IMPROVEMENTS IN MANUFACTURE OF COLORING MATTER SUITABLE FOR DYEING AND PRINTING
Year: 1869

page_text: LETTERS PATENT to William Henry Perkin, of Sudbury, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN
MANUFACTURE OF COLORING MATTER SUITABLE FOR DYEING AND PRINTING."
Scaled the 7th January 1870, and dated the 17th November 1869.
PROVISIONAL SPECIFICATION left by the said William Henry Perkin
at the Office of the Commissioners of Patents, with his Petition, on
the 17th November 1869.
I, WILLIAM HENRY PERKIN, of Sudbury, in the County of Middlesex,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE MANUFACTURE OF COLORING MATTER SUITABLE FOR DYEING AND PRINTING,"
to be as follows:-
This Invention has for its object improvements in the manufacture of
coloring matter suitable for dyeing and printing. For this purpose I
treat chlorinated anthracene with sulphuric acid (either the ordinary
strong acid or fuming acid may be used), and I then oxidize the product
by means of a suitable oxidizing agent, such, for example, as the biu-

page_text: oxido of lead. When the oxidation is complete the solution is not
fluorescent, whereas previously the dilute solution is usually strongly
I then further treat the solution in the manner described in the
Provisional Specification filed by me on the 16th day of July 1869,
No. 1948, and so obtain coloring matter. Brominated anthracene may
be used in place of anthracene, or I may use anthracene which is both
chlorinated and brominated.
In place of using an oxidizing agent in the manner above stated the
chlorinated anthracene or other anthracene compound above set forth
may be heated somewhat strongly with the sulphuric acid and the
process completed as before, but with the omission of the use of the
oxidizing agent.
.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Henry Perkin in the Great Seal Patent
Office on the 17th May 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM-
HENRY PERKIN, of Sudbury, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of November, in the
year of our Lord One thousand eight hundred and sixty-nine, in the
thirty-third year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Henry Perkin, Her special
licence that I; the said William Henry Perkin, my executors, adminis-
trators, and assigns, or such others as I, the said William Henry
Perkin, my executors, administrators, and assigns, should at, any time
agree with, and no others, from time to time and at all times there-
after 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 THE MANUFACTURE OF COLORING MATTER SUITABLE FOR
DYEING AND PRINTING," upon the condition (amongst others) that I, the
said William Henry Perkin, 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

page_text: 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 William Henry Perkin, do hereby
declare the nature of the 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
coloring matter suitable for dyeing and printing. For this purpose 1
treat chlorinated anthracene with sulphuric acid, and I oxidize the
product by means of a suitable oxidizing agent. I then further treat
the solution in a manner similar to that described in the Specification
of my Patent dated the 16th day of July 1869, No. 1948, and so
obtain coloring matter. Brominated anthracene may be used in place
of chlorinated anthracene, or I may use anthracene which is both
chlorinated and brominated.
In place of using an oxidizing agent in the manner above stated the
chlorinated anthracene or other anthracene compound above set forth
may be heated somewhat strongly with the sulphuric acid and the
process completed as before, but with the omission of the use of the
oxidizing agent after the treatment with sulphuric acid.
In order that my said Invention may be most fully understood and
readily carried into effect I will proceed to describe more in detail the
manner in which I prefer to conduct the manufacture.
I take commercial anthracene (more or less impure) and by heavy
pressure separate for the most part the oily impurities; I then dissolve
the anthracene in benzole and crystallize it therefrom, or in place of
benzole I employ coal tar naptha. I obtain chlorinated. anthracene by
the action of chlorine upon anthracene thus purified. I proceed as
follows: Anthracene in fine powder is spread out in thin layers, say,
of half an inch or less in thickness on trays of lead or other suitable
material, and placed in a chamber which is afterwards supplied with
chlorine gas.
The treatment with chlorine is continued for about
24 hours, in which time the anthracene will for the most part have
become chlorinated. The crude product may at once be employed for
the manufacture of coloring matter, but in preference it is first dissolved,
in benzole and crystallized therefrom. This process succeeds well at a

