CH302049A - Process for the preparation of a disazo dye. - Google Patents

Description

  

  Additional patent to main patent No. 298139. Process for the production of a disazo dye.



  It has been found that a valuable disazo dye is obtained such as the amino monoazo dyes of the formulas
EMI0001.0006
    condensed with each other by means of cyanuric chloride and the remaining third chlorine atom bound to the cyanuric ring is replaced by the remainder of the aminobenzene-3-sulfonic acid.



  The new dye forms a yellow powder that dissolves in water with a yellow color and dyes cotton and regenerated cellulose in very pure, yellow tones. After the one or two bath sewing process, yellow shades of very good wet and light fastness are obtained.



  The combination of the two aminomonoazofa dyes by means of cyanuric chloride and the replacement of the remaining third chlorine atom bound to the cyano ring by the remainder of the aminobenzene-3-sulfonic acid are expediently carried out in an aqueous, weakly alkaline medium. It is advisable to increase the H-Vert and / or the reaction temperature P <B> N </B> in each condensation stage compared to the previous one.

           Example: A solution of 49 parts of 4 '- (4 "-amino) - b enzoylamino - 2' - chloro - 4-oxy-1,1'-azobenzene-3-carboxylic acid-5-sulfonic acid and 10.6 parts of sodium carbonate 2000 parts of water are poured at 5 within 10 minutes into a slurry of 18.4 parts of cyanuric chloride in a little ice water and the hydrochloric acid formed is neutralized with a solution of 8.4 parts of sodium bicarbonate in 30 parts of water.

   The condensation has ended after one hour. A warm solution of 37.1 parts of 4'-amino-2'-chloro-4-oxy-1,1'-azobenzene-3-carboxylic acid-5-sulfonic acid in 1000 parts of water is then poured in and the temperature is maintained 12 hours with good stirring at 30 to 35. During this time, the solution of 10 parts of sodium bicarbonate in 35 parts of water is added dropwise. 37 parts of aniline-3-sulfonic acid are then poured in, the mixture is heated to between $ 5 and 90 for 2 hours, 10.6 g of sodium carbonate are sprinkled in and the condensation product is salted out with sodium chloride.

 

Claims (1)

Claim: Process for the preparation of a disazo dye, characterized in that the aminomonoazo dyes of the formulas EMI0002.0009 condensed with each other by means of cyanuric chloride and the remaining third chlorine atom bound to the cyanuric ring is replaced by the remainder of the aminobenzene-3-sulfonic acid. The new dye forms a yellow powder that dissolves in water with a yellow color and dyes cotton and regenerated cellulose in very pure, yellow tones. After the one or two bath re-coppering process, yellow shades of very good wet and light fastness are obtained. SUBClaims: 1. The method according to claim, characterized in that the condensation with cyanuric chloride and the replacement of the remaining third chlorine atom bound to the cyanuric ring by the 1test of aniline-3-sulfonic acid in aqueous, weakly alkaline medium and in in such a way that the pH value is increased at each condensation stage compared to the previous one. 2. Process according to claim, characterized in that the condensation with cyanuric chloride and the replacement of the remaining third chlorine atom bound to the Cva.nur- ring by the remainder of the aniline-3-sulfonic acid in an aqueous, weakly alkaline medium and in the manner dureheads that the reaction temperature is increased in each condensation stage compared to the previous one. 3. Process according to claim, characterized in that the condensation with cyanuric chloride and the replacement of the third remaining chlorine atom bound to the cyanuric ring with the remainder of the aniline-3-sulfonic acid is carried out in an aqueous, weakly alkaline medium and in the manner that both the pH and the reaction temperature are increased in each condensation stage compared to the previous one.