IMPROVEMENTS IN THE MANUFACTURE OF ANTHRACHINON, AND IN THE REGENERATION OF CHROMIC ACID IN THE SAID MANUFACTURE AND IN OTHER MANUFACTURES
Year: 1879

page_text: LETTERS PATENT to Joseph Anthony Dixon, of 175, West George Street,.
Glasgow, in the County of Lanark, North Britain, Solicitor, for the Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF ANTHRACHINON, AND IN THE
REGENERATION OF CHROMIC ACID IN THE SAID MANUFACTURE AND IN OTHER
MANUFACTURES." A communication from abroad by Wilhelm Meister, Doctor
Eugen Lucius, and Doctor Adolphus Brüning, all of Hoechst-am-Main, in the
Empire of Germany, persons carrying on business as Chemical Manufacturers
at Hoechst-am-Main, under the Firm of Meister, Lucius, and Brüning..
PROVISIONAL SPECIFICATION left by the said Joseph Anthony Dixon at,
the Office of the Commissioners of Patents on the 7th August 1879.
JOSEPH ANTHONY DIXON, of 175, West George Street, Glasgow, in the County
of Lanark, North Britain, Solicitor. "IMPROVEMENTS IN THE MANUFACTURE OF
ANTHRACHINON, AND IN THE REGENERATION OF CHROMIC ACID IN THE SAID
MANUFACTURE AND IN OTHER MANUFACTURES." A communication from abroad
by Wilhelm Meister, Doctor Eugen Lucius, and Doctor Adolphus Brüning, all of
Hoechst-am-Main, in the Empire of Germany, persons carrying on business ass
Chemical Manufacturers at Hoechst-am-Main, under the Firm of Meister, Lucius,
and Brüning.
In the preparation of anthrachinon in many manufacturing establishments bi-
chromate of potash and an acid are employed, and the liquor containing the
chromic oxide salt is allowed to run away. In other manufactories chromate of
lime and hydrochloric acid are applied to the same purpose, and in this case a
process is sometimes applied for the regeneration of the chromate of lime, which is
however attended with considerable drawbacks. The object of the present In-
vention and of the process hereinafter described is to remedy these disadvantages.
I oxidise the anthracine at first with bi-chromate of potash and hydrochloric acid
in the usual way, press out the crude anthrachinon contained in the product, bring
the liquor containing the chromic chloride formed into a suitable vat, add thereto
for each equivalent of the bi-chromate of potash used three equivalents of peroxide
of manganese (somewhat in the form of peroxide of manganese mud or slime, such
D

page_text: as is obtained by Weldon's regeneration), and heat with stirring. There results
the formation of chromic acid by an easy reaction according to the following
equation
:―
Cr, Cl + 3 Mn O,
-
2 Cr O, +3 Mn Cl₂.
As the artificial peroxide of manganese contains manganous oxide and also calcic
hydrate, a part of the chromic acid is precipitated in combination with manganese.
The precipitate and solution I apply direct, with addition of hydrochloric acid, to
the oxidation of a fresh quantity of anthracene. After the reduction of the
chromic acid I have, in the liquor pressed out from the anthrachinon, chromic
chloride and manganous chloride. The liquor is again heated with the like pro-
portion of peroxide of manganese as before, and it is then neutralized with milk
of lime, which precipitates the whole chromate of manganese formed. The chromate
of manganese is then pressed out, and is used, with the addition of hydrochloric
acid, for the oxidation of a fresh quantity of anthrachinon. The liquor separated
from the precipitate contains in solution, if milk of lime has been added only until
the solution became colourless and assumed a neutral reaction, the whole of the
manganese which has not combined to form chromate of manganese with the
chromic acid produced by the action of the peroxide of manganese. This solution
is therefore treated with milk of lime until the whole of the manganese is precipi-
tated, and the manganese which is so precipitated in the form of manganous oxide
is then reconverted into artificial peroxide of manganese by insufflation of air
according to Weldon's process.
While the anthracene is oxidised by the chromate of manganese the regeneration
of the peroxide of manganese is also proceeding, so that the latter may be ready to
be reapplied forthwith to the oxidation of the chromic chloride to chromic acid, as
herein before described.
The process may also be varied in the following manner, that is to say, by
applying chromate of potash and peroxide of manganese, with addition of hydro-
chloric acid, simultaneously in the first oxidation of the anthracene. In this way
the chromate of potash is first reduced, yielding chromic chloride, and the chromic
chloride so produced is straightway oxidised again, through the action of the per-
oxide of manganese present, to chromic acid, so that a continuous reduction,
reformation, and re-reduction of chromic acid goes on, and in this way the chromic
acid acts continuously as a carrier of oxygen from the peroxide of manganese to
the anthracene present.
