CH307975A - Process for the preparation of a chromium-containing monoazo dye. - Google Patents

Description

  

  Process for the preparation of a chromium-containing monoazo dye. Patent specification No. 261126 describes the preparation of water-soluble, complex chromium compounds of sulfonic acid group-free o, o'-dioxy and o, o'-carboxy-oxy-azo dyes, which contain at least one methylsulfonyl group as a hydrophilic substituent. The production of yellow, orange, red, brown, brown-violet and gray dyes is described.



  In further processing the subject of the invention, it has now been found that new, blue chromium-containing dyes can be produced that outperform the known similar dyes due to the purer hue and the better evening color of the wool dyes and otherwise have the same good fastness properties as those described in the patent mentioned above Have dyes if you have mono azo dyes of the general formula I.
EMI0001.0014
    which contain no acidic water-solubilizing groups, and in which X is hydrogen or halogen, R and R 'are low molecular weight, unsubstituted or substituted alkyl radicals, treated with chromium donating agents under conditions,

   cause the chromating of the dye with elimination of the alkyl radical R. As alkyl radicals R and R 'are preferred, the methyl 1- and ethyl group in question, but also the propyl, butyl, oxethyl, chloroethyl,

       11lethoxy or ethoxy ethyl group. The dyes which can be used according to the invention are obtained from diazotized aminohydroquinone dialkyl ethers by coupling with 3-methylsulfonyl-1-oxynaphthalene in an alkaline medium. The salts of trivalent chromium are suitable as chromating agents.

   They are expediently used in such quantities that there is at least 1 atom of chromium for every paring agent molecules, an excess of chromizing agent not interfering and often being used with advantage Cleavage of the alkyl radical R is favored by metallization at elevated temperatures.

   The work is preferably carried out at temperatures above 100, in aqueous solution or suspension under pressure, for example at 120-1.60, optionally in the presence of wetting and dispersing agents such as turkey red oil, or in alcohol.

   If necessary, you can also chromate in higher-boiling organic solvents and diluents in an open vessel, for example in ethylene glycol monomethyl or ethyl ether, in ethylene glycol, formamide, dimethylformamide or in the urea melt at 130 to 150. The new complex chromium compounds are obtained as dark, blue-violet powders that dissolve in water with a blue color, and in concentrated sulfuric acid with a violet color.

   If necessary, their solubility in water can be further improved by mixing small amounts of alkaline inorganic salts such as sodium carbonate or trisodium phosphate or with anionic wetting agents, detergents and dispersants such as soap or synthetic detergents. They dye wool and wool-like fibers, such as casein, super polyamide and super poly urethane fibers from neutral to weakly acidic baths in very genuine, clear blue tones.



  The present patent now relates to a process for the production of a chromium-containing monoazo dye. The process is characterized in that a monoazo dye of the formula
EMI0002.0013
    wherein R is a low molecular weight, substituted or unsubstituted alkyl radical which splits off under the chromating conditions, e.g. B. the methyl radical, means that chromabge bende agents can act.

      The new chromium-containing monoazo dye obtained is a dark blue powder that dyes wool from neutral or weakly acidic bath in clear, blue tones with very good fastness to washing, fulling and sea water.

           Example: 15.3 parts of 1-amino-2,5-dimethoxybenzene are dissolved in 250 parts of hot water with 35 parts of conc. Dissolved hydrochloric acid, cooled to 3 and, after addition of ice, diazotized with 6.9 parts of sodium nitrite (as 33% solution). The diazonium solution is poured at 0-3 into a solution of 25.4 parts of 3-methylsulfonyl-1-oxynaphthalene, 10

  5 parts by volume of 10N sodium hydroxide solution and 33 parts of anhydrous soda in 500 parts of water. When the formation of the dye has ended, the dye is isolated by adding sodium chloride, filtered off and dried. This gives a red-brown powder, which is heated to 145-155 in 750 parts of glycol with 27 parts of chromium acetate (corresponding to 7.6 parts of Cr203) and 2.5 parts by volume until the starting dye has disappeared, which takes about 3 hours the case is.

   This creates. a deep blue solution that is poured into 3000 parts of 15% saline while still hot. The dyestuff which has separated out is filtered off and washed with.

         15% saline solution and dries it. The dye is a dark blue powder that dissolves very well in hot water after grinding with trinate Color fastness to sea water.

   The dyeings are also characterized by very good light resistance and good friction resistance.

 

Claims (1)

PATENT CLAIM: Process for the production of a chromium-containing monoazo dye, characterized in that a monoazo dye of the formula 0-R OH N N_I I / l S02 CH3 0 CH3 wherein R is a low molecular weight, substituted or unsubstituted alkyl radical which splits off under the chromating conditions means, lets chromium-releasing agents act. The new chromium-containing monoazo dye obtained is a dark blue powder which dyes wool from a neutral or weakly acidic bath in clear, blue shades of very good fastness to washing, fulling and sea water. SUBClaims: 1. The method according to claim, characterized in that R is a methyl radical. 2. The method according to claim and dependent claim 1, characterized in that salts of trivalent chromium are used as the chromium-releasing agent.