IMPROVEMENTS IN THE MANUFACTURE OF AZO DYES FROM THE NITRO-SUBSTITUTION PRODUCTS OF BENZOL AND ITS HOMOLOGUES
Year: 1879

page_text: Filed 22nd March 1880.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CARL RUMPFF,
of the Firm of Friedrich Bayer and Company, of Elberfield, in the Kingdom of
Prussia, send greeting. WHEREAS Her most Excellent Majesty Queen Victoria
by Her Letters Patent under the Great Seal of Great Britain and Ireland, bearing
date at Westminster, the Twenty seventh day of March, One thousand eight hundred
and seventy nine, in the forty second year of Her reign, No. 1226, did for Herself Her
heirs and successors, give and grant unto me the said Carl Rumpff, Her special license
that I, the said Carl Rumpff my executors, administrators, and assigns, or such
others as I, the said Carl Rumpff my executors, administrators or 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 the Isle of Man, an Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF AZO DYES FROM THE NITRO-SUBSTITUTION PRODUCTS OF BENZOL
AND ITS HOMOLOGUES:" And whereas in pursuance and performance of a condition
in the said Letters Patent contained, I, the said Carl Rumpff, did within six
calendar months next after the date of the said Letters Patent cause a Specification
in writing under my hand and seal, particularly describing the nature of the said
Invention and in what manner the same was to be performed, to be duly filed
in the Great Seal Patent Office: And whereas since the filing of the said Speci-
fication I have been advised that the reference to a suitable amido-compound con-
tained in the part of the said Specification hereinafter particularly mentioned is
insufficient, and may also be held to be ambiguous and misleading, and I am for
the purpose of obviating all doubts respecting the said Specification desirous of
disclaiming such part of the said Specification. NOW KNOW YE, that I,
the said Carl Rumpff, by and with the leave of Her Majesty's Solicitor
General do hereby for the reasons aforesaid, and for effecting the objects
aforesaid strike out of the said Specification the words "or with the solution
of a suitable amido-compound," which occur in lines 37 and 38, on page 3

page_text: of the print of the said Specification printed by the Queen's Printers and published
at the Great Seal Patent Office, and in order that it may be clearly understood
what is the Invention which I now consider to be secured by the hereinbefore in
part recited Letters Patent, I shall proceed to repeat (omitting preamble and testing
clause) my said Specification as proposed to be amended by this present disclaimer
as follows:-
NOW KNOW YE, that I, the said Carl Rumpff, do hereby declare the nature
of my said Invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement thereof,
that is to say :-
This Invention has for its object improvements in the manufacture of azo-dyes
from the nitro-substitution products of benzol and its homologues.
For this purpose the nitro-substituted hydro-carbons of the aromatic group Cn,
H₂, n-6 are treated with such a quantity of fuming oil of vitrol that the
anhydride contents of the latter represent a little more than one molecule to one
the
A
molecule of nitro-body with which it is treated.
The transformation into the respective nitro sulphonic acids is thereby accom-
plished, and can if necessary be assisted by slightly warming the mixture, so that
when mixed with water perfect solution takes place.
The nitro-sulphonic acid solution thus obtained in an excess of sulphuric acid
is if necessary (generally but not always without further purification) mixed with
a further quantity of slightly diluted sulphuric acid or strong muriatic acid, so that
a suitable quantity of iron added to it accomplishes directly the reduction to the
amido-acid which remains in solution.
The solution thus obtained is then heated and super saturated with soda, by
which means all the resulting sodium salts of the acids contained in it are dissolved,
and at the same time the oxides and the carbonate of iron are separated from them.
In this part of the process I can use instead of iron, zinc or other suitable reducing
agent. I can also use potash instead of soda in the above operation, giving rise to
potassium salts instead of sodium salts. The solution thus purified together with
any wash waters of the residue is further diluted with water, and then mixed with
so much sulphuric acid or muriatic acid that after the beginning of the neutrali-
zation has taken place there still remains a little more acid than two equivalents
to one molecule of the original nitro-body.
