IMPROVEMENTS IN PREPARING RED, PURPLE, AND CERTAIN OTHER DYES
Year: 1861

page_text: LETTERS PATENT to Wentworth Lascelles Scott, of Bayswater, in the
County of Middlesex, Analytical Chemist, for the Invention of "IMPROVE-
PROVISIONAL SPECIFICATION left by the said Wentworth Lascelles Scott
at the Office of the Commissioners of Patents, with his Petition, on the
29th July 1861.
I, WENTWORTH LASCELLES SCOTT, of Bayswater, in the County of Middlesex,,
Analytical Chemist, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PREPARING RED, PURPLE, AND CERTAIN OTHER DYES," to be as
follows:-
The main feature of my Invention consists in the employment of binitro-
naphthaline as a basis for red and certain other dyes. For producing a
red dye, for instance, I proceed as follows:-I take binitro-naphthaline
and dissolve it in sulphuric acid, or other suitable solvent under an elevated
temperature, with or without the addition of a small proportion of sulpho-
naphthalic acid; I then add to the solution some reducing agent, such
as carbon, iron, tin, zinc, or other suitable metal or metallic salt; or I
introduce a current of sulphurous acid or other suitable gas, which acts as a
reducing agent until reaction is complete, or nearly so, which practice alone

page_text: will dictate. The liquid is allowed to cool, and is diluted with several times
its bulk of water, to which may be added a small quantity of nitroso-naphtha-
line, and the whole is boiled for a few minutes and filtered. Both on the
filter and in the filtrate a red coloring matter is present, which after being
purified is in a state to be used as a red dye. By varying the substances to
be combined with the binitro-naphthaline basis according to the color of the
dye to be produced, various dyes are obtained. By means of my Invention all
dyes which are now produced 'from madder, and from madder and its com-
pounds, besides others, are obtainable.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Wentworth Lascelles Scott in the Great Seal Patent Office
on the 29th January 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, L, WENTWORTH
LASCELLES SCOTT, of Bayswater, in the County of Middlesex, Analytical
Chemist, send-greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of July, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Wentworth Lascelles Scott, Her special licence that I, the said Wentworth
Lascelles Scott, my executors, administrators, and assigns, or such others as
I, the said Wentworth Lascelles Scott, 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 RED, PURPLE, AND CERTAIN OTHER DYES," upon
the condition (amongst others) that I, the said Wentworth Lascelles Scott,
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 per-
formed, 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 Wentworth Lascelles Scott, do hereby
declare the nature of my 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:-
.
The main feature of my Invention consists in the employment of binitro-
naphthaline as a basis for red and certain other dyes. I mix the substance
known as binitro-naphthaline with concentrated sulphuric acid, or other
suitable substance capable of dissolving or bringing to a liquid condition the
said binitro-naphthaline at the ordinary or at an elevated temperature, and I
then reduce or deoxidize the same by the addition of any metal, salt, acid,
gas, or other substance capable of producing that effect, continuing the
reaction until the required dye or colouring matter is perfectly formed.
I préfer to operate in the following manner, although I do not confine
myself to the exact and precise details of the process herein-after set forth, as
they may be varied with advantage according to the strength or quality of the
materials employed, and other collateral circumstances:-I first raise 10 parts
of sulphuric acid (the specific gravity of which should not be less than 1.750)
contained in a glass, porcelain, platinum, or other suitable vessel, to the
temperature of about 360° Fahrenheit, adding thereto from 2 to 4 parts of
binitro-naphthaline (or other homologous substance), and sometimes throwing
in a small quantity of sulpho-naphthalic acid, or of naphthaline. I then reduce
or deoxidize the mixture, preferring to employ for this purpose either strips of
zinc, or a current of sulphuric acid, or carbonic oxide gas, until a deep red or
brownish red colour appears fully developed on testing small portions of the
mixture. When cool I add a sufficiency of water and alkali to partly
neutralize the free acid, and boil the whole (I prefer under pressure) for a
short time. From the filtered liquor some of the coloring matter will
separate on cooling, while the remainder may be extracted from the pre-
cipitate by means of spirit, benzole, alkaline solutions, or a solution of alum.
This coloring matter, which I name dianthine, may be employed for
dyeing and printing on silk, wool, cotton, and other fabrics, threads, and yarns
in the same manner, various tints being communicated according to the
mordant employed.
In order to produce a red color having more or less of a scarlet tint, I
subject dianthine (prepared in manner previously described) to the action of
one of the various oxidizing agents known to chemists, such, for instance, as
concentrated nitric acid. I then treat the result of such action with ammonia,
or other suitable homologous or isomorphous base in the presence of an alcohol,
or otherwise.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I claim as my improve-

page_text: ments in the preparation of red, purple, and other dyes, herein-before
mentioned, the employment of binitro-naphthaline, substantially in manner
herein-before described..
In witness whereof, I, the said Wentworth Lascelles Scott, have here-
unto set my hand and seal, this Twenty-ninth day of January One 5
thousand eight hundred and sixty-two.
WENTWORTH L. SCOTT. (L.S.)