JP2928730B2 - Nitrophenol production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing 3-nitrophenol. More particularly, the present invention relates to a novel method for producing 3-nitrophenol from 1,3-dinitrobenzene.

[0002]

2. Description of the Related Art Conventionally, among nitrophenols, 1-nitrophenol and 4-nitrophenol have been produced on an industrial scale by nitration of phenol.
On the other hand, 3-nitrophenol (m-nitrophenol)
Is a very important compound as a raw material or intermediate of agricultural chemicals, pharmaceuticals, dyes and monomers of heat-resistant polymers.
As a method for producing 3-nitrophenol, 3-nitrobenzenesulfonic acid can be synthesized by diazotizing 3-nitroaniline and then hydrolyzing, in addition to a method conventionally used for melting 3-nitrobenzenesulfonic acid from 3-nitrobenzenesulfonic acid (Org. S
yn. Coll. Vol. 1 404 (1947)), 3-
A method of hydrolyzing an alkyl ether of nitrophenol (JP-A-59-157059) and a method of hydroxylating nitrobenzene with hydrogen peroxide are known.

[0003] However, all of these methods are rather complicated and require multiple steps. For example, in the method via 3-nitroaniline, the starting material 3-nitroaniline must be produced by a method such as half-reduction of 1,3-dinitrobenzene, and in the hydrolysis following the diazotization reaction, There is also the problem of corrosiveness due to the use of strong acids such as sulfuric acid.

[0004] As for the method via 3-nitrophenol alkyl ether, some methods for producing alcohol by reacting 1,3-dinitrobenzene with alcohol have been proposed (JP-A-58-180461). JP-A-59-44343, JP-A-61-238768.
), The reaction is also complicated, and the hydrolysis of the alkyl ether of 3-nitrophenol involves the problem of corrosiveness due to the use of a strong acid as in the above-mentioned method, and the need to recover and circulate the alcohol. However, this is not industrially advantageous.

[0005] In addition, the hydroxylation reaction of nitrobenzene with hydrogen peroxide also has insufficient regioselectivity, poor yield, and risks of explosion. Thus, despite the usefulness of 3-nitrophenol as a chemical, no industrially advantageous process for producing 3-nitrophenol has been known so far.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel method for producing such 3-nitrophenol in an industrially advantageous manner.

[0007]

Means for Solving the Problems The present inventors have prepared 1,3-
As a result of a detailed study of the reaction of dinitrobenzene with an alkali, the present inventors have found an industrially advantageous production method of 3-nitrophenol which does not have the disadvantages of the prior art, and reached the present invention.

That is, the present invention is a novel method for producing 3-nitrophenol by reacting 1,3-dinitrobenzene with an alkali in a solvent.

In the process of the present invention, 1,3-dinitrobenzene is used as a main raw material, which can be advantageously produced regioselectively by dinitration of benzene or nitration reaction of nitrobenzene, and is easy on an industrial scale. It can be obtained at low cost.

In the method of the present invention, an aprotic polar organic solvent is used as a reaction solvent. Such solvents include, for example, N, N-dimethylformamide, N, N
-Dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, 1,1,3,
3-tetramethylurea, 1,3-dimethyl-3,4,
5,6-tetrahydropyrimidinone, dimethylsulfoxide, sulfolane, hexamethylphosphoramide and the like. Among these solvents, N, N-dimethylformamide, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone and 1,1,3,3-tetramethylurea show excellent effects, Polar aprotic urea compounds such as 1,3-dimethylimidazolidinone and 1,1,3,3-tetramethylurea are preferred.

The alkali used for the reaction with 1,3-dinitrobenzene in the method of the present invention includes hydroxides and carbonates of alkali metals or alkaline earth metals. Specifically, for example, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium hydroxide,
Examples include potassium carbonate, potassium hydrogen carbonate, lithium hydroxide, lithium carbonate, magnesium hydroxide, calcium hydroxide and the like, and these can be used alone or in the form of a mixture of two or more. In the method of the present invention, sodium hydroxide (caustic soda) or potassium hydroxide (caustic potash) is preferably used from the viewpoint of emphasis on economy. The amount of the alkali used is 1,
It is usually used in an amount of at least equivalent, preferably at least 2 equivalents to 3-dinitrobenzene. Although it depends on the strength of the alkali and the reaction conditions, use of more than 3 equivalents may cause a side reaction, and is not economically preferable.

