CH142058A - Process for the production of a new vat dye. - Google Patents

Description

  

  Additional patent to main patent no. <B> 138316. </B> Process for the production of a new vat dye. The main patent no. 138316 describes the manufacture of a vat dye, which is characterized in that Bzl-Bzl'-dibenzanthronyl is treated with nitrating agents in such a way that mononitration takes place and that it does so The product obtained is fused with caustic alkalis.



  In a further development of this process, it has now been found that practically the same dye is obtained if, in the process of the main patent, the reduction of the nitro group is switched on before the fusing with caustic alkalis. It can therefore be assumed that in the process of the main patent, the first phase of the process that takes place in the process of melting with caustic alkalis is a reduction in the nitro group.



  The weakly N-containing vat dye obtained according to the present process is a dark powder. It dissolves <B>. -q </B> concentrated sulfuric acid dull blue-violet; when this solution iii water is poured in, purple-tinged blue flakes precipitate. In boiling toluene it dissolves with difficulty with a pale blue color and brown-red fluorescence, in hot nitrobenzene it dissolves green-tinged blue with a pale brown fluorescence, and in boiling aniline it is blue. The vat is bright blue-violet with a blue-gray flower.

   Cotton is dyed from it in very real, blue-gray tones after hanging and soaking.



  <I> Example: </I> 45.8 parts of Bzl-Bzl'-dibenzanthronyl become sulfur in <B> 10 </B> to 20 <B> '</B> in <B> 920 </B> parts - Entered acid monohydrate and stirred until completely dissolved. Over the course of half an hour, 10 to 20 parts of a mixture of equal parts of anhydrous sulfuric acid and nitric acid are added dropwise to this solution and held for a further two hours at the temperature mentioned. During the dropping of the mixed acid into the reaction liquid, the color changes from eosin red to brownish red.

    The reaction mass is poured onto ice and the precipitated, brown-yellow nitro earphone, the nitro <B> - </B> Bzl <B> - </B> Bzl '<B> - </B> dibenzantlironyl, by filtering in the usual way Way isolated. It dissolves in concentrated sulfuric acid with an eosin-red color. In contrast to the starting material, which has an intense yellow-red fluorescence, the new body shows only weakly brown-tinged fluorescence. It is very sparingly soluble in boiling glacial acetic acid and toluene.

   It can be recrystallized from hot nitrobenzene.



  <B> 80 </B> parts of the product obtained in this way are mixed with the same amount of water and the paste is slowly poured into a <B> 9.5 </B> to <B> 100 '</B> while stirring well warm solution of <B> 175 </B> parts of crystallized. Sodium sulfur is allowed to flow in in <B> 1000 </B> parts of water. The temperature is kept at <B> 95 </B> to <B> 100 </B> 'for two hours. The reaction product is then filtered off with suction, the residue washed with hot water until free from alkali and dried. The amino-Bzl-Bzl'-dibenzaiithronyl obtained in good yield is brown in color.



  200 parts of caustic alkali <B> A 86% </B> and <B> 100 </B> parts of 95% alcohol are then added to <B> while stirring and partially distilling off the <B> alcohol </B> > 160 '</B> heated. 20 parts of the reduction product described in the previous paragraph are then introduced into the clear melt in small portions over the course of half an hour. Even with the first additions, the melt turns greenish blue due to the formation of the leuco compound of the dye. Alcohol continues to distil off and ammonia escapes.

    When the entry is complete, the mixture is heated to 220 'and held for an hour at 220 to <B> 230'. </B> The last blue-gray (3 melt is dissolved in water after cooling and by blowing out at about <B> 80 'The leuco compound is oxidized. The dye is isolated in the usual way.

 

Claims (1)

PATENT CLAIM: A process for the production of a vat dye, characterized in that BzI-Bzl'-dibenzanthronyl is first treated with nitrating agents in such a way that mononitration takes place, then the nitration product is treated with reducing agents and the reduction product is then fused with caustic alkalis becomes. The new, weakly N-containing vat dye is a dark powder. It dissolves in concentrated sulfuric acid in a dull blue-violet; when the solution is poured into water, violet-tinged blue flakes precipitate. In boiling toluene it dissolves with difficulty with a pale blue color and brown-red fluorescence, in hot nitrobenzene it is green-tinged blue with a weak brown fluorescence <U> and </U> in boiling aniline blue. The vat is bright blue-violet with a blue-gray flower. Cotton is dyed from it in blue-gray tones that are vertical after hanging and soaking.