CS244713B1 - Process for producing brown dyes for non-textile materials - Google Patents

Abstract

A method for producing brown dyes for non-textile materials such as leather, paper, wood, consisting in treating waste filtrates from the production of coupling intermediates for organic dyes with 4-nitrotoluene-2-sulfonic acid or 4,4'-dinitrostilbene-2,2'-disulfonic acid. The treatment is carried out under boiling and in an alkaline lye environment at a pH of 9.5 to 13.5

Description

The invention relates to a process for the production of dyes of brown color for dyeing non-textile materials such as leather, paper and wood.

Dyes of brown shades were previously produced, but their production was stopped for hygienic reasons, because they were dyes based on carcinogenic benzidine. These dyes have recently been replaced and the pallet has been expanded by producing dyes according to AO 205 783, where waste filtrates from the production of water-soluble azo dyes have been used.

It has now been found that dyes of brown shades for non-textile materials can be produced by the process according to the invention, which consists in treating waste water from the production of coupling dyes for organic dyes, for example 4-nitro-2-aminophenol-6-sulfoacids. -nitro-2-aminophenol, 4-aminoacetanilide, N-methyl-o-anisidine-4-sulfoacid, 2-aminophenol-4-sulfamide, N-acetyl-p-phenylenediamine-2-sulfoacid, 4-chloro-2-amino -6-sulfo acids, 2,6-diamino-mesitylene-4-sulfo acids, N-methyl-1-acids or urea I-acids act with 4-nitrotoluene-2-sulfonic acid or 4,4'-dinitrostilbene-2,2 ' -disulfonic acid at a boiling point in an alkaline-alkaline medium at pH 9.5 to 13.5. The resulting dyes are isolated from the solution in a conventional manner, for example by salting.

An advantage of the process for preparing the brown shades according to the invention is the use of an organic component from process waste water. Dyes are produced in a simple way almost without increasing the consumption of domestic water. The main advantage is saving scarce raw materials, expanding the range of valuable and missing dyes on leather and other materials such as paper and wood. Depending on the type of starting waste water and the type of component used for the condensation, a relatively wide variety of water-soluble browns of yellow, red to green shades is obtained.

In order that the invention may be more fully understood, the following examples are provided.

He did

400 ml of the filtrates from the production of p-aminoacetanilide are mixed with 24 g of 100% p-nitrotoluene-2-sulfonic acid and the pH of the solution is adjusted to pH 10-11 by the addition of sodium hydroxide. Then 400 ml of 10 mol / ml sodium hydroxide solution are added. 1 and condensation is carried out by heating the reaction mixture to the boiling point for 4 hours. After the condensation was complete, the slurry was salted with 15-20% sodium chloride and acidified with hydrochloric acid to a pH of about 3. After isolation and drying, about 60 g of an orange-brown shade were obtained.

Example 2

400 iftl filtrates from the production of 4-nitro-2-aminophenol-6-sulfoacids, which are strongly acidic, are mixed with 24 g of 100% p-nitrotoluenesulfonic acid or 4,4'-dinitrostilbene-2,2'-disulfonic acid, the pH of the solution is The solution is adjusted to 10-11 by the addition of sodium hydroxide and 40 ml of 10 mol / l sodium hydroxide are added for the actual condensation, which lasts for 3.5 to 4 hours. After condensation, the dye is salted out with 10% sodium chloride to pH 2 to 3. After isolation and drying, 78 to 90 g of a dry brown dye of orange-brown shade are obtained on leather, paper and wood.

Example 3

800 ml of urea-1-acid waste filtrates are mixed with 48 g of 4-nitrotoluene-2-sulfonic acid or 4,4'-dinitrostilbene-2,2'-disulfonic acid and the pH of the reaction mixture is adjusted to 10 with sodium hydroxide solution. An additional 80 ml of 10 mol / L sodium hydroxide is added and condensed for 4 to 6 hours at boiling. The resulting dye is isolated by salting out 10-15% sodium chloride (v / v) and acidified with hydrochloric acid to give a weakly congo acid reaction. The dye suspension is filtered at 40-60 ° C. After drying, 85-120 g of a light brown shade are obtained.

Example 4

The filtrates from the production of 4-chloro-2-aminophenol-6-sulfoacid were treated in the same manner as in Example 3. 110-150 g of an orange-brown dry dye were obtained.

Example 5

The waste filtrates from the preparation of N-acetyl-p-phenyl endiamine-6-sulfoacid were treated in the same manner as in Example 3. 90 g of a dye of a reddish brown shade were obtained.

Example 6

Procedure as in Example 3, treated with filtrates from the preparation of N-methyl-1-acid. 40 to 65 g of dye are obtained, which can be advantageously used as nucleating components for mixing classic dark corostane brown on the skin.

Claims (1)

Process for producing brown dyes for non-textile materials such as leather, paper, wood, characterized in that waste water from the production of coupling dyes for organic dyes from the group comprising 4-nitro-2-aminophenol-6-sulfoacid, 4-nitro-2 -aminophenol, p-aminoacetanilide, N-methyl-o-anisidine-4-sulfoacid, 4-chloro-2-amino-6-sulfoacid, 2,6-diaminomesitylenesulfoacid, N-methyl-1-acid or urea-1-acid It is treated with 4-nitrotoluene-2-sulfonic acid or 4,4'-dinitrostilbene-2,2'-disulfonic acid in a caustic alkaline medium at pH 9.5 to 13.5 and the boiling point of the reaction mixture, whereupon the resulting dye is isolated.