JPS6050176B2 - Method for producing 1-chloro-2-methylanthraquinone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new method for producing 1-chloro-2-methylanthraquinone.

1-Chloro-2-methylanthraquinone is important as an intermediate in the production of vat dye bilanthrone represented by the following formula, and its industrial production involves chlorination of 2-methylanthraquinone in sulfuric acid. ing.

However, in this method, the yield is as low as 60% based on 2-methylanthraquinone, and the resulting product contains various impurities, resulting in poor purity. The present inventors have investigated various methods for producing 1-chloro-2-methylanthraquinone, which is useful as an intermediate, and have found that 4-
A novel 3-method prepared by mixing methyl phthalic acid or its anhydride with concentrated sulfuric acid or fuming sulfuric acid and reacting with chlorine.
Discovered chloro-4-methylphthalic acid and its production method,
An application has already been filed (Japanese Unexamined Patent Publication No. 53-124231).

Using this new compound as a raw material, benzene and Friedel
Crafts reaction to 3-chloro-4-sulfate 2-
(or 2-chloro-3-methyl-6-)benzoylbenzoic acid was obtained, and it was discovered that 1-chloro-2-methylanthraquinone could be obtained in high yield and purity by dehydration and ring closure, and the present invention was realized. completed.

That is, the present invention provides 3-chloro-4,-methylphthalic acid or 3-chloro-4-methylphthalic anhydride obtained by mixing 4-methylphthalic acid or its anhydride with concentrated sulfuric acid or fuming sulfuric acid and reacting the mixture with chlorine. Reacting acids with benzene, Friedel, and Crab gives 3-chloro-4-
A method for producing 1-chloro-2-methylanthraquinone, which comprises obtaining methyl-2-(or 2-chloro-3-methyl-6)benzoylbenzoic acid, and then heating the benzoic acid with a dehydration condensing agent to cause dehydration ring closure. .

In the method of the invention, 4-methylphthalic acid or 4-methylphthalic acid or
- methyl phthalic anhydride from the same weight to about 10% (
4-methylphthalic acid or 4-methylphthalic acid as a reaction accelerator.
-0.01-5% (by weight) based on methyl phthalic anhydride
In the presence of iodine, chlorine is absorbed and reacted at around room temperature (approximately 15°C). 4-methylphthalic acid or 4-
After absorbing approximately the same mole of chlorine as methyl phthalic anhydride, the reaction mixture was discharged into water and cooled, and the precipitated 3-chloro-4-methyl phthalic acid was taken out. weight) x xylene and boil to dissolve.

The resulting solution is allowed to cool, and the precipitated 3-chloro-4-methylphthalic anhydride is filtered off, washed with xylene, and dried. Melting point: 181.5 - 182.5 C (decomposed). Also,
This 3-chloro-4-methylphthalic anhydride can be easily converted into 3-chloro-4-methylphthalic acid by hydrolysis using a conventional method.

In the above chlorination reaction, 5-chloro-4-methyl phthalic anhydride is produced as a by-product along with 3-chloro-4-methyl phthalic anhydride, which is recrystallized from 3-chloro-4-methyl phthalic anhydride by recrystallization with xylene. Separated. 4-Methyl phthalic acid or 4-methyl phthalic anhydride is chlorinated in fuming sulfuric acid as described above. 3-chloro-4-methylphthalic acid or 3-chloro-4-methylphthalic acid obtained by
Chloro-methyl phthalic anhydride *8 can then be reacted with benzene to obtain 3-chloro-4-methyl-2- (or chloro-3-methyl-6-)benzoylbenzoic acid with high purity and high yield.

That is, 3-chloro-4-methylphthalic acid or 3-
In the Friedel-Crafts reaction of chloro-4-methyl phthalic anhydride with benzene, benzene is used in a molar ratio of 1 or more to the phthalic acid or phthalic anhydride.

An inert solvent (for example, tetrachloroethylene) or excess benzene itself is used as the solvent. Anhydrous aluminum chloride, clear water ferric chloride, boron fluoride, tin tetrachloride, etc. are used as the catalyst. However, anhydrous aluminum chloride is particularly preferred.The amount of catalyst used is preferably 2 molar ratio or a small excess amount relative to the phthalic acid or phthalic anhydride.The reaction is Although the reaction proceeds satisfactorily at a temperature of room temperature (about 15°C) to 100°C, a particularly suitable temperature for the operation of the reaction is 50 to 80°C.
It is. It is desirable to carry out the reaction under the above conditions until the generation of chlorine-hydrogen gas stops, usually over a period of one hour or more. Then, the reaction mixture is decomposed by discharging it into water or ice water containing a small amount of hydrochloric acid, and the target product is left as a residue by steam distillation to distill off the solvent or excess benzene. By extracting this with a dilute aqueous alkaline solution and making the extract acidic, 3-chloro-4-methyl-2-(or 2-chloro-methyl-6-)benzoylbenzoic acid can be obtained with high purity and high yield. By dehydrating and ring-closing this 3-chloro-4-methyl-2-(or 2-chloro-3-methyl-6-)benzoylbenzoic acid, 1-chloro-2
-Methylanthraquinone (■) is obtained.

Dehydration ring closure of 3-chloro-4-methyl-2 (or 2-chloro-3-methyl-6-)benzoylbenzoic acid is carried out by heating the benzoic acid together with a dehydration condensing agent.

