THE PRODUCTION OF NEW COLORING MATTERS, AND DYEING AND PRINTING WITH THE SAME.
Year: 1881

page_text: LETTERS PATENT to Otto Nicholas Witt, Ph.D., and Horace Koechlin, both
of Mülhausen (Alsace), in the Empire of Germany, for an Invention of
"THE PRODUCTION OF NEW COLORING MATTERS, AND DYEING AND PRINTING
WITH THE SAME.
"

page_text: slightly alkaline or neutral, or if it be acid, the acid should be acetic and not a
mineral acid.
For a practical production of our dye-stuffs, we generally prefer the second
method, and we will now describe as an instance our process for producing on a
manufacturing scale a blue dye-stuff from amidodimethylaniline and phenol.
The necessary amidodimethylaniline we prepare by reducing nitrosodimethy-
laniline with zinc dust. For this purpose we dissolve in a wooden vat
10 lbs. nitrosodimethylaniline-hydrochloride in 100 gallons of water, and raise
the temperature of the solution to about 45-50° centigrade, we then introduce
10 lbs. of best zine dust, and stir vigorously until the liquid has become quite
colorless. We then filter and keep the clear liquid ready for use.
In another vat we dissolve
12 lbs. of pure phenol and
10 lbs. of potassic bichromate in
12 lbs. caustic soda solution, marking 38° on Beaume's hydrometer, and
20 gallons of water.
We mix this solution with the amidodimethylaniline solution obtained as
described above. When a complete mixture has been obtained, we gradually add
ordinary acetic acid. The new colouring matter is instantaneously produced, and
precipitated in the shape of a very fine blue powder. If a further addition of
acetic acid does no longer increase the quantity of colouring matter formed, the
whole is filtered in a filter press, the cakes well washed and dried at a temperature
not exceeding 60° C.
Instead of thus preparing the dye stuffs and applying them to the fabric by the
well known processes of dyeing and calico printing, they may be formed on the
fibre itself. This way of their production offers certain advantages, especially in
calico printing. There are several methods which may serve the same purpose, but
as all of them are based on the processes already expounded, we shall only give a
few receipts which we have found particularly useful.
1st Process. Padd the calico in a solution of naphtolsodium and dry, then print
on the material thus prepared a thickened solution of nitrosodimethylaniline-
hydrochloride containing some reducing agent, such as stannous oxyde, grape
sugar, or the like.
2nd Process. Padd the calico in a solution of grape sugar, or other reducing
agent and dry. Then print with a thickened mixture of nitrosodimethylaniline-
bydrochloride and a naphtol-sodium.
3rd Process. Print on bleached calico a thickened mixture of paramidodime-
thylaniline and naphtol sodium, dry, steam, and pass through potassic bichromate
when the blue colour will appear.
In all these examples the phenols named may be replaced by corresponding
quantities of other phenols, and the amido or nitroso compounds by other bodies of
the same classes.

page_text: The same dye stuffs are obtained if a mixture of the said phenols with paramido
derivatives (such as paramidodimethylaniline, paraphenylenediamine, paramido-
phenol, or their derivatives and homologues) be exposed to the action of
oxidizing agents, such as, for instance, potassic bichromate, potassic ferricyanide,
potassic permanganate, ammonio-cupric salts, or ammonio cupric oxyde calcic, or
any other hypochlorites, or any other compounds acting in a similar manner.
To insure a complete reaction, it is necessary that the mixture should be slightly
alkaline or neutral, or if it be acid, the acid should be acetic, or any other organic
and not a mineral acid.
For a practical production of our dye stuffs, we generally prefer the second
method, and we will now describe as an instance our process for producing on a
manufacturing scale a blue dye stuff from amidodimethylaniline and phenol.
The necessary amidodimethylaniline we prepare by reducing nitrosodimethyl-
aniline with zinc dust, without however limiting ourselves to that method,
amidodimethylaniline prepared from nitrodimethylaniline, or by any other process
of reduction being equally applicable. We prefer however for the present the
following mode of working
10lbs. nitrosodimethylaniline hydrochloride are placed in a wooden vat and
dissolved in 100 gallons of water of about 45-50° centigrade. When a complete
solution has been obtained, we introduce gradually 10 lbs. of best zinc dust, and
stir vigorously until the liquid has become quite colorless. We then filter and
keep the clear liquid ready for use.
In another vat we dissolve
12 lbs. of pure phenol, and
10 lbs. of potassic bichromate in 12 lbs. caustic soda solution, marking 38° on
Beaume's hydrometer. and 20 gallons of water