After complete reduction of the peroxide of manganese and of the chromate of
potash used I precipitate with milk of lime, and the precipitated manganous oxide
is, as before, reoxidised by insufflation of air. After the artificial peroxide of
manganese has settled down, and the supernatant solution of chloride of calcium
has been drawn off, the whole precipitate is transferred into the oxidation vat, and
with addition of hydrochloric acid the oxidation of a fresh quantity of anthracene
commences. In this way both the chromic acid and the peroxide of manganese are
constantly regenerated, and brought back again and again into the cycle or circular
course of the process.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Joseph Anthony Dixon in the Great Seal Patent Office on the
10th January 1880.
JOSEPH ANTHONY DIXON, of 175, West George Street, Glasgow, in the County
of Lanark, North Britain, Solicitor. "IMPROVEMENTS IN THE MANUFACTURE OF
ANTHRACHINON, AND IN THE REGENERATION OF CHROMIC ACID IN THE SAID
MANUFACTURE AND IN OTHER MANUFACTURES." A communication from abroad
by Wilhelm Meister, Doctor Eugen Lucius, and Doctor Adolphus Brüning, all of
Hoechst-ain-Main, in the Empire of Germany, persons carrying on business as
Chemical Manufacturers, at Hoechst-am-Main, under the Firm of Meister, Lucius,
and Brüning.
In the preparation of anthrachinon in many manufacturing establishments bi-
chromate of potash and an oxygen acid are employed, and the liquor containing
the chromic oxyde salt is allowed to run away. In other manufactories chromate
of lime and hydrochloric acid are applied to the same purpose, and in this case a
process is sometimes applied for the regeneration of the chromate of lime, which
is however attended with considerable drawbacks. The object of the present
Invention and of the process hereinafter described is to avoid the disadvantages
attending the recovery of the chromic acid in the chromate of lime process.
I oxydise the anthracene at first in the usual way with bichromate of potash and
hydrochloric acid; I press out the crude anthrachinon produced; I then bring the
liquor which contains the chromic chloride formed into a suitable vat; I add thereto
for cach equivalent of the bichromate of potash used three equivalents of peroxyde
of manganese (Un O₁), (somewhat in the form of the peroxyde of manganese mud
or slime, such as is obtained in Weldon's regeneration process), and heat with
stirring. There results the formation of chromic acid by an easy reaction according
to the following equation:-
Cr, Cl, +3 Mn O₂ = 2 Cr O, + 3 Mn Cl.
As the artificial peroxyde of manganese constains manganous oxyde and also calcic
hydrate, a part of the chromic acid is precipitated in combination with manganese.
The precipitate and solution I apply direct, with addition of hydrochloric acid, to
the oxydation of a fresh quantity of anthracene. After the reduction of the
chromic acid I have, in the liquor pressed out from the anthrachinon, chromic
chloride and manganous chloride. The liquor is again heated with the like pro-
portion of peroxyde of manganese as before, and it is then neutralized with milk
of lime, which precipitates the whole chromate of manganese formed. The chromate
of manganese is then pressed out, and is used, with the addition of hydrochloric
acid, for the oxydation of a fresh quantity of anthracene. The liquor separated
from the precipitate contains in solution, if milk of lime has been added only until
the solution became colorless and assumed a neutral reaction, the whole of the
manganese which has not combined to form chromate of manganese with the
chromic acid produced by the action of the peroxyde of manganese. This solution
is therefore treated with milk of lime until the whole of the manganese is pre-
cipitated, and the manganese which is so precipitated in the form of manganous
oxyde is then reconverted into artificial peroxyde of manganese by insufflation of
air according to Weldon's process.
While the anthracene is being oxydised by the chromate of manganese and
hydrochloric acid (giving in the residual liquor, after pressing out the anthrachinon,
chromic chloride and manganous chloride, as before, which are to be treated with
peroxyde of manganese and milk of lime, as already described), the regeneration of
the peroxyde of manganese from the manganous hydrate precipitated after pre-
cipitation and removal of the manganous chromate, as above described, is also
proceeding, so that the latter may be ready to be reapplied forthwith to the

page_text: oxydation to chromic acid of the chromic chloride which is being produced in the
process of oxydising the anthracene, as before described.
The process may also be varied in the following manner, that is to say :-I apply,
along with hydrochloric acid, chromate of potash and peroxyde of manganese
simultaneously to the first oxydisation of the anthracene. In this way the chromate
of potash or the chromic acid thereof is first reduced; chromic chloride and
chloride of potassium are produced, and the chromic chloride so produced is
straightway oxydised again through the action of the peroxyde of manganese
present to chromic acid, so that a continuous reduction, reformation, and re-
reduction of chromic acid goes on, the chromic acid acting continuously as a carrier
of oxygen from the peroxyde of manganese to the anthracene present until the
peroxyde of manganese is exhausted and wholly converted into manganous chlorido,
and no longer regenerates the chromic acid, which. consequently remains at length
wholly converted into chromic chloride.
