or amino lower alkylphenol in which the benzene nuclear hydrogen is substituted with a lower alkyl group such as a methyl group or an ethyl group, and p-aminophenol or m-aminophenol is preferably used.

Examples of halonitrobenzenes include p-chloronitrobenzene, chlornitrobenzenes such as 0-chlornitrobenzene, bromonitrobenzenes such as p-bromonitrobenzene and O-bromonitrobenzene, and fluoronitrobenzenes such as p-fluoronitrobenzene and 0-fluoronitrobenzene. p-iodonitrobenzene,
Iodonitrobenzenes such as O-iodonitrobenzene or heronitrolower alkylbenzenes in which the benzene nuclear hydrogen is substituted with a lower alkyl group such as a methyl group or an ethyl group are used. The amount of halonitrobenzene used in this reaction is usually 0.5 to 8 moles, preferably 0.9 to 1.1 times, more preferably 0.5 to 8 moles, more preferably 0.9 to 1.1 moles, relative to the aminophenols. 95
~1.05 mole times.

A mixed solvent of N-methyl-2-pyrrolidone and water is used as the reaction medium. Generally, N-methyl-2-pyrrolidone has strong hygroscopicity and is difficult to maintain in a dry state, but since the present invention uses N-methyl-2-pyrrolidone containing water, it is not necessary to dry it. Therefore, the recovered N-methyl-2-pyrrolidone can be easily reused.

In this mixed solvent, the moisture content is preferably 20% by weight or less.

This water may be contained in N-methyl-2-pyrrolidone in advance, or may enter the reaction system along with the alkali metal hydroxide described below, or both may be present.

The amount of the mixed solvent to be used may vary depending on the solubility of the reaction raw materials, aminophenols and halonitrobenzenes, in the i-combination medium, but is generally 1 to 15 times the amount of aminophenols, preferably It is 2 to 10 times the weight, more preferably 8 to 5 times the weight.

The method of the present invention is carried out by reacting in the above mixed solvent while adding an alkali metal hydroxide.

Here, examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, etc., and the amount used is usually more than the stoichiometric amount and less than 1.1 times the mole of the halonitrobenzene, preferably 1 to 1. 08 mole times.゛If the amount of alkali metal hydroxide used exceeds 1.1 times the mole of halonitrobenzene, a large amount of azoxy compounds with nitro groups reacted will be produced as by-products, and the yield and purity of the target product will tend to decrease. be.

The reaction temperature varies depending on conditions such as the type of halonitrobenzene used, the type of mixed solvent, and the amount used, but is usually in the range of 50 to 90°C.

The reaction time varies depending on the reaction temperature, the type of reaction raw materials, etc., but is usually in the range of 1 to 15 hours, preferably 8 to 15 hours.
The range is 8 hours. Unnecessary prolongation of reaction time is undesirable since it increases side reactions and reduces yield and purity.

As described above, in the present invention, aminophenols and tohalonitrobenzenes are reacted in the mixed solvent while adding an alkali metal hydroxide, but adding the alkali metal hydroxide all at once causes an exothermic reaction. As a result, the temperature inside the system tends to rise rapidly, which tends to increase undesirable side reactions. Therefore, it is preferable to gradually add the compound continuously or intermittently.

The reaction method may be batch, semi-batch or continuous.

It is also effective to carry out the reaction under an atmosphere of an inert gas such as nitrogen or in an air stream.

In the reaction solution produced by the method of the present invention, inorganic salts that are usually produced as a result of the reaction are precipitated, so after removing the inorganic salts by filtration etc., the solvent is removed and recovered by distillation etc. The desired aminodiphenyl ethers are obtained.

Alternatively, after recovering the solvent from the reaction solution by an operation such as distillation, it can be poured into a large amount of water, and the solvent can be obtained by filtration or branching operation.

Of course, the present invention is not limited to the method described above for removing the target product from the reaction solution.

Thus, according to the method of the present invention, aminodiphenyl ethers can be obtained industrially and easily in high yields, and this can be led to diaminodiphenyl ether by reduction, for example, and can be used as a raw material for various compounds. Ru.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way.

In the examples, parts and % represent parts by weight and % by weight, respectively.

Example 1 450 parts of N-methyl-2-pyrrolidone and 9 parts of water were charged into a 114-bottle flask equipped with a stirrer, a thermometer, and a water-cooled tube, and 109 parts of m-aminophenol and 154 parts of p-chloronitrobenzene ( After adding 0.98 mol times), the temperature was raised to 80°C. Subsequently, 40 parts (1 mole) of sodium hydroxide powder was added over a period of 8 hours. After the addition was completed, the mixture was kept at the same temperature for an additional hour.

After the reaction was completed, the reaction solution was neutralized, and the precipitated sodium chloride was removed from door to door. The Oki liquid was flash distilled to remove N-methyl-2-pyrrolidone and water, resulting in 3-amino-4'
- 280 parts of nitrodiphenyl ether (contains 196% ff)
) I got it.

The yield was 96% based on m-aminophenol.

Example 2 A reaction was carried out in the same manner as in Example 1 except that 24 parts of water was used instead of 9 parts of water in Example 1.

After the reaction was completed, the reaction solution was neutralized and heated under reduced pressure of 500 to 150 million yen.
N-methyl-2-pyrrolidone and water were distilled off while raising the internal temperature to 0°C.

After the pressure inside the system was returned to normal, it was cooled to 80°C, 450 parts of water was added, and after stirring for 30 minutes, the mixture was separated to obtain 245 parts of an oil layer.

The amount of 3-amino-4'-nitrodiphenyl ether in Oil M was 89%, and the yield based on m-aminophenol was 95%.

Example 3 The reaction and post-treatment were carried out in the same manner as in Example 1, except that 66 parts (1 mole) of potassium hydroxide with a content of 85% was used instead of 40 parts of sodium hydroxide powder in Example 1, and 8-amino -4'-nitrodiphenyl ether 237 parts (including n9
8%＞woxt:. The yield based on m-aminophenol was 96%.

Example 4 The reaction and post-treatment were carried out in the same manner as in Example 1 except that p-aminophenol was used instead of m-7 minophenol.
-amino-4'-nitrodiphenyl ether 228
m (containing ffl 95%) was obtained. The yield based on p-aminophenol was 94%.

Comparative Example I The reaction was carried out in the same manner as in Example 1 except that dimethylformamide was used instead of N-methyl-2-pyrrolidone.

After the reaction was completed, the reaction solution was analyzed and found to be p-nitrophenol, which is a hydrolyzate of p-chloronitrobenzene, a decomposition product of dimethylformamide, and N, which is a reaction product of dimethylamine and parachloronitrobenzene.

A large amount of N-dimethyl-paranitroaniline is produced as a by-product, and 3
-The yield of amino-4'-nitrodiphenyl ether is
It was less than 40 Solo with respect to m-aminophenol.

Claims (1)

[Claims] A method for producing aminodiphenyl ethers, which comprises carrying out a condensation reaction of aminophenols and halonitrobenzenes in a mixed solvent of N-methyl-2-pyrrolidone and water while adding an alkali metal hydroxide.