JPS6215072B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an improved method for producing 1-amino-4-bromoanthraquinone-2-sulfonic acid or a salt thereof.

1-Amino-4-bromoanthraquinone-2-
Sulfonic acid is an important intermediate for anthraquinone dyes and is obtained by bromination of 1-aminoanthraquinone-2-sulfonic acid.

At that time, 1-amino-2-bromanthraquinone, 1-amino-2,4-dibromanthraquinone, or 1-amino-4-bromanthraquinone (hereinafter referred to as "by-products") are produced as by-products, and the yield is is known to reduce Methods for preventing the production of these by-products are known from known literature, and can be broadly classified as follows.

One method is to salt out or neutralize 1-aminoanthraquinone-2-sulfonic acid in water to form fine crystals of the alkali metal salt of 1-aminoanthraquinone-2-sulfonic acid, which is then brominated. Among these methods, one method that can be particularly improved is a method in which bromination is carried out under weak acidity.
(West German Patent No. 2303746, Czechoslovakia Patent No.
(No. 169459) However, although this method suppresses the production of by-products, the crystal form of the alkali metal salt of 1-aminoanthraquinone-2-sulfonic acid is not appropriate (if it is not a thin needle-like crystal), or the mixing during bromination may occur. If this is not sufficient, a large amount of unreacted 1-aminoanthraquinone-2-sulfonic acid remains, resulting in a low yield of the desired product.

The other method involves brominating 1-aminoanthraquinone-2-sulfonic acid in concentrated sulfuric acid. (Ciekoslovakia Patent No. 122317) This method is based on 1-aminoanthraquinone-2
- Since the bromination is carried out with the sulfonic acid completely dissolved in the sulfuric acid, the problems of crystal formation and mixing as in the former do not occur. In order to carry out this method industrially more advantageously, 1-aminoanthraquinone is consistently converted to 1-amino-4-bromoanthraquinone-2.
- A method for obtaining sulfonic acid has been proposed. For example, a method is known in which 1-aminoanthraquinone is sulfonated in sulfuric acid containing SO ₃ and then brominated in sulfuric acid (Japanese Patent Application Laid-open No. 54-48747-9).
However, this method has the problem that excessive sulfonation and hydroxylation of 4-position bromine occur in the sulfonation step, resulting in a decrease in yield. Although these side reactions are suppressed by the addition of alkali metal sulfates, the total yield of 1-amino-4-bromoanthraquinone-2-sulfonic acid is about 83% from 1-aminoanthraquinone, which is not sufficient. do not have. Also known is a method (Japanese Patent Publication No. 30510/1983) in which 1-aminoanthraquinone is sulfonated in an inert organic solvent, extracted with sulfuric acid, and then brominated in sulfuric acid. However, according to the example, the yield of this method is 83%.
In addition, since chlorosulfonic acid is used as the sulfonating agent, there is a drawback that there are significant restrictions on the material of the equipment when post-treatment and purification steps are included.

The present inventors conducted intensive studies to overcome the above-mentioned drawbacks, and found that 1-aminoanthraquinone was treated with a sulfonating agent in an inert organic solvent, extracted with sulfuric acid, and then brominated in sulfuric acid. In producing -amino-4-bromoanthraquinone-2-sulfonic acid, sulfonation is carried out using a specific amount of sulfuric acid or fuming sulfuric acid in a specific temperature range, and during bromination, 1-aminoanthraquinone-2-sulfonic acid is produced.
The present invention was completed based on the discovery that the desired product could be obtained in good yield by using sulfuric acid or fuming sulfuric acid at a molar ratio of 8.0 to 15.0 to 2-sulfonic acid.

That is, in the present invention, 1-aminoanthraquinone is reacted with a sulfonating agent in an inert organic solvent to form 1-aminoanthraquinone-2-sulfonic acid, which is extracted with sulfuric acid and then brominated in sulfuric acid. In producing 1-amino-4-bromoanthraquinone-2-sulfonic acid or its salt, sulfonation is carried out using sulfuric acid or fuming sulfuric acid at a molar ratio of 1.0 to 1.5 to 1-aminoanthraquinone at a temperature of 160 to 190°C. 1-amino-4-bromoanthraquinone-2-sulfone, characterized in that the bromination is carried out using sulfuric acid or fuming sulfuric acid in a molar ratio of 8.0 to 15.0 to 1-aminoanthraquinone-2-sulfonic acid. This is a method for producing an acid or its salt.

The inert organic solvent used in the present invention includes 1.
Examples include aromatic halogenated hydrocarbons such as 2-dichlorobenzene, 1,2,4-trichlorobenzene, and 1,3,5-trichlorobenzene, saturated hydrocarbons such as decane, dodecane, and decalin, and nitrobenzene. . Industrially, 1,2-dichlorobenzene is preferably used, and the amount used is 1
-2 to 20 times the weight of aminoanthraquinone.

