Improvements in and relating to the Manufacture of Hydrazine or Diamidogen and its Salts.
Year: 1891

page_text: Date of Application, 20th Apr., 1891
Complete Specification Left. 19th Jan., 1892-Accepted, 20th Feb., 1892
PROVISIONAL SPECIFICATION.
Improvements in and relating to the Manufacture of Hydrazine or
Diamidogen and its Salts.
I JAMES YATE Jonsson of 47 Lincoln's Inn Fields in the County of
Middlesex Gentleman, do hereby declare the nature of this invention, which has
been communicated to me from abroad by The Badische Anilin and Soda Fabrik
of Ludwigshafen on Rhine in the Empire of Germany, to be as follows :—
This invention relates to the manufacture of hydrazine or diamidogen (NII_NH)
and its salts by nitrating guanidine under suitable conditions to obtain a nitro-
compound, reducing this nitro-compound to an amido-guanidine compound and
finally converting this amido-compound into hydrazine or diamidogen or a salu
thereof as desired by means of the so called hydrolytic decomposition.
In carrying out this invention guanidine-thio-cyanate is a convenient body from
which to start in preparing the nitro-guanidine. This guanidine salt can be
obtained as is well known, by the action of heat on ammonium-thio-cyanate (see
Berichte der Deutschen Chemischen Gesellschaft 7, 95 and seq.). To obtain the
nitro-derivative it is subjected to the action of nitric acid preferably in sulphuric
acid solution.
The nitro-derivative can be reduced by the action of zine-dust or iron filings in
the presence of acetic, hydrochloric, or sulphuric acid or by means of sodium
amalgam in the presence of water or dilute acids. The amido-derivative so
obtained can be converted into the desired compound hydrazine, ammonia and
carbonic acid by the action of alkaline solutions, the alkaline earths, of mineral
acids, or even by water alone by heating under pressure.
To further explain the nature of the invention, I give an example of a way in
which it can be carried into effect, but the details of all the steps of the process
may be considerably varied as hereinbefore indicated. The parts are by weight.
Mix about one hundred parts of guanidine-thio-cyanate carefully with about one
hundred and ninety parts of rectified sulphuric acid: an energetic reaction takes
place and arrangements should be made for carrying off any noxious fumes. Cool
the mixture to about sixty degrees Centigrade and then add about one hundred
and ninety parts of fuming sulphuric acid containing about ten per cent. free
anhydride (SO,); stir and allow the mixture to cool to the temperature of the
atmosphere, then add about one hundred parts of nitric acid containing about
ninety per cent. of real nitric acid (HNO,). Allow the nitric acid to act for a few
minutes and then before the temperature of the mixture begins to rise and a more
vigorous action to take place pour the whole into about one thousand three hundred
parts of water. The nitro guanidine separates out immediately, and can be purifiel
if desired by recrystallization from water. Instead of the thio-cyanate of guanidine
other compounds of guanidine can be used and instead of nitric acid nitrates may be
employed.
To convert this nitro-compound into the amido-compound mix about one hundred
parts thereof with about three hundred and fifty parts of zinc dust, adding enough
water to make a stiff paste, to this add gradually about sixty parts of glacial acetic
acid. During the treatment with acetic acid ice should be added in such quantities
that the temperature at no time exceeds about forty degrees Centigrade. After
the acid is added maintain the liquid at this temperature until a test portion of the
liquid treated with a ferrous salt and an alkali gives no red colouration. Filter and
concentrate the solution by boiling down then add about fifty parts of concentrated
sulphuric acid in order to convert the amido compound into its sulphate which
separates out on standing if the solution has been sufficiently concentrated.

page_text: Instead of the zinc-dust, iron filings can be used and other acids can be
substituted for the nectic acid in the reduction, which can also be effected by means
of sodium amalgam and other reducing agents as hereinbefore explained, also the
amido guanidine can be isolated in the form of salts with acids other than sulphuric
ncid such as nitric and hydrochloric acids.
It is not necessary to isolate a salt of amido guanidine in order to prepare
hydrazine the solution obtained after reduction may be used preferably after con-
centration. Thus the concentrated solution obtained as hereinbefore described (or
a solution of an equivalent quantity of an isolated salt in about five hundred parts
of water) may be boiled with about one hundred and twenty parts of caustic soda
in a vessel fitted with an inverted condenser until ammonia is no longer liberated.
The formation of the hydrazine is then finished and it can be precipitated as
sulphate by means of sulphuric acid, or the base can be distilled off and subsequently
converted into any desired salt.
As hereinbefore explained the hydrolysis of amido guanidine can be effected by
the use of a variety of reagents which are in this respect equivalent to the caustic
soda prescribed in the example.
Hydrazine or diamidogen is capable of use in the production of various chemical
and pharmaceutical compounds.
Dated this 20th day of April 1901
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in and relating to the Manufacture of Hydrazine or
Diamidogen and its Salts.
JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of
Middlesex Gentleman do hereby declare the nature of this invention (which has
been communicated to me from abroad by The Badische Anilin and Soda Fabrik
of Ludwigshafen on Rhine in the Empire of Germany) and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement:-
This invention relates to the manufacture of hydrazine, or diamidogen (NH,NH,)
and its salts by nitrating guanidine under suitable conditions to obtain a nitro
compound reducing this nitro compound to an amido guanidine compound and
finally converting this amido compound into hydrazine or a salt thereof as desired
by means of the so called hydrolytic decomposition.
In carrying out this invention either the guanidine thio-cyanate or the guanidine
carbonate is a convenient body from which to start in preparing the nitro guanidine.
The guanidine thio-cyanate can be obtained, as is well known, by the action of heat
on ammonium thio-cyanate (see Berichte der Deutschen Chemischen Gesell-
schaft 7, 95 et seq.) and the guanidine carbonate can be obtained from the
guanidine thio-cyanate by double decomposition with potassium carbonate. To
obtain the nitro-derivative the salt is subjected to the action of nitric acid
preferably in sulphuric acid solution. The nitro-compound so obtained appears to
he identical with the compound called by Josselin " Nitrosognanidine
Journal of the Chem. Soc. 31, 132 and 36, 613).
The nitro-derivative can be reduced by the action of zinc-lust or iron filings in
the presence of acetic, hydrochloric, or sulphuric acid, or by means of sodium
amalgam, in the presence of water, or dilute acids. The amido derivative so
obtained can be converted into the desired compound hydrazine by the action of
various reagents capable of promoting hydrolysis, such as alkalies, the alkalit.e
earths, mineral acids, or even water alone on heating under pressure.
Ammonia and carbonic acid are formed as bye-products of the reaction which
appears to take place in two stages. In the first a compound which may be termed

