JP2898553B2 - Method for producing 3-aminophenol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing aminophenol from an aromatic nitro compound. More specifically, the present invention relates to a novel method for producing 3-aminophenol from 1,3-dinitrobenzene.

[0002]

2. Description of the Related Art As a method for producing 3-aminophenol (meta-aminophenol), a method of sulfonation, reduction and alkali melting using nitrobenzene as a starting material has been known for a long time. However, since this method uses a large amount of a strong acid or a strong base, there is a danger of environmental pollution due to wastewater or waste, corrosion of the production equipment, and even explosion, and there are some environmental problems.

On the other hand, a method for producing 3-aminophenol by a half-amination reaction of a liquid phase using resorcin as a starting material has been proposed, and the development of a selective catalyst used in this method has been reported ["Petroleum". Journal, 35, P3
67-375 (1992)]. However, the raw material resorcinol is obtained by the so-called cumene method, which is a general method for synthesizing aromatic phenols, but in order to obtain resorcinol, a multi-step process is required from benzene and propylene. It is not always economical even on an industrial scale because it involves by-products such as acetone and acetone.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel method for producing -aminophenol using an aromatic nitro compound easily supplied industrially.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on such problems, and as a result, have found a new reaction method for producing 3-aminophenol in good yield from 1,3-dinitrobenzene as a starting material. They have found and completed the present invention.

That is, the present invention provides a method for reacting 1,3-dinitrobenzene with an alkali in a specific solvent and then neutralizing the reaction product and then reducing it with hydrogen, or neutralizing the product after reducing it with hydrogen. , 3-aminophenol.

[0007] The 1,3-dinitrobenzene used as a starting material in the process of the present invention is a compound which can be easily produced at an advantageous regioselectivity by the nitration reaction of nitrobenzene and can be obtained at a low cost.

[0008] Examples of the alkali used in the method of the present invention include hydroxides and carbonates of alkali metals or alkaline earth metals. Specifically, for example, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, lithium hydroxide, lithium carbonate, magnesium hydroxide, calcium hydroxide, etc. They can be used alone or in the form of a mixture of two or more. In the method of the present invention, one or two kinds of sodium hydroxide or potassium hydroxide are preferably used from the viewpoint of emphasis on economy, and particularly, sodium hydroxide has a high reaction yield. preferable. The amount of alkali used in the reaction is usually at least equivalent, preferably 2 to 3 equivalents to 1,3-dinitrobenzene. Although it depends on the strength of the alkali and the reaction conditions, if it is more than 3 equivalents, a side reaction may occur, which is not economically preferable.

The solvent used in the reaction with an alkali in the method of the present invention may be an aprotic polar organic solvent. Such solvents include N, N-dimethylformamide, N, N-dimethylacetamide, N
-Methyl-2-pyrrolidone, N, N'-dimethylimidazolidinone (1,3-dimethylimidazolidinone),
N, N, N ', N'-tetramethylurea (1,1,
3,3-tetramethylurea), 1,3-dimethyl-
3,4,5,6-tetrahydropyrimidinone, dimethylsulfoxide, sulfolane, hexamethylphosphoramide and the like. Among these solvents, polar aprotic urea compounds such as 1,3-dimethylimidazolidinone and 1,1,3,3-tetramethylurea exhibit excellent effects such as suppressing side reactions. Is preferred.

In the method of the present invention, the reaction between 1,3-dinitrobenzene and an alkali in the above-mentioned solvent is preferably carried out in the presence of a small amount of water. Due to the presence of water, not only is the reaction efficiently performed in a state where the alkali is dissolved, but also the conversion of 1,3-dinitrobenzene to a 3-nitrophenol derivative which is considered to be an intermediate is promoted with high selectivity. is there. The amount of water preferably used depends on the type of alkali or solvent used,
The weight ratio to the alkali used is in the range of 0.5 to 5. If the amount of water is less than this range, the effect is small, and if it exceeds this range, the reaction speed may be slow, which is not preferable.

Further, in the reaction between 1,3-dinitrobenzene and an alkali, for the purpose of suppressing a side reaction,
A small amount of amines or sulfonic acids may be added in the range of about 1 to 10 mol% based on 3-dinitrobenzene.

Specific examples of such additives which are particularly effective include, for example, hydroxylamine (or a salt thereof), sulfamic acid, paratoluenesulfonic acid,
Examples thereof include, but are not limited to, trifluoromethanesulfonic acid.

In the method of the present invention, 1,3-dinitrobenzene is reacted with an alkali in the above-mentioned solvent and then neutralized and then catalytically reduced with hydrogen, or catalytically reduced with hydrogen before neutralizing and then neutralized. By summing, the desired 3-aminophenol can be obtained.

