DE49857C - Process for the preparation of amido - /? - naphthol and a - (j - dioxynaphthalene disulfonic acids - Google Patents

Description

IMPERIAL

PATENT OFFICE

Sulfonic acids, of the neighboring α - β - dioxynaphthalene (ß-hydronaphtoquinones) have not been known up to now. Disulfonic acids of this body can be traced back to Winning way easily and smoothly.

If one of the two well-known disulfonic acids R and G of ß-naphthol or from a mixture of these with the aid of any diazo compounds in a known manner Azo dyes prepared in this way are reduced by means of an acidic tin chloride solution a colorless solution, which was used in addition to that for diazotization, in the reduction regenerated amine contains the acidic sodium salt of an amido-ß-naphfoldisulfonic acid, which precipitated in crystallized form from this solution by the addition of common salt can be.

Example:

40 kg of the sodium salt of anilinazo, known commercially under the name "Orange G" - β - naphthol disulphonic acid are dissolved in 250 liters of boiling water. To this solution the warm solution of 45 kg of tin chloride in 50 l of hydrochloric acid (spec. weight 1.19), whereupon complete 'discoloration' the liquid enters. If you dissolve 60 kg of common salt in the colorless solution obtained, so the acidic sodium salt of amidonapbtoldisulfonic acid soon separates:

(NH,

C H

s O ₃ H
SO ₃ Na

in white crystals, which can be collected and dried

This salt suffers if you dissolve it in boiling water and the solution briefly Time in the boil, a molecular rearrangement, which is shown by the following equation is expressed:

OH

SO ₂ H '

SO ₃ Na

OH OH

SO ₃

SO ₃ Na ',
that is, the acidic sodium salt of amidos-naphtholedisulphonic acid is transformed into the neutral sodium ammonium salt of the corresponding dioxynaphthalenedisulphonic acid when water is absorbed. All of the described phenomena apply in exactly the same way, whether a derivative of one or the other of the two known naphthol disulfonic acids or a mixture of both was used as the starting product.

The resulting disulfonic acids of dioxynaphthalene are extremely easily soluble. For their use, separation is not required at all, but that by boiling the solution obtained with water of the amidonaphthol compound can be used directly. This use is based on that this solution corresponds in almost all properties to a dissolution of tannin and As a result, it is suitable for all applications for which tannin was previously used became. She falls z. B. a glue solution slightly acidified with acetic acid and dissolves

therefore use it for tanning animal hides. It also falls on the dissolutions of all basic ones Aniline peat and can therefore be used in dyeing and especially in cotton printing instead of Tannins can be used as a stain. For this reason, the disulfoic acids des a-ß-Dioxynaphtalins are called "naphtotannins".

Claims (1)

Patent Claims: i. The preparation of the acidic sodium salts of the amido-ß-naphthol-disulphonic acids by reduction the corresponding azo dyes (Orange G, Ponceau 2 G, Orange III, Ponceau G T, Ponceau R T, Ponceau G, Scarlet G, Ponceau 2 R, Ponceau 3 R, Phenetol Red, Coccinin B, Cresol Red, Crystal ponceau, Echtroth B, Bordeaux G and B, Thiorubin, Neucoccin, Echtroth D, Benzidine blue) with acidic tin chloride solution and separation of the product formed with table salt. The preparation of salts of the disulphous acids of a-ß-dioxynaphthalene by cooking the acidic sodium salts mentioned in claim 1 with water.