page_text: semi-carbazide seems to be formed and this, by further hydrolysis, is converted into
hydrazine.
To further explain the invention I give an example of a way in which it can be
carried into effect, but the details of all the steps of this example may be
considerably varied as hereinbefore indicated. The parts are by weight.
Mix about one hundred parts of guanidine thio cyanate carefully with about one
hundred and ninety parts of concentrated sulphuric acid: an energetic reaction
takes place and arrangements should be made for carrying off any noxious fumes.
Cool the mixture to about sixty degrees Centigrade and then add about one
hundred and ninety parts of fuming sulphuric acid containing about ten per cent.
free anhydride (SO₁) and heat for about an hour at a temperature of about one
hundred degrees Centigrade stir and allow the mixture to cool to the temperature
of the atmosphere (or, especially if working with large quantities, cool to about five
degrees Centigrade) then add about one hundred parts of nitric acid containing
about ninety per cent, or more, of real nitric acid (HNO₁).
Allow the nitric acid to act for a few minutes and then, before a more vigorous
action begins to take place, pour the whole into about one thousand three hundrel
parts of water. The nitroguanidine separates out immediately, and can be purified
if desired by recrystallisation from water. By employing the carbonate of
guanidine instead of thio-cyanate the first part of the operation is simplified, as
the carbonate need only be dissolved in the sulphuric acid mixture and the
decomposition of the thiocyanic acid is rendered unnecessary.
Instead of the thiocyanate or carbonate of guanidine other compounds thereof.
can be used and instead of nitric acid nitrates may be employed. Further
guanidine nitrate yields the nitroguanidine on treatment with strong sulphuric acid
with or without the addition of nitric acid.
To convert this nitro-compound into the amido compound, mix about one hundred
parts thereof with about three hundred and fifty parts of zinc-dust adding enough
water to make a stiff paste, to this add gradually about sixty parts of glacial acetic
acid. During the treatment with acetic acid ice should be added in such quantities
that the temperature is kept low and at no time rises to about forty degrees
Centigrade. After the acid is added maintain the liquid at or about this
temperature until a test portion, treated with a ferrous salt and an alkali, gives no
red colouration. Filter and concentrate the solution by boiling down till about six
hundred parts remain, then add about fifty parts of concentrated sulphuric acid, in
order to convert the amido compound into its sulphate, which separates out on
standing, if the solution has been sufficiently concentrated.
Instead of the zinc-lust iron filings can be used, and other acids can be substituted
for the acetic acid in the reduction which can also be effected by means of sodium
amalgam and other reducing agents as hereinbefore explained also the amido-
guanidine can be isolated in the form of salts with acids other than sulphuric acid
such as uitric and hydrochloric acids.
It is not necessary to isolate a salt of ainidoguanidine in order to prepare
hydrazine, the solution of a salt thereof obtained by reducing the nitroguanidine
may be used, preferably after concentration. Thus in proceeding with the
manufacture, either the concentrated solution of the acetic acid salt obtained as
hereinbefore described or a solution of an equivalent quantity of an isolated salt in
about five hundred parts of water may be taken; and this is boiled with about one
hundred and twenty parts of solid caustic soda in a vessel fitted with an inverted
condenser until aminonia is no longer liberated. The formation of the hydrazine is
then finished and it can be precipitated, as sulphate by means of sulphuric acid, or
the base can be separated in any other known way, such as by distilling and
subsequently converting into any desired salt.
As hereinbefore explained the hydrolysis of amido guanidine can be effected by
the use of a variety of reagents which are in this respect equivalent to the caustic
soda prescribed in the example.

page_text: Hydrazine or diamidogen is capable of use in the production of various chemical
and pharmaceutical compounds.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. The manufacture of hydrazine (diamidogen) by first preparing nitro-guanidine
then reducing this nitro-compound to amido-guanidine and finally subjecting this
amido-guanidine to hydrolysis with, or without, converting the hydrazine formed
into a salt thereof all substantially as hereinbefore described.
2. The manufacture of hydrazine (diamidogen) by first preparing nitroguanidine
by treatment of a guanidine salt with nitric acid in sulphuric acid solution, then
reducing the nitro-compound obtained to an amido compound by means of zinc-dust
and acetic acid and finally subjecting this amido-compound to hydrolysis by
treatment with a caustic alkaline solution, with or without subsequently converting
the hydrazine formed into a salt thereof all substantially as hereinbefore described
in the example.
3. The manufacture of hydrazine (diamidogen) or a salt thereof by subjecting
amidoguanidine to hydrolytic treatment substantially as described.
Dated this 19th day of January 1892.
J. H. JOHNSON & Co.,
Agents.