IMPROVEMENTS IN PREPARING COLORING MATTERS SUITABLE FOR DYEING AND PRINTING
Year: 1879

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
PREPARING COLORING MATTERS SUITABLE FOR DYEING AND PRINTING."
A communication from abroad by Heinrich Caro, of Mannheim, in the Empire
of Germany, Chemist to the Badische Anilin and Soda Fabrik, of Mannheim
aforesaid.
Sealed the 19th March 1880, and dated the 29th December 1879.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 29th December 1879.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. * IMPROVEMENTS IN PREPARING COLORING MATTERS SUITABLE FOR
DYEING AND PRINTING." A communication from abroad by Heinrich Caro, of
Mannheim, in the Empire of Germany, Chemist to the Badische Anilin and Sodu
Fabrik, of Mannheim aforesaid.
This Invention relates to the preparation of yellow colouring matters soluble in
water and suitable for dyeing and printing. According to their chemical consti-
tution they are the nitro sulpho acids of alpha-napthol, and chiefly the sulpho acids
of dinitro napthol.
The said sulpho acids cannot be prepared by the direct action of sulphuric acid
upon dinitronapthol nor by the action of nitric acid upon the napthol-monosulpho
acids, the only sulpho acids of alpha-napthol hitherto known. As is well under-
stood by chemists the said monosulpho acids upon being treated with nitric acid
loose their sulpho groups, and are converted into dinitronapthol.
Now this Invention consists in preparing the nitro sulpho acids of alpha-napthol
by the action of nitric acid upon such naptholsulpho acids as result from increasing
either the strength or the relative proportion of the sulphuric acid employed or the
temperature or the duration of the process beyond what is required for converting
alpha-napthol into its mono sulpho compounds. Thus new napthol sulpho acids are
produced, and especially a trisulpho acid of napthol which upon treatment with
nitric acid will retain one or more of their sulpho groups and become changed into
nitro sulpho acids, and chiefly into the sulpho acids of dinitronapthol.

page_text: In the above process sulphuric acid may be employed in its concentrated fuming
or anhydrous condition, or in any form or combination in which it is capable of
being used for the preparation of sulpho acids generally speaking.. The precise
conditions of the process may be ascertained by the following test :-From time to
time a sample is withdrawn from the mixture of the naptholsulpho acids and the
said sample is dissolved in or gently heated with an excess of nitric acid and after-
wards diluted with water. If a considerable precipitate is produced, consisting of
dinitronapthol, and if the filtered solution shows little or no precipitate upon the
addition of caustic potash the action of the sulphuric acid is to be continued or be
increased by either raising the temperature or by adding a further supply of sulphuric
acid. At last a point will be arrived at where a sample of the napthol sulpho acids
thus produced after treatment with nitric acid will remain clear or nearly so upon
the addition of water, whilst caustic potash will then throw down an abundant
precipitate consisting of the potassium salts of the dinitronapthol sulpho acids.
This point being arrived at the formation of the new naptholsulpho acids is com-
plete, and the result of the operation may at once be submitted to the action of
nitric acid, or the naptholsulpho acids may be first converted into their alkaline
salts and then whether purified or not, whether separated from one another or not
by crystallization or otherwise the said saline compounds of the naptholsulpho
acids may be treated with nitric acid. The said treatment with nitric acid consists
in adding nitric acid of sufficient strength and quantity to convert the napthol-
sulpho acids into a partly crystallized mixture of nitrosulpho acids, which may be
obtained in a mercantile condition by preparing their soluble lime salts from which
by mutual decomposition with the alkaline carbonates their corresponding alkaline
salts may be produced and further purified or separated by crystallization or
otherwise.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the 26th
June 1880.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN PREPARING COLORING MATTERS SUITABLE FOR
DYEING AND PRINTING." A communication from abroad by Heinrich Caro, of
Mannheim, in the Empire of Germany, Chemist to the Badische Anilin and Soda
Fabrik, of Mannheim aforesaid.
The said Invention relates to the preparation of yellow coloring matters soluble 3
in water and suitable for dyeing and printing.
According to their chemical constitution they are the nitro sulpho acids of alpha-
napthol and chiefly the sulpho acids of dinitronapthol.
The said sulpho acids cannot be prepared by the direct action of sulphuric acid
upon dinitronapthol, nor by the action of nitric acid upon the naphol-monosulpho 4

