JPH0597781A - Method for producing alkylaminophenol - Google Patents

Abstract

(57) [Summary] [Object] To provide a method for producing an alkylaminophenol with a high selectivity and a high yield, and without causing corrosion or the like of a reactor. [Structure] The following formula (1) The aminophenols and dialkyl sulfuric acid represented by
The reaction is carried out in the absence of a solvent while maintaining the temperature of the reaction system within the range of 30 to 70 ° C. A method for producing an alkylaminophenol, which comprises producing an alkylaminophenol represented by:

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing alkylaminophenol. More specifically, it relates to a method for producing an alkylaminophenol useful as a dye for heat-sensitive paper, pressure-sensitive paper or an agrochemical intermediate at a high selectivity.

[0002]

In Japanese Patent Publication No. 62-40349, a benzene-based amine having a primary or secondary amino group is treated with a dialkyl sulfuric acid in a water solvent in the presence of magnesium oxide or magnesium hydroxide. ~ 100 ° C
At a temperature of 1, to alkylate the primary or secondary amino group to produce a benzene-based amine having a secondary or tertiary amino group.

In Japanese Patent Publication No. 62-40350, similarly, a benzene amine having a primary or secondary amino group is used as an acid binder in an acetic acid water solvent using a dialkyl sulfuric acid as an alkali metal. Of the alkali metal hydroxide, alkali metal hydroxide or alkaline earth metal hydroxide of any of the above, is reacted at a temperature of 60 to 100 ° C. under a condition of pH 7 or lower to convert the primary or secondary amino group. A method for producing a benzene-based amine having a secondary or tertiary amino group by alkylation is disclosed.

In any of the above methods, since water is used as a reaction solvent, there is a problem to be solved in that the dialkyl sulfuric acid is hydrolyzed to cause corrosion of the reaction apparatus and decrease in selectivity. ..

On the other hand, when an aromatic hydrocarbon such as toluene or xylene is used as the reaction solvent, there is a problem that the yield is lowered when the target product is refined, and in the case where no solvent is used, the reaction heat is reduced. There is a problem that it is difficult to control.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a new process for producing alkylaminophenol.
Another object of the present invention is to provide a method for producing alkylaminophenol with high selectivity.

Still another object of the present invention is to provide a method for producing an alkylaminophenol with a high selectivity and a high yield without causing corrosion or the like of a reactor. Further objects and advantages of the present invention will be apparent from the following description.

[0008]

[Means for Solving the Problems] The following formula (1)

[0009]

[Chemical 3]

The aminophenols represented by and the dialkylsulfuric acid are added to the reaction system at a temperature of 30 to 70 ° C. without a solvent.
The following formula (2)

[0011]

[Chemical 4]

This is achieved by a method for producing an alkylaminophenol characterized by producing an alkylaminophenol represented by

The aminophenols used in the present invention are compounds represented by the above formula (1), and include unsubstituted aminophenols such as orthoaminophenol, metaaminophenol and paraaminophenol, and N.
Monoalkyl substitution such as -ethyl-m-aminophenol, N-methyl-m-aminophenol, Nn-butyl-m-aminophenol, N-isoamyl-m-aminophenol, N-cyclohexyl-m-aminophenol Includes aminophenols or mixtures thereof.

As the dialkyl sulfuric acid, those in which the alkyl group is a lower alkyl group having 1 to 4 carbon atoms are preferably used. Preferred examples of the dialkyl sulfuric acid include dimethyl sulfuric acid, diethyl sulfuric acid, di-n-propyl sulfuric acid, di-iso-propyl sulfuric acid, and di-n-butyl sulfuric acid.

The reaction between aminophenol and dialkylsulfuric acid must be carried out in the absence of a solvent while maintaining the temperature of the reaction system in the range of 30 to 70 ° C. That is, according to the study of the present inventor, as long as the temperature of the reaction system is maintained in the range of 30 to 70 ° C., alkylaminophenol can be obtained in a high selectivity and a high yield in the absence of the reaction solvent. It was revealed that it can be generated. The preferred reaction temperature is between 45 and 55 ° C.

In order to maintain the temperature of the reaction system within the range of 30 to 70 ° C., for example, a reaction vessel is charged with a predetermined amount of dialkyl sulfuric acid, and aminophenols are gradually or continuously added thereto. The method of adding while tracking the temperature is preferably carried out.

When a monoalkylaminophenol is used as a starting material for the dialkylaminophenol as the alkylaminophenol, the dialkyl sulfuric acid is preferably 0.8 per mol of the monoalkylaminophenol.
It is desirable to use it in a ratio of about 2.0 mol, more preferably 1.0 to 1.2 mol. Further, in the case of producing a dialkylaminophenol from an alkylaminophenol having no alkyl group as a raw material, the dialkyl sulfuric acid is preferably 1.8 per mol of the aminophenol.
It is desirable to use it in an amount of ˜4.0 mol, more preferably 2.0˜2.2 mol. After completion of the reaction, the desired product forming a salt with monoalkyl sulfuric acid is hydrolyzed with a basic compound to give the desired product in a free base form.

Examples of the basic compound include sodium carbonate,
Weakly basic compounds such as sodium bicarbonate and potassium carbonate are advantageously used in the form of aqueous solutions. It is desirable that the aqueous solution of the basic compound is gradually and continuously added to the reaction system after the reaction.