page_text: temperature from 18 centigrade to 21 centigrade. The anthracene may
be further chlorinated, but no additional advantage is thereby obtained,
and hence it is not recommended; but I may mention that if the
chlorinating process be continued for a considerable longer time more
chlorine will be absorbed and products produced containing chlorine in
larger proportion. This operation may be assisted by heat.
Another method of chlorinating anthracene which gives more uniform
results with samples of anthracene varying in their degrees of purity is as
follows:-I take anthracene in powder and mix it with benzole in the
proportion of about one part by weight of anthracene and four or five
parts by weight of benzole, and pass chlorine through the mixture until
it becomes a crystalline paste owing to the formation of chlorinated
anthracene. This chlorinated anthracene is then collected on a filter,
and when well drained freed from adhering benzole by evaporation
or otherwise. My practice is to take one part of crystallized chlo-
rinated anthracene and mix it with 4 or 5 parts of sulphuric acid, cither
ordinary concentrated acid or fuming. The mixture is then heated
gradually up to 130° centigrade or 150° centigrade, or until the product
when well mixed with boiling water dissolves. When using fuming acid
it is not necessary to heat the mixture to the same extent. The product
is then diluted with 3 or 4 times its bulk of water, and binoxide of
manganese added in excess, and the whole well boiled until a portion of
the solution when diluted does not appear fluorescent as it did before
treatment with the binoxide of manganese; it is then poured off from any
binoxide of manganese that is left undissolved, and caustic lime in the
form of milk of lime added in slight excess, or until the solution is
alkaline; it is then boiled and filtered and the residue repeatedly
washed with water. The filtrate is then concentrated, and by preference
carbonate of potash or soda added until carbonate of lime is no longer
precipitated; it is then filtered off from the precipitate and evaporated
to dryness. This product is then mixed with about twice its weight
of caustic potash or soda, or a mixture of these dissolved in a small
quantity of water, and gradually heated up to, about 180° or 210°
centigrade, or until a portion when withdrawn and dissolved in water
gives a copious yellow precipitate upon the addition of hydrochloric
acid. The product is then dissolved in water acidulated with sulphuric,
bydrochloric, or other suitable acid and thrown on a filter, and the pre-
cipitate washed until neutral or nearly so. This product may be used

page_text: for dycing and printing in the same manner as preparations of madder.
The coloring matter contained in the yellow filtrate may be precipitated
by neutralizing the solution with carbonate of soda and allowing it to
stand, when it will principally settle down as a dark colored precipitato,
which can be collected upon a filter or otherwise, and may be used for
the preparation of pigments by precipitating its solution with alumina,
baryta, or other base by usual methods, thus forming pigments or lakes.
If it be desired to obtain more soluble coloring matter as the chief
product the heating with caustic alkali should occupy a shorter time, or
the amount of alkali used should be less, say, by one-half. On the other
hand if the more soluble coloring matter has been obtained by mistake
it may be converted into the less soluble by a second treatment with
caustic alkali. Caustic baryta or strontia may be used instead of caustic
potash or caustic soda with more or less success. Other oxidizing agents
may be used in place of binoxide of manganese, such as binoxide of
lead or nitric acid. Milk of lime is employed by preference to separate
the sulphuric acid and precipitate the oxide of manganese held in
solution, but other products such as baryta may be employed, or when
manganese or similar agent is not used carbonate of lime or baryta can
be employed. Sometimes instead of diluting the products of the action
of sulphuric acid upon the chlorinated anthracene I elevate the tem-
perature gradually to about 210° centigrade, and keep the substance
heated to about this point until a portion of the product when diluted
with water is no longer fluorescent. The product may then at once be
neutralized with milk of lime, filtered, and heated as already described.
When working in this manner it is better to use the fuming sulphuric
acid, but for the first process the ordinary strong acid works well.
As already mentioned brominated anthracene may be used in place
of chlorinated anthracene, as may also anthracene which is both
chlorinated and brominated. I do not recommend the use of these
substances on account of their greater expense, but they can be pre-
pared as follows:-The brominated anthracene may be prepared by
submitting finely powdered anthracene, purified in the manner which I
have described, in thin layers to the action of bromine vapour for about
24 hours. I can employ the product in this condition, or (by preference)
after crystallization from benzole. By prolonging the treatment of
anthracene with bromine, or subjecting the crystallized product to the
action of bromine, the anthracene can be made to take up a further

page_text: quantity of bromine, but no advantage is thus attained, and in the
subsequent working the test by fluorescence will be found less available.
The same I find to be the case when working with anthracene which
(for my purpose) is over chlorinated. Anthracene both chlorinated and
brominated may be obtained by exposing chlorinated anthracene to.
the action of bromine vapour, or by treating brominated anthracene
suspended in benzole with chlorine gas.
Coloring matter may be prepared from any of these substances in the
manner described in respect to chlorinated anthracene.
I claim treating chlorinated anthracene or brominated anthracene, or
partly chlorinated and partly brominated anthracene, with sulphuric
acid, producing therefrom coloring matters suitable for dycing and
printing purposes in the manner herein-before described.
In witness whereof, I, the said William Henry Perkin, have here.
unto set my hand and seal, this Thirteenth day of May, in the
year of our Lord One thousand eight hundred and seventy.