An Improved Method of Producing Formiate of Ammonia and Hydrocyanic Acid therefrom.
Year: 1893

page_text: Date of Application, 20th Feb., 1893
Complete Specification Left, 21st Sept., 1893-Accepted, 11th Nov., 1893
PROVISIONAL SPECIFICATION.
An Improved Method of Producing Formiate of Ammonia and
Hydrocyanic Acid therefrom.
I PIERRE ROGAtien de LambiLLY of 28 Rue de Strasbourg, Nantes in the
Republic of France Chemist do hereby declare the nature of this invention to be
as follows:
The object of this invention is to provide an improved method of producing
hydrocyanic acid without the use of cyanides and it is based upon the production
of formiate of ammonia followed by its decomposition by heat.
It is known that hydrocyanic acid is the nitrile corresponding to formiate of
ammonia and that it is formed in a certain quantity when the latter salt is
dehydrated. Formiate of ammonia melts at about 120° and thereupon commences
to lose water formning its amide, the formamide, which latter between 180 and 200°
by further dehydration produces hydrocyanic acid or formo nitrile.
These reactions may be represented as follows ;—
The two successive reactions may also be graphically represented omitting the
intermediate stage as follows;-
HCNHO, HCN + 2 H₂O
===
It is true that a certain quantity of carbonic oxide and ammonia is disengaged at
the same time but the production of hydrocyanic acid is large.
The suitability of the process will largely depend on the simple and cheap
production of formiate of ammonia.
It is known that the passage of a current of carbonic oxide over a caustic alkali
under a degree of heat varying with the alkali chosen, an alkaline formiate is
produced as follows ;-
CO+NaHO =
HCNaO,
where Na may be replaced by equivalent of another alkali.
The temperature for caustic soda is about 200° or as I have noticed about the
temperature at which formiate of soda melts. It appeared therefore that if
carbonic oxide could be passed into ammonia held in situ in aqueous solution, at
about 120° which is the temperature of the melting point of formiate of ammonia
this latter salt should be produced.
This may be done by the following method. The carbonic oxide previously.
saturated with ammonia by passage through liquid ammonia or otherwise, is passed
through a tube containing an absorbent body such as platinised carbon or charcoal
spongy platinums or other suitable material and heated to a temperaturo of
between 110° and 130°. The vapours of formiate of ammonia which will be thereby
produced and then passed through a second similarly charged tube but heated to a
higher temperature, about 200°. The vapours will be thus converted into water
and hydrocyanic acid which may be received in an alkaline solution to which
there may be added a salt of iron if ferrocyanide is desired.
'
The carbonic oxide may be subjected to a preliminary heating to improve its
power of saturation, while the addition of alcohol or ether to the ammoniacal liquid
improves the combination of the ammonia as carbonic oxide is more readily soluble
herein than in water.

page_text: As no decomposition of the alcohol or ether occurs in this process any of these
that may be carried over may be recovered without loss from the ultimate solution.
Dated this 20th day of February 1893.
R. HADDAN,
Agent for Applicant.
COMPLETE SPECIFICATION.
An Improved Method of Producing Formiate of Ammonia and
Hydrocyanic Acid therefrom.
I, PIERRE ROGATIEN DE LAMBILLY of 28 Rue de Strasbourg Nantes in the
Republic of France, 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 :-
Hydrocyanic acid is the ultimate resultant of the dehydration of formiate of
ammonia by heat. Formiate of ammonia melts at about 110° C. and upon further
elevation of the temperature commences to part with water producing first an
anhydride, the formamide. This in its turn as the temperature continues to rise
gives off more water until at a temperature rather above 210° C. hydrocyanic acid
alone remains. These two successive dehydrations may be represented by the
following formula.
ayarocyanic acid and water according to the following formula.
==
HCNHO₂ = HCN + 2 H₂O.
The temperature necessary for this complete dehydration should not be less
than 210° C. and may rise up to about 300° C.
The suitability of this process will largely depend upon a simple and cheap
production of the formiate of ammonium necessary. This body I produce by the
following method :—
I pass a current of carbonic monoxide gas saturated with the vapours arising
from aqueous solution of ammonia through a tube or battery of tubes filled with
porous bodies capable of occluding or condensing gases, such as pumice stone or
bone charcoal platinized or not, heated to a temperature of from 100° to 130° C.
Formiate of ammonium in the form of vapour is thus produced and may be con-
densed and collected if desired, or utilized for the further production of hydrocyanic
acid by passing the vapours immediately and directly into a further tube or battery
of tubes filled with gas absorbent materials similarly to the first tube or set of
tubes, but heated to a temperature above 210° C. As has been previously mentioned
the vapours of formiate are resolved into water and hydrocyanic acid to be
employed in any desirable way for instance by freeing this body from water
and collecting it or by absorbing it in an alkali, on making use of it for
manufacturing or other purposes.
I do not confine myself to any particular method of saturating the carbonic mon-
oxide with ammonia; a simple method consists in passing the gas through a
concentrated solution of ammonia, the gas being previously heated if desired to
increase its power of saturation.
There is always a possibility that the production of hydrocyanic acid will not
be the only result of the above described process, since in the second dehydration

page_text: here is a tendency to produce a secondary reaction resulting in the resolution of
the formate into carbon monoxide and ammonia chus
не логирате со сигрой поножные ани аищонта осци
HÌNH,O = CO + NH
but the production of hydrocyanic acid is nevertheless in such case sufficiently
abundant and it may be separated from the monoxide of carbon and ammonia and
the latter recovered without loss.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed I declare that what I
claim is -
1. The method of producing formiate of ammonium consisting in passing a
mixture of carbonic monoxide and vapours from an aqueous solution of ammonia
through a tube or tubes containing platinized or non-platinized absorbent bodies
and heated to a temperature between 100° and 130° C.
2. The method of producing hydrocyanic acid consisting in passing the vapours
of formiate of ammonium through a tube or tubes containing platinized or
non-platinized absorbent bodies and heated to a temperature above 210° C.
3. The method of producing hydrocyanic acid consisting in passing a mixture
of carbonic monoxide and vapours from an aqueous solution of ammonia first through
a tube or tubes charged with absorbent bodies and heated to between 100° and
130° C., and afterward through a similarly charged tube or tubes heated to above
210° C.
Dated this 1 I..
1000
R. HADDAN,
Herbert Haddan & Co.,
18, Buckingham Street, Strand, London, Agent for Applicant.