The Manufacture or Production of a Trihydroxynaphthalene Monosulpho Acid.
Year: 1893

page_text: Date of Application, 18th Oct., 1893
Complete Specification Left, 18th July, 1894-Accepted, 15th Sept., 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 a Trihydroxynaphthalene
Monosulpho Acid.
1 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 to be as follows: :-
Armstrong and Wynne (see Proceedings of the Chemical Society, of the
year 1890, page 133) have proved that the naphthalenetetrasulpho acid obtained
by sulphonating naphthalene (see Seuhofer in the Berichte der Deutschen
Chemischen Gesellschaft, volume 8, page 1486) possesses the composition repre-
sented by the following formula :—
My foreign correspondents have described in the Specification of the German
Patent No. 40893, that the above naphthalenetetrasulpho acid is, by melting with
alkalies, first converted into an alphanaphtholtrisulpho acid (a,-naphthol ẞ, as B₁
trisulpho acid), and that, on melting with alkalies for a longer period, a dihydroxy-
naphthalenedisulpho acid is formed. It is further stated in the Specification of the
German Patent No. 67563, that two isomeric dihydroxynaphthalenedisulpho acids
are produced in the last-named process.
My foreign correspondents have now found, that a trihydroxynaphthalenemono-
sulpho acid in a pure state is formed, when the above naphthalenetetrasulpho
acid, or salts thereof, are melted with alkalies at temperatures rising above
230 degrees centigrade. The trihydroxynaphthalene sulpho acid thus formed,
Dossesses the following formula :-

page_text: PRODUCTION OF α₁ ẞ, az TRIHYDROXYNAPHTHALENE ẞ-SULPHO ACID FROM
NAPHTHALENETETRA SULPHO ACID.
1 part of naphthalenetetrasulphonate of sodium is mixed with 2 parts of potassa,
and the mass is heated at 280 degrees centigrade. The melted mass, as soon as
the reaction is complete, is dissolved in water, and the resulting solution is
acidulated by means of muriatic acid. The sodium salt of trihydroxynaphthalene-
monosulpho acid then separates in the form of compact needles.
The neutral salts of the trihydroxynaphthalenemonosulpho acid so formed
dissolve in water with a red color, and the watery solutions thereof shew a light
blue fluorescence. On adding a solution of chloride of lime to watery solutions
of the acid salts of the above trihydroxynaphthalenemonosulpho acid, a wine-
yellow color is produced, which disappears again if an excess of chloride of lime
is added. Ferric chloride produces a brown color in watery solutions of the acid
salts of the said trihydroxynaphthalenemonosulpho acid.
The directions given in the above example can be varied; for instance, in place
of potassa, soda, or mixtures of potassa and soda, can be used. The process can be
carried out in open or closed vessels, and the salts of naphthalene tetrasulpho acid
employed in the above example can be replaced by salts of a-naphtholtrisulpho acid, or
dihydroxynaphthalenedisulpho acid, these two acids being formed by melting
naphthalenetetrasulpho acid at not too high a temperature.
Dated this 18th day of October 1893.
NEWTON & SON,
Agents for the Applicant.
COMPLETE SPECIFICATION.
The Manufacture or Production of a Trihydroxynaphthalene
Monosulpho Acid.
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 :-
Senhofer was the first to prepare a naphthalenetetrasulphonic acid by
sulphonating naphthalene (see Berichte der Deutschen Chemischen Gesellschaft,
volume 8, page 1486).
It has been shewn by my foreign correspondents, in the Specification of the
German Patent No. 40,893, that, by fusing the said naphthalenetetrasulphonic
acid with alkalies, it is first converted into a naphtholtrisulphonic acid, and that
a dihydroxynaphthalenedisulphonic acid is formed by further fusing the said
naphtholtrisulphonic acid with alkalies.
Later researches have shewn, that the naphthalenetetrasulphonic acid obtained
by Senhofer, is a mixture of tetrasulphonic acids, and that the so-called naphtha-
lenetetrasulphonic acid of Senhofer is converted, when fused with alkalies, into
two naphthol trisulphonic acids. It is further stated in the Specification of the
German Patent No. 67563, that two isomeric dihydroxynaphthalene disulphonic
acids are produced in the process described in the Specification of the German
Patent No. 40,893.
My foreign correspondents have now found, that trihydroxynaphthalenemono-

page_text: PRODUCTION OF TRIHYDROXYNAPHTHALENEMONOSULPHONIC ACID FROM
NAPHTHALENETETRASULPHONIC ACID.
1 part of naphthalenetetrasulphonate of sodium is mixed with 2 parts of potash,
and the mass is heated at 280 degrees centigrade. When the action is complete,
the mass is dissolved in water, and the solution is acidulated with muriatic acid..
The potassium salt of trihydroxynaphthalenemonosulphonic acid then separates
in the form of compact needles.
The neutral salts of the trihydroxynaphthalene monosulphonic acid so formed,.
dissolve in water, affording red coloured solutions, which shew a slight blue
fluorescence. On adding a solution of chloride of lime to solutions of the said acid
salts of the said trihydroxynaphthalenemonosulphonic acid in water, a wine-yellow
colour appears, which disappears if an excess of chloride of lime is added. Ferric
chloride produces a brown colour in solutions of the acid salts of the said
trihydroxynaphthalene monosulphonic acid.
The directions given in the foregoing example can be varied; for instance,.
mixtures of potash and soda can be used in place of potash. The process can
be carried out in open or closed vessels. Tríbydroxynaphthalenemonosulphonic
acid is also obtained by using, in the process illustrated by the foregoing
example, the naphthalenetetrasulph which can be produced by heating
naphthalene-beta, beta-disulphonic acid with fuming sulphuric acid, at tempera-
tures above 260 degrees centigrade. Instead of the salts of naphthalenetetra-
sulphonic acid used in the above example, corresponding quantities of the salts.
of the naphtholtrisulphonic acids, or of the two dihydroxynaphthalenedisulphonic
acids which are formed, as above mentioned, by fusing naphthalenetetrasulphonic
acid, or salts thereof, with alkalies, at not too high a temperature may be used.
These naphtholtrisulphonic acids are formed by fusing Senhofer's naphthalene-
tetrasulphonic acid, or salts thereof, with soda, at temperatures not above
200 degrees centigrade, whilst the said two dihydroxynaphthalenedisulphonic
acids are obtained on fusing Senhofer's naphthalenetetrasulphonic acid, or alkaline
salts thereof, with soda, at temperatures not above 250 degrees centigrade. The
naphtholtrisulphonic acid and dihydroxynaphthalenedisulphonic acid, or salts of
these acids obtainable, in an analogous manner, by fusion with soda, from the
naphthalenetetrasulphonic acid derived from naphthalene-beta,-beta-disulphonic
acid, can also be used in the process illustrated by the foregoing example.
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
from abroad), I declare that what I claim is :-
1. The process for producing trihydroxynaphthalenemonosulphonic acid as
herein described, and consisting in fusing with alkalies, at temperatures above
240 C., either
1) naphthalenetetrasulphonic acids-(obtained by sulphonating either
(a) naphthalene, or
(b) naphthalene beta beta. disulphonic acid) :

page_text: 2. As a new product of manufacture, the new trihydroxynaphthalenemono-
ulphonic acid produced by the process herein before defined, or by any other means
affording the same result.
จ
T
NEWTON & SON,
Agents for the Applicant.