Improvements relating to the Production of Cyanogen Compounds, and to the Preparation of Materials for Use therein.
Year: 1895

page_text: Date of Application. 10th Aug., 1895
Complete Specification Left, 20th Apr., 1896-Accepted, 23rd May, 1896
PROVISIONAI. SPECIFICATION.
Improvements relating to the Production of Cyanogen Compounds,
and to the Preparation of Materials for Use therein.
We, Dr. ADOLPH FRANK, Analytical Chemist, of No. 80, Leibnitzstrasse,
Charlottenburg, and Dr. NIKODEM ČARO, Analytical Chemist, of No. 31, Calvin-
strasse, Berlin, both in the German Empire, do hereby declare the nature of this
invention to be as follows:-
The
It has been stated before now, by Moissan (in his "Comptes rendus" for 1894,
p. 503), that, when nitrogen passes over or in contact with the heated carbides of
calcium, barium and strontium, no reaction or combination takes place.
applicants, however, have ascertained by investigation that nitrogen is absorbed by
carbides, if conducted, in the presence of water vapour, over or in contact with the
carbides contained in closed vessels (such as tubes, retorts or the like) heated to a
degree approaching red heat, with the formation of cyanogen compounds, the
corresponding cyanides being formed. These cyanides will be formed when the
carbides of the metals of the alkaline earths (such as calcium, barium, strontium
or magnesium) are employed, and also when the carbides of alkali-metals (such as
potassium, sodium or lithium) are used; so, too, cyanides are obtained, when
mixtures of the various carbides are used. And the same effect is produced when
the carbides contain other substances, such as alkalies (potash, soda), or 'alkaline
earths (lime, baryta, strontia, magnesia) or the salts thereof. The carbide mixtures
may be prepared either by mixing the several ready-made carbides; or by treating
the crude substances or agents required for the production of carbides (such as the
oxides or carbonates of the corresponding alkalies or alkaline earths, or the free
metals) with the requisite amount of carbon in any desired or well known manner,
80 as, by a direct process, to convert them into carbides; or, again, by mixing the
carbides of suitable alkaline earths, or mixtures thereof, with alkalies or salts of
alkalies.
In preparing carbides from free metal and carbou, experiment has shown it to be
advisable where metals are used, which would become volatilized at the temperature
required for the formation of carbides (such, for instance, as potassium, sodium and
magnesium, and also zinc which, chemically, is related to the last-mentioned metal)-
to submit such metals, together with the carbon (or coal) to the action of the
required high temperature after confining them in closed vessels; when the desired
carbide will form as a result of the action exercised upon the carbon by the metallic
vapour.
The experiments which have led to the present discovery have shown that if, in
carrying out the process above indicated, iron, or iron compounds, be added to the
material from which the carbide is to be formed, the corresponding cyanogen
compounds in the form of ferro-cyanogen combinations-will be obtained by
treating the mixture in the manner above stated.
The manner in which this invention is to be performed may be better illustrated
by the following examples:
(1.) Barium carbide, obtained in the well known manner, after being finely
reduced or divided, is introduced into a retort of tubular shape, made of refractory
material (preferably fire-clay). The retort should be fitted with suitable means or

