DE2738824A1 - PROCESS FOR SEPARATING DINITROANTHRACHINONS FROM REACTION RESIDUE MIXTURES OF ANTHRACHINON NITRATION - Google Patents

Description

CIBA

CLBAUElGY AG. CH -4002 Basel

1-10678 / +

attorney 3 file 28 374

Germany

August 29, 1977

Process for separating dinitroanthraquinones from Reaction residue mixtures from anthraquinone nitration

The present invention relates to a process for separating dinitroanthraquinones from mixtures of reaction residues the anthraquinone nitration, which after the separation of the reaction products 1,5- and 1,8-dinitroanthraquinone and contain smaller or larger amounts of undesired hydroxynitroanthraquinones. It is characterized by that the solid residue mixtures with conc. Treated sulfuric acid or oleum between room temperature and 80 ° C and the dinitroanthraquinones are separated off from the suspension obtained by means of filtration.

Depending on the further intended use, the separated products can be washed neutral and dried.

The nitration of anthraquinone with nitric acid to dinitroanthraquinones mainly results in 1,5- and 1,8-dinitroanthraquinones as main products. In addition, however, there are horrific amounts that make up about 50% of sales can, mixtures of dinitroanthraquinones, which in addition to non-quantitatively deposited 1,5- or 1,8-dinitroanthraquinone the other isomers in solid form, such as 1,6- and 1,7-, 2,6- and 2,7-dinitroanthraquinone and isomers Contain hydroxynitroanthraquinones.

However, these dinitroanthraquinone mixtures are also valuable intermediates for dye synthesis.

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others for the production of disperse dyes after conversion or substitution of the nitro groups to amino groups. These further reactions are carried out in an acidic or alkaline medium. If the further processing of the isomeric dinitroanthraquinones takes place in an alkaline medium, the presence of the hydroxynitroanthraquinones is an essential one This is an obstacle, since the reaction mass then turns dark brown to black and is practically unusable. For this Basically, a separation of the dinitroanthraquinone isomers from the hydroxynitroanthraquinone isomers is absolutely necessary. Surprisingly, this was achieved by a simple cleaning operation of the solid residue mixture with conc. sulfuric acid or oleum. Another element of surprise is that by means of the inventive method a separation of the α- and β-isomers, Nitroanthraquinones can be achieved. If oleum is used, no large SOo concentrations are required. An SO-j content of up to 20% is sufficient.

The separation operation proceeds in detail, for example, as follows: After the nitration of anthraquinone and the extensive separation of 1,5- and 1,8-dinitroanthraquinone in 3 to 6 times the amount of conc. Suspended sulfuric acid or oleum and stirred at temperatures between room temperature and 110 ⁰ C, preferably room temperature and 60 ° C, for 1 to 16, preferably 2 to 8 hours. It is then filtered off and the press cake is poured into ice / ice water. A precipitate is formed which consists of dinitroanthraquinone isomers. This is filtered off, washed neutral with water and dried. The dinitroanthraquinones obtained can now be processed further both in an acidic and, in particular, in an alkaline medium without any negative side effects.

The new process is of particular importance as the nitration reaction residues are removed by a simple cleaning process separated from the unwanted Hydroxynitroanthraquinones and accessible in this way for further processing be made.

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The new procedure is illustrated by the following examples:

example 1

15 g of a residue mixture from the anthraquinone nitration after extensive separation of 1,5- and 1,8-dinitroanthraquinone of the composition:

6.4% 1,5-dinitroanthraquinone, 32.9% 1,6-dinitroanthraquinone, 15.4% 1,7-dinitroanthraquinone, 21.1% 1,8-dinitroanthraquinone, 2.7% 2,6- / 2,7-dinitroanthraquinone and 18.5% hydroxynitroanthraquinone, are introduced into 67 g of sulfuric acid monohydrate and the resulting suspension for 6 hours at room temperature stirred. It is then filtered through a glass frit and enters the press cake obtained in ice / ice water, a light yellow precipitate being obtained, which is suctioned off, washed with hot water and dried in vacuo.

