The Treatment of Amido-guanidine for the Manufacture of a New Compound and of Products derived therefrom.
Year: 1892

page_text: Date of Application, 4th Feb., 1892
Complete Specification Left, 25th Oct., 1892-Accepted, 17th Dec., 1892
PROVISIONAL SPECIFICATION.
The Treatment of Amido-guanidine for the Manufacture of a New
Compound and of Products derived therefrom.
I 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 & Soda Fabrik of
Ludwigshafen on Rhine in the Empire of Germany) to be as follows:-
In the Specification of my Application for Letters Patent No. 6786 of 1891, the
production of amido-guanidine and its conversion into hydrazine or diamidogen
are described.
My foreign correspondents have discovered that the said amido-guanidine can
by treatment with nitrous acid, be converted into a new compound which they
name diazoguanidine; and that this compound is capable of transformation into
useful articles of manufacture. Thus by suitable treatment, say, with sodium
acetate, it yields another new compound, which may be termed amido tetrazotic
acid; this can be diazotised and used in the manufacture of colouring matters.
The above mentioned diazo guanidine is also under suitable conditions (say, by
treatment with caustic soda) susceptible of a decomposition yielding azothydric
acid (NH) or a salt thereof. This compound derives its value from the fact that
it is a powerful explosive and the herein described new process renders it possible
to produce this body on a commercial scale for use in the arts.
As a convenient means of further explaining the nature of the invention the
following general examples of methods of carrying it into effect are given.

page_text: diazoguanidine decomposes under this treatment forming acetic acid and the new
product-amido tetrazotic acid.
On cooling a solution which has been sufficiently concentrated, crystals of this
new amido acid are obtained and can be purified by recrystallization from water.
The compound thus obtained appears to have the composition represented by the
formula
CN,H NH, H₂O.
On heating, it loses its water of crystallization and yields a product melting at
about ore hundred and ninety eight to one hundred and ninety nine degrees
centigrade.
Instead of the sodium acetate employed in the above example other acetates can
be used, and other salts which in this respect act in a similar manner, such as for
instance certain salts of other organic acids certain borates, carbonates, oxides and
hydrates of the heavy metals and of magnesium; ammonia can also be used.
When employing the compounds of the heavy metals (such as for instance
copper) which yield insoluble salts with tetrazotic acid, it is advisable to take
twice the quantity of metallic compound given in the above example, so that all
the tetrazotic acid is obtained in the form of the insoluble metallic compound.
The tetrazotic acid can then be set free and isolated in any suitable way, such as
by treatment with a stronger acid, or in the case of copper or similar compounds
by the aid of sulphuretted hydrogen.
If ammonia be used, the tetrazotate of ammonia, which is formed in the presence
of an excess of the alkali, decomposes spontaneously to a great extent during the
evaporation, giving the free acid and ammonia. The rest of the acid can be set
free by the addition of a mineral acid. Simultaneously with the formation of the
tetrazotic acid by the action of ammonia, a secondary reaction resulting in the
formation of azothydric acid, takes place, and by suitably conducting the treat-
ment in the presence of a copper or silver salt, or by using another alkali as
described under the next example, this can be made the exclusive or the main
product of the treatment.
PRODUCTION OF AZOTHYDRIC ACID.
Mix together a solution of one molecular proportion of a salt of diazoguanidine
and rather more than two molecular proportions of caustic soda. Sodium azotate
(that is the sodium salt of azothydric acid) is rapidly formed. Acidify with a
mineral acid and distil off the azothydric acid, which can then be converted into
any desired salt. Instead of isolating the acid by distillation it can be precipitated
in the form of a metallic salt, by the addition of a slightly acidulated solution of a
salt of such metals as will yield azotates but slightly soluble or insoluble in water.
Such salts are for instance, those of lead, mercury (mercurous salts) and silver.
Instead of caustic soda in the above example, caustic, potash can be used, and
also the alkaline earths; and as aforesaid ammonia under suitable conditions also
brings about the conversion of diazoguanidine into azothydric acid. On boiling
diazoguanidine salts with dilute mineral acids, azothydric acid is formed and can be
distilled off and isolated in any suitable manner.