page_text: devices for the admission and discharge of the gases. The nitrogen required to
bring about a reaction-which may be air, wholly or partly freed from oxygen in
the well known manner-is thoroughly saturated with water vapour; for which
purpose it is preferably conducted through a vessel containing water. After heating
the retort nearly to a red heat, the nitrogen, thus charged with moisture, is
introduced into such retort. For a charge of from 15 to 17 kilograms of barium
carbide, from 2 to 2 cubic meters of nitrogen will be sufficient. The nitrogen is
preferably introduced into the retort under a moderate pressure, and at a rate of
speed enabling the operation to be completed in about two hours. The resulting
mass, after cooling, is treated with water. From any carbide that may remain
unaltered, acetylene will be evolved, which may be intercepted and collected
separately; while barium cyanide will be obtained in the form of a solution, which
may be extracted and treated in the well known manner.
(2.) Calcium carbide as such, on being similarly treated, failed to give a satis-
factory result. But a mixture of calcium carbide and barium carbide, as well as one
of calcium carbide and sodium carbide (obtained in the ordinary manner from
soda-lime, and carbon) will give the desired result. The product of the reaction,
obtained through the joint action of nitrogen and the vapour of water (by a process
similar to that described with reference to the first example) may-like the product
obtained according to the first example-be washed or lixiviated with water ; and
any acetylene which may be evolved should be collected separately, while the
solution may be further treated with a view to its conversion into cyanide. For
this purpose hydrogen cyanide or hydrocyanic acid may be extracted from the
solution by the addition of an acid-preferably by introducing carbonic acid into
the solution-after which such gas (hydrogen cyanide) is brought in contact with
the metallic oxide the cyanogen salt of which it is desired to obtain. Or the desired
cyanide can be extracted from the solution by the process of "double decomposition."
Thus by an admixture of the carbonate of an alkali, the cyanide of an alkaline earth
may be converted into the cyanide of the corresponding alkali, which remains in
solution, and into the carbonate of such alkaline earth, obtained in the condition of
a precipitate.
(3.) Whether barium carbide or calcium carbide be dealt with, the result obtained
by carrying out the process more fully described with reference to the first example,
may be improved by first mixing the carbides, or a mixture of the same (to be treated
by that process) with a caustic alkali or an alkaline carbonate, and only subjecting
it to the reaction indicated after this has been done. The product of the reaction
may then be further treated in accordance with the second example.
(4.) Carbides of alkalies (such as potassium, sodium, lithium) whether taken each
separately, or mixed together, will yield the corresponding cyanides, if treated in
accordance with the first example, even in the presence of alkaline earths (such
as lime, baryta, strontia, magnesia or the like) or of their salts; such cyanides being
separated from the product of the reaction by lixiviation with water.
As regards temperature, a dark red heat has been found favourable to the satis-
factory performance of the process. Where a lower temperature is employed, the
action of the nitrogen generally proves to be too slow; while a material increase of
the temperature beyond the limit stated is apt to occasion a partial decomposition
and a proportionate diminution of the yield.
In order to take fuller advantage of the nitrogen, a number of retorts, arranged
in succession, or a battery of retorts, may be employed, which arrangement will also
"enable the operations to be conducted continuously.
Dated 10th day of Aucnst 1905
D. YOUNG & Co.,
11 & 12 Southampton Buildings, London, W.C.,
Agents for the Applicants.

page_text: Improvements relating to the Production of Cyanogen Compounds,
and to the Preparation of Materials for Use therein.
We, Dr. ADOLPH FRANK, Analytical Chemist, of No. 80, Leibnitzstrasse,
Charlottenburg, and Dr. NIкODEM CARO, Analytical Chemist, of No. 1 Roonstrasse,
late of No. 31, Calvinstrasse, Berlin, both in the German Empire, 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 :-
And
It has been stated before now, by Moissan (in the "Comptes rendus" for 1894,
p. 503), that, when nitrogen is passed over or in contact with the heated carbides
of calcium, barium and strontium, no reaction or combination takes place, this
statement being based directly upon experiments made with chemically pure carbides.
The applicants, however, have ascertained by investigation that nitrogen is absorbed
by such chemically pure carbides, with the formation of cyanogen compounds, if
conducted, in the presence of water vapour, over or in contact with the carbides
contained in closed vessels (such as tubes, retorts or the like) and heated to a
temperature approaching that. of red heat, the corresponding cyanides being formed..
These cyanides will be formed when the carbides of the metals of the alkaline earths"
(such as calcium, barium, strontium or magnesium) are employed, and also when
the carbides of alkali-metals (such as potassium, sodium or lithium) are used; so,
too, cyanides are obtained, when mixtures of the various carbides are used.
the same effect is produced when the carbides contain other substances, such as
alkalies (potash, soda), or alkaline earths (lime, baryta, strontia, magnesia) or the
salts thereof. In this case, in which chemically pure carbide is not present, the
presence of water vapour can be dispensed with. The presence of water vapour is
also unnecessary, even with chemically pure carbides, if the nitrogen be applied in
a chemically bound or combined form, so that it is given off or liberated as free
nitrogen and can thus come into operation in statu nascenli. The carbide mixtures
may be prepared either by mixing the several ready-made carbides; or by treating
the crude substances or agents required for the production of carbides (such as the
oxides or carbonates of the corresponding alkalies or alkaline earths, or the free
metals) with the requisite amount of carbon in any desired or well known manner,
so as, by a direct process, to convert them into carbides; or, again, by mixing the
carbides of suitable alkaline earths, or mixtures thereof, with alkalies or salts of
alkalies.
In preparing carbides from free metal and carbon, experiment has shown it to be
advisable where metals are used which would become volatilized at the temperature
required for the formation of carbides (such, for instance, as potassium, sodium,
and magnesium, and also zinc which, chemically, is related to the last mentioned
metal) to submit such metals, together with the carbon (or coal), to the action of
the required high temperature after confining them in closed vessels; when the
desired carbide will be formed as a result of the action exercised upon the carbon by
the metallic vapour.
The experiments which have led to the present discovery have shown that if, in
carrying out the process above indicated, iron, or iron compounds, be added to the
material from which the carbide is to be formed, the corresponding cyanogen
compounds in the form of their ferro-cyanogen combinations-will be obtained by
treating the mixture in the manner above stated.
The manner in which this invention is to be performed may be better illustrated
by the following examples:
(1.) Barium carbide, obtained in the well known manner, after being finely reduced
or divided, is introduced into a retort of tubular shape, made of refractory material

page_text: (preferably fire-clay). The retort should be fitted with suitable means or device
for the admission and discharge of the gases. The nitrogen required for th
reaction which may be air, wholly or partly freed from oxygen, in the wel
known manner is thoroughly saturated with water vapour; this is absolutely
necessary when employing nitrogen in the free condition with chemically pure
carbides; with carbides containing oxides or salts, even in small quantities, or wher
employing nitrogen in a bound or combined form, however, it is not absolutely
necessary. This saturation with water vapour is advantageously effected by con-
ducting the gas through a vessel containing water. After heating the retort nearly
to a red heat, the nitrogen, thus charged with moisture, is introduced into such
retort. For a charge of from 15 to 17 kilograms of barium carbide, from 2 to
2 cubic meters of nitrogen will be sufficient. The nitrogen is preferably introduced
into the retort under a moderate pressure, and at a rate or speed enabling the
operation to be completed in about two hours. The resulting mass, after cooling, is
treated with water. From any carbide that may remain unaltered, acetylene will
be evolved, which may be intercepted and collected separately; while barium cyanide
will be obtained in the form of a solution, which may be extracted and treated in the
well-known manner.
(2) Calcium carbide as such, on being similarly treated, failed to give a satis
factory result. But a mixture of calcium carbide and barium carbide, as well as
one of calcium carbide and sodium carbide (obtained in the ordinary manner from
soda-lime and carbon,) will give the desired result. The product of the reaction,
obtained through the joint action of nitrogen and the vapour of water (by a process
similar to that described with reference to the first example) may-like the product
obtained according to the first example-be washed or lixiviated with water; and
any acetylene which may be evolved should be collected separately, while the solution
may be further treated with a view to its conversion into cyanide. For this purpose,
hydrogen cyanide or hydrocyanic acid may be extracted from the solution by the
addition of an acid-preferably by introducing carbonic acid into the solution―
after which such gas (hydrogen cyanide) is brought in contact with the metallic
oxide, the cyanogen salt of which it is desired to obtain. Or the desired cyanide
can be extracted from the solution by the process of "double decomposition."
Thus by an admixture of the carbonate of an alkali-metal, the cyanide of a metal of
the alkaline earths may be converted into the cyanide of the corresponding alkali-
metal, which remains in solution, the carbonate of such metal of the alkaline earths
being obtained in the condition of a precipitate.
(3) Whether barium carbide or calcium carbide be dealt with, the result obtained
by carrying out the process more fully described with reference to the first
example, may be improved by first mixing the carbides, or a mixture of the same
(to be treated by that process) with a caustic alkali or an alkaline carbonate, and
only subjecting it to the reaction indicated after this has been done; in this modi-
fication of our process the presence of water-vapour is not absolutely necessary.
The product of the reaction may then be further treated in accordance with the
second example.
(4) Carbides of alkalies (such as potassium, sodium, lithium) whether taken each
separately, or mixed together, will yield the corresponding cyanides, if treated in
accordance with the first example, even in the presence of alkaline earths (such as
lime, baryta, strontia, magnesia or the like) or of their salts; such cyanides being
separated from the product of the reaction by lixiviation with water.
As regards temperature, a dark red heat has been found favourable to the satis-
factory performance of the process. Where a lower temperature is employed, the
action of the nitrogen generally proves to be too slow; while a material increase of
the temperature beyond the limit stated is apt to occasion a partial decomposition
and a proportionate diminution of the yield.
In order to take fuller advantage of the nitrogen, a number of retorts, arranged 5
in succession, or a battery of retorts, may be employed, which arrangement will
also enable the operations to be conducted continuously.

page_text: Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that
what we claim is :-
1. A process for the preparation of cyanogen compounds by the action of nitrogen
(free or combined) and, when necessary (for example, with chemically pure carbides)
steam upon the carbides of the metals of the alkaline earths or of the alkali-
metals, as the case may be.
2. A modification of the process hereinbefore described, in which the action of
nitrogen (free or combined) and, when necessary, steam upon carbides of the metals
of the alkaline earths or of the alkali-metals, as the case may be, takes place in the
presence of alkalies or alkaline earths, or of the salts thereof.
3. The preparation of carbides from those metals which will become volatilized
at the temperature necessary for the formation of carbides (such metals being, for
example, potassium, sodium or magnesium), by heating the metal to be dealt with,
in closed vessels, in the presence of carbon, so that the metal is in the condition of
vapour when it comes to exercise its action upon the carbon, substantially as herein-
before described.
4. The production of ferro-cyanogen compounds by the process hereinbefore
described and by the employment, in addition to the other reagents, of iron or
compounds of iron.
Dated this 20th day of April 1896
D. YOUNG & Co.,
11 & 12 Southampton Buildings, London, W.C.,
Agents for the Applicants.