IMPROVEMENTS IN THE MANUFACTURE OF COLORING MATTER SUITABLE FOR DYEING AND PRINTING.”ATION
Year: 1872

page_text: LETTERS PATENT to William Meister, Dr. Eugen Lucius, and Dr.
Adolph Brüning, of Hoechet, near Frankfort-on-the-Main, in
Germany, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF COLORING MATTER SUITABLE FOR DYEING AND PRINTING.”
PROVISIONAL SPECIFICATION left by the said William Meister, Dr.
Eugen Lucius, and Dr. Adolph Brüning at the Office of the Com-
missioners of Patents, with their Petition, on the 6th September
1872.
We, WILLIAM MEISTER, Dr. EUGEN LUCIUS, and Dr. ADOLPH
BRUNING, of Hoechet, near Frankfort-on-the-Main, in Germany, do
hereby declare the nature of the said Invention for “IMPROVEMENTS IN
THE MANUFACTURE OF COLORING MATTER SUITABLE FOR DYEING AND PRINTING," to
be as follows:-
Our Invention has for its object improvements in the method of
·making artificial alizarine.

page_text: ог
Our process consists in a new way of making "anthrachinone"
"oxanthracene." For this purpose we heat anthracene for some timo
with a mixture of bichromate of potash and diluted nitric acid. The
anthrachinone thus obtained in a more or less pure state is boiled for
some hours with fuming nitric acid; the anthrachinone dissolves in the
acid, and causes the solution to become yellow.
By the addition of water to the acid solution, after having boiled some
time, a yellowish precipitate is formed, which consists essentially of
mononitro-anthrachinone. The diluted nitric acid filtered from the
precipitate is used for the oxidation of anthracene into anthrachinone.
The precipitate washed with water is put into a concentrated solution of
caustic soda or other alkali. The alkaline mass is heated to a tempera-
ture of about 170 to 220 degrees of the centigrade thermometer, and
this temperature is maintained until the bluish violet color of the
product ceases to become more intense, which is best seen when a small
portion of the solution is dissolved in water. The mass is cooled and
dissolved in boiling water, and the solution filtered. The hot filtered
solution is treated with hydrochloric acid, or any other suitable acid in
excess, and a brownish yellow precipitate falls, which, after it has been.
washed with water, is suitable for dyeing and printing in the same
way as the coloring matters obtained from madder. The residue of the
alkaline mass left on the filter consists essentially of regenerated
anthrachinone, which, after it has been transformed again into nitro-
anthrachinone, is used for further production of coloring matter.
Pure alizarine can be obtained from the coloring matter mentioned
above in various ways, such as by extraction with ether or other
suitable dissolving liquids, and evaporation or precipitation there-
from.
"
SPECIFICATION in pursuance of the conditions of the Letters, Patent,
filed by the said William Meister,. Dr. Eugen Lucius, and Dr. 30
Adolph Brüning in the Great Scal Patent Office on the 6th, March
1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
MEISTER, Dr. EUGEN LUCIUS, and Dr. ADOLPH BRUNING, of, Hoechet,
near Frankfort-on-the-Main, in Germany, send greeting.
35

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of September, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said William Meister, Dr. Eugen Lucius, and
Dr. Adolph Brüning, Her special license that we, the said William
Meister, Dr. Eugen Lucius, and Dr. Adolph Brüning, our executors,
administrators, and assigns, or such others as we, the said William
Meister, Dr. Eugen Lucius, and Dr. Adolph Brüning, our executors;
administrators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
MANUFACTURE OF COLORING MATTER SUITABLE FOR DYEING AND PRINTING," upon
the condition (amongst others) that we, the said William Meister, Dr.
Eugen Lucius, and Dr. Adolph Brüning, our executors or administrators,
by an instrument in writing under our, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
0
THE
NOW KNOW YE, that we, the said William Meister, Dr. Eugen
Lucius, and Dr. Adolph Brüning, do hereby declare the nature of
our said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following
statement (that is to say) :-
Our Invention has for its object improvements in the manufacture of
coloring matter suitable for dyeing and printing.
The process consists, first, in the manufacture of the substance known
as anthrachinone or oxanthracene. For this purpose anthracene is
heated for some length of time with a mixture of bichromate of potash,
and diluted nitric acid. The anthrachinone thus obtained in a more
or less pure state is boiled during some hours with fuming nitric acid.
The anthrachinone' dissolves in the said acid, and causes the solution'
to become yellow.

