CH136833A - Process for the preparation of a valuable vat dye. - Google Patents

Description

  

      Process for the preparation of a valuable chick dye. The main patent describes a process for preparing a valuable vat dye in which aminodibenza.n- thron, which can be obtained by reducing the mononitrodibenzanthrone formed by nitrating dibenzanthrone, condenses with an anthraquinone which is negatively substituted in the 1-position becomes.



  Ice has now been found that a similar valuable vat dye is obtained if 2 moles of aminodibenzanthrone, which can be obtained by reducing the nononitrodibenza.nthrone produced by nitrating dibenzanthrone .. with 1 mole. Of a double-necked pyranothrone, can be prepared by halogenating pyran- thron in nitrobenzene, condensed.

       The condensation is expediently carried out in high-boiling solvents or diluents, and acid-binding agents can also be added here. The use of catalysts is often advantageous, as which, for example, mixtures of sodium acetate and copper salts can be used.



  The new vat dye is a black powder; it is soluble in concentrated sulfuric acid with a violet color and dyes cotton from a blue vat in black, exceptionally real shades.



  <I> Example: </I> 5G parts of dibromopyranthrone in 1000 parts of nitrobenzene with 94 parts of the amino, dibenzanthrone, 10 parts of copper acetate and 40 parts of sodium acetate are boiled with stirring until the resulting reaction product is bromine-free. Then it is worked up as usual.



  The aminodibenzanthrone can be produced during the reaction from the corresponding nitro compound and a reducing agent, for example hydrazine hydrate or sulfur. Instead of the dibromopyranthrone, the equivalent amount of dichloropyranthrone or chlorobromopyranthrone can also be used. _

 

Claims (1)

PATENT CLAIM: Process for the preparation of a valuable vat dye, characterized in that 2 moles: Aminodiben7, a, n-th, ron, which can be obtained by reducing the mononitrodibenzanthrone produced by nitrating dibenzanthrone, with 1 Mol. Of a doubly halogen-substituted pyranthrone, which can be produced by halogenating pyranthrone in nitrobenzene, condensed. The new vat dye is a black powder; it is soluble in concentrated sulfuric acid with a violet color and dyes cotton from a blue vat in black; excellent real tones. 17N TERAN CLAIMS 1. Process according to patent claim, characterized in that the condensation is carried out in a high-boiling solvent. 2. Process according to claim, characterized in that the condensation is carried out in a high-boiling diluent. 3 .. Process according to the patent claim, characterized in that the condensation is carried out in counter wax of acid-binding agents. -9 -. Method according to claim, characterized in that the condensation is carried out in the presence of catalysts.