IMPROVEMENTS IN OBTAINING ANTHRACENE
Year: 1871

page_text: LETTERS PATENT to Henry James Fenner, of No. 4, Park Place,
Greenwich, in the County of Kent, Oil Refiner, and Frederick
Versmann, of No. 150, Fenchurch Street, in the City of London,
Ph.D., Consulting and Analytical Chemist, for the Invention of
PROVISIONAL SPECIFICATION left by the said Henry James Fenner
and Frederick. Versmann at the Office of the Commissioners of
Patents, with their Petition, on the 23rd December 1871.
We, HENRY JAMES FENNER, of No. 4, Park Place, Greenwich, in the
County of Kent, Oil Refiner, and FREDERICK VERSMANN, of No. 150,
Fenchurch Street, in the City of London, Ph.D., Consulting and
Analytical Chemist, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN OBTAINING ANTHRACENE,” to be as follows:-
The object of this Invention is to obtain anthracene from coal tar
pitch. We are aware that attempts have been made to obtain anthracene

page_text: Although we prefer to carry on these last operations in two separate
sets of stills, retorts, or vessels, if desired we distil the heavy oil from
the coal tar, and then by increasing the heat separate the anthracene in
the same apparatus. The anthracene thus obtained from pitch is mixed
with a viscid heavy oil, from which it may be readily separated by
filtration or otherwise.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry James Fenner and Frederick Versmann in
the Great Seal Patent Office on the 22nd June 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ПENRY
JAMES FENNER, of No. 4, Park Place, Greenwich, in the County of
Kent, Oil Refiner, and FREDERICK VERSMANN, of No. 150, Fenchurch
Street, in the City of London, Ph.D., Consulting and Analytical Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of December, in
the year of our Lord One thousand eight hundred and seventy-one, in
the thirty-fifth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto us, the said Henry James Fenner and
Frederick Versmann, Her special licence that we, the said Henry
James Fenner and Frederick Versmann, our executors, administrators,
and assigns, or such others as we, the said Henry James Fenner and
Frederick Versmann, our 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 OBTAINING ANTHRACENE," upon the con-
dition (amongst others) that we, the said Henry James Fenner and
Frederick Versmann, our executors or administrators, by an instrument
in writing under our, 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.

page_text: NOW KNOW YE, that we, the said Henry James Fenner and Frederick
Versmann, do hereby declare the nature of our said Invention, and in
what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement, that is to say :-
The object of the Invention is to obtain anthracene from coal tar
pitch by the process of manufacture herein-after described.
We are
aware of experimental attempts having already been made to obtain
anthracene from pitch, but so far as we have been able to ascertain the
attempts to do so have not been practically successful and have not
proved of commercial value.
The adoption of the process of manufacture invented by us and
employed as herein-after described will enable the products of pitch to
be obtained in regulated order, and anthracene will be produced with the
requisite certainty at ascertained temperatures and known stages in the
process, and when so produced will be found of a very superior character
compared with any that may have been produced in the experimental
attempts above referred to. The anthracene can be obtained by our
process in a comparatively pure state, with only a small proportion, if
any, of other hydrocarbons such as naphthaline or chrysene mixed
therewith.
In carrying out our improvements we either operate upon the pitch
after it has been obtained by the ordinary process, and as it is met
with in the market, or we combine as herein-after described. the
operation of separating anthracene with the operation of distilling the
oils, and the consequent production of pitch from the coal tar. In any
case in order to effect our object we employ progressively increasing
temperatures, and eventually a very high temperature, say about 600 or
800 degrees Fahrenheit, by heat externally applied. We find that in
conducting our process of distilling pitch we obtain at a temperature of
about 400° Fah., an oil comparatively free from solid hydrocarbons. We
continue to raise the temperature to from 500° to 600°, when the oil
becomes richer in solid matters, and is found to contain naphthaline in
excess with a small proportion of anthracene; the latter increases as
higher temperatures are employed, the production of anthracene becom-
ing abundantly in excess at from 600° to 700°. Above these temperatures
we find that the production of anthracene decreases, and chrysene will
be chiefly obtained.

page_text: In treating the pitch which has been obtained separately we usually
reduce it to small convenient sizes, and then mix it with oil or residuum
obtained by a previous distillation of pitch or with other dry absorbent
carbonaceous matter. We do not however confine ourselves to the use
of such mixture. The effect of using the mixture is that the pitch
when heated in the retort or other vessel absorbs the heat gradually from
the commencement without rising or frothing, whereas pitch alone rises,
and if not carefully watched has a tendency to froth and choke the
delivery passage as long as moisture is left in the pitch. This we have
found to be a necessary and important part of the process when treating
pitch that has stood for some time exposed to the air or moisture.
The pitch thus mixed with the oil or absorbent carbonaceous matter
is put into a still, retort, or other suitable vessel, which we make of cast
iron, in order to enable it properly to stand the high heats which we use
in our process of manufacture. The heat is applied externally, and is
progressively raised to and then continued at a very high temperature,
say from 600° to 700° Fahrenheit, as long as any liquid or gaseous
products pass over. The oily liquid that passes over at these high
temperatures is found to be very rich in anthracene; naphthaline and
chrysene are present in comparatively small proportions. The vapours
passing over are then condensed by the cooling influence of the atmo-
sphere acting on the conducting pipes, and the products obtained by the
condensation are run into a suitable tank, where they are allowed to
repose or precipitate in order to complete the settling of the products.
The condensation is thus effected by the action of the atmosphere on the
conducting pipes, and we do not employ the ordinary worm or coil in
tanks of cold water for that purpose, as the liquid becomes thick and the
anthracene solidifies or tends to solidify before it reaches the end of the
worm. We find it advantageous to assist the distillation by keeping up
a partial vacuum in the still or retort, by which the products of distilla-
tion will pass away more quickly and at a lower temperature than under
ordinary pressure. This partial vacuum may be kept up by means of
an exhauster or blower, or other suitable means.
Figure 1 represents a plan view and Figure 2 a side view partly in
section of apparatus such as we have found to answer well in carrying
into effect our method of working. a represents a cast-iron vessel in
which the coal tar pitch is placed for distillation by the heat of a fire in
the furnace b; c, c, are flue spaces by which the heat from the fire-

