CH194090A - Process for the preparation of a new, water-soluble, secondary disazo dye. - Google Patents

Description

  

  Process for the preparation of a new, water-soluble, secondary disazo dye. According to the present invention, a new, water-soluble, secondary disazo dye is obtained by coupling dia.zo- tied p-aminophenyl-β-hydrogyethyl ether with m-toluidine methanesulfonic acid, removing the methanesulfonate group by hydrolysis, diazotizing the amino a thus obtained zo connection,

      Coupling of the resulting diazoazo compound with phenol and conversion of the dye thus formed into its soluble sulfuric acid ester by treatment with a sulfonating agent.



       Example: 153 parts of p - aminophenyl -, B - hydrogy- äthyläther are dissolved in 3000 parts of water and 925 parts of 10% hydrochloric acid and diazotized by adding 169 parts of sodium nitrite. The solution, the diazo compound obtained in this way, is then slowly stirred into a

   ice-cold solution of 223 parts of the sodium salt of m-toluidine methanesulfonic acid in 3000 parts of water, to which 168 parts of sodium bicarbonate have been added.

   (The sodium m-toluidine methanesulfonate can be produced by allowing equimolecular amounts of m-toluidine, formaldehyde and sodium bisulfite to act together in an aqueous medium.) The mixture is set at 0 to 10 ' Stirred C) until the reaction is complete and then will. Salted with 1-0A (weight for volume) sodium chloride.



  The monoazo compound is then filtered off and 6000 parts of water at <B> 50 '</B> C are added. After cooling to 20 ° C., a solution of 1.26 parts of caustic soda in 320 parts of water is added, and the mixture is heated to 55 to 60 ° C. and kept at this temperature for 11/9 hours.

   The insoluble aminoazo compound thus obtained is filtered off, washed thoroughly with water and then resuspended in a mixture of 500.0 parts of water and 9.25 parts of 10% hydrochloric acid. 69 parts of sodium nitrite are gradually added and the suspension is stirred for several hours at 20 to 25 ° C. until the diazotization is complete.

    The diazoazo compound solution is filtered, if necessary, to remove any insoluble material. The filtrate is cooled to 5 ° C. and slowly added to a 5 ° C. solution of 93 parts of phenol in 8000 parts of water and 40 parts of caustic soda, to which 20 parts of anhydrous sodium carbonate have been added. The disazo compound is salted with 10% (weight for volume) sodium chloride, filtered and the filter paste is dried.

   The dry dye is then gradually added, while stirring, 3.5 parts of concentrated sulfuric acid (monohydrate) and the mixture is stirred for a few hours. The solution thus obtained is then poured into ice and the precipitated sulfuric acid ester dye is filtered off and washed with 5% salt water. The coloring paste is ground with sodium carbonate until it becomes alkaline and then dried.



  The new dye forms a brown powder, dissolves in hot water with an orange color and, with concentrated sulfuric acid, gives a reddish-blue solution. It dyes acetate rayon in orange tones, which is good durability against acids, alkalis, washing and light, if it is applied from a neutral dye bath containing 1% salt. It is also suitable for printing on

 

Claims (1)

PATENT CLAIM: Process for the production of a new, water-soluble, secondary disazo dye, characterized in that diazotized p-aminophenyl-s-hydrogyäthylether is coupled with m-toluidine methanesulfonic acid, the methanesulfonate group is removed by hydrolysis, the aminoazo compound thus obtained diazotized, the resulting diazoazo compound is coupled with phenol and the dye thus formed is converted into its soluble sulfuric acid ester by treatment with a sulfonating agent. The new dye forms a brown powder and, when dissolved in hot water, results in an orange solution and in concentrated sulfuric acid a reddish-blue solution. It dyes acetate rayon in shades of orange that is durable against acids, alkalis, washing and light when applied from a neutral dye bath containing <B> 170 </B> salt. It is also suitable for printing on acetate rayon.