CS205783B1 - Method of treatment of refuse waters from the production of soluble azo-dyes - Google Patents

Description

Method of waste water treatment from production of soluble paints

The invention relates to a process for the treatment of waste water from the production of water-soluble azo dyes, whereby dyes of brown shades on the skin, paper and wood are obtained.

Up to now, technological waste waters have been leaving azo dyes production, contaminated with unreacted starting active or passive components, reaction intermediates or by-products, resulting from side reactions to a wastewater treatment plant, where the costs were treated with lime milk and green glass. However, with the large amount of wastewater present, the capacity of the treatment station is not sufficient and so a part of it leaves the plant directly, leading to considerable pollution of the watercourse.

These drawbacks are partly overcome by the wastewater treatment process from the production of soluble azo dyes, which leads to the formation of brown shades according to the present invention, which is based on the fact that waste water from the production of dyes and binders, such as direct and direct light dyes , direct fixed metals, complexed chromium acids, leather dyes and reactive dyes, add sulfoacid aromatic nitro compounds, for example 4-nitrotoluene-2-sulfoacid or 4,4'-dinitrostilbene-2,2-dieulfoacid, and in a caustic alkaline environment condensation is carried out at boiling point and the dye is isolated. The dyes produced according to the invention, in which they employ organic constituents from process waste water, are obtained by a simple process205 783

205 703 almost without increasing the consumption of domestic water. In addition, these dyes will expand the product range by the desired and valuable dyes while improving the quality of wastewater. Using this method, maximum efficiency in producing soluble azo dyes can be achieved. The main advantages of the wastewater treatment according to the invention are the saving of scarce raw materials, the expansion of the palette of valuable and still missing dyes on the skin and other materials such as paper and wood.

The process according to the invention can process technological waste waters from the production of dyes, direct and direct light-fast dyes, direct fixed metals, acidic, acidic complexed chromium (complex 1: 1 and 1 with 2) leather dyes and reactive dyes. Depending on the type of starting waste water and the type of component used for condensation, a relatively wide variety of water-soluble browns of yellow, red to green shades is obtained.

To illustrate the invention in greater detail, the following examples are provided:

Example 1

800 ml of the waste filtrates which are collected during the isolation of the unsaponified red base P3B (intermediate dye) are introduced and 48 g of 100% p-nitrotoluene sulfo acid or dinitrostilbendisulfo acid are added. The stirred slurry was basified with 10 N potassium hydroxide solution to pH 10.5-11 and another 80 mL of 10 N sodium hydroxide solution was added. The reaction suspension is heated to boiling and condensed under boiling for 3 to 5 hours. Upon completion of the condensation, the resulting suspension is salted out with 5 to 10% salt, based on the volume of the solution, adjusted to pH with a slightly congic acid reaction with hydrochloric acid, and after cooling to 60 to 40 ^° , the resulting dye is filtered. Approximately 100 g of dry brown dye of a tan to brown color is obtained to dye leather and paper.

Example 2 '

800 ml of waste filtrates from the production of yellow base L4G (intermediate dye for direct permanent dye) are introduced, 55 g of 100% nitrotoluenesulfonic acid are added and 30 ml of 10 N sodium hydroxide are added to this mixture. The reaction mixture is heated to boiling with stirring and condensed at this temperature for 3-5 hours. After the condensation has ended, the resulting suspension is salted out with 5 to 10 7 salts. (depending on the effluent) based on the volume of the solution, the pH is adjusted with hydrochloric acid to a weak congo acid reaction (pH oca 3) and after cooling to 60-40 ° C the dye is filtered. 65 to 70 g of dry substance of the orange-brown shade are obtained.

Example 3

To 800 ml of the filtrates after isolation of the disazo dye Saturn navy blue LPG (direct permanent dye) is first added 48 g of 100% 4-nitrotoluene-2-sulfonic acid or 2,2'-dinitrostilbene-4,4'-disulfoic acid, then approx. 20 ml of 10 N sodium hydroxide solution to adjust the pH to 11.5 to 12 and then another 80 ml of 10 N NaOH at boiling point are condensed with stirring for 4 hours to form a dye. After completion of the condensation, the resulting suspension was high with 10% solid salt based on the volume of the solution, and the pH was adjusted with hydrochloric acid to a congo acid reaction (pH ca. 3). After filtering and drying, 150 to 200 g of dye on leather or green-brown paper is obtained.

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Example 4

Procedure as in Example 3, treated with filtrates from the production of Corostan Brown DGR (leather dye) to obtain 100-120 g of a brown dye.

Example 5

Following the same procedure as in Example 3, the filtrates from the production of Egacid Yellow M (acid dye) were processed to obtain 80-13% of a tan-dye skin dye.

Example 6

Following the procedure of Example 3, the filtrates were treated to isolate chromolan green greens BL (a complex dye with a chromium complex) to obtain 60 to 80 g of a brown dye.

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It is also possible to process a mixture of filtrates or process waste water from the production of soluble azo dyes, which contain waste filtrates from a number of azo production plants.

Claims (1)

OBJECT OF THE INVENTION A process for the treatment of waste water from the production of soluble azo dyes and dyes, for example, direct and dormant light-stable dyes, direct fixed metals, acidic and acidic complex chromium-bound dyes, leather dyes and reactive dyes, characterized in , for example 4-nitrotoluene-2-sulfoacid or 4,4'-dinitrostilbene-2,2'-disulfoacid at boiling point and in caustic alkaline medium at pH 9.5 to 13.5, whereupon the resulting dye is isolated.