The Manufacture or Production of Derivatives of Hydroxyanthra- quinone.
Year: 1895

page_text: Date of Application, 1st July, 1895
Complete Specification Left, 31st Mar., 1896-Accepted, 2nd May, 1896
[Communicated from abroad by THE FARBENFABRIKEN, vormals FRIEDRICH
BAYER & Co., of Elberfeld, Germany.]
The Manufacture or Production of Derivatives of Hydroxyanthra-
quinone.
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 to be as follows:-
In the Specification of the Letters Patent No. 975, of January 16th 1894,
granted to me, a process for the production of derivatives of hydroxyanthraquinone,
such as quinizarin and purpurin, was described, which process consisted either in
introducing nitrous acid into a heated solution prepared by dissolving anthraquinone
and boric acid in sulphuric acid, or in mixing, first, the necessary agents, eiz. :—
anthraquinone, boric acid, sulphuric acid, & salts of nitrous acid, or such com-
pounds which yield nitrous acid in the presence of sulphuric acid, and subsequently
heating the so formed mixtures at elevated temperatures.
It might have been expected that beta-hydroxyanthraquinone would yield
purpurin as chief product, if treated in an analogous manner. My foreign
correspondents have, however, now made the discovery, that only a very small
quantity of of purpurin is produced by treating beta hydroxyanthraquinone with
nitrous acid and sulphuric acid in the presence of boric acid in the above defined
manner, quinizarin being obtained as chief product in this process, and they have
ascertained that beta-hydroxyanthraquinone can therefore be profitably used for
the production of quinizarin.
My foreign correspondents give the following example, in order to illustrate one
method of treating hota-hydrox vanthraquinons in the shora defined mennar The
To a solution prepared from 10 parts of beta hydroxyanthraquinone and 200 parts
of sulphuric acid (of 100 per cent. H₂SO), 10 parts of crystallised boric acid and
13 parts of nitrite of sodium are added, and the so-formed liquid is heated during during
several hours at about from 220 to 230 degrees Centigrade, until it has assumed an
intense yellowish-red colour, and a sufficient quantity of quinizarin is formed
(which may be distinguished by spectroscopic research). After cooling, the mass
is poured into water, and the resulting liquid is boiled off. The precipitate is
filtered off. The researches of my foreign correspondents have shewn that the
so-formed product contains a small quantity of purpurin, which is formed together
with quinizarin in the process. They have succeeded in separating this compound
from the quinizarin by treating the above mentioned precipitate with a solution
of sulphate of alumina, the purpurin being thereby dissolved.
After filtering off, the residue is dried, and may be recrystallised by means of
glacial acetic acid. The quinizarin is thus obtained in a pure form.
In order to convert beta hydroxyanthraquinone into quinizarin by means of
the process herein before defined, my foreign correspondents do not limit them-
selves to the directions given in the above example, as these may be varied. For

page_text: instance, the sodium nitrite used in the example may be replaced by the corre-
sponding quantities of other nitrites, nitrous acid in gaseous state may be
introduced into a solution of beta hydroxyanthraquinone and boric acid in
concentrated sulphuric acid; the temperature may vary within certain limits;
and, in accordance therewith, the time of reaction will be longer or shorter.
The boric acid may be replaced by salts of boric acid or other boron compounds
(as, for instance, boron trichloride), which yield boric acid in the presence of
sulphuric acid.
This invention in general relates to the production of quinizarin as chief product
from beta hydroxanthraquinone by means of nitrous acid and sulphuric acid in
the presence of boric acid or the like.
NEWTON & SON,
Agents for the Applicant.
The Manufacture or Production of Derivatives of Hydroxyanthra-
quinone.
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 :-
In the Specification of the Letters Patent No. 975, of January 16th 1894,
granted to me, a process was described for the production of derivatives of
hydroxyanthraquinone, such as quinizarin and purpurin, the which process
consisted either in introducing nitrous acid into a heated solution of anthra-
quinone and boric acid in sulphuric acid, or in first mixing the necessary agents,
viz., anthraquinone, boric acid, sulphuric acid, and salts of nitrous acid, or compounds
yielding nitrous acid, when mixed with sulphuric acid, and subsequently heating the
mixtures at elevated temperatures. It was to be supposed that betahydroxyanthra-
quinone would yield purpurin, as chief product, if treated in an analogous manner.
My foreign correspondents have, however, now made the discovery that only a
very small quantity of purpurin is produced by treating betahydroxyanthraquinone
with nitrous acid and sulphuric acid in the presence of boric acid in the above
defined manner, quinizarin being obtained instead, as chief product, in this process,
so that betahydroxyanthraquinone can be used with advantage for the production
of quinizarin.
The
My foreign correspondents give the following example, in order to illustrate a
method of treating betahydroxyanthraquinone in the above defined manner.
parts are by weight.
EXAMPLE.
A solution of 10 parts of betahydroxyanthraquinone in 200 parts of sulphuric
acid (100 per cent. H.SO.) having been prepared, 10 parts of crystallized boric
acid and 13 parts of nitrite of sodium are added, and the liquid mixture is heated
during several hours at about 220 to 230 degrees Centigrade, until it has
assumed an intense yellowish-red color, and a considerable quantity of quinizarin
is formed (which may be ascertained by spectroscopic examination).
cool, the mass is poured into water, & the liquid having been heated to boiling, the
precipitate is filtered off. The product contains a small quantity of purpurin
formed together with quinizarin in the process, which may be separated from the
quinizarin by treating the precipitate with a solution of sulphate of alumina,
When

page_text: the purpurin being thereby dissolved. If the residue is dried and recrystallised
from glacial acetic acid, quinizarin is obtained in a pure form.
In order to convert betahydroxyanthraquinone into quinizarin by means of the
process hereinbefore defined, my foreign correspondents do not limit themselves to
the directions given in the above example, as these may be varied. For instance,
instead of the sodium nitrite prescribed in the example, the corresponding quantities
of other nitrites may be used, or gaseous nitrous acid may be introduced into a
solution of betahydroxyanthraquinone and boric acid in concentrated sulphuric
acid, and the temperature may be varied within certain limits, in which case the
time occupied in effecting the change will also vary.
Instead of boric acid, salts of boric acid, or other boron compounds (as, for
instance, boron trichloride), yielding boric acid in the presence of sulphuric acid,
may be used.
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 :-
The production of hydroxyanthraquinones, viz., quinizarin, as chief product, and
purpurin, from betahydroxyanthraquinone, which process consists either in intro-
ducing nitrous acid into a heated liquid containing betahydroxyanthraquinone,
boric acid, or the like, and sulphuric acid, or in heating, at elevated temperatures,
mixtures prepared from betahydroxyanthraquinone, boric acid, or the like,
sulphuric acid, and salts of nitrous acid, or other compounds which yield nitrous
acid, when used together with sulphuric acid.
Dated this 31st day of March 1896.
NEWTON & SON,
Agents for the Applicant.