The sulfuric acid used for sulfonation is preferably 85% or more concentrated sulfuric acid or 10% or less fuming sulfuric acid, and the amount used is 1
- 1.0 to 1.5 molar ratio, preferably 1.0 to 1.1 molar ratio to aminoanthraquinone.

The reaction temperature for sulfonation is 160 to 190℃, and the water produced is either expelled with an inert gas or azeotropically refluxed with an inert organic solvent at normal pressure or reduced pressure, and condensed in the middle of the reflux line. It is preferable to separate the liquid and extract it. Alkali metal sulfates or bisulfates may be added to suppress oxidation by-products. The reaction usually completes in 2 to 20 hours.

The sulfuric acid used for sulfuric acid extraction is 90% or more concentrated sulfuric acid or
20% or less of fuming sulfuric acid is preferred, and the amount used is at least 5 molar ratio, preferably at least 6 molar ratio, based on the produced 1-aminoanthraquinone-2-sulfonic acid. The extraction temperature is below 95°C, preferably below 85°C.

The sulfuric acid concentration during bromination is 85% or more concentrated sulfuric acid or
Adjust to a range of 20% or less fuming sulfuric acid, preferably 90% or more concentrated sulfuric acid, or 10% or less fuming sulfuric acid. The amount of sulfuric acid used is 8.0 to 15.0 molar ratio, preferably 9.0 to 1-aminoanthraquinone-2-sulfonic acid.
~15 molar ratio. If the amount of sulfuric acid used is further reduced, 1-aminoanthraquinone-2-sulfonic acid will remain unreacted and the yield will decrease, which is not preferable. Further, the use of sulfuric acid in a molar ratio of 15 or more does not hinder the reaction, but is not economical.

Brominating agents include bromine or alkali metal bromides such as sodium or potassium bromide, or hydrogen bromide. Bromine is particularly preferably used industrially, and the amount used is 0.5-1.3 molar ratio, preferably 0.5-1.0 molar ratio to 1-aminoanthraquinone-2-sulfonic acid. The reaction temperature for bromination is 75℃-110℃, preferably 80℃-105℃
It is. It is preferable to add the brominating agent gradually at the reaction temperature. During the reaction, a conventional halogenation catalyst such as iodine may be added. Also, pyridine,
Nitrogen-containing heterocyclic bases such as quinoline are also effective. Reaction time is usually 2-24 hours.

Post-treatment and purification steps after completion of the reaction can be carried out by methods known per se, for example, as follows.

After the reaction is complete, excess bromine is removed and the reaction mixture is diluted with water to dissolve 1-amino-4-bromoanthraquinone-2-sulfonic acid in the aqueous layer. Then, a slight water-insoluble by-product is removed by filtering or extraction with an inert organic solvent.
Alternatively, when diluting with water, by adding an inert organic solvent, most of the sulfuric acid used can be extracted and recovered into the aqueous layer, and the organic solvent layer containing the target product can be diluted.
By-products may be removed by liquid separation. This method is advantageous because the amount of subsequent treatment liquid is further reduced.

Next, add alkali to the resulting aqueous layer to adjust the concentration of Glauber's salt to an appropriate concentration, and separate the precipitated crystals.
A highly pure target product containing almost no by-products can be obtained.

According to the method of the present invention, the yield of the target product is much higher than any method described in known literature, and the industrial value of the present invention is high.

Next, the present invention will be explained in more detail with reference to Examples. In the text, parts represent parts by weight, and % represents weight %.

Example 1 1200 parts of 1,2-dichlorobenzene with purity of 98.2%
101.8 parts of 1-aminoanthraquinone was suspended, and then 1.2 parts of sodium bisulfate was added. After 47.0 parts of 98% sulfuric acid was added dropwise at 100-110°C with stirring, the mixture was heated to 180°C and kept at 180-182°C for 8 hours. During this time, produced water was removed from the system by azeotropy. Chromatography showed that the starting material had almost completely disappeared. After the reaction was completed, the mixture was cooled to 70°C, 470 parts of 98% sulfuric acid was added, and after stirring at 70°C for 30 minutes, the mixture was allowed to stand still for liquid separation.

55.6 parts of bromine was added to the obtained sulfuric acid layer over 3 hours.
It was added dropwise at a temperature range of ~90°C. According to chromatography, the bromination reaction was completely completed. After distilling off the residual bromine under reduced pressure, the reaction mixture was poured into ice water at 9,000 ml.
The target product was dissolved at 85-90°C, and by-products were removed by heating. Next, 830 parts of a 48% sodium hydroxide aqueous solution was added dropwise to the solution at 85°C.
It was cooled to 25°C, and the precipitated crystals were separated and dried. 182.8 parts of orange crystals were obtained. The purity of 1-amino-4-bromanthraquinone-2-sulfonic acid is 89.0%
and the yield from 1-aminoanthraquinone is
It was 95.0%.