The solution is then allowed to cool, and is diazotised by adding one molecule
of sodium nitrite to each molecule of the above, and the solution so obtained is
mixed with the solution in an excess of alkali of one molecule of one of the group
of the phenol bodies (simple or complex hydroxil substituted aromatic hydro
carbons and their further substitution products).
The coloring matter can be either crystalized out directly or can be precipitated
with common salt, and after collection can be used either at once or after further
purification by recrystallization or solution and reprecipitation.
The amido-sulphonic acid solution obtained by iron or other reducing agent as
above can also be decomposed at the boiling heat by milk of lime. In addition to
the oxides of iron gypsum is thereby precipitated, and the amido sulphonic acids
remain in solution as salts of calcium.
The diazotising process can then be carried out at once by means of sodium
nitrite and muriatic acid.
In all cases however where the calcium salts of the sulpho acids of the dyes are
not sufficiently soluble in water either the amido-sulphonate of calcium (before the
diazotising) or the precipitated salt of the dye should be transformed into a sodium
salt by boiling it with the proper quantity of soda.
I am aware that in the preparation of coloring matters diazo-sulphonic acids of
the hydro-carbons Cn H2 n-6 have before been employed, but they have been
prepared from the amido compounds. By this means other isomeric amido-
sulphonic acids are obtained differing from those which I obtain from the nitro-

page_text: sulphonic acids, for example, my sulphanilic acid in the metasulphonic acid of
aniline and my amido-toluol sulphonic acid obtained from nitro-toluol bears a
similar relation to the raw material. These bodies yield dyes differing in constitu-
tion and shade from all others hitherto obtained.
Another important feature in this process consists in the fact that I proceed from
the nitro-compounds of the aromatic hydro-carbons, and totally avoid the separate
production of the intermediate products, such as amido derivatives, sulphonic acids,
and amido-sulphonic acids.
By the conversion of the nitro body into dyes in one and the same solution the
process is very much simplified; in its application on a large scale a great number
of sources of loss are completely avoided.
The above described method of manufacture admits of the following slight
modification.
The nitro-substituted hydro-carbons of the aromatic series On H 2 n-6 are
mixed with as much fuming oil of vitriol that the anhydride contents of the latter
represents somewhat more than two molecules for one molecule of the nitro-hydro
carbon used.
When spontaneous reaction has nearly ceased the mixture is heated for several
hours to about 80° or 100° C.
Common sulphuric acid is added if necessary until its total amount corresponds
at least three molecules for one molecule of the nitro-hydro carbon and the solution
diluted with water reduced by an excess of iron or zinc, or other suitable reducing
agent. The solution of amido-disulphonic acid of the hydro-carbon thus formed is
treated in the same way, purifying diazotising and acting upon an alkaline solution
of a phenol body as already described for the nitro-monosulphonic acids of aromatio
hydro carbons.
I claim the production of azo-dyes in the following manner, viz., by the direct
conversion of nitro substitution products of benzol and its homologues into nitro-
sulphonic acids, of these into amido-sulphonic acids, and so subsequently into the
dyes, as hereinbefore specified.
In witness whereof, I, the said Carl Rumpff; have hereunto set my hand
and seal, this Third day of February, One thousand eight hundred and
35 CHAS. C. BRYCE, Merchant,
141, West George St., Glasgow, Witness.
J. A. DIXON, of 175, West George St.,
Glasgow, Solicitor, Witness.
CARL RUMPFF. (L.S.)

page_text: LETTERS PATENT to Carl Rumpff, of the Firm of Friedrich Bayer and
Company, of Elberfeld, in the Kingdom of Prussia, and of 141, West George
Street, Glasgow, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF AZO-DYES FROM THE NITRO-SUBSTITUTION PRODUCTS OF BENZOL AND ITS
HOMOLOGUES."
PROVISIONAL SPECIFICATION left by the said Carl Rumpff at the Office of
the Commissioners of Patents on the 27th March 1879.
