Improvements in the Manufacture or Production of Cyanogen Compounds.
Year: 1896

page_text: Date of Application, 15th Jan., 1896-Accepted, 21st Mar., 1896
COMPLETE SPECIFICATION.
Improvements in the Manufacture or Production of Cyanogen
Compounds.
We, ALBRECHT VON RAD, D.Ph. Chemist, and JACOB ROSENFELS, Chemical
Manufacturer, both of Pfersee-Augsburg in the Kingdom of Bavaria, do hereby.
declare the nature of this invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
It has recently been endeavoured to produce chemical compounds of cyanogen
from coal and free nitrogen in presence of an alkali or of an alkaline earth by the
action of heat, but these endeavours have proved interesting from a scientific point
of view only, and have possessed no practical utility. The fact that the chemical
combination of the free nitrogen with the carbon in the presence of an alkali or an
alkaline earth takes place at so high a temperature that a white heat has to be
employed, is the chief factor preventing the practical employment of this process
for the production of cyanogen compounds, because owing to the intense heat, the
wear and tear of the apparatus is greater than can be practically allowed. A
further reason for the failure of the process is found in the additional fact that
large masses have to be kept at a white heat for a long time. The expenses and
inconveniences thus involved, apart from the further fact that the process gives a
poor yield of cyanogen and its compounds, suffice to condemn it from a commercial
standpoint.
By proceeding according to our invention as hereinafter described these incon-
veniences and excessive expenses are to a large extent avoided, and a larger yield
of cyanogen compounds is obtained.
Instead of employing coal as the source of carbon we employ suitable carbides,
with which only a moderate red heat is required. Barium or calcium carbides or
both of them together are preferably employed, in different ways, with different
results. As an example of the simplest method we may employ, barium or calcium
carbide at a red heat, is acted upon by free nitrogen. In this manner cyanogen
is produced, especially when barium carbide is used. But a more economical
production may be obtained by mixing in about molecular proportion, the powdered
barium carbide with dried alkaline carbonate, and exposing the mixture to the action
of free nitrogen at a red heat or thereabouts.
It is probable that in this operation a mutual reaction takes place. For example
if potassium carbonate be employed, the calcium and the potassium may change
places, producing a carbide of potassium, caustic lime, and carbon dioxide which
becomes at once reduced to carbon monoxide by some excess of calcium carbide.
0.0, + K,00,
T
.It would appear that such a mutual reaction must occur between carbides and
alkaline carbonates, because otherwise, the reception of free nitrogen at a red heat,
for producing cyanogen would not be explicable, as all recent experiments tend to
shew that a mixture of coal and an alkaline carbonate can bind free nitrogen so as to
form cyanogen, if it is exposed to a great that is to say white heat.
The production of cyanogen by free nitrogen at a red heat acting upon potassium
carbide according to our invention may be readily understood from the following
quotation

page_text: Ammonia may be employed as the source of nitrogen, the mixture of the carbide and
alkaline carbonate being exposed at a red heat to an atmosphere of ammonia, when
cyanogen compound is abundantly produced as shewn by the following equation:-
when
cyanogen compound is abundantly produced as shewn by the following equation:-
K,C,+2 NH3 = 2 K(NC) + 6 H.
===
This simple, and almost perfect transformation of ammonia into cyanogen by
means of the heated mixture of carbide and alkaline carbonate illustrates the
importance of the use of carbides also for the manufacture of potassium ferro-
cyanide from potassium carbonate and nitrogenous animal matters. Thus, proceeding
according to existing methods, calcium carbide may be added in molecular
proportion, but only a red-heat is employed, when the nitrogen from the animal
matters is much better utilized, for the generation of the cyanogen, and a much
more profitable result is secured.
The use of carbides according to this invention is of great importance to the
electro-chemical industry, which is now engaging itself with advantage in the
production of these carbides which may be produced at a very low cost especially
when power is available at a cheap or moderate rate.
Among the advantages resulting from the adoption of this invention may be
mentioned: That only a red heat is required with a corresponding saving of fuel
and wear and tear. The abundance of atmospheric nitrogen, free of cost, utilized
in the production of the cyanogen. When using ammonia the almost theoretical
available quantity of cyanogen is obtained. In the manufacture of ferrocyanide of
potassium, the operation may be kept free from disturbing elements by using pure
materials, whilst the cost is greatly reduced. Quantities of about one-tenth of what
are necessary in the existing process for the manufacture of ferrocyanide may be
employed, making the operation more convenient and profitable. Soda may be
used instead of the more expensive potash.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
The manufacture or production of cyanogen and cyanogen compounds by means
of carbides substantially as hereinbefore described.
Dated this 14th day of January AD 1896
W. E. HEYS & SON,
Agents for the Applicants.