CS242003B1 - Process for the preparation of 2-amino- and 2,6-diaminoanthraquinone - Google Patents

Abstract

A method for producing 2-amino- and 2,6-diaminoanthraquinone by ammonolysis of the corresponding salts of anthraquinone sulfonic acids, whereby the filtrates are oxidized with oxidizing agents, preferably hydrogen peroxide or oxygen, after product separation, and after concentration and optional clarification are returned to the process. Preparation of a valuable intermediate for the production of organic dyes with the possibility of simple and efficient recycling of arsenic compounds back to the process.

Description

The present invention relates to a process for the preparation of 2-amino-amino and 2,6-diaminoanthraquinone which is ammonium and 2,6-diaminoanthraquinone by ammonolysis of the addition of the corresponding anthraquinone sulfonic acid salts of the corresponding anthraquinone sulfonic acid salts. with an aqueous ammonia solution at elevated levels

One method of industrial production of 2-a- temperature and pressure, following the equation

The sulphite anion formed during the reaction is highly reactive to the starting material and the product formed, and its action produces undesirable side-substances in the reaction mixture, which leads to a decrease in the purity and yield of the products produced. The sulphite anion must therefore be removed from the reaction product, most often by oxidizing it to a sulphate anion. A number of inorganic agents, for example nitrates, dichromates, chlorates, manganese dioxide or certain organic substances, for example nitrobenzene or sodium 3-nitrobenzenesulfonate, can be used as oxidizing agents for this purpose. However, far best results are obtained when using pentavalent arsenic compounds, such as sodium hydrogen sulphite, which are reduced to trivalent arsenic compounds in reaction with the sulphite ion to eliminate the adverse effects of the sulfite ion. After ammonolysis, the low-soluble 2-amino- or 2,6-diaminoanthraquinone formed is isolated from the reaction mixture by filtration, whereby the trivalent arsenic compounds, together with ammonium chloride and other substances, pass into the filtrate. Due to the high toxicity of arsenic compounds, these filtrates cannot be discharged into waste water, but they must first be removed from toxic substances, most often by precipitation of arsenic compounds in the form of sparingly soluble substances, such as calcium arsenate. . However, this process is considerably disadvantageous, both for environmental reasons, since considerable amounts of toxic arsenic waste are generated, as well as for economic reasons, as this results in irreversible losses of expensive arsenic compounds.

For these reasons, the possibility of recycling arsenic compounds back to ammonolysis has been investigated. One possibility is the use of arsenic acid resulting from the decomposition of calcium arsenate with sulfuric acid. This seemingly simple method has a number of disadvantages - an excess of sulfuric acid must be used to decompose calcium arsenate; after filtering off the sparingly soluble calcium sulfate, the resulting mixture of sulfuric acid and arsenic acid, from which it is very difficult to quantitatively isolate the arsenic acid. Another disadvantage of this process is the formation of calcium sulfate contaminated with arsenic compounds.

Another method for the regeneration of sodium arsenate is the process based on the oxidation of the filtrates after isolation of the mono- and respiratory tract. diamino anthraquinones, converting the salts contained therein into a cation exchange column to the free acids, and isolating arsenic acid from the filtrates thus treated by liquid extraction. However, the disadvantage of this process is the need for expensive equipment (cation exchange column, extraction columns), the use of liquid ion exchangers as extraction agents, and the fact that the ammonium chloride contained in the filtrates, which can be used in further ammonolysis, is wasted.

Research has now found that the disadvantages of the foregoing methods can be overcome by carrying out the production of 2-amino- and resp. 2,6-diaminoanthraquinone according to the invention based on direct recycling of the oxidized filtrates after isolation of the 2-amino and resp. 2,6-diaminoanthraquinone. It has surprisingly been found that the substances present in these oxidized filtrates together with arsenate compounds, i.e., in particular, sodium sulfate, sodium anthraquinone-2-sulfonate, 2-aminoantraquinone and its predominantly sulfonated derivatives, respectively. sodium anthraquinone-2,6-disulfonate, sodium 2-amino-6-anthraquinone sulfonate,

The diamino anthraquinone and its predominantly sulphonated derivatives do not adversely affect the course of ammonolysis, as does ammonium chloride, which is also returned to ammonolysis by this process. By using oxidized filtrates after isolation of the 2-amino- and resp.