CARL RUMPFF, of the Firm of Friedrich Bayer and Company, of Elberfeld,
in the Kingdom of Prussia, and of 141, West George Street, Glasgow. “IM-
PROVEMENTS IN THE MANUFACTURE OF AZO-DYES FROM THE NITRO-SUBSTITUTION
PRODUCTS OF BENZOL AND ITS HOMOLOGUES."
This Invention has for its object improvements in the manufacture of azo-dyes
from the nitro-substitution products of benzol and its homologues.
For this purpose the nitro-substituted hydrocarbons of the aromatic group CD, H₂, n-6,
are treated with such a quantity of fuming oil of vitriol that the anhydride contents
of the latter represent a little more than one molecule to one molecule of the nitro
body with which it is treated.
The transformation into the respective nitro-sulphonic acids is thereby accom-
plished, and can if necessary be assisted by slightly warming the mixture, so that
when mixed with water perfect solution takes place.
The nitro-sulphonic acid solution thus obtained in an excess of sulphuric acid is
if necessary (generally but not always without further purification) mixed with
a further quantity of slightly diluted sulphuric acid or strong muriatic acid, that a
suitable quantity of iron added to it accomplishes directly the reduction to the
amido-acid which remains in solution.
The solution thus obtained is then heated and super saturated with soda, by
which means all the resulting sodium salt of acids contained in it are dissolved, and
at the same time the oxides and the carbonate of iron are separated from them. In
this part of the process I can use instead of iron zinc or other suitable reducing
177

page_text: agent;
I can also use potash instead of soda in the above operation, giving rise to
potassium salts instead of sodium salts.
The solution thus purified, together with any wash waters of the residue is
further diluted with water and then mixed with so much sulphuric acid or muriatic
acid that after the beginning of the neutralization has taken place there still remains
a little more acid than two equivalents to one molecule of the original nitro-body.
The solution is then allowed to cool and is di-azotised by adding one molecule of
sodium nitrite to each molecule of the above, and the solution so obtained is mixed
with the solution in an excess of alkali of one molecule of one of the group of the
phenol bodies (simple or complex hydroxyl, substituted aromatic hydrocarbons,
and their further substitution products) or with the solution of a suitable amido-
compound.
The colouring matter can be either crystallized out directly or can be precipitated
with common salt, and after collection can be used either at once or after further
purification by recrystallization, or solution and reprecipitation.
The amido-sulphonic acid solution obtained by iron or other reducing agent as
above can also be decomposed at the boiling heat by milk of lime. In addition to
the oxides of iron gypsum is thereby precipitated, and the amido-sulphonic acids
remain in solution as salts of calcium.
The diazotizing process can then be carried out at once by means of sodium
nitrite and muriatic acid.
In all cases however where the calcium salts of the sulpho-acids of the dyes are
not sufficiently soluble in water either the amido-sulphonate of calcium (before the
diazotising) or the precipitated salt of the dye should be transformed into a sodium
salt by boiling it with the proper quantity of soda.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
tho said Carl Rumpff in the Great Seal Patent Office on the 27th September
1879.
CARL RUMPFF, of the Firm of Friedrich Bayer and Company, of Elberfeld,
in the Kingdom of Prussia, and of 141, West George Street, Glasgow.
"IM-
PROVEMENTS IN THE MANUFACTURE OF AZO-DYES FROM THE NITRO-SUBSTITUTION
PRODUCT OF BENZOL AND ITS HOMOLOGUES."
This Invention has for its object improvements in the manufacture of azo-dyes
from the nitro-substitution products of benzol and its homologues.
For this purpose the nitro-substituted hydro-carbons of the aromatic group CD, H₂,n-c,
are treated with such a quantity of fuming oil of vitriol that the anhydride contents
of the latter represent a little more than one molecule to one molecule of the nitro-
body with which it is treated.
The transformation into the respective nitro-sulphonic acids is thereby accom-
plished, and can if necessary be assisted by slightly warming the mixture, so that
when mixed with water perfect solution takes place.
The nitro-sulphonic acid solution thus obtained in an excess of sulphuric acid is
if necessary (generally but not always without further purification) mixed with a
further quantity of slightly diluted sulphuric acid or strong muriatic acid, so that a
suitable quantity of iron added to it accomplishes directly the reduction to the
amido-acid which remains in solution.