9.0 g of a pale yellow crystalline product are obtained which only changes color to a pale pale yellow in alkaline solution and whose elemental analysis corresponds exactly to the composition of dinitroanthraquinone.

Using the same amount of the dinitroanthraquinone residue mixture and sulfuric acid monohydrate as described in Example 1 and proceed according to the in Table I, Columns 1 and 2, given reaction conditions, a purified dinitroanthraquinone mixture is obtained in the in Column 3 indicated yields.

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Table I.

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E.g. 1 2 3 2 reaction time Reaction temperature yield 3 2 h Room temperature 7.8 g 4th 4 h Room temperature 8.7 g 5 8 h Room temperature 9.0 g 6th 6 h 40 ° C 8.1 g 4 h 60 ° C 7.3 g

Example 7

18 g residue mixture of the composition: 3.7% 1,5-dinitroanthraquinone, 40.0% 1,6-dinitroanthraquinone, 13.7% 1,7-dinitroanthraquinone, 12.5% 1,8-dinitroanthraquinone, 5.5% 2,6- / 2,7-dinitroanthraquinone and 24.7% hydroxynitroanthraquinone are introduced into 54 parts of oleum (5% SOo content) and the suspension obtained was stirred for 2 hours at room temperature. It is filtered through a glass frit and carries out the obtained press cake on ice, whereby a light yellow dense precipitate is obtained, which is sucked off, washed with hot water and dried in vacuo.

11.2 g of a light yellow colored product are obtained, whose elemental analysis corresponds to the composition of dinitroanthraquinone.

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Example 8

300 g residue mixture of the composition:

1.3% 1-nitroanthraquinone, 0.2% 2-nitroanthraquinone, 6.4% 1,5-dinitroanthraquinone, 32.9% 1,6-dinitroanthraquinone, 15.4% 1,7-dinitroanthraquinone, 21.1% 1,8-dinitroanthraquinone, 2.1% of 2,6-dinitroanthraquinone, 2,6-dinitroanthraquinone and 2.7% 18.0% Hydroxynitroanthrachinon are suspended in 1340 g of sulfuric acid monohydrate with stirring to 100 - 102 ⁰ C and heated Maintained at this temperature for 3 hours. The mixture is then cooled to 20-25 ° C., filtered through a glass frit and the presscake obtained is introduced into 1500 ml of water with stirring. The mixture is stirred for 30 minutes at room temperature, filtered and the press cake is washed neutral with water.

A yellow colored crystalline product is obtained which essentially consists of a mixture of 1,5- and 1,8-dinitroanthraquinone and does not contain any ß-nitroanthraquinone isomers.

Analysis of the purified product mixture:

0.4% 1-nitroanthraquinone, 28.2% 1,5-dinitroanthraquinone, 1.2% 1,6-dinitroanthraquinone, 1.6% 1,7-dinitroanthraquinone, 62.0% 1,8-dinitroanthraquinone.

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Claims (7)

^^^ claims (l / Process for separating dinitroanthraquinones from reaction residue mixtures of the anthraquinone nitration, which arise after the extensive separation of the reaction products 1,5- and 1,8-dinitroanthraquinone and contain hydroxynitroanthraquinones, characterized in that the solid residue mixtures are mixed with concentrated sulfuric acid or oleum between Treated room temperature to 110 ° C, and the dinitroanthraquinones separated from the suspension obtained by means of filtration. 2. The method according to claim 1, characterized in that that the separated products are washed and dried neutrally. 3. The method according to claims 1 and 2, characterized in that that the treatment is carried out between room temperature and 60 ° C. 4. Process according to Claims 1 to 3, characterized in that sulfuric acid monohydrate or oleum is used with up to 20% SO-j content used. 5. Process according to Claims 1 to 4, characterized in that the reaction is carried out for 1 to 16, preferably 2 to 8 hours. 6. Process according to Claims 1 to 5, characterized in that the sulfuric acid or oleum in the 3- to 6 times the amount used for the reaction residue mixture used. 7. The dinitroanthraquinones obtained by the process according to Claims 1 to 6. 809810/0819 ORIGINAL INSPECTED