CH132803A - Process for the preparation of a stain dye. - Google Patents

Description

  

      1- Process for the preparation of a stain dye. The main patent describes a process whereby a valuable mordant dye is obtained by diazotizing the amino group in p-amino-0-stilfobenzolazosalicylic acid and coupling it with salyic acid.



  It has now been found that a similar dye is obtained if the amino group in the mono-, a7, o-dye is diazotized with p-amino-o-sulfoberi7, olazo-i-netakresotinic acid and coupled with irieta-1Zi-esotinsätire.

         p-Ainino-o-sulfoberizolazo-meta-cresotinic acid can be obtained in various ways, for example: 1. -Mionoacetyl-p-phenylenediamine-sulfonic acid is diazotized and coupled with meta-cresotinic acid. In the azo dye obtained, the acetyl group is eliminated by saponification and the free amino group is formed.



  2. p-nitrilin-o-sulfonic acid is diazotized and coupled with meta-cresotinic acid in a known manner. In the monoazo dye obtained, the nitro group is reduced to the amino group. <B> 3. </B> p-Phonylenediaminesulfonic acid is diazo- tated and coupled with ineta-cresotinic acid.



  The body retained in one way or another is further diazotized and coupled with nieta-ki-esotinic acid. The same final dye is always obtained.



  The process is illustrated by the following example: <B> 351 </B> parts of p-amino-o-sulfobenzolazo-metacresotinic acid are mixed with <B> 30 </B> parts of hydrochloric acid in the form of a fine aqueous suspension while cooling and diazotized by slowly adding <B> 7 </B> parts of sodium nitrite. The <B> - </B> poorly soluble, red-brown colored diazo body is filtered off and, in the moist state, gradually at <B> 0-5 '</B> C into a mixture of <B> 170 </B> Parts meta-cresotinic acid, <B> 1000 </B> parts of water,

   40 parts of caustic soda and <B> 500 </B> parts of magnesium carbonate are stirred in. The coupling compound, which initially shows a brown-black color, turns yellow-brown after a while. After the <B> coupling </B> process is complete, the mass is acidified and filtered. The dyestuff separated out in this way is dissolved in hot water and borax, filtered, possibly again separated in acidic form and then redissolved in water and borax and salted out with common salt.



  In this example the coupling can also be carried out with the help of soda or soda soda.



  The new dye dissolves in water with a brownish-yellow color, which changes to red-violet when caustic soda is added. In concentrated sulfuric acid it dissolves in a blue color. By diluting this solution with water, it is precipitated as dark brown flakes.



  The new dye dyes honored wool in brownish orange tones. Printed with chrome stain on cotton, it gives strong brownish orange nuances, which are more reddish than those of the dye of the main patent and have good fastness properties.

 

Claims (1)

PATEN'rAXSPUüCll: Process for the preparation of a pickling agent, characterized in that the free amino group in p-Amirio-o-stilfobenzolazo-meta-cresotinic acid is diazotized and coupled with meta-cresotinic acid. The new dye dissolves in water with a brownish-yellow color, which changes to red-violet when caustic soda is added. In concentrated sulfuric acid it looks blue. By diluting this solution with water it is precipitated as dark brown flakes. The new dye stains chromed wool in brownish orange tones. Printed with chrome stain on cotton, it gives strong brownish orange nuances that are more reddish than those of the dye of the main patent and have good fastness properties.