page_text: In preparing amido-tetrazotic acid and azothydric acid by methods which yield
these bodies in admixture with one another they can readily be separated in any
suitable way, such as by distilling off the azothydric acid from the mixture after
acidification if necessary.
In working with azothydric acid and its compounds great care must be taken to
avoid dangerous explosions.
1000
COMPLETE SPECIFICATION.
The Treatment of Amido-guanidine for the Manufacture of a New
Compound and of Products derived therefrom.
I 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 :-
In the Specification of Letters Patent No. 6786 of 1891 the production of
amidoguanidine and its conversion into hydrazine or diamidogen are described.
My foreign correspondents have discovered that by treatment with nitrous acid
the said amidoguanidine can be converted into a new compound which they name
din zoguanidine, and that this compound is capable of transformation into useful
articles of manufacture. Thus by suitable treatment (say with sodium acetate) it
yields another new compound, which may be termed amido-tetrazotic acid, this can
be diazotised and used in the manufacture of colouring matters. The said
diazoguanidine is also under suitable conditions (say by treatment with caustic
soda) susceptible of a decomposition in a different way yielding azothydric
acid (N,H) or a salt thereof. This compound derives its value from the fact, that
it is a powerful explosive, and the herein described new process renders it possible
to produce this body on a commercial scale for use in the arts.
As a convenient means of further explaining the nature of the invention and the
best means with which I am acquainted for carrying the same into effect I give the
following general examples premising that I do not limit myself to the precise
THE MANUFACTURE OF "DIAZOGUANIDINE
OR A SALT THEREOF.
Mix together a solution of one molecular proportion of amidoguanidine-CN.H.
(or an equivalent quantity of a salt thereof) with a mineral acid (say, sulphuric
acid) taking so much acid, that one equivalent of free mineral acid is present; then
run in a solution of one molecular proportion of sodium nitrite, taking care that
the temperature of the solution does not rise high enough to cause the decomposition
of the product formed. The temperature must not be permitted to rise above
forty to forty five degrees centigrade. The solution thus obtained contains the
desired diazoguanidine, which can, if desired, be isolated in the form of a salt.
Thus in case it be desired to obtain the nitrate of diazoguanidine (a salt which
readily crystallizes) this can be effected by treating the nitrate of amido-guanidine
in the manner described in the above example but using nitric acid as the mineral
acid, then on treating with nitrous acid, the nitrate of diazoguanidine is formed in
solution and when the solution is evaporated at a low temperature the said nitrate
of diazoguanidine is obtained as a crystalline residue. This product can be

page_text: On heating, it loses its water of crystallization and yields a product melting at
about one hundred and ninety eight to one hundred and ninety-nine degrees
centigrade.
Instead of the sodium acetate employed in the above example other compounds
that have a mild alkaline reaction and neutralize mineral acids, can be used, such
for instance as other acetates, certain salts of other organic acids and certain
borates, carbonates, oxides, and hydrates of the heavy metals and of magnesium ;
ammonia can also be used.
When employing the compounds of the heavy metals (such as for instance
copper) which yield insoluble salts with tetrazotic acid, it is advisable to take
twice the quantity of metallic compound given in the above example, so that all
the tetrazotic acid is obtained in the form of the insoluble metallic compound.
The tetrazotic acid can then be set free and isolated in any suitable way, such as
by treatment with a stronger acid, or, in the case of copper or similar compounds,
by the aid of sulphuretted hydrogen.
If ammonia be used, the tetrazotate of ammonia, which is formed in the presence
of an excess of the alkali, decomposes spontaneously to a great extent during the
evaporation, giving the free acid and ammonia. The rest of the acid can be set
free by the addition of a mineral acid. Simultaneously with the formation of the
tetrazotic acid by the action of ammonia a secondary reaction takes place resulting
in the formation of azothydric acid and by suitably conducting the treatment in
the presence of a copper or silver salt or by using a fixed caustic alkali as described
under the next example this can be made the exclusive or at least the main product
of the treatment.
EXAMPLE 3.
PRODUCTION OF AZOTHYDRIC ACID.
Mix together a solution of one molecular proportion of a salt of diazoguanidine
and rather more than two molecular proportions of caustic soda. Sodium azotate
(that is the sodium salt of azothydric acid) is rapidly formed. Acidify with a
mineral acid and distill off the azothydric acid, which can then be converted into
any desired salt thereof. Instead of isolating the acid by distillation it can be
precinitated in the form of a motellia colt her the addition of a alightly acidulated

page_text: solution of a salt of such metals as will yield azotates but slightly soluble or
insoluble in water. Such salts are for instance those of lead mercury (mercurous
salts) and silver.
Instead of caustic soda in the above example caustic potash can be used and also
the alkaline earths; and as aforesaid ammonia, under suitable conditions, also
brings about the conversion of diazoguanidine into azothydric acid. On boiling
diazoguanidine salts with dilute mineral acids azothydric acid is formed, and can
be distilled off and isolated in any suitable manner.
In preparing amido-tetrazotic acid and azothydric acid by methods which yield
these bodies in admixture with one another they can readily be separated in any
suitable way, such as by distilling off the azothydric acid from the mixture after
acidification if necessary.
In working with azothydric acid and its compounds care must be taken to avoid
dangerous explosions.
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 :-
1. The production of a new compound, namely "diazoguanidine," or of salts
thereof by the treatment of amido-guanidine with nitrous acid substantially as
herein before described.
2. The production of "amido-tetrazotic acid" by first preparing diazoguanidine
in the manner herein described and claimed by the first claiming clause and then
converting it by the action of heat in the presence of an acetate (or of other salts
oxides, or hydrates as herein explained) into amido-tetrazotic acid all substantially
as described.
3. The conversion of diazoguanidine into amido-tetrazotic acid substantially as
hereinbefore described.
4. The production of azothydric acid by first preparing diazoguanidine in the
manner herein described and claimed by the first claiming clause and then con-
verting it into azothydric acid or a salt thereof by the action of a fixed caustic
alkali or of ammonia either alone or in the presence of a copper or a silver salt all
substantially as described.
5. The conversion of diazoguanidine into azothydric acid substantially as herein-
before described.
6. As new articles of manufacture "diazoguanidine" "amido-tetrazotic acid "
and "azothydric acid" such as can be obtained substantially as hereinbefore
described.
Ti with day of October 1800
J. H. JOHNSON & Co.,
Agents.