Example 2 300 parts of 1,2,4-trichlorobenzene and 1-
Suspend 24.2 parts of aminoanthraquinone (96% purity) and add 13.8 parts of 100% sulfuric acid at 100-110°C with stirring.
After dropping 100% of
It was kept warm for hours. Water generated during this time was removed from the system by blowing N ₂ gas. After the reaction is complete, cool to 80°C, add 61.2 parts of 100% sulfuric acid to 80°C.
After stirring at °C for 1 hour, the mixture was allowed to stand still for liquid separation.

To the sulfuric acid layer thus obtained, 0.2 parts of iodine was added, and 16.6 parts of bromine was added dropwise over 5 hours at a temperature of 95 to 100°C. According to chromatography, the bromination reaction was complete. After removing excess bromine under reduced pressure, 300 parts of water was added to the reaction mixture, the target product was dissolved at 90-95°C, and by-products were removed by heating. Next, add 48% sodium hydroxide aqueous solution to the liquid.
After dropping 110 parts at 80°C, the crystals were cooled to 30°C, separated, and dried. 44.3 parts of orange crystals were obtained. 1-Amino-4-bromoanthraquinone-2
- The purity of the sulfonic acid was 88.3%. The yield of 1-amino-4-bromoanthraquinone-2-sulfonic acid is calculated from 1-aminoanthraquinone.
It was 93%.

Example 3 500 parts of 1,2-dichlorobenzene with purity of 97.9%
suspending 42.5 parts of 1-aminoanthraquinone,
Additionally, 0.5 part of sodium bisulfate was added. under stirring
After dropping 21.3 parts of 90% sulfuric acid at 100-110℃,
The temperature was raised to 180°C and kept at the same temperature for 10 hours. During this time, the water produced was removed from the system by azeotropy. Chromatography showed that most of the starting material had disappeared. After the reaction is complete, cool to 50℃ and add 98% sulfuric acid.
After adding 168 parts and stirring at 50°C for 30 minutes, the mixture was allowed to stand still for liquid separation.

95 26.8 parts of bromine was added to the obtained sulfuric acid layer over 6 hours.
It was added dropwise in the temperature range of -100°C. According to chromatography, most of the starting material had disappeared and the bromination reaction had been completed. After removing residual bromine under reduced pressure, 1,2-dichlorobenzene 116 was added to the reaction mixture.
221 parts of water was added dropwise at 60° C. over 2 hours with gentle stirring. After cooling to 30°C, the mixture was allowed to stand to separate into two layers, and 266 parts of the upper layer (aqueous layer) was separated.

Next, 690 parts of water, 0.4 parts of activated carbon, and 2.2 parts of diatomaceous earth were added to the organic solvent layer, heated at 90-95°C for 2 hours, and separated after heating to obtain 118 parts of 1,2-dichlorobenzene layer. Obtained. 56 parts of 45% sodium hydroxide was added dropwise to the aqueous layer at 85°C to obtain 81.2 parts of orange crystals. 1-Amino-4-bromoanthraquinone-2
The purity of the sulfonic acid was 89.1%, and the yield calculated from 1-aminoanthraquinone was 94%.

Comparative example (method according to Japanese Patent Publication No. 55-30510) Purity 96% in 800 parts of 1,2-dichlorobenzene
104.2 parts of 1-aminoanthraquinone was suspended, and then 62.4 parts of chlorosulfonic acid was immediately added dropwise. The temperature was increased to 110°C to 115°C for 14 hours.
After cooling to below 70°C, 700 parts of 100% sulfuric acid was added, stirred, and left to separate. 1-Aminoanthraquinone-2-sulfonic acid was extracted from the lower layer. 60 parts of bromine was added to the sulfuric acid solution at 88°C to 92°C. Dropped over a temperature range for 4 hours,
Furthermore, unreacted 1-aminoanthraquinone-2-
The mixture was stirred and kept at 90°C until the sulfonic acid content was 1% or less. After the reaction was completed, it was cooled to 50°C, discharged into warm water, and diluted to a 10% sulfuric acid concentration. Then filtered, washed with warm water, and added 1,2-dichlorobenzene to the washing liquid.
800 parts were charged, stirred, and then allowed to stand for liquid separation. 45% sodium hydroxide was added to the aqueous layer for salting out, and the mixture was filtered and dried at room temperature to obtain 160.5 parts of orange crystals. 1-
The purity of amino-4-bromoanthraquinone-2-sulfonic acid was 88.6%, and the yield from 1-aminoanthraquinone was 83.0%.

Claims (1)

[Claims] 1 1-Aminoanthraquinone is sulfonated using a sulfonating agent in an inert organic solvent to give 1-aminoanthraquinone-2-sulfonic acid, which is extracted with sulfuric acid and subsequently brominated in sulfuric acid to form 1-aminoanthraquinone-2-sulfonic acid. - In producing 4-bromoanthraquinone-2-sulfonic acid or its salt, the sulfonation is 1.0 to 1.5 to 1-aminoanthraquinone.
160-190℃ using molar ratio of sulfuric acid or fuming sulfuric acid
1-amino-4-bromanthraquinone-, which is characterized in that it is carried out at a temperature range of A method for producing 2-sulfonic acid or a salt thereof.