Thereafter, when the reaction solution is allowed to stand still, the alkali salt of monoalkylsulfate is separated into an aqueous phase and the alkylaminophenol is separated into an oil phase. The oil layer is usually 96% for the purpose of producing dialkylaminophenol, for example.
It contains the above alkylaminophenol.

When it is desired to further obtain alkylaminophenol with high purity from this oil layer, the aminophenol having a purity of, for example, 99% or more can be obtained by subjecting it to a purification method known per se, such as distillation or recrystallization. Obtainable.

[0021]

The present invention will be described in more detail with reference to the following examples. Example 1 (1) After thoroughly replacing the inside of the glass reaction vessel with nitrogen,
Diethylsulfuric acid 160.4 g (1.04 mol) was charged and the temperature was raised to 50 ° C. with stirring (the reaction temperature was 5 until completion of the reaction).
Maintained at 0 ° C). With stirring, 54.5 g (0.5 mol) of meta-aminophenol was continuously fed over 2 hours. It was easy to control the heat of reaction by continuously supplying meta-aminophenol. 2 more after-reactions
Stirring was continued for hours.

(2) Next, 386.1 g (1.02 mol) of a 28 wt% sodium carbonate aqueous solution was continuously supplied over 2 hours. It was easy to generate carbon dioxide and control the reaction temperature by continuously supplying the sodium carbonate aqueous solution.
After the post-reaction was further performed for 1 hour, the mixture was cooled and allowed to stand, and oil-water separation was performed.

When a portion of the oil layer was taken and analyzed by gas chromatography (hereinafter abbreviated as GC), its composition was as shown in Table 1.

[0024]

[Table 1]

(3) Oil-water The separated oil layer was heated to 50 ° C., and then stirred, 50 g of methanol and 50 g of water were added and gradually cooled. After cooling to 15 ° C. and solid-liquid separation, the solid content was dried. The solid content after drying was 76.9 g.
A part of the solid content was collected and analyzed by GC. The results are shown in Table 2.

[0026]

[Table 2]

From the above results, the total yield from reaction to purification was 93 mol%.

Example 2 (1) The same operation as in Examples 1 (1) and (2) except that the diethyl sulfate in Example 1 (1) was replaced with 131.1 g (1.04 mol) of dimethyl sulfate. When a part of the oil layer was collected and analyzed, the results shown in Table 3 were obtained.

[0029]

[Table 3]

(2) The same purification operation as in Example 1 (3) was carried out to obtain 64.4 g of a solid content after drying. When the solid content was analyzed by GC, it was as shown in Table 4.

[0031]

[Table 4]

From the above results, the total yield from reaction to purification was 93.8 mol%.

Comparative Example 1 After thoroughly replacing the inside of a glass reaction vessel with nitrogen, 54.5 g (0.5 mol) of meta-aminophenol water (50 g) was charged and the temperature was raised to 50 ° C. with stirring. The reaction temperature was maintained at 50 ° C. until the end of the reaction. Diethyl sulfate 1 with stirring
60.4 g (1.04 mol) and 386.1 g (1.02 mol) of 28% aqueous sodium carbonate solution were continuously fed simultaneously over 2 hours. After the post-reaction was carried out for 1 hour, the mixture was cooled and allowed to stand, and oil-water was separated.

A part of the oil layer was taken and analyzed by GC. The composition was as shown in Table 5.

[0035]

[Table 5]

Comparative Example 2 After thoroughly purging the inside of a glass reaction vessel with nitrogen, 54.5 g (0.5 mol) of metaaminophenol and 160.4 g (1.02 mol) of diethyl sulfuric acid were charged and gradually stirred. The temperature was raised. However, a rapid reaction occurred immediately after reaching 45 ° C, and the reaction temperature rapidly increased to 135 ° C in 4 minutes. This method was interrupted because it was difficult to control the reaction temperature.

Example 3 N-ethyl-m-aminophenol (hereinafter referred to as "NEMAP") was added to 0.10 mol of diethylsulfate.
10 mol were added at 50 ° C. under stirring in 45 minutes. Furthermore,
The reaction was carried out at 50 ° C for 9 hours. Then, 0.10 mol of NH ₄ HCO ₃ (solid) was added, and the mixture was reacted at 50 ° C. for 1 hour.

After that, 50 ml of water and 15 ml of toluene were added, and the organic layer separated from the oil and water was concentrated.
16.88 g of 1.2% N, N-diethyl-m-aminophenol (hereinafter referred to as "DEMAP") was obtained.
NEMAP conversion 99.7%, DEMAP yield 93.
It was 3%. Table 6 shows the analysis results during the reaction up to 9 hours.

[0039]

[Table 6]

[0040]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michio Tanaka 6-2, Waki, Waki-cho, Kuga-gun, Yamaguchi Mitsui Petrochemical Industry Co., Ltd.

Claims (1)

[Claims] 1. The following formula (1): The aminophenols and dialkyl sulfuric acid represented by
The reaction is carried out in the absence of a solvent while maintaining the temperature of the reaction system in the range of 30 to 70 ° C., and the reaction is carried out by the following formula (2): A method for producing an alkylaminophenol, which comprises producing an alkylaminophenol represented by: