Improvements in the Manufacture of Cyanogen Compounds and the Treatment of Substances used therein.
Year: 1891

page_text: Date of Application, 25th Mar., 1891
Complete Specification Left, 23rd Jan., 1892-Accepted, 25th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Cyanogen Compounds and the
Treatment of Substances used therein.
We JOHN JAMES HOOD of 21 Shepherd's Bush Road in the County of
Middlesex, and ALFRED GORDON SALAMON of 1 Fenchurch Avenue in the
City of London, Analytical Chemists, do hereby declare the nature of this
invention to be as follows:-
It is known that compounds of the cyanogen radicle (CN) may be formed
from ammonia by acting upon this latter body with carbon bisulphide. The
improvements herein described have reference to this chemical re-action, and have
for their object to enable the re-action to be applied on a commercial scale for the
production of several of the cyanide compounds.
The first stage of our process consists in heating gently to about the tem-
perature of boiling water in closed vessels carbon bisulphide and ammonia with
the hydrated peroxide of manganese known as "Weldon mud" washed free from
calcic chloride and dried. Hereby there is formed, the quantities of material
being in proper equivalents, sulpho-cyanides of manganese and lime, sulphide of
manganese and free sulphur.
Instead of employing "Weldon mud," prepared as described, the peroxide
obtained by igniting the carbonate of manganese may be employed, or native ore
known as wad.
+
The resulting mass is washed, the insoluble residue of manganese sulphide and
free sulphur exposed to the air to revivify, and employed a second time.
The sulpho-cyanides of manganese and lime in solution may be crystallised and
employed in commerce.
In order to form the prussiates from these sulpho-cyanides, we precipitate with
such alkali salts as will throw down the lime and manganese. By preference we
employ the carbonates of soda or potash. Carbonic acid having a greater affinity
for manganese than for lime-this we utilize if we add sodic or potassic carbonates
as above stated, inasmuch as the carbonate of manganese is precipitated first
before the lime comes down, and can be taken out and used in the ordinary
way, igniting the carbonate of manganese produced to form peroxide and again
employing this peroxide as above set forth.
The solution now contains sulpho-cyanide of the alkali soda or potash, which we
crystallize and send into commerce. From the potash salt we form aluminic
sulpho-cyanide by mixing it with aluminic sulphate and crystallizing out potash
alum, leaving aluminic sulpho cyanide in solution. To form the yellow prussiate
from the alkali sulpho cyanides, we evaporate, mix with sufficient iron filings or
borings, and ignite gently thereby forming ferro cyanide of soda or potash,
sulphide of the alkali and sulphide of iron, the ferro cyanide is washed out, and
crystallized from the alkali sulphide of iron, or we proceed by igniting the soda
sulpho cyanide with iron, washing out the soda prussiate, precipitating with
calcic chloride, forming calcium ferro-cyanide, and decomposing this salt with
soda potash or ammonia carbonate thereby obtaining a pure solution of alkali
prussiate free from sulphide which may be crystallized.
Instead of employing peroxide of manganese in the first stage of our operations,
we may employ hydrated ferric oxide native or artificial, the form we prefer being
that known as Irish bog oxide. In this case, we obtain sulphide of iren (which
may be revivified by exposure to air and again used) and sulpho cyanide of
ammonia. This sulpho cyanide of ammonia we convert into the soda or potash salt
by heating with the alkali sulphides or carbonates and proceed to form the

page_text: prussiates as before described, or we make aluminic sulpho cyanide with aluminic
sulphate as in the case of the potash salt above described.
ERNEST SALAMAN,
61 & 62, Chancery Lane, W.C., Agent for the Applicants.
The requisite amount or charge of base or bases is introduced into cylinders or
other suitable digestors capable of withstanding the high pressure generated through
the reaction and heated externally or internally by steam and the requisite amount
of ammonia and carbon-bi-sulphide are all run in at once or these two materials are
pumped into the digestor in small quantities at a time to keep the reaction con-
tinually going on and prevent the pressure rising too high and too suddenly as may
be the case if the whole of the ammonia and bi-sulphide is added at once.

page_text: When the reaction is completed the resulting mass is washed. The insoluble
residue of manganese sulphide and free sulphur is exposed to the air to revivify and
employed a second time.
The sulpho-cyanide of manganese or lime in solution may be crystallised and
employed in commerce. Or we precipitate the bases, lime or manganese with the
alkaline salts (carbonates, sulphates or sulphides) and send such alkaline sulpho-
cyanides into commerce.
In order to form the prussiates from the sulpho-cyanides we precipitate with the
carbonate of soda or potash or such alkaline salts as will throw down the lime and
manganese. If dealing with a mixture of sulpho-cyanides of manganese and lime
we utilise the fact that carbonic acid has a greater affinity for manganese than for
lime by first adding sodic or potassic carbonates as above stated in sufficient quantity
to precipitate the carbonate of manganese and this material can be taken out and
used in the ordinary way after ignition as peroxide of manganese and we may
again employ the peroxide as above set forth. When the carbonate of manganese
has been precipitated we add a further quantity of sodic or potassic carbonate
to precipitate the lime. The resulting solution now contains sulpho-cyanide of the
alkali soda or potash which we crystallise and send into commerce. From the
potash salt we form aluminic sulpho-cyanide by mixing it with aluminic sulphate
and crystallising out potash alum leaving the aluminic sulpho-cyanide in solution.
To form the yellow prussiate from the alkaline sulpho-cyanides we evaporate
and mix with sufficient iron filings, or borings and ignite gently thereby forming
ferro-cyanide of soda or potash sulphide of the alkali and sulphide of iron. The
ferro-cyanide is washed out and crystallised from the alkali sulphide.
Instead of employing natural or artificial manganese peroxide as above described
in the first stage of our operations we may employ hydrated ferric-oxide native or
artificial the form we prefer being that known as Irish bog oxide.
In this case we obtain sulphide of iron (which may be revivified by exposure to
air and again used), and sulpho-cyanide of ammonia. The sulpho-cyanide of
ammonia we convert into the soda or potash salt by heating with the alkaline
sulphides or carbonates and proceed to form the prussiates as before described
or we mix ammonic sulpho-cyanide with aluminic sulphate as in the case of the
potash salts above described. This reaction in the case of oxide of iron may be
represented thus :-
(a) CS, +2 NH, NH, (CNS) + H2S
=
(b) FeO 3 H₂S = Fе₂S₂+ 3 H₂O
the oxide of iron only acting upon the sulphuretted hydrogen whilst half the
ammonia added acts as a base for the sulpho-cyanic acid. Or we add a second
base an alkali or alkaline earth preferably caustic or slaked lime to take the
place of the ammonia thereby converting all the ammonia into the cyanogen
radicle as sulpho-cyanide of lime or other base as in the case of the peroxide of
manganese before described.
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 :-

page_text: V. The production of sulpho-cyanide of ammonia by acting upon carbon-
bi-sulphide with ammonia in presence of hydrated-oxide of iron substantially as
described.
VI. In the production of sulpho-cyanide of lime substantially as described the
employment of hydrated ferric-oxide for the purpose stated.
Dated this 23rd day of January 1892.
ERNEST SALAMAN,
61, Chancery Lane, London, Agent for Applicants.