In the method of the present invention, nitrophenol is produced by reacting 1,3-dinitrobenzene with an alkali in the above-mentioned solvent, followed by neutralization. The reaction can be carried out at a temperature as low as about room temperature, but at such a temperature, the reaction is slow and a long time is required until the reaction is completed. Therefore, the heating is usually performed at a temperature higher than room temperature. A preferred range of the reaction temperature is 50 ° C to 150 ° C. If the temperature is lower than 50 ° C., the reaction is slow, and the reaction requires a long time. If the temperature is higher than 150 ° C., undesired side reactions may occur. A particularly preferred temperature range is from 100C to 140C.

In the method of the present invention, undesirable side reactions such as formation of 3,3'-dinitrodiphenyl ether and formation of 3,3'-dinitroazobenzene are caused by carrying out the reaction in the presence of a small amount of water in the reaction system. May be suppressed. The amount of water preferably used varies depending on the type of alkali or solvent used, but it is in the range of 0.5 to 5 in weight ratio to the alkali used. Below this range, there is almost no effect. If it exceeds, the rate of the reaction is undesirably reduced. Thus, it is not necessary to remove the stoichiometric amount of water produced by the reaction. When the alkali is used for the reaction, the reaction may be carried out with the water present in the system even when the alkali is charged in the state of an aqueous solution. Further, using a solvent such as benzene, toluene, or xylene which is inert to the reaction, the amount of water can be appropriately controlled at the same time as controlling the reaction temperature by reflux.

In order to suppress side reactions in the reaction between 1,3-dinitrobenzene and alkali, 1,3
A small amount of amines or sulfonic acids may be added in the range of about 1 to 10 mol% based on dinitrobenzene. Specific examples of such additives that are particularly effective include, but are not limited to, hydroxyamine (or a salt thereof), sulfamic acid, paratoluenesulfonic acid, and trifluoromethanesulfonic acid.

It is considered that the reaction in the method of the present invention proceeds according to the stoichiometric formula shown below.

[0016]

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Further, in order to isolate as free 3-nitrophenol from the reaction product, it is necessary to treat with a suitable neutralizing agent (HB) as shown below.

[0018]

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Here, the neutralizing agent is usually an inorganic acid,
For example, hydrochloric acid, sulfuric acid, nitric acid and the like are used. However, an organic acid compound having a higher acidity than 3-nitrophenol (pKa = 8.399), for example, formic acid, acetic acid, propionic acid, benzoic acid and the like may be used if necessary. Can also be used.

The 3-nitrophenol obtained by the method of the present invention as described above can be easily separated by a method known to those skilled in the art, specifically, as follows. For example, (a) a method in which a neutralizing agent is added after the completion of the reaction and 3-nitrophenol is separated simultaneously with the recovery of the reaction solvent by distillation, or (b) most of the reaction solvent is removed under reduced pressure, A method in which water or a non-polar organic solvent in which free 3-nitrophenol is not dissolved is added to the residue to cause precipitation, and a method in which water-soluble by-products are removed by washing with water or the like to separate the mixture is employed. The thus obtained 3-nitrophenol can be further purified, if necessary, by means obvious to those skilled in the art, such as recrystallization or precision distillation.

[0021]

Embodiments of the present invention will be described below in detail. The present invention is not limited by these examples.

Example 1 In a 100 ml flask,
4.2 g (0.025 mol) of 1,3-dinitrobenzene
And 1,3-dimethylimidazolidinone (DMI) 40m
and 3.2 g (0.075 mol) of 9
A solution obtained by dissolving 5% sodium hydroxide (caustic soda) in 3 ml of water was added, and the mixture was stirred at 120 ° C. for 1 hour under a nitrogen atmosphere. After completion of the reaction, the solvent was distilled off under reduced pressure, and ethyl acetate and water were added to the residue. The aqueous layer was neutralized to pH 4 with a 4N aqueous hydrochloric acid solution, and the ethyl acetate layer was extracted and separated. Separated by column chromatography. Thus 1.84 g of 3-nitrophenol were obtained. This corresponds to a yield of 53% based on the 1,3-dinitrobenzene used.

Example 2 Instead of 1,3-dimethylimidazolidinone (DMI) as a reaction solvent, 1,1,
Example 1 using 40 ml of 3,3-tetramethylurea
The reaction was carried out in the same manner as described above. As a result, 1.53 of 3-nitrophenol was obtained (44% yield).

Example 3 40 ml of 1,3-dimethylimidazolidinone (DMI) as a reaction solvent, 5.0 g of 85% potassium hydroxide (caustic potassium) as an alkali and water 5
4.2 g for 1 hour at 110 ° C. according to Example 1
Of 1,3-dinitrobenzene was reacted and treated in the same manner as in Example 1. As a result, 1.46 g of 3-nitrophenol was obtained (42% yield).