page_text: We mix this solution with the amidodimethylaniline solution obtained as
described above. When a complete mixture has been obtained, we gradually add
ordinary acetic acid. The new coloring matter is instantaneously produced and
precipitated in the shape of a very fine blue powder. If a further addition of
acetic acid does. no longer increase the quantity of coloring matter formed, the
whole is filtered in a filter press, the cakes well washed and dried at a temperature
not exceeding 60° C. Or the cakes may be reduced into a paste and brought into
commerce as such; or they may be treated with a strong caustic soda solution to
remove the chromic oxyde, which they still contain, and after being well washed,
they may be dried or reduced into a paste. This is indeed the method we have
found to be most satisfactory.
As an instance of the preparation of our dye stuffs by the first method, we add
the following:-
18.6 lbs. of nitrosodimethylaniline hydrochloride are placed in a wooden vat and
dissolved in
100 gls. of water of about 45-50° centigrade. In another vat we dissolve
15 lbs. of a napthol, and
5 lbs. sal ammoniac (ammonium hydrochloride) in
15 lbs. caustic soda solution of the strength above given and 20 gallons of water.
We then mix both solutions and slowly and gradually introduce
5 lbs. of best, zinc dust, stirring vigorously all the while. The blue coloring
matter is formed at once, and may be collected and purified as described above.
The zinc dust may be replaced by any other reducing agent, such as stannous
oxyde, grape sugar, or any other, the quantities given being purely empirical may
also be varied in wide limits.
Instead of thus preparing the dye stuffs and applying them to the fabric by the
well known processes of dyeing and calico printing, they may be formed on the
fibre itself. This way of their production offers certain advantages, especially in
calico printing. There are several methods which may serve the same purpose, but
as all of them are based on the process already expounded, we shall only give a
few receipts which we have found particularly useful.
1st Process. Pad the calico in a solution of a naphtolosodium and dry. Then
print on or apply to the materials thus prepared a thickened solution of nitroso-
dimethylaniline hydrochloride containing some reducing agent, such as stannous
oxyde, grape sugar, or another substance acting in a similar manner.
2nd Process. Pad the calico in a solution of grape sugar, or other reducing
agent, and dry. Then print with or apply a thickened mixture of nitrosodimethyl-
aniline hydrochloride and a naphtolsodium.
3rd Process. Print or apply on bleached calico a thickened mixture of para-
midodimethylaniline and a naphtolsodium, dry, steam, and pass through potassic
bichromate, when the blue color will appear.
In all these examples the a naphtol may be replaced by corresponding quantities
of other phenols, and the amido or nitroso compounds by other bodies of the same
class, the nitroso compounds also by chloroquinoneimides.
We may also in the process given above for the production of a blue coloring
matter from amidodimethylaniline and phenol, replace either of these two bodies
by corresponding quantities of other compounds of the same class, the result is in
all cases a coloring matter, the shade of which is different, according to the
ingredients used in its production.
We would remark that there exists a class of compounds not to be confounded
with those to which this Specification relates, namely, the dye stuffs described by
Witt and by Meldola, obtained by acting on nitrosodimethylaniline with phenols in
an acetic acid solution, and at temperatures near the boiling point. These bodies
are quite different from those obtained by means of our Invention herein described.
We claim,-
First. As a new manufacture the new dye stuffs, the product of our Invention.

page_text: Second. The production of new dye stuffs by the action of aromatic nitroso
bodies or chloroquinoneimides upon phenols in an alkaline solution, with or
without the presence of reducing agents and ammonia.
Third. The production of the same dye stuffs by oxydation of alkaline, neutral
or feebly acid mixtures of phenols with paramido derivatives, of primary, secondary,
or tertiary amines or phenols.
Fourth. The production of the same substances on the fibre by adaptation of
the above reactions.
In witness whereof, I, the said Otto Nicholas Witt, have hereunto set my
hand and seal, this Nineteenth day of September, in the year of our Lord
One thousand eight hundred and eighty one.
OTTO N. WITT. (L.S.)