Improvements in the Manufacture or Production of Colouring .Matters Derived from Anthraquinone.
Year: 1893

page_text: Date of Application, 25th July, 1893
Complete Specification Left, 23rd Apr., 1894-Accepted, 25th May, 1894
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE FARBENFABRIKEN vormals FRIEDRICH
BAYER & Co., of Elberfeld, in the Empire of Germany.]
Improvements in the Manufacture or Production of Colouring
.Matters Derived from Anthraquinone.
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:-
It is known that until recently it was not possible to produce dye-stuffs possessing
a sufficient clearness and purity, on a practical scale, by heating diorthonitro
anthraquinone with concentrated or fuming sulphuric acid.
My foreign correspondents have described in the Specification of application for
Letters Patent No. 17674, dated 4th October 1892, a method of obtaining coloring
matters (yielding very pure and clear shades) with a good result. The last
named method is based on the employment of sulphur sesquioxide, or sulphur, in
the presence of fuming sulphuric acid.
My foreign correspondents have now found a new and simple method, which
likewise yields very good results. This new process consists in heating dinitro
anthraquinone, or analogous products, with concentrated or fuming sulphuric acid,
with an addition of boric acid or salts thereof, or such substances which, when
employed in the presence of sulphuric acid, are transformed into boric acid.
Coloring matters are thus obtained which possess brilliancy and intensity, whilst
under the same conditions, without employing boric acid or the like, raw products
result which are of no technical value, and require costly purification for conversion
into valuable dye-stuffs.
The action of the boric acid is based on the fact that the hydrogen atoms of the
hydroxylic groups contained in the hydroxy nitro anthra quinone compounds
formed during the reaction, are replaced by radicles of boric acid, so-called boric
ethers being formed immediately. The researches of my foreign correspondents
have shown, that the said boric ethers are stable in the presence of concentrated
or fuming sulphuric acid, even at the highest temperatures, and, owing to the
formation of ether in the hydroxylic groups, the coloring matters are protected
from too far reaching an action of the respective chemical agents which can be
employed.
My foreign correspondents have ascertained that, for instance, the boric ether
of alizarin cannot be converted into alizarin bordeaux by means of the process
described in the Specification of Letters Patent No. 8725, dated 5th June 1890,
and that the boric ether of alizarin bordeaux cannot be transformed by heating
with concentrated sulphuric acid into hexahydroxyanthraquinone, that is to say,
by means of the process described in the Specification of Letters Patent No. 17712,
dated 4th November 1890. In these two cases, alizarin and alizarin bordeaux are
protected from the oxidising action of the sulphuric acid.
The following example will serve to illustrate the nature of this invention, and
the manner in which it can be carried into practical effect. The parts are by
weight.

page_text: per cent.
10 parts of dinitro anthraquinone, 15 parts of crystallized boric acid, and
300 parts of sulphuric acid, at 66 degrees Baumé (containing from 92 to 93
of pure sulphuric acid), are heated in an enamelled vessel. An energetic reaction
begins at from about 220 to 230 degrees centigrade, and the temperature is raised
to from 250 to 260 degrees centigrade. When the reaction is completed, the mass
is heated for a quarter of an hour at 220 degrees centigrade. After cooling,
the mixture is poured into 4000 parts of cold water; the resulting liquid is boiled,
and the separated dye stuff is filtered off. The latter consists for the most part,
of hexahydroxyanthraquinone described in the Specification of Letters Patent
No. 17712, dated 4th November 1890, and of a small quantity of a product which
contains nitrogen, and is probably a hexahydroxyanthraquinone derivative. The
dye-stuff produces, on wool mordanted with chromium salts, the same shades which
result from alizarin cyanine R.
Of course, my foreign correspondents do not limit themselves to the directions
given in the said example. The proportions mentioned therein, for instance, can
be varied within certain limits. The sulphuric acid employed may be of another
degree of concentration, without departing from the nature of the present
invention. If, for instance, in the above example, in place of sulphuric acid
at 66 degrees Baumé, stronger acids, for instance, monohydrated sulphuric acid,
or moderately fuming sulphuric acid be employed, hexabydroxy anthraquinone is
produced in a less, and the dye stuff containing nitrogen is formed in a higher,
degree, relatively, as the acid employed is stronger. By reason thereof, the
resulting direct products give greener shades on wool mordanted.
If stronger acids, for instance, fuming sulphuric acid (containing 30 per cent. of
sulphuric anhydride), be used, sulpho acids of the respective dye stuffs are
formed.
The boric acid employed in the above example, in general, can be replaced by
such boron compounds (such as salts of boric acid, boron trichloride, or the like)
which, when employed in the presence of sulphuric acid, yield boric acid.
My foreign correspondents have ascertained that the pure di ortho nitro
anthraquinone can be replaced by the isomeric compounds, or the raw mixture of
nitro-anthraquinones resulting from an energetic nitration of authraquinone, or
anthracene, or by the sulpho acids thereof.
Dated this 25th day of July 1893.
NEWTON & SON,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture or Production of Colouring
Matters Derived from Anthraquinone.
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:-
Until recently it was not possible to produce dye-stuffs of sufficient brilliance and
purity, on a practical scale, by heating diorthonitroanthraquinone with concentrated
or fuming sulphuric acid.
My foreign correspondents have now found a new and simple method of
producing pure brilliant dye-stuffs from dinitro anthraquinone or the like, which
yields very good results, consisting in heating dinitroanthraquinone, or analogous
products, with concentrated or fuming sulphuric acid, together with boric acid or
salts thereof, or substances which yield boric acid, when used together with
sulphuric acid.