The solution thus obtained is then heated and super saturated with soda, by
which means all the resulting sodium salts of the acids contained in it are dissolved,
and at the same time the oxides and the carbonate of iron are separated from them.
In this part of the process I can use instead of iron, zinc or other suitable reducing
agent; I can also use potash instead of soda in the above operation, giving rise to
potassium salts instead of sodium salts.
The solution thus purified, together with any wash waters of the residue, is
further diluted with water and then mixed with so much sulphuric acid or muriatic
acid that after the beginning of the neutralisation has taken place there still
remains a little more acid than two equivalents to one molecule of the original
nitro-body.
The solution is then allowed to cool, and is diazotised by adding one molecule of
sodium nitrite to each molecule of the above, and the solution so obtained is mixed
with the solution in an excess of alkali of one molecule of one of the group of the
phenol bodies (simple or complex hydroxil, substituted aromatic hydro-carbons and
their further substitution products) or with the solution of a suitable amido-
compound.
The colouring matter can be either crystallized out directly or can be precipitated
with common salt, and after collection can be used either at once, or after further
purification by recrystallization, or solution and reprecipitation.
The amido-sulphonic acid solution obtained by iron or other reducing agent, as
above, can also be decomposed at the boiling heat by milk of lime. In addition to
the oxides of iron gypsum is thereby precipitated, and the amido-sulphonic acids
remain in solution as salts of calcium.
The diazotising process can then be carried out at once by means of sodium nitrite
and muriatic acid.
In all cases however where the calcium salts of the sulpho-acids of the dyes are
not sufficiently soluble in water, either the amido-sulphonate of calcium (before the
diazotising) or the precipitated salt of the dye should be transformed into a sodium
salt by boiling it with the proper quantity of soda.
I am aware that in the preparation of colouring matters diazo-sulphonic acids of
the hydro-carbons C, H, no have before been employed, but they have been pre-
pared from the amido compounds. By this means other isomeric amido-sulphonic

page_text: acids are obtained differing from those which I obtain from the nitro-sulphonic acids.
For example, my sulphanilic acid is the meta-sulphonic acid of aniline, and my
amido-toluol sulphonic acid obtained from nitro-toluol bears a similar relation to
the raw material. These bodies yield dies differing in constitution and shade from
all others hitherto obtained.
Another important feature in this process consists in the fact that I proceed from
the nitro-compounds of the aromatic hydro-carbons and totally avoid the separate
production of the intermediate products, such as amido-derivatives, sulphonic acids,
and amido-sulphonic acids.
By the conversion of the nitro body into dyes in one and the same solution the
process is very much simplified; in its application on a large scale a great number of
sources of loss are completely avoided.
The above described method of manufacture admits of the following slight
modification:—
The nitro-substituted hydro-carbons of the aromatic series C, H, are mixed
with as much fuming oil of vitriol that the anhydride contents of the latter
represents somewhat more than two molecules for one molecule of the nitro-
hydrocarbon used.
When spontaneous reaction has nearly ceased the mixture is heated for several
hours to about 80° or 100° C.
Common sulphuric acid is added if necessary until its total amount corresponds
at least three molecules for one molecule of the nitro-hydrocarbon and the solution
diluted with water reduced by an excess of iron or zinc, or other suitable reducing
agent. The solution of amido-disulphonic acid of the hydro-carbon thus formed is
treated in the same way, purifying, diazotising, and acting upon an alkaline solution
of a phenol body, as already described, for the nitro-monosulphonic acids of aromatic
hydrocarbons.
I claim the production of azo-dyes in the following manner, viz., by the direct
conversion of nitro-substitution products of benzol and its homologues into nitro-
sulphonic acids; of these into amido-sulphonic acids, and so subsequently into the
dyes, as herein before specified.
In witness whereof, I, the said Carl Rumpff, have hereunto set my hand
and seal, this Twenty sixth day of September, in the year of our Lord
One thousand eight hundred and seventy nine.