In this case, it is preferable that the first reaction of 1,3-dinitrobenzene with an alkali in a solvent is carried out at a relatively elevated temperature. That is, the preferred temperature is in the range of 80 to 180 ° C, and more preferably in the range of 90 to 150 ° C. If the reaction temperature is low,
A large amount of by-products such as 2,4-dinitrophenol may be formed, which is not preferable. When the reaction is performed at a high temperature exceeding the above range, 3,3′-azooxybenzene,
3,3'-azobenzene and furthermore, these higher-order reductive condensation reactions are not preferable because they may occur remarkably. The reaction time varies depending on the reaction temperature, the kind of the alkali and the solvent used, and furthermore, the stirring speed, the reaction device and the type, etc.
The reaction is usually carried out in a range of several minutes to several hours, preferably in a range of 30 minutes to 3 hours depending on the selection of reaction conditions.

As a method for producing the desired 3-aminophenol from the reaction product (intermediate) obtained under the above conditions, a general method of catalytic reduction is employed.

This reduction reaction can be carried out in the solvent used in the reaction between 1,3-dinitrobenzene and an alkali, which is simpler. Other solvents used for the reduction can be used.

Examples of such a solvent include water, methanol, ethanol, isopropanol, isobutanol, methyl cellosolve, ethyl cellosolve, ethylene glycol,
Alcohols such as propylene glycol, diclime, dioxane and tetrahydrofuran, glycols and ethers are used, but hexane, cyclohexane,
Aliphatic or aromatic, hydrocarbons, esters such as benzene, toluene, ethyl acetate, butyl acetate, dichloromethane, chloroform, 1,1,2-trichloroethane,
Halogenated hydrocarbons can also be used. These solvents may be used alone or as a mixture of two or more.

As the reduction catalyst, a reduction catalyst generally used for reduction with hydrogen, for example, palladium, platinum, rhodium, ruthenium, Raney cobalt, Raney nickel,
Copper, iron, etc. can be used. These catalysts can be used in the form of metal, but usually those supported on a carrier such as alumina, silica gel, carbon and barium sulfate are used. Among these, those in which palladium or platinum is supported on carbon are preferred when used industrially. The use amount of these catalysts is suitably in the range of 0.01 to 20% by weight as a metal based on the substance to be reduced. The reaction temperature is usually in the range of 0 to 150 ° C, preferably 20 to 10 ° C.
0 ° C. The pressure of hydrogen is from normal pressure to 50 kg /
usually carried out in cm ^2.

In this case, after the reaction of 1,3-dinitrobenzene with alkali, the reaction product may be subjected to a reduction reaction without neutralization, but the reaction product may be subjected to hydrochloric acid, sulfuric acid or phosphoric acid. After a predetermined amount of a mineral acid such as acetic acid or benzenesulfonic acid or the like is added and neutralized, a reduction reaction may be performed.

As described above, in the method of the present invention, first, a first stage in which 1,3-dinitrobenzene and an alkali are reacted in a solvent, and then a second stage in which a catalytic reduction reaction with hydrogen is carried out. Done in stages. Upon completion of the first-stage reaction, when the reaction proceeds to the second-stage reaction, the reaction solvent is distilled off from the reaction mixture as necessary, replaced with a solvent for the reduction reaction, a catalyst is added, and hydrogen is added. To perform the second-stage reduction reaction under normal pressure or under pressure. In this case, the above-mentioned acid may be added to the reaction system before the reduction reaction, that is, after the first-stage reaction, to neutralize the reaction system. You may add up. In any method, after separating the catalyst and the like, it can be isolated as free 3-aminophenol by a method such as distillation which is usually performed. In the simplest case, the same reaction vessel is used, the first-stage reaction solvent is used as it is, and after the completion of the first-stage reaction, the second-stage reaction is carried out without intermediate treatment such as neutralization. It can also be carried out subsequently to the eye reduction reaction.

Thus, according to the method of the present invention, (1) 1,
After the 3-dinitrobenzene is reacted with an alkali in a solvent and then catalytically reduced with hydrogen, the reaction product is neutralized with an acid, or (2) 1,3-dinitrobenzene is reacted with an alkali in a solvent. Then, after neutralization with hydrogen, a method of reducing the reaction product with hydrogen can be adopted, and in any case, the desired product can be obtained with a high yield.

[0022]

According to the method of the present invention as described above, 1,3-dinitrobenzene which is easily available is industrially advantageously used.
An aminophenol can be produced;

The 3-aminophenol obtained by the method of the present invention can be used not only as a raw material for dyes (for example, heat-sensitive dyes) and pigments, but also as a raw material for producing pharmaceuticals and agricultural chemicals, and as a heat-resistant polymer monomer, particularly polyamide and polyimide. It is also useful as an intermediate of a compound as a raw material.

[0024]

The present invention will be described in more detail with reference to the following examples. However, these examples are for describing specific examples of the present invention, and the present invention is not limited thereto.

