Manufacture of Alkaline Cyanides and Ferrocyanides.
Year: 1894

page_text: Date of Application, 30th Aug. 1894
Complete Specification Left. 9th May, 1895-Accepted, 15th June, 1895
TRUVIDIONAL SPECIFICATION.
Manufacture of Alkaline Cyanides and Ferrocyanides.
I, Dr. GUSTAV KRAEMER, of No. 7 Flottwell Strasse Berlin, in the Empire of
Germany, Chemist, do hereby declare the nature of this invention to be as
follows:-
:-
As raw material for the production of potassium cyanide is employed carbazol
or the anthracene residues containing carbazol, such as are obtained in enriching
crude anthracene according to the various processes with benzol sulphurous acid or
pyridiu.
The carbazol or the said residues are heated together with the corresponding
quantity (to be calculated according to the percentage of carbazol) of potash or
soda, either in solid condition or dissolved in a little water, in a cast iron vessel
provided with stirring apparatus, and the heat is gradually raised to from 260°
to 280° C. for potash or to from 320° to 340° C. if soda is used, and the mass is
maintained at this temperature for some time. The potassium or sodium carbazol
thus obtained will then have become well deposited, so that it can be readily
separated from the impurities contained in the carbazol or anthracene residues
employed.
The carbazol salt thus obtained is then heated gradually to a bright red heat in
suitable vessels either by itself or with the addition of certain quantities of potash,
carbonate of soda or caustic potash, to which is added the necessary quantity of
iron powder if it is desired to obtain yellow prussiate of potash. The mass having
been maintained for some time at the said heat, the melt is then lixiviated and the
Iye treated for the production of potassium cyanide or yellow prussiate of potash,
in the usual manner.
For obtaining potassium carbazol, which is undoubtedly preferable for the
preparation of the cyanide compounds, the following will serve as an example :
200 kilos, of an anthracene residue containing about 40 per cent. carbazol, such as
is easily obtained in the enriching of crude anthracene, are heated under continual
stirring together with 30 kilos. of commercial potassium hydrate in a vessel
provided with stirring apparatus, until the temperature of 260° to 280° C. has been
reached, and the water produced by the reaction has been distilled off, which
generally takes place after about 3 hours. The melt is then left standing for a
short time, is then discharged into suitable moulds, and after cooling, the cake of
potassium carbazol is separated from the layer of solid anthracene hydrocarbons
lying above it.
The crude potassium carbazol thus obtained is then broken up and at once
introduced into a similar melting vessel, and is gradually heated up to a bright red
heat, when it is converted into potassium cyanide under separation of carbon, while
small quantities of carbazol, ammonia, and combustible gases escape. A still better
yield is obtained if there is added to the melt certain quantities of a flux such as
potash, carbonate of soda &c.
Of the nitrogen of the carbazol there is converted by this means 50 per cent. and
more into cyanogen, a yield such as is not obtainable from any other nitrogenous
material.

page_text: Similar good results may be obtained with sodium carbazol, which has not yet
been mentioned in literature, and the preparation of which is only slightly more
difficult, owing to the higher reaction temperature.
Dated this 30th day of August 1894.
ABEL & IMRAY,
Agents for the Applicant.
manufacture of Alkaline Cyanides and ferrocyanide.
I, Dr. GUSTAV KRAEMER, of No. 7 Flottwell Strasse, Berlin, in the Empire of
Germany, Chemist, 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 :-
As raw material for the production of potassium cyanide is employed carbazol
or the anthracene residues containing carbazol, such as are obtained in enriching
crude anthracene according to the various processes with benzol, sulphurous acid,
or pyridin.
The carbazol or the said residues are heated together with the corresponding
quantity (to be calculated according to the percentage of carbazol) of potash or
soda either in solid condition or dissolved in a little water, in a cast iron vessel
provided with stirring apparatus, and the heat is gradually raised to from 260°
to 280° C. for potash or to from 320° to 340° C. if soda is used, and the mass is
maintained at this temperature for some time. The potassium or sodium carbazol
thus obtained will then have become well deposited, so that it can be readily
separated from the impurities contained in the carbazol or anthracene residues
employed.
The carbazol salt thus obtained is then heated gradually to a bright red heat in
suitable vessels either by itself or with the addition of certain quantities of potash,
carbonate of soda or caustic potash, to which is added the necessary quantity of
iron powder if it is desired to obtain yellow prussiate of potash. The mass having
been maintained for some time at the said heat, the melt is then lixiviated and the
lye treated for the production of potassium cyanide or yellow prussiate of potash,
in the usual manner.
For obtaining potassium carbazol, which is undoubtedly preferable for the
preparation of the cyanide compounds, the following will serve as an example:
200 kilos. of an anthracene residue containing about 40 per cent. carbazol, such as
is easily obtained in the enriching of crude anthracene, are heated under continual
stirring together with 30 kilos. of commercial potassium hydrate in a vessel
provided with stirring apparatus, until the temperature of 260° to 280° C. has been
reached, and the water produced by the reaction has been distilled ott, which
generally takes place after about 3 hours. The melt is then left standing for a
short time, is then discharged into suitable moulds, and after cooling, the cake of
potassium carbazol is separated from the layer of solid anthracene hydrocarbons
lying above it.
The crude potassium carbazol thus obtained is then broken up and at once
introduced into a similar melting vessel, and is gradually heated up to a bright red
beat, when it is converted into potassium cyanide under separation of carbon, while
small quantities of carbazol, animonia, and combustible gases escape. A still
better yield is obtained if there is added to the melt certain quantities of a flux
such as potash, carbonate of soda &c.
Of the nitrogen of the carbazol there is converted by this meaus 50 per cent.,
and more, into cyanogen, a yield such as is not obtainable from any other
nitrogenous material.

page_text: Similar good results may be obtained with sodium carbazol, which has not yet
been mentioned in literature, and the preparation of which is only slightly more
difficult, owing to the higher reaction temperature.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The manufacture of potassium and sodium cyanides and ferrocyanides by
heating carbazol or potassium carbazol or sodium carbazol together with caustic
potash or soda or their carbonates, with or without the addition of iron, substantially
as described.
ABEL & IMRAY,
Agents for the Applicant.