DE583224C - Process for the production of cobalt-containing azo dyes - Google Patents

Description

It has been found that valuable cobalt-containing dyes are obtained if o-Oxyazo dyes of the general formula

OH

R ₁ -Nr-Nf

OH I J-OH,

where R ₁ denotes an aryl radical which is not _{substituted by any group containing the SO 2} group or by any carboxyl group, treated with suspensions of cobalt compounds in a neutral medium.

As cobalt-releasing agents, oxides, hydroxides, hydrates, carbonates of cobalt can be used with or without additives of neutral reacting salts, such as. B. sodium sulfite or table salt can be used.

The cobalt-containing dyes obtainable by the present process can especially for the production of lightfast, colored lacquers, which differ from cellulose esters and ethers, artificial and natural resins can be used.

Example 1

2.63 parts of the dye from diazotized! 4-chloro-2-amino-i-oxybenzene and resorein are boiled in 250 parts of water and a 0.65 part of cobalt corresponding Amount of a freshly precipitated and neutral washed cobalt sulfide suspension several Time heated to boiling on the reflux condenser. After cooling down, the resulting Cobalt prevention separated by adding a little table salt, washed out and with dried at a moderate temperature. It is a dark brown powder that settles in Water with red, in caustic soda with deep red and in concentrated sulfuric acid with brownish-yellow color dissolves. With the bluish-tinged red solution of the cobalt compound in zapon lacquer, red coatings are obtained on metal foils.

Example 2

5.48 parts of the dye from diazolated 4-nitro-2-arnino-i-oxybenzene and resorcinol are boiled in 400 parts of water and _{heated to boiling with 5.4 parts of cobalt dioxide (Co 2} O ₃ ) for 24 hours. After cooling, the precipitated dye is filtered off, washed and dried. The cobalt compound formed is separated from excess metal oxide by dissolving in soda and dried at a moderate temperature. It represents a purple-brown puI

Claims (1)

ver dar which is in water with cherry red, Dissolves in lye with a brownish-red color and in concentrated sulfuric acid with a brownish-yellow color. With a solution of the cobalt compound in nitrocellulose you get on metal foÜen lightfast scarlet coatings. Example 3 5.5 parts of the dye from diazotized! to 5-nitro-2-arnino-i-oxybenzene and resorcinol are boiled in 200 parts of water and mixed with an equivalent of 1.18 parts of cobalt Amount of a freshly precipitated and neutral washed cobalt hydroxide suspension added and heated to boiling for 1 hour on the reflux condenser. After it has cooled down the resulting cobalt compound was precipitated with acetic acid, filtered and washed out. After drying, a dark brown powder is obtained that dissolves in organic solvents dissolves easily with burgundy paint. With a solution of the cobalt compound in Nitro or acetyl cellulose lacquer is obtained on metal foils or other suitable substrates Wine-red to bordeaux-red lightfast coatings. .PATIiN ¹ J ¹ ANSJL ¹ KUCHl Process for the production of cobalt-containing azo dyes, characterized in that, that one o-oxyazo dyes of the general formula OH !-OH, _t - JN = JN - ' ^N f I
OH where R ₁ denotes an aryl radical which is not _{substituted by any group containing the SO 2} group or by any carboxyl group, treated with suspensions of cobalt compounds in a neutral medium. -