CH147797A - Process for the preparation of a water-insoluble azo dye. - Google Patents

Description

  

  Process for the preparation of a water-soluble azo dye. It has been found that low-nuclear or condensed aromatic systems which contain a free amino group in one nucleus and an arylamino group in another nucleus represent diazo components which, when coupled with oxynaphthoylarylamines, are valuable dyes deliver.

   Of these bases, those whose non-arylated, ie, two free amino group-containing basic structures are capable of forming substantive azo dyes, have the remarkable property of providing azo dyes of particularly deep hues.



  The bases of the type mentioned are generally capable of providing nitrosodiazo compounds on exposure to 2 mol of nitrite in acidic media, which give red to red-brown colorations when coupled to 2,3-oxynaphtoylarylamines; After treatment with suitable reducing agents, in some cases with saponifying agents, these colorings, which are probably based on the formation of nitrosoazo dyes, change into the colors of the simple, non-nitrosated azo dyes.



  The bases in the aryl nuclei can be substituted as desired, but should not contain any water-solubilizing groups, such as sulfo or carboxyl groups.



  The dyes can be produced in bulk, on substrates or on the fiber. The subject of this patent is a process for the preparation of a water-insoluble azo dye, which is characterized in that the nitrosodlazo compound of 4-amino-4'-phenylamiiiodiphenyl is mixed with 2. 3-oxynaphthoic acid-5'-cblor -2'-toluidid coupling. The action of the two components on one another can also take place in the presence of a substrate.



  The nitroso dye produced in substance forms a boron red powder and delivers. if produced on the fiber, a bordeaux red coloration which, on aftertreatment with alkaline reducing agents, turns into a muted, very reddish-tinged dark blue of good fastness to washing, chlorine and light.

    <I> Example: </I> <B> 2.6 </B> parts by weight of 4-amino-4'-phenylamino-diplienyl (= plienylbenzidine), S., 5 parts by volume of concentrated hydrochloric acid, <B> 100 </ B > Parts of the volume of water are boiled, cooled with ice and diazotized and nitrosated with a 10% solution of 1.4 parts by weight of sodium nitrite. The solution obtained in this way is allowed to run into a solution of <B> 3,

  11 </B> Divide weight 2.3-Oxyriaphtoesäiii-e-5'-cbloi - 2-tolui- did, <B> 2.5 </B> Ratimteile -.Nati, otilatigc 40 'B6, <B> 100 < / B> Rough parts' water. The nitroso dye thus formed is bordeaux red. He is sucked off and washed with water. By heating the aqueous suspension with alkaline reducing agents, for example.

    Very dilute solutions of sodium sulphite, sodium sulphite or sodium phenylhydi-azii) -stilfosaurem, to which a little caustic soda or soda is expediently added, the dye becomes reddish-tinged dark-pale.

 

Claims (1)

<B> PATENT CLAIM: </B> Process for the preparation of a water-insoluble azo dye, characterized in that the nitposodiazo compound of 4-amino-4'-phenylamino-dipbenyl with 2.3-Oxynapl) toesätire-5'-chloro-2 ' -toluidid couples. The nitroso dye, which is produced in substance, forms a red powder and, if produced on the fiber, produces a red color which, when treated with alkaline reducing agents, turns into a covered, very reddish dark blue of good detergency, chlorine and light clarity.