SU68311A1 - The method of obtaining oxy-fuxone dyes - Google Patents

Description

The oxidation of aminotriphenylmethane derivatives to the corresponding fuxonimide dyes is carried out in the art by the use of various oxidizing agents. The oxidation of oxytriphenylmethane derivatives into the corresponding oxy-fuxons has not been studied sufficiently and does not always lead to the desired results.

There is a method for the oxidation of oxitriphenylmethane derivatives to oxy-fuxone dyes, which consists in the fact that the leuco-dye compound dissolved in an organic solvent containing hydrogen chloride is treated with an organic nitrite, such as amyl nitrite. In this case, the oxyfuxone dye in the form of hydrochloride falls out of solution.

The disadvantage of this method is that for its implementation it is necessary first of all to synthesize organic nitrite, which has a high toxic effect, which not only increases the cost, but also complicates the application of this method. In addition, when organic nitrites are used as a result of the oxidation reaction, the corresponding alcohol is formed, which makes it difficult to further regenerate the solvent and partially dissolves the resulting dye, which reduces the yield of the latter.

Oxidation of oxitriphenylmethane derivatives in oxy-fuxone dyes can be accomplished by passing nitrogen oxides through a solution of a leuke derivative in a neutral organic solvent containing hydrogen chloride. The oxidizing agent is nitrogen dioxide, the amount of which in the mixture of oxides of nitrogen determines the consumption of the latter. The dye falls out of solution in the form of hydrochloride. The use of oxides and nitrogen as an oxidizer eliminates all the disadvantages of the method described above.

The oxidation can be carried out in a closed system, in which the excreted nitrogen oxide is continuously converted into nitrogen dioxide, which significantly reduces the consumption of oxidant and is more convenient in terms of production safety.

Example 1 - 336 g of 4,4-dioxy-3,3-dimethoxytriphenylmethane is dissolved in 1 l of amyl acetate and 250 g of amyl acetate saturated with dry hydrogen chloride to a content of 18% is added to the solution. Through this solution at 25-30 ° and with good stirring is passed within 4-6 hours. The current of nitrogen oxides, containing, their mixture of oxides and nitrogen dioxide, obtained by acidification in a special vessel, is 150 g of sodium nitrite with strong sulfuric acid and passed through a tube with anhydrous chlorine calcium. As the reaction proceeds, the oxy-fuxone dye hydrochloride precipitates as a fine-crystalline powder. After passing the oxides of nitrogen, the mixture is stirred for another two hours, the precipitated precipitate is filtered off, well pressed on the filter, washed with amylacetate and dried. The yield is 330 g. After stirring the filtrate with soda solution, and then with water, the amyl acetate used as a solvent can be easily recovered by distillation.

Example 2. 382 g of 4,4,4-trioxy 3, 3,3-trimethoxytriphenylmethane are dissolved in 800 g of ethyl acetate and another 400 g of ethyl acetate is added to the resulting solution, through which dry hydrogen chloride was previously passed to a content of 14%. A mixture of nitrogen oxides enriched with nitrogen dioxide, obtained by mixing 2.5 moles of nitric oxide with air or oxygen in a special OR mixer, is passed through the mixture at 10–15 ° for six hours with good stirring. manganese or other mineral peroxide. As the reaction proceeds, the hydroxyhydroxfluxone dye (rubrofen or rubracol) precipitates as a melrucrystalline powder. The reaction mixture is stirred for another two hours, after which the dye precipitate is filtered, wrung well on the filter, washed with ethyl acetate and dried. Yield - 350 g of product containing 95% dye.

Example 3. The reaction product obtained by standing a mixture of molten 152 g of vanillin and 248 g of gua cola, saturated with dry hydrogen chloride (in accordance with the description of the author's certificate No. b1312 as a crystalline product) was dissolved in 800 g of amyl acetate without purification. To the resulting solution was added 250 g of amyl acetate, containing 18% dry hydrogen chloride. A stream of a mixture of nitrogen oxides enriched with nitrogen dioxide is passed through the resulting solution at 10–15 ° with good stirring for six hours. After that, the mass is stirred for another two hours, the precipitated precipitate is filtered off, pressed on the filter, washed with amylacetate and dried. The yield of 95% product - 330 g

Example 4. In a closed vessel equipped with a stirrer, an inlet tube reaching the bottom of the vessel, and a discharge tube, 382 g of 4,4,4-trioxy-3,3,3-trimethoxytriphenylmethane are charged, 800 ml of amyl acetate are added and after dissolving another 250 g of amyluacetate containing 18% hydrogen chloride.

The inlet and outlet tubes are included in a closed system in which nitric oxide is oxidized to nitrogen dioxide when oxygen is added or passed over mineral peroxides. Some quantity of nitrogen dioxide containing nitrogen oxides is introduced from the outside into the system; the latter are continuously circulated through a solution of a triphenylmethane derivative, where nitrogen dioxide is deoxidized, and through an oxidizing tank, where oxidation of nitric oxide occurs. The reaction is carried out until the leuco-compound is completely oxidized to a dye hydrochloride, which is isolated as indicated in the previous examples.

- 3 - # 68311

The subject matter of the invention is that as an oxidizing agent at 1. The method of obtaining oxy-fuxone-containing nitrogen dioxide, out dyes by oxidation of their leu-2. The use of the method according to claim 1 for kosoedineniyah in the environment of the organic oxidation of leuco compounds, a semi-solvent in the presence of chlorinated hydrogen according to the author’s testimony of a hundred, different No. 68312.