page_text: Under similar conditions, when boric acid is not used, crude products of no
technical value, requiring much purification, are formed.
As to the action of the boric acid, my foreign correspondents assume that the
hydrogen atoms of the hydroxyl groups in the hydroxyanthraquinone derivatives
formed during the process, are immediately displaced by radicles of boric acid,
boric ethers being formed, which, according to the researches of my foreign corre-
spondents, are stable in presence of concentrated or fuming sulphuric acid, even at
high temperatures.
The following example will serve to- illustrate the nature of this invention,
and the manner in which it can be carried into practice. The parts are by
weight.
A mixture of 10 parts of diorthonitroanthraquinone, 10 parts of crystallised boric
acid, and from 200 to 300 parts of sulphuric acid at 66 degrees Baumé (containing
from 92 to 93 per cent. of pure sulphuric acid), is heated in an enamelled vessel
while constantly stirred. An energetic action begins at from about 220 to
230 degrees centigrade, the temperature rising to from 250 to 260 degrees. When
the action is complete, the mass is allowed to cool, and the mixture is then poured into
3,000 parts of cold water. The resulting liquid is boiled, and dye-stuff which
separates is filtered off from the hot liquid, and washed with water, in order to
remove the adherent acids.
The dye-stuff so produced consists, in great part, of the hexahydroxyanthra-
quinone described in the Specification of Letters Patent No. 17712, dated
4th November 1890, together with a small quantity of a product containing
nitrogen, very similar that formed by the action of ammonia on hexahydroxyanthra-
quinone, as mentioned in the Specification of Letters Patent No. 8702, dated
21st May 1891. It also contains small quantities of the alizarin hexacyanine
described in the Specification of Letters Patent No. 4871, dated 18th March 1891.
The said dye-stuff produces intense blue shades on wool mordanted with chromium
salts.
My foreign correspondents do not, however, limit themselves to the directions
given in the said example. The proportions mentioned therein, for instance, can
be varied within certain limits. The process can also be carried out at lower
temperatures, for instance, at from 190 to 200 degrees centigrade. In this case,
heating must be continued during a longer period. The product so formed is
identical with that obtained on following the directions given in the above example.
Moreover, the sulphuric acid used may be of another degree of concentration, with-
out departing from the nature of the present invention. Thus, if, in the above
example, stronger acids, for instance, monohydrated sulphuric acid, or moderately
fuming sulphuric acid, be substituted for sulphuric acid at 66 degrees Baumé, a
smaller proportion of hexahydroxyanthraquinone is produced, and a larger propor-
tion of the said dye-stuff' containing nitrogen is formed, according to the strength of
the acid used. By reason thereof, the products give greener shades on mordanted
wool.
On using a weaker sulphuric acid in place of the sulphuric acid at 66 degrees
Baumé, the product contains but a very small quantity of the substance containing
nitrogen, hexahydroxyanthraquinone being almost exclusively produced, and in a
very nearly pure state.
If stronger acids, for instance, fuming sulphuric acid (containing 30 per cent.
of sulphuric anhydride) be used, sulpho acids of the respective dye-stuffs are
formed.
In order to illustrate more fully the valuable effect produced by the use of boric
acid, or the like, the following table is given, showing the products formed on
heating diorthonitroanthraquinone respectively with monohydrated sulphuric acid
or sulphuric acid at 66 degrees Baume, or sulphuric acid at 60 degrees Baumé, in
each case whether with or without boric acid. The colors of the solutions obtained
on dissolving the said products respectively in soda lye and concentrated sulphuric
acid, also the spectra which the sulphuric acid solutions of the said products show,
:

page_text: Instead of the boric acid prescribed in the above example, boron compounds (for
instance, salts of boric acid, or boron trichloride, or the like) may be used, which,
in presence of sulphuric acid, yield boric acid.
My foreign correspondents have ascertained that in place of pure diorthonitro-
anthraquinone, the isomeric compounds, or the crude mixture of nitroanthraquinones
formed by energetic nitration of anthraquinone or anthracene, or the sulpho acids
of the nitro compounds herein before defined, can be employed.
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. For the production of dye-stuffs capable of dyeing with the aid of mordants
from diorthonitroanthraquinone, or other nitroanthraquinones, or nitroanthraquinone
sulphonic acids and concentrated or fuming sulphuric acid, the use of boric acid,
or other boron compounds, which, when used together with sulphuric acid, act in a
similar manner.
2. The process for producing dye-stuffs capable of dyeing with the aid of
mordants, which process consists in allowing concentrated or fuming sulphuric acid
to act in the presence of boric acid, or other boron compounds (which, when used,
with sulphuric acid, act in a similar manner), on diorthonitroanthraquinone, or
isomeric dinitroanthraquinones, or the crude mixture of nitroanthraquinones
obtained on energetically nitrating anthraquinone or anthracene, or on the sulphonic
acids of these nitroanthraquinones.
3. As products of manufacture, the dye-stuffs obtained by means of the process
herein before defined.
NEWTON & SON,
Agents for the Applicant.