A NEW MANUFACTURE OF VIOLET AND BLUE AZO-DYES
Year: 1885

page_text: I, HERBERT JOHN HADDAN of 67, Strand, in the City of Westminster, Civil
Engineer, do hereby declare the nature of said invention for A NEW MANUFACTURE
OF VIOLET AND BLUE AZO-DYES, a communication to me from abroad by the
Farbenfabriken, vorm. Bayer & Co, a joint Stock Company, of Elberfeld, in the
German Empire, to be as follows:-
My correspondents have found, that by combination of Tetrazoditolyl, of the
tetrazo-combinations of the ortho- and para toluol, or a mixture of both (obtained
by alcaline reduction of ortho- or para-nitrotoluol, or of the mixture of both,
that is to say the technical introtoluol) with naphtols (a and B naphtol-dioxy-
naphtaline etc) or the mono- and disulpho-acids of the same, blue azo coloring
matters can be produced, which differ essentially from the corresponding benzidin
coloring substances.
While tetrazodiphenyl (formed by the diazotizing of benzidin) produces with
naphtols and the sulpho acids of the same bordeaux to violet coloring matters,
which are adapted almost only for dyeing wool and, owing to their dull tone,
represent no salcable trade products, the action of tetrazoditolyl on these com-
binations initiates a series of new blue azo-colouring substances, which are adapted
to dye from blueish violet to deep dark blue not only wool in the acid bath, but
above all unmordanted cotton in a slightly alcaline bath.
The most important new combinations the inventors have obtained, are the
following.
Tetrazoditolyl gives with a naphtol a monosulpho acid (produced by sulphonating
a naphtol or by the decomposition of diazotized naphtionic acid (the same is
obtained by the Bach process or by sulphonating a naphtylamine with 4 parts
monohydrated sulphuric acid at 80-100° C) a beautiful, acid-proof blue, with
B naphtol-a-monosulpho acid a blue bordeaux, with Schäffer's C-naphtol-
B monosulpho acid a blue violet, with B naphtola disulpho-acid (R salt) a
reddish blue; with naphtol-ẞ disulpho-acid (Ĝ salt) a dull blue, with so-called

page_text: B-naphtol-y-disulpho-acid a beautiful clear blue; with a or ẞ naphtol a blue or
violet coloring substance, insoluble in water, which, by treatment with sulphuric
acid can be rendered soluble in water.
These coloring matters are produced by the tetrazo combinations of the tolidin,
or of one of their salts, being caused to run upon the solutions of the naphtols
or of the sulpho acids of the same, which solutions have been kept alkaline till
the end. The formation of the coloring matter may also be effected in any acetato
solution.
The following may serve as an example of the production of the coloring
substances.
An acid-proof coloring substance dyeing wool blueish violet, cotton deep dark
blue, which coloring substance the inventors call azo-blue, is preferably obtained in
the following manner.
50 kilos of sulphate of tolidin are mixed in 1000 litres of water, 60 kilos of
hydrochloric acid of 20° B are added, and a solution of 22 kos. of nitrite of soda
(nitrous salt) is slowly introduced together with the required quantity of ice.
The thus obtained chloride of tetrazoditolyl is subsequently caused to run slowly
into a solution of 85 kilos of a naphtol-a monosulpho salt of soda, and 40 kos.
of soda, in 2000 litres of water. The azo-blue is separated in the form of a
dark blue precipitate. The precipitation is completed by adding common salt,
subsequently filtering and drying.

page_text: I, HERBERT JOHN HADDAN, of 67 Strand, Westminster, do hereby declare the
nature of this Invention which has been communicated to me from abroad by the
Farbenfabriken vorm Bayer & Co, of Germany and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement:-
It has been found that by the combination of Tetrazo-ditolyl or of the Tetrazo
compounds of ortho- and para-tolidine or a mixture of both (obtained by alkaline
reduction of ortho- or para-nitro-toluol, or of a mixture of both, that is to say
nitrotoluol) with naphthol (alpha and beta naphthol-dioxy-naphthaline etc) or the
mono and disulpho-acids of the same from violet to blue azo dyes or colouring
matters can be produced which differ essentially from the corresponding benzidine
dyes.
Tetrazo diphenyl (formed by diazotizing benzidine) forms with naphthols and the
sulpho acids thereof bordeaux blue to violet colouring matters, which are not fast
and are only suitable for dyeing wool and owing to their dull tone are of little
commercial value but by causing tetrazo-ditolyl to act on these combinations as
hereinafter described a series of fast blue azo dyes is obtained which are capable of
dyeing unmordanted cotton from blue violet to deep dark blue in a slightly
alkaline bath.
The following may be taken as examples of the most important combinations
obtained according to this Invention.
Tetrazo ditolyl with alpha naphthol alpha monosulpho acid (produced by
sulphurising alpha naphthol or by the decomposition of diazotized naphtionic acid)
forms a beautiful acid proof blue dye; with beta naphthol alpha monosulpho acid
it forms a bordeaux blue with Schäffer's beta naphtol-beta monosulpho acid a
blue violet with beta naphthol alpha disulpho acid (R salt) a reddish blue with
beta naphthol-beta disulpho acid (G. salt) a dull blue with alpha or beta naphthol
a blue or violet coloring substance or dye insoluble in water but which can be
rendered soluble by treatment with sulphuric acid.
These coloring matters are produced by causing the tetrazo combinations of
tolidines or of one of their salts to run into solutions of naphthols or of the sulpho
acids thereof which solutions are maintained alcaline to the end. The formation
of the coloring matter may also be effected in an acetic acid solution.
The following may be taken as an example of the manufacture of a dye by
means of this invention.
An acid proof colouring substance or dye (azo blue) dyeing wool a blue violet or
cotton a reddish blue is obtained preferably by proceeding as follows.
Fifty (50) kilos of sulphate of tolidine are mixed in one thousand (1000) litres
of water and sixty (60) kilos of hydrochloric acid of twenty (20) degrees Beaume
being stirred in with a sufficient quantity of ice after which a solution of twenty
two (22) kilos of nitrite of soda is gradually introduced.

page_text: The tetrazo ditolyl chloride thus obtained is subsequently caused to run slowly
into a solution of eighty five (85) kilos of soda salt of alpha naphthol-alpha
monosulpho acid and forty (40) kilos of soda in two thousand (2000) litres of
water. The azo-blue is separated in the form of a dark blue precipitate. The
precipitation is completed by adding common salt after which the product is
filtered and dried.
Having now particularly described and ascertained the nature of this Inven-
tion and in what manner the same is to be performed I declare that what
I claim is,―
1. A process for obtaining violet and blue azo dyes by the action of tetrazo
ditolyls or their salts upon naphthols and their mono and disulpho acids substan-
tially as herein before described.
2. The new azo dye obtained by the combination of tetrazo ditolyls or their salts
with naphthols and their mono and disulpho acids substantially as hereinbefore
described.