Examples of the dehydration condensation agent include sulfuric acid, fuming sulfuric acid, polyphosphoric acid, phosphorus pentoxide, and anhydrous hydrogen fluoride. Among these dehydration condensing agents, sulfuric acid and fuming sulfuric acid have excellent performance as dehydration condensing agents and are relatively easy to handle, and are therefore particularly suitable for the method of the present invention.
The concentration of sulfuric acid used is preferably 95% or more, and in the case of fuming sulfuric acid, the free sulfuric anhydride (SO3) concentration is preferably in the range of 10% or less. If the concentration of sulfuric acid is lower than this, it will be difficult for dehydration ring closure to occur smoothly, and if the concentration of fuming sulfuric acid is too high than the above range, handling will be difficult and impurities will be generated during dehydration closure. It becomes easier to do. The amount of sulfuric acid or fuming sulfuric acid used is 3-chloro-4-methyl-2- (or 2-chloro-3
-Methyl-6-) It is 2 to 1 times the amount of benzoylbenzoic acid. If the amount of sulfuric acid or fuming sulfuric acid used is less than this, it will be difficult to stir the reaction solution, and if the amount used is too large, not only will there be no special benefit for the dehydration closed reaction, but the post-treatment of the reaction will be difficult. It becomes troublesome. If the heating temperature of 3-chloro-4-methyl-2-(or 2-chloro-3-methyl-6-)benzoylbenzoic acid and the above-mentioned dehydration condensation agent is too low, the dehydration ring-closing reaction will not be carried out sufficiently, and if it is too high, dehydration will occur. Side reactions such as chlorination reactions are more likely to occur.

Therefore, the heating temperature is preferably in the range of 80 to 130°C, particularly preferably in the range of 100 to 110'C. It is appropriate to heat for 1 to 5 hours under the above conditions. After carrying out the dehydration ring-closing reaction as described above, the reaction solution is discharged into a large amount of water, and the precipitate is filtered out.

By washing this with a dilute aqueous alkali solution and then with water and drying, highly pure 1-chloro-2-methylanthraquinone can be obtained in a high yield. The method of the present invention is a method using a completely different reaction route from the conventionally known method for producing 1-chloro-2-methylanthraquinone. -Chloro-2-methylanthraquinone can be easily produced.
The method of the present invention will be explained below with reference to Examples.

In the text, parts mean parts by weight. Example 13 - Synthesis of chloro-4-methylphthalic anhydride 10y of 4-methylphthalic anhydride, 50y of 5% fuming sulfuric acid, and 0.1 da of iodine were mixed and stirred at 20-25°C at a rate of 7 mUmin. Chlorine gas was passed through 911r and absorbed.

The reaction mixture was then drained into 250 g of water, cooled and
Strain off the precipitate, wash with a small amount of water, dry at 70°C,
9.2q of crude chlorinated 4-methylphthalic acid nuclei were obtained.
The composition (weight %) of this product was as follows as a result of analysis by gas chromatography. 5-Chloroux 4-
Methyl form: 33.1%, 3-chloro-4-methyl form: 4
2.8%, 3,5-dichloro-4-methyl form: 6.1%
, Others: 1.6%.

From the above crude chlorinated 4-methylphthalic acid nuclei, 3-
The chloro-4-methyl compound and 5-chloro-4-methyl compound were separated by recrystallization as follows.

1 part of crude 4-methylphthalic acid nucleic chloride was added to 5 parts of xylene.
It was boiled in a vacuum and dissolved as an anhydride.

This solution is quickly cooled to room temperature, and the precipitate is filtered off and washed with a small amount of xylene. The operation of dissolving this product in xylene and precipitating it was repeated 4 to 5 times to obtain 3-chloro-4-methyl phthalic anhydride that was nearly S pure on gas chromatography. This product was colorless prismatic or columnar crystals with a melting point of 133-135C. Production of 23-chloro-4-methyl-2-(or 2-chloro-3-methyl-6-)benzoylbenzoic acid.

While stirring, anhydrous aluminum heptaide salt was gradually added to a mixture of benzene and 29.5 parts of 3-chloro-4-methylphthalic anhydride while cooling with water and keeping the temperature at room temperature (15 to 20°C). added to.

Further, the temperature was raised to 50 to 60°C while stirring, kept at this temperature for 4 hours, and then cooled. The reaction solution was also decomposed by discharging it into ice water containing a small amount of hydrochloric acid, and the entire amount was steam distilled to remove unreacted benzene and water. The solid residue was extracted with a dilute aqueous sodium hydroxide solution, and the extract was acidified with hydrochloric acid to obtain a white solid precipitate. This was filtered, washed with water, and dried to 36 parts of 3-chloro-4-methyl-2-(or 2-chloro-3-methyl-6-)penzoylbenzoic acid (87 parts of theoretical yield).
4%) was obtained. This was recrystallized from xylene and had a melting point of 224 to 226 °C. Preparation of 31-chloro-2-methylanthraquinone 1 part of 3-chloro-4-methyl-2-(or 2-chloro-3-methyl-6-)benzoylbenzoic acid was mixed with 3 parts of 98% sulfuric acid and heated to 110'C with stirring. Heated for 3 hours.

Claims (1)

[Claims] 1 3-chloro-4-methylphthalic acid or 3-chloro-4 obtained by mixing 4-methylphthalic acid or its anhydride with concentrated sulfuric acid or fuming sulfuric acid and reacting with chlorine.
-Friedel-Krantz reaction of methyl phthalic anhydride with benzene to obtain 3-chloro-4-methyl-2-(or 2-chloro-3-methyl-6-)benzoylbenzoic acid, followed by dehydration condensation of the benzoic acid. 1. A method for producing 1-chloro-2-methylanthraquinone, which comprises heating together with an agent to cause dehydration and ring closure.