Example 1 4.3 g (0.107 mol) of sodium hydroxide (caustic soda) was dissolved in 12 ml of water and mixed in a 200 ml flask in 80 ml of dimethylimidazolidinone (DMI). The temperature was raised to ° C and stirred. Then, 1,3-dinitrobenzene (MD
NB) (8.4 g, 0.05 mol) was dissolved in DMI (20 ml) and added dropwise over about 35 minutes, followed by stirring for 1 hour while maintaining the temperature as it was in a nitrogen stream. Then, the solvent D under reduced pressure
MI was distilled off, the residue was transferred to a hydrogenation reactor using about 100 ml of ethanol, and 500 mg of 5% Pd / C was added.
In addition, at room temperature, H ₂ initial pressure of 10 atm, H ₂ reduced by absorption
The hydrogen reduction reaction was performed while supplementing the pressure. The absorption of hydrogen stopped in about 2 hours. The reaction mixture was washed with 4N hydrochloric acid using P
After neutralization to around H = 7, gas chromatography (G
As a result of quantitative analysis using C), it was found that 4.6 g (yield 84%) of 3-aminophenol was obtained.

Example 2 A mixture comprising 80 ml of dimethylimidazolidinone (DMI), 4.3 g (0.107 mol) of sodium hydroxide (caustic soda) and 12 ml of water was reacted at 125 ° C. in the same manner as in Example 1. And then 1,3-dinitrobenzene (MDNB) is added to D
The solution dissolved in 20 ml of MI was dropped over about 50 minutes. After the completion of the dropwise addition, the reaction is carried out for 1 hour.
Transfer the contents directly to a 500 ml autoclave,
% Of Pd / C was added 500 mg, H ₂ initial pressure 10k at room temperature
The hydrogen reduction reaction was performed while replenishing hydrogen at g / cm ² . 2
After stirring for a period of time to stop the absorption of hydrogen, the mixture was similarly neutralized with 4N hydrochloric acid to around PH = 7 and quantitatively analyzed by GC. As a result, 4.7 g (yield 86%) of 3-aminophenol was produced. I knew I was doing it.

Example 3 In the same reaction as in Example 2, dimethylimidazolidinone (DM
80 ml of tetramethylurea (TMU) instead of I)
Was used to carry out a similar reaction. In this case, after completion of the dropping of 1,3-dinitrobenzene (MDNB) in the first-stage reaction, 4
The reaction was completed by stirring for a period of time. Next, the reaction mixture was transferred to a 500 ml autoclave without changing the solvent as it was, and a hydrogen reduction reaction was similarly performed. 3.4 g as a result
(62% yield) of 3-aminophenol was obtained.

Example 4 The same reaction as in Example 1 was carried out except that 6.6 g (0.1 mol) of 85% pure potassium hydroxide was used instead of sodium hydroxide. As a result, 2.9 g (yield 53%) of 3-aminophenol was obtained.

Example 5 As in Example 1, 4.4 g of sodium hydroxide (caustic soda), 12 ml of water, DMI
80 ml of the mixture was heated to 130 ° C., and then 8.4 g of 1,3-dinitrobenzene and 9% of sulfamic acid were added thereto.
What melt | dissolved 7 mg in DMI20ml was dripped. The reaction treatment was carried out in the same manner as in Example 1, and the resultant was subjected to hydrogen reduction and analyzed.
%) Was formed.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-271105 (JP, A) JP-A-53-65833 (JP, A) JP-A-50-142525 (JP, A) JP-A 63-658 280046 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C07C 213/02 C07C 215/76

Claims (8)

(57) [Claims] 1. A process for producing 3-aminophenol, comprising reacting 1,3-dinitrobenzene with an alkali in a solvent, catalytically reducing with hydrogen, and then neutralizing. 2. A process for producing 3-aminophenol, comprising reacting 1,3-dinitrobenzene with an alkali in a solvent, neutralizing the resultant, and then catalytically reducing the resulting product with hydrogen. 3. The method for producing 3-aminophenol according to claim 1, wherein a polar aprotic solvent is used as a reaction solvent between 1,3-dinitrobenzene and an alkali. 4. The process for producing 3-aminophenol according to claim 3, wherein a polar aprotic urea compound is used as a reaction solvent between 1,3-dinitrobenzene and an alkali. 5. As a polar aprotic urea compound,
N, N′-dimethylimidazolidinone or N, N,
The method for producing 3-aminophenol according to claim 4, wherein N ', N'-tetramethylurea is used. 6. The method for producing 3-aminophenol according to claim 1, wherein one or a mixture of two or more selected from sodium hydroxide and potassium hydroxide is used as the alkali. 7. The process for producing 3-aminophenol according to claim 1, wherein the reaction between 1,3-dinitrobenzene and the alkali is carried out in the presence of a small amount of water. 8. The process for producing 3-aminophenol according to claim 1, wherein a small amount of amines or sulfonic acids is added in the reaction between 1,3-dinitrobenzene and alkali. .