CH302402A - Process for the preparation of a trisazo dye. - Google Patents

Description

  

  <B> Additional patent </B> to main patent no. 299709. Process for the production of a trisazo dye. A valuable trisazo dye has been found to be obtained if
EMI0001.0004
    couples with 8-oxyquinoline.



  The new dye forms a blackish powder that dissolves in concentrated sulfuric acid with a blackish blue and in water with a violet color and colors cotton in navy blue shades with good light and wash fastness using the one or two bath post-copper plating process.



  The amino disazo dye used as the starting material is expediently converted into diazotized 2-methyl-4-amino-5-methoxy-4'-oxy-5'-chloro-1,1'-azobenzene-3'-carboxylic acid by coupling 2- (4'-aminophenyl) -amino-5-oxy-riaphtba.lin-7,3'-disulfonic acid.

   The diazotization of the aminodisazo dye advantageously follows the so-called indirect method by, for example, a solution or suspension which contains the aminodisazo dye in the form of an alkali salt and advantageously also a small excess of free alkali and the required amount of nitrite combined with an excess of dilute hydrochloric acid.



  The coupling of the diazodisazo compound with the 8-oxyquinoline is advantageously carried out in an alkaline, e.g. B. alkali carbonate or earth a diazo compound of the aminodisazo dye of the formula alkali hydroxide alkaline medium, if desired with the addition of coupling-promoting substances such as pyridine.



  <I> Example: </I> 33.5 parts of 2-1 methyl-4-amino-5-methoxy-4'-oxy-5'-chloro-1,1'-azobenzene-3'-carboxylic acid are added the amount of sodium hydroxide solution necessary for neutralization is dissolved in 700 parts of warm water, mixed with 7 parts of sodium nitrite as a four-fold normal solution and, after cooling to 10 to 12, by adding dilute hydrochloric acid, consisting of 35 parts of 301% hydrochloric acid and 100 Share water,

       diazotized. When the diazotization is complete, coupling is carried out at 0 to 5 with a sodium carbonate alkali solution of 41 parts of 2- (4'-aminophenyl) -amino-5-oxynaphthalene-7,3'-disulfonic acid. The mixture is stirred for a few hours, heated to 50, neutralized with hydrochloric acid until brilliant yellow paper shows almost neutral, and the dye is precipitated by adding 20 parts of sodium chloride to 100 parts by volume of coupling mixture.

   After cooling, it is filtered off and washed with <B> 25 </B> / o sodium chloride solution. The dye is dissolved in 1500 parts of m ater with the addition of 12.5 parts of 30% sodium hydroxide solution,

   mixed with 7 parts of sodium nitrite as a four times normal solution and diazotized at 10 to 15 by pouring in 60 parts of 30% strength hydrochloric acid, which were diluted with 120 parts of water. The mixture is stirred for a few hours, the excess nitrite is destroyed with sulfamic acid, a weak hydrochloric acid solution of 14 is first given

  5 parts of 3-oxyquinoline and then a solution of 60 parts of sodium carbonate in 250 parts
EMI0002.0026
    with E-Oxychin.olin couples. The new dye forms a blackish powder that dissolves in concentrated sulfuric acid with a blackish blue and in water with a violet color, and cotton is added after the one or two bath copper water. The temperature is maintained at 5 to 10 by adding ice.

   When the coupling is complete, the mixture is heated to about 70, 1.0 parts of sodium chloride per 100 parts by volume of reaction mixture are added and the dye is filtered off.

 

Claims (1)

PATENT CLAIM Process for producing a trisazo dye, characterized in that a diazo compound of the amino disazo dye of the formula process is dyed in navy blue shades of good lightfastness and washfastness. SUBClaim: Method according to patent claim, characterized in that the coupling is carried out in an alkaline medium.