page_text: By the addition of water to the acid solution, after having been boiled
some time, a yellowish precipitate is formed, which precipitate essen-
tially consists of mononitro-anthrachinone. The diluted nitric acid filtered
from the precipitate is used for the oxidation of anthracene into anthra-
chinone. The precipitate washed with water is put into a concentrated
solution of caustic soda or other alkali. The alkaline mass is heated up
to a temperature of about 170-220° centigrade, and this temperature
maintained until the bluish violet color of the product ceases to become
more intense, which is best seen when a small portion of the solution is
dissolved in water. The cooled mass is dissolved in boiling water, and
filtered. The hot filtered solution is heated with hydrochloric acid, or any
other suitable acid in excess, and gives a brownish yellow precipitate,
which, after it has been washed with water is fit and suitable for direct
dyeing and printing in the same way as the colors obtained from madder.
The residue of the alkaline mass left on the filter consists essentially of
regenerated anthrachinone, which after it has been transformed again into
nitro-anthrachinone is used for further production of coloring matter.
Pure alizarine can be obtained from the coloring matter mentioned
above in different ways by the extraction with ether or other suitable
substances.
In order that the said Invention may be fully understood and readily
carried into effect we will now describe the details of our manu-
facture.
In performing the operation of obtaining anthrachinone we employ
anthracene, which by well-known means has been purified as much as
possible, and the melting point of which lies between 207° and 210°
centigrade. One part by weight of such an anthracene is heated up to
boiling point with twelve parts by weight of nitric acid of 1.05 specific
gravity, and one-fourth part by weight of bichromate of potash, and
maintained at this temperature for some length of time, say three hours,
until the mixture has become crumbling and triturable. The heating of
the anthracene with the mixture of nitric acid and bichromate of potash
has to be performed in vessels not easily acted upon by the acid. For
this purpose we employ well enamelled iron boilers or vessels of clay.
The product thus obtained has the appearance of a yellowish powder.
When dried and powdered this body represents a crude anthrachinone
in a form adapted to a further treatment as herein-after described.
We heat one part by weight of anthrachinone up to boiling point with

page_text: six parts of fuming nitric acid of 1.50 specific gravity, and this tem-
perature is kept up for some length of time, say again three hours. The
anthrachinone dissolves completely in the boiling acid, and the operation
is finished if a portion of it having been taken out and allowed to cool
down is found not to separate any more anthrachinone. The boiling we
perform in clay vessels closed, but provided with a waste pipe which
permits the escaping vapours of the azotic gases to enter into a con-
denser, which serves for regeneration and condensation of the nitric acid.
By the inuence of the boiling nitric acid on the anthrachinone, nitro-
anthrachinone, or better, mononitro-anthrachinone is obtained. This
compound is dissolved in our process in the surplus of the acid, and is
precipitated by dilution of the acid solution with water. The mononitro-
anthrachinone separates in form of a yellow precipitate, which after it
has been washed and dried may be used, direct for further treatment.
The diluted nitric acid filtered from the precipitate of the nitro-
anthrachinone serves together with the acid obtained out of the
condenser for the oxidation of anthracene into anthrachinone.
The before-described mononitro-anthrachinone well washed and dried
is put into a concentrated solution of caustic soda or other alkali. The
proportions we use are one part by weight of mononitro-anthrachinone,
and nine to twelve parts by weight of solution in water of caustic soda
at 1-3 to 1.4 specific gravity, or nine to twelve parts by weight of solution.
in water of caustic potash at 1-3 to 1·4 specific gravity. The mixture
of the mononitro-anthrachinone with alkali in vessels fitted up for such
purpose is heated up to a temperature of 170-230 degrees centigrade,
and this temperature maintained until the formation of the coloring
matter is completed. This point is attained when the precipitate which
hydrochloric acid or other suitable acid separates from the filtered
alkaline solution no longer increases in quantity. The cooled mass is
dissolved in boiling water, and filtered. The hot solution treated with
hydrochloric acid or any other suitable acid settles down as a brownish
yellow precipitate, which after it has been washed with water is fit and
suitable for direct dyeing and printing in the same way as the colors
obtained from madder.
The residue of the alkaline mass left on the filter consists essentially
of regenerated anthrachinone, which, after it has been transformed again
into nitro-anthrachinone is used for further production of coloring
matter.

page_text: Pure alizarine can be obtained from the coloring matter mentioned
above in different ways by the extraction with ether or other suitable
substances.
Having thus described the nature of our said Invention, and the
manner of performing the same, we would have it understood that we
do not confine ourselves to the exact details described; but what we
claim is the manufacture of coloring matter suitable for dyeing and
printing,―
First. By the production of the anthrachinone from anthracene by
means of bichromate of potash and diluted nitric acid.
Secondly. By the production of the mononitro-anthrachinone from the
anthrachinone by means of fuming nitric acid.
And, thirdly. By heating this mononitro-anthrachinone with alkaline
substances.
In witness whereof we, the said William Meister, Dr: Eugen
Lucius, and Dr. Adolph Brüning, have hereunto set our hands
and seals, this Twenty-eighth day of February, in the year of
our Lord One thousand eight hundred and seventy-three.