JPS5925773B2 - 1. Method for producing 5-diphenoxy-anthraquinone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing 1,5-diphenoxyanthraquinone.

More specifically, the present invention relates to a method for obtaining 1,5-diphenoxy-anthraquinone by reacting 1,5-dietroanthraquinone with an alkali metal phenolate in an inert organic solvent insoluble in water. 1,5-Diphenoxy-anthraquinone is an important intermediate in the production of dyestuffs, and it is well known that dinitroanthraquinone can be obtained by nitration and subsequent hydrolysis.

Conventionally, the general method for producing 1,5-diphenoxy-anthraquinone is to sulfonate anthraquinone using mercury as a catalyst, and then 1,5-disulfonic acid with hydrochloric acid and sodium chlorate. 5-Jigroll-
anthraquinone, and then this substance and a large excess of phenol are heated and melted in the presence of potassium carbonate to react,
This is a method for producing 1,5-diphenoxy-anthraquinone.

However, in recent years, due to the problem of environmental pollution caused by mercury, a nitration method has been considered in place of the sulfonation method. The reaction of 1,5-dinitro-anthraquinone obtained by nitration of anthraquinone with phenol has been described in the literature, and is a method of melting using excess phenol which also serves as a solvent.

However, excessive use of phenol is not only economically disadvantageous, but also has the disadvantage that its recovery is industrially difficult and that it significantly degrades wastewater. Therefore, recently, a method of condensation using a water-soluble organic solvent such as dimethylformamide as a reaction medium has been proposed according to German Published Patent Application No. 2232446.

However, although this method also reduces the amount of phenol used, the solvent itself is expensive and water-soluble, so its recovery is industrially disadvantageous.
The present inventor discovered the present invention by studying the reaction between 1,5-dinitroanthraquinone and phenol without using excessive phenol and using an inexpensive and easily recovered solvent. That is, using a water-insoluble solvent such as chlorpenzole, diglorpenzole, trichlorobenzene, xylene, toluene, or nitrobenzene as a solvent,
It has been found that the desired 1,5-diphenoxy-anthraquinone can be obtained in good yield and purity by performing the reaction using a stoichiometric amount or a slight excess of alkali metal phenolate.

After the reaction, the solvent used can be diluted with methanol or the like to precipitate and separate the target product, or the solvent can be recovered by steam distillation after the reaction. Potassium or sodium phenolate is preferred as the alkali metal phenolate; either a phenolade prepared according to generally well-known methods is used, or, preferably, the phenol and a calculated amount of caustic soda or caustic potash are combined in the reaction medium. The water produced is removed by distillation.
It is possible to react by adding phenolad and then 1,5-dinitro-anthraquinone. When potassium phenolate is used, the reaction is carried out at 70°C to 14°C.
When sodium phenolade is used, the process proceeds at about 100°C to 140°C.

Also, passing nitrogen gas slowly into the reactor during the reaction gives favorable results. The present invention will be specifically described below with reference to Examples.

In the example, part and? "" indicates parts by weight and percent by weight, respectively. Example 1 6.0 parts of 1.5-dinitro-anthraquinone was added to 30 parts of chlorobenzole, followed by 5.8 parts of potassium phenolate, heated, and reacted at 100°C for 3 hours.
Incubate at ℃ for 1 hour.

After cooling, 30 parts of methanol was added and the precipitated crystals of 1,5-diphexianthraquinone were filtered off. After washing with water and drying, yellow-orange crystals are obtained.

Yield: 7.1 parts, analysis by gas chromatography showed purity of 975%, melting point: 1R, TLC etc. showed 1.5% purity.
- Confirmed that it was diphenoxy anthraquinone. Example 2 35 parts of chlorobenzole and 4.2 parts of phenol 85%;
Add 3.1 parts of caustic potash and add 1 part of caustic potash under a gentle stream of nitrogen.
The temperature was set at 25°C, and the water produced was distilled off together with chlorbenzole.

Then, the mixture was cooled to 70°C, 6.0 parts of 1,5-dinitro-anthraquinone was added, and the reaction was carried out in the same manner as in Example 1. 100
℃ and then steam distilled the chlorobenzole,
The residue is heat aged.

7.4 parts of 1,5-diphenoxy anthraquinone were obtained.

Example 3 4.2 parts of phenol and 2.0 parts of caustic soda were added to 35 parts of chlorobenzole, and the mixture was heated to 125° C. while slowly passing nitrogen through the mixture, and the produced water was distilled off.

Then, the mixture was cooled to 100°C, 6.0 parts of 1,5-dinitro-anthraquinone was added, the temperature was raised to 130°C, and the mixture was reacted for 7 hours.

The solvent was recovered by steam distillation in the same manner as in Example 2, and 1.5-
7.2 parts of diphenoxy anthraquinone were obtained. Example 4 5.8 parts of potassium phenolate in 40 parts of xylene, 1.
Add 6.0 parts of 5-dinitro-anthraquinone and bring to 130°C.
The mixture was reacted for 3 hours and treated in the same manner as in Example 1 to obtain 7.3 parts of 1,5-diphenoxy anthraquinone.

Claims (1)

[Claims] 1. A method for producing 1,5-diphenoxy-anthraquinone, which comprises reacting 1,5-dinitro-anthraquinone and an alkali metal phenolate in an inert organic solvent insoluble in water.