IMPROVEMENTS IN PREPARING COLORING MATTERS FOR DYEING AND PRINTING
Year: 1863

page_text: LETTERS PATENT to Augustus William Hofmann, of Fitzroy Square, in
the County of Middlesex, F.R.S., Professor in the Royal College of
Chemistry, for the Invention of "IMPROVEMENTS IN PREPARING COLORING
MATTERS FOR DYEING AND PRINTING."
Sealed the 29th August 1863, and dated the 22nd May 1863.
PROVISIONAL SPECIFICATION left by the said Augustus William
Hofmann at the Office of the Commissioners of Patents, with his
Petition, on the 22nd May 1863.
I, AUGUSTUS WILLIAM HOFMANN, of Fitzroy Square, in the County of
Middlesex, F.R.S., Professor in the Royal College of Chemistry, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN PREPARING COLORING
MATTERS FOR DYEING AND PRINTING," to be as follows:-
This Invention has for its object improvements in preparing coloring
matters for dyeing and printing. For these purposes I take the substance
now well known as "rosaniline," being the base obtained from the various
salts of rosaniline found in commerce under the names of "roseine,"
magenta,' and also by other names, and which is usually prepared from
aniline and the homologues thereof, and I mix it with the iodides, bromides,
or other salts of the "alcohol radicals," such as iodide of ethyl, methyl,
or amyl, or bromides of the same. I employ the substances, by preference, in
the proportion of one equivalent of rosaniline to three equivalents of the salt

page_text: of the alcohol radical; I then heat the mixture either alone or together with
methylatic spirit to a temperature between 212 and 300 Fahrenheit in a close
vessel under pressure; it is convenient to use an iron boiler provided with a
safety valve. I continue the heat until the desired result is obtained. During
the heating the mixture passes through several phases of coloration, being
eventually converted into a blue substance. If the process is stopped before
the whole is converted into the blue, the mixture is then of a violet or purple
color. For the purpose of dyeing and printing the mixture may be used in
the same manner as that in which the aniline colors are employed.
I
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Augustus William Hofmann in the Great Seal Patent Office
on the 20th November 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, AUGUSTUS
WILLIAM HOFMANN, of Fitzroy Square, in the County of Middlesex, F.R.S.,
Professor in the Royal College of Chemistry, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of May, in the year of our Lord One
thousand eight hundred and sixty-three, in the twenty-sixth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Augustus William Hofmann, Her special licence that I, the said Augustus
William Hofmann, my executors, administrators, and assigns, or such others
as I, the said Augustus William Hofmann, my 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 PREPARING COLORING MATTERS FOR DYEING AND PRINTING,"
upon the condition (amongst others) that I, the said Augustus William
Hofmann, my executors or administrators, by an instrument in writing under
my, 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.
NOW KNOW YE, that I, the said Augustus William Hofman, do hereby
declare the nature of the said Invention, and in what manner the same is to

page_text: 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 preparing coloring matters
for dyeing and printing. For these purposes I take the substance now well
known as "rosaniline," being the base obtained from the various salts of
rosaniline found in commerce under the names of "roseine,"
1966 magenta," and
also by other names, and which is usually prepared from aniline and the
homologues thereof; I mix it with the iodides or bromides of the "alcohol
radicals," such as iodide of ethyl, methyl, amyl, propyl, or capryl, or bromides
of the same.
I employ the substances, by preference, in the proportion of one
equivalent of rosaniline to three equivalents of the salt of the alcohol -radical;
I then heat the mixture either alone or together with spirit to a temperature
of 212° (or it may be somewhat higher) in a close vessel under pressure.
is convenient to use an iron boiler provided with a safety valve; I continue
the heat until the desired result is obtained. During the heating the mixture
passes through several phases of coloration, being eventually converted into a
violet or blue violet substance. Within certain limits the longer the process
is continued the bluer the mixture will become. For the purpose of dyeing
and printing the mixture may be used in the same manner as that in which
the aniline colors are employed.
It
The following is the manner in which I prefer to proceed:-I take 1 part
by weight of rosaniline, 2 parts by weight of iodide of ethyl, and about 2 parts
of strong methylated spirit or alcohol, and I heat these substances together in
a suitable close vessel, either of glass or metal, capable of sustaining the
pressure generated to a temperature, by preference, of 212° Fahrenheit for
three or four hours, or until the whole of the rosaniline is converted into new
coloring substance; I then allow it to cool, and dissolve the syrupy mass in
methylated spirit or alcohol, which alcoholic solution may be used for dyeing
and printing in the same manner as that in which other ordinary aniline
colors are employed. Or in order to recover the iodine, which is a somewhat
expensive substance, I take the product either before or after dissolving it in
spirit, and boil it with an alkali, and I then obtain the base of the new color
in the insoluble portion whilst the iodine is held in solution as a soluble
iodide. I then wash the base free from all salts, and dissolve it together with
another acid, such as hydrochloric acid in alcohol, and employ this alcoholic
solution in the manner before described; or in place of bydrochloric acid and
alcohol I use acetic acid and water, and employ this aqueous solution for
dyeing or printing. By this process I produce a new coloring matter which
dyes silk and wool of a beautiful violet, blue violet, or red violet tint. In

page_text: place of the iodide of ethyl, the iodides of methyl, amyl, and propyl, capryl,
and the bromides of ethyl, methyl, amyl, and propyl, capryl, may be employed,
but not so conveniently, as they are more expensive.
Having thus described the nature of my said Invention, and the manner
of performing the same, I would have it understood that I do not confine
myself to the exact details of the process herein-before given; but what I
claim is, the production of new coloring substances by the action of the iodides
and bromides of alcohol radicals on rosaniline, as herein-before described.
In witness whereof, I, the said Augustus William Hofman, have here-
unto set my hand and seal, this Seventeenth day of November, in
the year of our Lord One thousand eight hundred and sixty-three.
AUGUSTUS WILLIAM HOFMANN. (L.s.)
AUGUSTUS WILLIAM HOFMANN. (L.s.)