page_text: place 6 may be retained as long as possible in contact with the surface
of the vessel a; d, is a pipe with a stop-cock d³, by which pitch may be
supplied to this vessel a; and e is a pipe by which the anthracene and
matters combined therewith obtained in the distillation are conducted in
the form of vapor from the vessel a to a condensing chamber f, but in
the
passage of the vapors along. the pipe e they become cooled by the
action on that pipe e of the surrounding atmosphere, and the products
of condensation thence flow by one or other of the branch pipes e¹, e³, e³,
to the receiving tank g. The oil collected in the vessels or tanks fand g
will be drawn off therefrom through suitable taps or outlets.
When the product distilled at about 400° begins to issue from a it
passes along e and at first reaches to and part being principally non-
condensed vapor or gas enters f as the temperature is raised and
anthracene begins to pass over; the richer oily product containing
anthracene passes along e¹ into the chamber g. The temperature being
still further raised or continued at a high standard, such as from 600° to
700°, the oily product distilled becomes more charged with anthracene;
the tap in the branch pipe e' is then opened, and if necessary owing to
the increasing density of the oil the tap in the tube e³ is opened so as to
provide as required a short and ready passage for the distilled product
into the receiving vessel g.
When combining the production of anthracene according to our
Invention with the distillation of heavy oils from coal tar, thus making
one continuous process of the two operations, a method of manufacture
which we have found to give beneficial results that have not hitherto
been obtained, we proceed as follows:-We distil the heavy oils from
coal tar in the usual way in a wrought-iron still or boiler such as has
been hitherto used for such distilling process, and we connect such vessel
with a set of cast-iron stills or retorts or other suitable vessels a, such as
have been already referred to, taking care however that they may be
capable of withstanding the high heat which we use in our process.
The connection thereto is made by means of a pipe or pipes provided
with stop-cocks or other simple regulating means. As soon as the
heavy oils have been worked off in the wrought-iron vessel then a
residuum of pitch is left, and without allowing the pitch to cool it is at
once run off into a set of vessels a, which have been previously heated,
and in which the distillation is at once proceeded with, until the liquid

page_text: or gaseous products desired have passed over to the condenser, aided in
some cases by the use of a partial vacuum such as above described.
This continuous treatment of the pitch constitutes a novel feature in
the process of manufacture invented by us, and will be found economical
in regard to cost and beneficial in result.
Figure 3 represents by a sectional view apparatus arranged to operate
according to this method of working. m is a pipe by which liquid pitch
may be conducted from the boiler, which is not shewn in the Drawings,
to branches d with taps d, by which to supply vessels a such as
already referred to; m¹ is a tap in the pipe m to regulate or to stop the
supply as required. The vapor generated in these vessels a will be con-
ducted to a condensing chamber or condensing chambers fand 9, or to
other suitable condensing apparatus, for the condensation as stated. It
would be possible after distilling the oils to. continue to treat the pitch
residuum in the same vessel by applying higher temperatures, but we
have found that the cost of carrying on such a mode of manufacture
would be so great, owing to the destruction of the wrought-iron appa-
ratus which is found suitable for the distillation of the oils from the tar
above referred to, that we do not recommend the continued operation to
be carried on in the same vessel, but we recommend it to be carried on
in separate vessels as above described. The employment of heat
internally applied, either by means of steam or hot air, is not advan-
tageous, and forms no part of our Invention.
We find, as has been already mentioned, that the anthracene obtained
from coal tar pitch by our process of distillation is at the comparatively
lower temperatures mixed more or less with naphthaline, and at the
higher temperatures is more or less mixed with chrysene. When it is
desired to obtain the anthracene as pure as possible this is effected by
employing a mean of the temperatures between that which gives excess
of naphthaline and that which gives excess of chrysene. By testing the
nature of the distilled product from time to time it may soon be found
by experience in what way and to what extent the temperatures may be
varied and regulated.
The anthracene distilled from pitch by our process as above described
will be found to be mixed with a viscid heavy oil, from which it may be
readily separated by filtration and washing with oils of less specific
gravity, or petroleum or other spirit, or by other convenient modes of
separation.

page_text: Having thus described our Invention, and the means which we adopt
in carrying the same into effect, we would have it understood that we do
not confine ourselves to the apparatus described, as such may be varied
without departing from the peculiar character of our Invention. But
we would have it understood that what we claim is the process above
described of obtaining anthracene from coal tar pitch by the employment
of regulated high temperatures, externally applied and substantially as
described.
Also we claim the use of a partial vacuum to assist the passage of the
products of distillation as above described.
Also we claim the combination of the manufacture of anthracene
from coal tar pitch, with the distillation of oils from coal tar by a con-
tinuous process, substantially as described.
In witness whereof, we, the said Henry James Fenner and Frederick
Versmann, have hereunto set our hands and seals, this Twenty- ]
second day of June, in the year of our Lord One thousand
eight hundred and seventy-two.