Example 4 1,3-Dimethylimidazolidinone (DM) was placed in a stainless steel flask having a capacity of 300 ml.
I) 80 ml and sodium hydroxide 4.3 g, water 12
Then, the mixture was heated to 130 ° C. 1,3-Dinitrobenzene 8.4 was added to 20 ml of DMI in a nitrogen stream while stirring.
g (0.05 mol) was slowly added dropwise. After the completion of the dropwise addition, the mixture was further stirred for 1 hour. After completion of the reaction, DMI was distilled off under reduced pressure, and 200 ml of ethyl acetate and 100 ml of water were added to the residue, and the mixture was acidified with hydrochloric acid as in Example 1 to extract and separate the ethyl acetate layer. The ethyl acetate layer was quantitatively analyzed by gas chromatography to confirm that 5.2 g of 3-nitrophenol had been produced (yield 7).
5%).

[Embodiment 5] In the same manner as in Embodiment 4, the capacity 3
160 ml of 1,3-dimethylimidazolidinone (DMI), 8.6 g of sodium hydroxide and 40 ml of water were placed in a 00 ml stainless steel flask, and the temperature was raised to 125 ° C. 16.8 g of 1,1 in 40 ml of DMI with stirring
A solution of 3-dinitrobenzene and 140 mg of hydroxylamine hydrochloride was added dropwise over about 50 minutes. After completion of the dropwise addition, the mixture was further stirred at the same temperature for 1 hour to complete the reaction. After treating in the same manner as in Example 4, the ethyl acetate layer was concentrated and distilled under reduced pressure to obtain 128 to 130 ° C / 3 mmHg.
12.2 g (crude yield 88%) was obtained. This was confirmed by gas chromatography to be 95% pure 3-nitrophenol. When the ethyl acetate layer before distillation was quantitatively analyzed by gas chromatography,
It was found that 2.7 g of 3-nitrophenol had been produced (yield: 91%).

Example 6 In the same manner as in Example 4, 1,3-dimethylimidazolidinone (DMI) was used as the reaction solvent.
The reaction was carried out at 130 ° C. for 3 hours using 1,1,3,3-tetramethylurea instead of. As a result, 4.9 g of 3-nitrophenol was obtained (yield: 71%).

[Embodiment 7] In the same manner as in Embodiment 4, the capacitance 3
A 100 ml stainless steel flask was charged with 80 ml of 1,3-dimethylimidazolidinone (DMI), 4.4 g of sodium hydroxide and 12 ml of water, and heated to 130 ° C.
While maintaining the same temperature, 8.4 g of 1 in 20 ml of DMI
What melt | dissolved 3-dinitrobenzene and 97 mg of sulfamic acid was dripped over about 35 minutes. After completion of the dropwise addition, the mixture was further stirred at the same temperature for 1 hour, treated in the same manner as in Example 4, and quantitatively analyzed by gas chromatography. As a result, it was found that 6.4 g of 3-nitrophenol was produced (yield: 92%).

Example 8 As an additive during the reaction, trifluoromethanesulfonic acid 10 was used instead of sulfamic acid.
The reaction and treatment were carried out exactly as in Example 7, except that 0 mg was used. As a result of a quantitative analysis similarly by gas chromatography, it was found that 6.1 g of 3-nitrophenol was produced (yield: 88%).

[0030]

According to the method of the present invention as described above, 3-- by using a raw material which can be easily and inexpensively obtained on an industrial scale.
Nitrophenol can be produced effectively. The 3-nitrophenol obtained by the method of the present invention is very useful as a raw material or intermediate of agricultural chemicals, pharmaceuticals, dyes, and monomers of heat-resistant polymers.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C07C 205/22 C07C 201/12

Claims (6)

(57) [Claims] 1. A process for producing 3-nitrophenol, comprising reacting 1,3-dinitrobenzene with an alkali in a solvent and then neutralizing with an acid. 2. The method according to claim 1, wherein sodium hydroxide or potassium hydroxide is used as the alkali. 3. The process according to claim 1, wherein a polar aprotic solvent is used as the solvent. 4. The method according to claim 3, wherein a polar aprotic urea compound is used as the solvent. 5. The method according to claim 4, wherein 1,3-dimethylimidazolidinone or 1,1,3,3-tetramethylurea is used as the solvent. 6. The method according to claim 1, wherein the reaction is carried out in the presence of a small amount of water.
The method according to any one of claims 1 to 5.