DE571596C - Process for the preparation of leuco compounds of anthraquinone dyes - Google Patents

Description

Process for the production of leuco compounds of anthraquinone vat dyes The production of stable acidic derivatives of the leuco compounds of vat dyes has been described, for example, in British patents 24 & 802, 245 587e 247 787, 251491. `Of these compounds, the acidic sulfuric acid esters are particularly important for dyeing and printing. Since they form salts with alkalis, they are water-soluble and can be applied to the fiber in this form and converted back into the insoluble vat dyes through oxidation. These sulfuric acid esters of leuco compounds of anthraquinone vat dyes form commercially available dyes as sodium salts, e.g. B. under the name Soledon colors, but they are not very durable, nor as soluble as is desirable for dyes of this type.

It has now been shown that the salts of the acid sulfuric acid esters of leucoanthraquinone vat dyes with oxyalkylamines. Surprisingly, they are more durable and dissolve better than the alkali salts. When they are used, the objection raised against the acidic derivatives commercially available today, that they are not durable and that they are becoming more and more insoluble, does not apply. Bases of the following general type can thus be used, tr use ,, wherein Alk represents an alkyl or oxyalkyl radical and R1, R. represent hydrogen, alkyl, oxyalkyl or polyQxyalkyl radicals. The following procedure can be used to prepare the new soluble compounds.

The sodium salt of the acid sulfuric acid ester of the leucoanthraquinone dye is in the form of a paste - treated with an organic acid, the free Acid is precipitated. This is separated off and then by adding a mixture dissolved by diethanolamine and triethanolamine.

Connections made in this way are sufficiently durable, in order to remain unchanged even in the absence of a reducing agent; moreover are they water soluble.

The implementation of the new method can, for example, in the following Species successes: zooo parts by weight of the Soledon jade green paste (sulfuric acid ester the leuco connection of Soledon jade green, Color Index No. iioi) known dye are mixed in a vessel with 1,000 parts of water, whereupon a 20% acetic acid solution is carefully added while stirring for so long until an acidic reaction occurs. The temperature of the mixture is increased to 20 ° Held at 25 °. The leucosulfuric acid ester which has become free precipitates and is filtered off and washed out with a little water until the filtrate reacts neutrally. The Filter cake is squeezed out to remove as much moisture as possible. To 25o Parts of this filter cake add up to 250 parts of diethanolamine.

The addition of acetic acid gives a leuco-sulfuric acid ester because an equilibrium arises, whereby the free ester is formed.

The addition of the diethanolamine dissolves the dye and the concentration the thick, pasty mass is twice as large as that of the original dye. It is advisable to work with the exclusion of oxygen, although this is not entirely the case necessary is. The amount of ethanolamine used can be chosen differently, just as the amount of water in the product can vary without it To change properties. It is also possible in the exemplary embodiment instead of diethanolamine use monoethanolamine, triethanolamine or methyldipropanediolamine and achieves the same results, and can also be used in place of the dye mentioned another soluble acidic derivative of the leuco compound of an anthraquinone vat dye use.

Instead of making the organic salt in the manner described, you can add the organic base to a printing paste with the same success which uses the soluble acidic derivative of the leuco vat dye. For example can such a printing paste, which is made from 100 parts of the available as a commodity, acidic Derived from one of the leucoier bonds of an anthraquinone vat dye with 8o Parts of one of the bases mentioned above and 82o parts of English rubber starch mass mixed as a thickener, in the usual way for printing Cotton, silk or wool can be used. After printing, the goods are q. Soaped up to 5 minutes in the usual way and treated in an oxidizing bath, which is either ferric chloride, sodium nitrite and sulfuric acid or ammonium persulfate contains.

You need the free, acidic derivative of the vat dye leuco compound not to isolate in order to obtain a more soluble product. The immediate addition the organic bases described to the commercially available dye apparently leaves compounds of higher solubility arise or only act as a solvent. In each Trap, the solubility is improved and the tendency to precipitate is very considerable decreased.

Claims (2)

PATENT CLAIMS: i. Process for making durable water-soluble Leuco compounds of anthraquinone vat dyes, characterized in that acidic sulfuric acid esters of leuco compounds of anthraquinone vat dyes or their alkali salts with one or more oxyalkylamines, e.g. B. with Di- or Triethanolamine, or both, treated: 2. The method according to claim i, characterized in that the alkali salt of the acid sulfuric acid ester with an organic acid, for. B. with acetic acid, and the acidic compound precipitated dissolves in one or more oxyalkylamines. BERLIN. PRINTED IN DL @ 'hEICHSDRUCIIEIZEi