After this complete reduction of the peroxyde of manganese and of the chromate
of potash used, and after removal of the crude anthrachinon formed, I pre-
cipitate the liquor with milk of lime, and the precipitated manganous oxyde and
chromium hydroxyde are reoxydised, as before, by insufflation of air. After the
artificial peroxyde of manganese so reformed has, along with the manganous
chromate, settled down, the supernatant solution of chloride of calcium is drawn off,
and the whole precipitate, containing the peroxyde and chromate of manganese
together, is transferred into the oxidation vat, and with addition of hydrochloric
acid the oxydation of a fresh quantity of anthracene commences. The chromate
of manganese is reduced by the hydrochloric acid and anthracene, with liberation
of oxygen and formation of chromic chloride and manganous chloride. The chromic
chloride so produced is immediately reconverted into chromic acid by the peroxyde
present, with formation of more manganous chloride, and so the chromic acid acts
in carrying oxygen from the peroxyde to the anthracene until the whole of the
peroxyde has again been converted into manganous chloride, as before, and the
whole chromic acid into chromic chloride, when, after removal of the anthrachinon
from the liquor, I treat the liquor, as before, with milk of lime and aërate it, draw
off the calcium chloride, and apply the residue, consisting of chromate and peroxyde
of manganese, to the oxydation of more anthracene, and so on. In this way both
the chromic acid and the peroxyde of manganese are constantly regenerated,
and brought back to act again and again in the cycle or circular course of the
process.
It is obvious that wherever chromic acid, or a salt thereof decomposable by
hydrochloric acid, is used along with hydrochloric acid in other manufactures for
purposes similar to that for which it is used in the manufacture of anthrachinon,
there will be a like formation of chromic chloride, which permits the reaction
expressed in the equation given above,
Cr, Cl 3 Mn O₁ = 2 Cr 0, + 3 Mn Cl₂,
to be employed to reconvert it into chromic acid. The chromic acid so regenerated
may then, according to the requirements and conditions of the particular manu-
facture, either be continuously reduced and regenerated by the action of hydrochloric
acid and peroxyde of manganese, both present simultaneously, as long as the
peroxyde lasts, and the resulting chromic chloride may then be regenerated and
re-applied over and over again; or by the use of peroxyde and milk of lime in the
way described such chromic acid may be recovered in the separate form of chromate
of manganese, which may either be applied with hydrochloric acid as the immediate
oxydizing agent, or, if anything in the particular manufacture should forbid
the use of a salt of manganese, the chromate precipitated, which is a hydrated
chromate, may be treated with boiling solution of caustic potash or soda, to which
it will give up its chromic acid, forming the potassic or sodic salt; or may by known
means be converted into the salt of any other convenient base, and the chromic
chloride formed by the hydrochloric acid in applying the chromate of manganese,
or of any other convenient base substituted for manganese; to the oxydation of a

page_text: fresh quantity of substance, may be regenerated, separated, and applied over and
over again, as before. I therefore claim the regeneration of the chromic acid from
chromic chloride by the action of peroxyde of manganese, which is a process sus-
ceptible of general application, whether used in the manufacture of anthrachinon
or other manufacture, and that in whatever way the chromic acid so regenerated
requires to be treated, or in whatever form it may require to be recovered or
applied, according to the exigencies of of any particular manufacture.
Having thus described the said Invention and the manner of performing the same,
I explain that I do not claim the discovery of the fact that chloride of manganese
can by precipitation with lime and insufflation of air be converted into peroxyde,
that fact being previously well known and applied, but what I do claim is,―
First. The application of chromic acid, regenerated from chromic chloride by
peroxyde of manganese, and of chromate of manganese to the oxydation of anthracene
into anthrachinon, in manner herein before described, or in manner substantially the
same.
Second. The regeneration of the chromic acid with peroxyde of manganese, and
the recovery thereof in the form of chromate of manganese, in the manufacture of
anthrachinon; as also, in connexion with the process herein before described for the
manufacture of anthrachinon, and as a step thereof, but not otherwise, the conversion
of the chloride or oxyde of manganese into peroxyde, all in manner hereinbefore
described, or in manner substantially the same.
Third. The regeneration of chromic acid from chromic chloride by means of
peroxyde of manganese, in manner hereinbefore described, or in manner substantially
the same, in other processes of chemical manufacture.
In witness whereof, I, the said Joseph Anthony Dixon, have hereunto set my
hand and seal, this Seventh day of November, in the year of our Lord One
thousand eight hundred and seventy nine.
JOSEPH ANTHONY DIXON. (L.S.)