Patent GB-176833-A (GB)
Title: The manufacture of dyestuffs
IPC: C09B57/00
Filed: 1920-10-14
Abstract: The dyestuffs described in the parent Specification are obtained by condensing b -naphthoquinone, or a substitution product thereof, with a sulphurized arylamine having the sulphur-containing group in the orthoposition to the amino-group, of one of the following classes:-(1) o-aminoarylmercaptans, (2) o-aminoarylthiosulphonic acids, (3) o-aminoaryldisulphides, (4) the products (described in Specification 17417/14) of interaction of disulphur dichloride with aromatic amino compounds, and the derivatives thereof obtained by treatment with water and alkali; sulphurized arylamines containing a mono- or di-alkylamino group in the para position to the primary amino group are excluded.  The products are acid mordant dyes if they contain acid groups but vat dyes if free from such groups.  According to examples:-(1) b -naphthoquinone or 3 : 4-dichlor-b -naphthoquinone is condensed in presence of acetic acid and sodium acetate with o-aminothiophenol, preferably as zinc mercaptide or as hydrochloride; the product dyes wool from the vat violet-blue changed to bluish green by afterchroming; by warming with fuming sulphuric acid, or by using for the condensation b -naphthoquinone-4 : 6- or 4.7- disulphonic acid a mordant dyestuff is obtained; the o-aminothiophenol may be replaced by aniline-o-thiosulphonic acid (Specification 4792/00) or by o-aminodiphenyl disulphide; (2) 3 : 4 dichlor-b -naphthoquinone is condensed as in example 1 with the product of reaction of disulphur dichloride with aniline; the product dyes wool from the vat violet changed to bright bluish-green by afterchroming; instead of the direct product of the action of disulphur dichloride on aniline, the transformation products obtained by treatment with water may be used; by condensing the product of reaction of disulphur dichloride on p-anisidine with b -naphthoquinone or a halogen derivative thereof, a similar dyestuff is obtained: (3) the aminothiophenol obtained from 1-chlor-2-nitrobenzene-5-sulphonic acid by treatment with polysulphides and subsequent reduction, is condensed with 3-chlor-b -naphthoquinone; the product yields fast bluish-green shades when dyed or printed in the usual manner for acid mordant dyestuffs; a similar dyestuff is obtained from the corresponding aminothiophenolcarboxylic acid (from 1-chlor-2-nitro-5-benzoic acid) by condensing with b -naphthoquinone-4 : 6-disulphonic acid; the direct products of reaction of disulphur dichloride on a - and b -naphthylamine or their sulphonic acids, for example 2-naphthylamine-6-or 7-sulphonic acid, or their products of transformation of an o-aminoarylmercaptan character (obtained according to Specifications 17417/14 and 18292/14) yield similar dyestuffs when condenced with b -naphthoquinone or its derivatives or sulphonic acids.  1-Amino-2-thiophenol-4-sulphonic acid is obtained by boiling 1-chlor-2-nitrobenzene-5-sulphonic acid with alcoholic sodium sulphide solution and sulphur and reducing the resulting nitrodiphenyldisulphide disulphonic acid with zinc and caustic soda; the solution of the aminothiophenol sulphonic acid so obtained is directly employed in the above described dyestuff condensation. 1-Amino-2-thiophenol-4-carboxylic acid is similarly obtained from 1-chlor-2-nitro-5-benzoic acid.