2,6-diaminoanthraquinone feedstocks for ammonolysis Instead of employing pure sodium bisulfate and ammonium chloride, 2-amino- and 2,6-diaminoanthraquinone can be produced in even higher yields and comparable purities to those of the newly deployed sodium bisulfate and ammonium chloride, compared to hitherto. The process used generates considerable savings in sodium arsenate and ammonium chloride.

In the proposed procedure, the filtrates formed after isolation of the 2-amino- and 2-amino-2-amino-2-amino-2-amino-2-amino-2-amino-2-amino-2-amino-2-amino-2-amino-2-amino-2-amino-2-amino-2-amino-2-amino. 2,6-diami242

It undergoes an oxidation reaction with noanthraquinone with a suitable oxidizing agent such as hydrogen peroxide or air under the catalytic action of a heavy metal cation to convert arsenic compounds to arsenic. The filtrates thus treated, optionally after concentration and clering, are used instead of pure sodium arsenate and ammonium chloride in the next step in ammonolysis.

This production process can be illustrated by the following examples.

Example 1

81.1 g of sodium anthraquinone-2-sulfonate, 40.6 g of sodium hydrogen sulphate, 36.1 g of ammonium chloride and 230 ml of a 26% aqueous ammonia solution are charged into the autoclave, heated to 195 ° C and at this temperature and pressure of 4. It is allowed to react for 14 hours with stirring. The resulting 2-amino anthraquinone was collected by filtration. The yield of 2-aminoantraquinone is 84%, its purity is 97%.

Example 2

The filtrates of the previous example containing 80 g of sodium arsenite per liter were treated with 35 ml of 30% hydrogen peroxide at 85 ° C for 3 hours. After the oxidation was complete, the solution was evaporated to a volume of 150 ml. The solution obtained is introduced into an autoclave with 81.1 g of sodium anthraquinone-2-sulfonate and 230 ml of a 26% aqueous ammonia solution and left to react for 14 hours at 200 [deg.] C. under 3.5 MPa. The yield of 2-aminoantraquinone is 86%, its purity is 97%.

0 3

Example 3

The filtrates of Example 1 were oxidized with 35 ml of 30% hydrogen peroxide at 85 ° C for 3 hours. After the oxidation was complete, the solution was evaporated to a volume of 290 ml. The solution obtained is charged together with 81.1 g of sodium anthraquinone-2-sulfonate and 51 g of liquid ammonia and left to react for 14 hours at 200 ^DEG C. under a pressure of 40 bar. The yield of 2-aminoantraquinone is 86.5%, its purity is 97.1%.

Example 4

47.7 g of sodium anthraquinone-2,6-disulfonate, 37 g of sodium hydrogen sulphate, 26.5 g of ammonium chloride and 210 ml of a 26% solution of ammonia in water are introduced into the autoclave. The autoclave is heated to 210 ° C and reacted at this temperature and pressure of 4.5 MPa for 12 hours. The resulting 2,6-diaminoanthraquinone is isolated by filtration. The yield of 2,6-diaminoanthraquinone is 63%, the purity 93.5%.

Example 5

The filtrates of Example 4, containing 105 g of sodium arsenite per liter, are oxidized with atmospheric oxygen for 10 hours with the addition of 3 g of copper sulfate at 80 degrees Celsius. The oxidized filtrates are sclerified with 7 g of diatomaceous earth, concentrated to a volume of 260 ml and, together with 47.4 g of sodium anthraquinone-2,6-disulfonate and 50 g of liquid ammonia. The mixture was allowed to react for 12 hours at 210 ° C and 4.5 MPa. The resulting 2,6-diaminoanthraquinone is isolated by filtration. The yield of 2,6-diaminoanthraquinone is 63%, purity 94.5%.

Claims (1)

SUBJECT Process for the preparation of 2-amino- and 2,6-diaminoanthraquinone by ammonolysis of the corresponding anthraimony sulfoacid salts, characterized in that after separation of the product, the filtrates are oxidized with oxi- yNALEZA reagents, preferably hydrogen peroxide or oxygen, and returned to the process after concentration.