The Manufacture or Production of Azo Dye-stuffs. COLOURING MATTER OBTAINED FROM AND DIHYDROXY- DIAZOBENZENE NAPHTHALENE DISULPHONIC ACID, HEREINBEFORE TERMED "
Year: 1894

page_text: Date of Application, 12th Feb., 1894
Complete Specification Left, 10th Nov., 1894--Accepted, 15th Dec., 1894
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE FARBENFABRIKEN, vormals FRIEDRICH
BAYER & Co., of Elberfeld, in the Empire of Germany.]
The Manufacture or Production of Azo Dye-stuffs.
I, HENRY EDWARD NEWTON of The Office for Patents, 6, Bream's Buildings,
Chancery Lane, London, E.C., Patent Agent, do hereby declare the nature of
this invention to be as follows:-
My foreign correspondents have discovered some time since that the naphthalene
tetra sulphonic acid obtained by heating naphthalene-ß, B-disulphonic acid with
sulphonating agents, yields, by melting with alkalies, two isomeric dihydroxy
naphthalene disulphonic acids, which can easily be separated, as the one (the
60-called Red Acid ") at once crystallises out, on acidulating the melted mass,
whilst the other (the so-called Yellow Acid"), owing to its ready solubility,
remains dissolved in the mother liquor, from which it can be isolated by adding
potassium chloride, cooling, and filtering off.
6
My foreign correspondents have now, found, that the dihydroxynaphthalene
disulphonic acid hereinbefore termed "yellow acid," possesses the very remarkable
property (hitherto not known of any hydroxynaphthalene sulphonic acid), to yield
pure yellow azo dye-stuffs, when combined with certain diazo compounds, these dye-
stuffs being adapted for dyeing wool in acid baths.
i
One method of producing these yellow azo colouring matters, is illustrated by the
following example. The parts are by weight.
COLOURING
MATTER OBTAINED FROM
AND DIHYDROXY-
DIAZOBENZENE
NAPHTHALENE DISULPHONIC ACID, HEREINBEFORE TERMED " YELLOW
ACID."
The diazobenzene solution obtained in the well known manner from 2.) parts of
anilin, 50 parts of muriatic acid, and 15 parts of sodium nitrite, is allowed to flow
into a solution which is prepared from 90 parts of dihydroxynaphthalenedisulphonic
acid (so-called "yellow acid"), and contains an excess of soda. The resulting
solution at once assumes a yellow colour, and, on adding muriatic acid, the azo
dye-stuff thus formed separates in little lustrous reddish crystals, which are filtered
off. The colouring matter can also be obtained in beautiful brilliant green
flat needles, if it is redissolved in hot solutions of common salt, and these solutions
are allowed to cool.
The dye-stuff thus produced dyes wool a pure yellow, possesses a high intensity or
dyeing power, and is capable of giving very even shades, when dyed together with
other colouring matters. The resulting shades are not materially altered either by
acids or by alkalies, and withstand the action of light in a high degree.
Similar colouring-matters result, if the aniline used in the above example is,
replaced by other amines or substituted amines, such as meta-nitraniline, para-
nitraniline, ortho-toluidine, para-toluidine, or the like. The dye-stuffs thus obtained

page_text: likewise yield yellow shades, and are in general similar to that produced as described
in the above example.
D
T 1
1004
NEWTON & SON,
Agents for the Applicant.
I HENRY EDWARD NEWTON of The Office for Patents 6 Bream's Buildings,
Chancery Lane in the County of London, Patent Agent, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
My foreign correspondents discovered some time ago that the naphthalene-
tetrasulphonic acid obtained, for instance, by heating naphthalene beta, beta,
disulphonic acid with sulphonating agents, when fused with alkalies, yields two
isomeric dihydroxynaphthalene disulphonic acids, which can be easily separated,
as the one (the so-called dihydroxynaphthalene disulphonic acid Ŕ) at once
crystallizes out on acidulating the melted mass, whilst the other (the so-called
dihydroxynaphthalene disulphonic acid Y), owing to its ready solubility, remains
dissolved in the mother liquor, from which it can be isolated by adding potassium
chloride, cooling, and filtering off.
My foreign correspondents have now found, that the dihydroxynaphthalene
disulphonic acid Y hereinbefore referred to, possesses the very remarkable property
(hitherto not known to be possessed by any hydroxynaphthalene sulphonic acid) of
yielding yellow azo dye-stuffs, when combined with certain diazo compounds, these
dye-stuffs being adapted for dyeing wool in acid baths.
One method of producing these yellow azo colouring-matters, is illustrated by
the following example. The parts are by weight.
COLOURING-MATTER OBTAINED FROM MOLECULAR PROPORTIONS OF DIAZO
BENZENE AND THE DIHYDROXYNAPHTHALENE DISULPHONIC ACID Y
HEREINBEFORE REFERRED TO.
The diazo benzene solution obtained in the well-known manner from 20 parts of
aniline, 50 parts of muriatic acid, and 15 parts of sodium nitrite, is allowed to flow
into a solution prepared from 70 parts of dihydroxynaphthalene disulphonic acid
(so-called dihydroxynaphthalene disulphonic acid Y) containing an excess of
soda. The solution at once assumes a yellow colour, and on adding muriatic
acid, the azo dye-stuff separates in small lustrous reddish crystals, which are
filtered off. The colouring-matter can be obtained in beautiful brilliant green flat
needles by redissolving it in a hot solution of common salt, and then allowing solution
to cool.
The dye-stuff tbus produced dyes wool a pure yellow, possesses a high intensity or
dyeing power, and is capable of giving very even shades, when dyed together with
other colouring matters. The shades are not materially altered either by acids or
by alkalies, and withstand light in a high degree.
Similar colouring-matters are formed if, instead of the aniline used in the
above example, the equivalent quantities of other mono-amines or of mono-
nitramines of the benzene series, such as ortho-toluidine, para-toluidine, meta
nitraniline, para-nitraniline, or the like, are used. The dye-stuffs thus obtained
are in general similar to that produced as described in the above example. The
dye-stuff from meta nitraniline also yields pure yellow shades on wool in acid baths,

page_text: whilst the colouring-matters from para-toluidine and para nitraniline produce yellow.
shades of a faintly reddish hue, and the dye-stuff from ortho toluidine yields yellow
shades of a slightly brownish hue.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
1. The production of mono azo dye-stuffs from the dihydroxynaphthalene
disulphonic acid Y herein before referred to, by coupling one molecular proportion
of the diazo derivatives of mono amines or mono nitramines of the benzene series,
with one molecular proportion of the dihydroxynaphthalene disulphonic acid Y, or
an alkaline salt thereof.
2. The process for producing yellow mono azo colouring-matters capable of
dyeing wool, which process consists in combining one molecular proportion of
dihydroxynaphthalene disulphonic acid Y, or an alkaline salt thereof, with one
molecular proportion of aniline, ortho-toluidine, para-toluidine, meta-nitraniline,
or para-nitraniline.
3. As new products of manufacture, the new dye-stuffs produced by the process
hereinbefore defined, or by any other means affording the same result.
Dated this 6th day of November 1894.
NEWTON & SON,
Agents for the Applicant.