page_text: acids, the only sulpho acids of alpha napthol hitherto known. As is well under-
stood by chemists the said mono sulpho acids upon being treated with nitric acid
lose their sulpho groups and are converted into dinitro napthol.
Now this Invention consists in preparing the nitro sulpho acids of alpha napthol
by the action of nitric acid upon such napthol sulpho acids as result from increasing
either the strength or the relative proportion of the sulphuric acid employed, or
the temperature or the duration of the process beyond what is required for con-
verting alpha-napthol into its monosulpho compounds. Thus new napthol sulpho
acids are produced, and especially a trisulpho acid of napthol, which upon
treatment with nitric acid will retain one or more of their sulpho groups and
become changed into nitrosulpho acids, and chiefly into the sulpho acids of dinitro-
napthol.
In the above process sulphuric acid may be employed in its concentrated fuming
or anhydrous condition, or in any form or combination in which it is capable of
being used for the preparation of sulpho acids. The precise conditions of the
process may be ascertained by the following test:-From time to time a sample is
withdrawn from the mixture of the napthol sulpho acids and the said sample is
dissolved in or gently heated with an excess of nitric acid, and afterwards diluted
with water. If a considerable precipitate is produced, consisting of dinitronapthol,
and if the filtered solution shows little or no precipitate upon the addition of caustic
potash, the action of the sulphuric acid is to be continued or to be increased by
either raising the temperature or by adding a further supply of sulphuric acid. At
last a point will be arrived at where a sample of the napthol sulpho acids thus
produced, after treatment with nitric acid, will remain clear or nearly so upon the
addition of water, whilst caustic potash will then throw down an abundant preci-
pitate consisting of the potassium salts of the dinitronapthol sulpho acids. This
point being arrived at the formation of the new napthol sulpho acids is complete
and the result of the operation may at once be submitted to the action of nitric
acid or the napthol sulpho acids may be first converted into their alkalino salts, and
then whether purified or not, whether separated from one another or not by crys-
tallization or otherwise, the said saline compounds of the naptholsulpho acids may
be treated with nitric acid. The said treatment with nitric acid consists in adding
nitric acid of sufficient strength and quantity to convert the napthol sulpho acids
into a partly crystallized mixture of nitro sulpho acids, which may be obtained in a
mercantile condition by preparing their soluble lime salts from which by mutual
decomposition with the alkaline carbonates their corresponding alkaline salts may
be produced and further purified or separated by crystallization or otherwise.
As an example of the manner in which the said Invention may be carried out I
proceed as follows :—
FIRST STEP. PREPARATION OF THE SULPHO ACIDS OF APHA NAPTHOL.
About ten parts by weight of pure or commercial alpha napthol are gradually
mixed with about twenty parts by weight of fuming sulphuric acid, containing
about 25 per cent. of sulphuric anhydride, and the mixture is kept well agitated
by preference at a temperature of from 40 to 50 degrees centigrade until a sample
of the same upon being dissolved in water will produce a clear solution or
Dearly so.
This point being arrived at I convert the mono sulpho acids thus formed into
their higher sulpho compounds by gradually adding about 18 parts by weight
of fuming sulphuric acid containing about 70 per cent. of sulphuric anhydride,
and the mixture is kept well agitated, and its temperature its maintained at about
from 40 to 50 degrees centigrade until the conversion into the desired sulpho
acids is perfect or nearly so, which point may be ascertained by withdrawing a
sample of the said mixture from time to time and submitting it to the above
described test with nitric acid and caustic potash,

page_text: SECOND STEP-PREPARATION OF THE NITRO SULPHO ACIDS OF ALPHA NAPTHOL.
The result of the first step of this process is then diluted with about 75 parts of
water, and gradually mixed with about 25 parts by weight of nitric acid of about
1.38 specific gravity. The mixture is kept well agitated, and its temperature
should not be allowed to rise above 50 degrees centigrade. After about 12 hours'
standing in the cold a crystallisation will be observed to have taken place, chiefly
consisting of the mono sulpho acid of dinitronapthol, the mother liquor of the said
crystals containing other nitro sulpho compounds, and amongst them the disulpho
acid of dinitronapthol.
In order to further separate and purify the nitro sulpho acids of alpha naphthol 1
thus produced I prefer first to effect a mechanical soparation of both the crystallised
compounds and of their mother liquor, and I then convert the crystallised nitro
sulpho acids into their potassium, sodium, or ammonium salts.
The coloring matters contained in the said acid mother liquor may likewise be
obtained in a marketable condition by adding an excess of caustic lime, filtering
and decomposing the soluble lime salts thus produced by means of alkaline car-
bonates in order to prepare their corresponding alkaline salts and by preference
their potassium compound.
Having now described and particularly ascertained the nature of the said Inven-
tion, and the manner in which the same is or may be used or carried into effect, I
would observe in conclusion that I wish it to be understood that I do not confine
myself to the exact details as above described, as the proportions, weights, tempera-
tures, concentration of acids, processes of purification and separation, and so forth,
may be varied to a large extent, without materially changing the result of the
above described process, but what I consider to be novel and original and therefore
claim as the Invention secured to me by the hereinbefore in part recited Letters
Patent is,-
First. The preparation of a tri sulpho acid of alpha naphthol, or of such sulpho
acids of alpha naphthol which upon treatment with nitric acid will retain one or
more of their sulpho groups and become changed into nitro sulpho acids, and chiefly
into the sulpho acids of dinitronaphthol, substantially as herein before described.
Second. The preparation of nitrosulpho acids of alpha napthol, and chiefly of the
sulpho acids of dinitronaphthol by the action of nitric acid upon the above described
sulpho acids of alpha naphthol, substantially as herein before described
In witness whereof, I, the said John Henry Johnson, have to this my Speci-
fication set my hand and seal, this Twenty fifth day of June, One thousand
eight hundred and eighty
J. HENRY JOHNSON. (LS.)